Dairy

Dairy Animal Welfare

Public Expectations of a Dairy Farm - UBC Dairy Centre Report (2016)

Click here for article in pdf format.

The European community has placed some effort into understanding the public’s views of animal agriculture, including the dairy industry. However, little is known about the expectations of the dairy industry by North American citizens.

To provide some insight on this issue we conducted two studies, one where we asked participants how they would describe the ideal dairy farm and the second where participants were surveyed before and after touring a dairy farm.

In the first study we conducted an online survey with 468 American citizens. In this survey we asked a single open-ended question: What do you consider to be an ideal dairy farm and why are these characteristics important to you? The responses were coded into themes (Fig 1). Participants generally cited more than one characteristic with multiple reasons for each.

The most commented issues related to the “cow” herself, reflecting concerns about cow treatment. For example, many participants commented on how important it was that the farmer and workers treated cows humanely. For example, people commented on the value of treating the animals with “respect,” “fairly,” “kindly,” “with love,” and with “dignity”.

Participants also mentioned aspects related to the business operation, suggesting that the ideal farm should also be profitable, productive, and efficient. Some participants also suggested that the farm should be small, organic, operated by family farmers, and committed to their community (e.g., offering tours or selling their products locally). Participants also said that the farmers should be efficient, educated, loving, and competent.

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Fig 1.  Emergent themes that arose from the responses of 468 Americans to an on line survey where they were asked to describe an ideal dairy farm.

Some participants also commented on the importance of the quality of production, stating that the ideal dairy farm must produce high-quality milk products and that these products be clean and safe to consume. However, they rejected the use of hormones, antibiotics or other chemicals for the purposes of increasing production but did state that animals should be treated when sick. The respondents also suggested that the cow’s quality of life influences the quality of the milk she produces, which in turn influences human health.

In a second study, we interviewed 50 Canadian participants before and after a self-guided tour of our University dairy farm (the UBC Dairy Education and Research Centre in Agassiz, BC). Our aim was to assess how participants perceived dairy farms and whether their perceptions changed after visiting a working farm.

Participants were asked about any concerns that they had before the tour.  The four most frequently raised issues prior to the tour were quality of feed provided to the animals, whether cows had access to pasture, if they had sufficient space and whether they were treated with care.

As we had expected, some perceptions improved after participants visited the farm. For example, people commented positively on the quality of care provided to the cows and calves on this farm. However, participants also discovered new issues or had their existing concerns reinforced when they visited the farm. For example, after the visit participants commented on cow-calf separation, lack of pasture access, space, and poor hygiene.

A common belief is that ‘educating the public’ will help people to better understand farming practices, and thus help to confront any objections built upon public ignorance. Thus a second aim of this study was to also test participant knowledge of dairy farming practices before and after the farm visit, to determine if visiting the farm increased knowledge and increased acceptance. The quiz questions used to test the knowledge level of the participants related to basic dairy husbandry practices. On average, participants answered 3 of the 5 questions correctly before the tour. After the tour performance increased, with people answering 4 of 5 questions correctly, but the people who did best on the test were no more positive in their perception of the farm.

As a final question, participants were asked how confident they were that dairy cows have a good life. Before visiting the dairy farm a little less than half of the participants said that they were confident that dairy cows had a good life (Fig 2). After visiting the farm less that 25% responded that they were confident, with the remainder either unsure or were not confident in the quality of life of dairy cows.

graph 

Fig 2. Responses from 50 individuals who were asked how confident they were that dairy cattle have a good life before and after touring a dairy farm

Both studies illustrate the importance that members of the public put on an animal’s freedom to move and their ability to fulfill natural and highly motivated behaviors like grazing on pasture. Thus participants, who became acquainted with the practices of early cow-calf separation and lack of access to pasture, tended to lose confidence in dairy farming. Both studies also illustrated the importance that respondents placed on the actions and attitudes of the people responsible for the care of cattle on dairy farms.

In summary, the values of the public (for example, concerning the importance of care and pasture access) appeared to play a key role in determining their expectations for the modern dairy farm. Public education may be important in allowing for informed debate on contentious topics, but the results of these studies suggest that education alone will not make the public more supportive of dairy farming. Exposure to livestock farming may resolve certain concerns, but other concerns will likely persist, especially when practices conflict with deeply held values around animal care. Assurances that animals are well treated, and are able to perform important natural behaviors will improve the social sustainability of the dairy industry.

 

UBC Dairy Education & Research Centre
Faculty of Land and Food Systems Nelson Dinn, Manager Email dinn@shawbiz.ca
6947 No. 7 Highway, P.O. Box 202, Agassiz, BC V0M 1A0 Telephone 604-796-8410 Fax 604-796-8413
www.landfood.ubc.ca/dairy_centre

 

 

 

 

 

 

Disease

Effect of Metritis on Intake, Milk Yield and Culling Risk (2012)

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Effect of Metritis on Intake, Milk YIeld, and Culling Risk - pdf format

UBC DAIRY RESEARCH REPORTS

Effect of Metritis on Intake, Milk Yield, and Culling Risk

Metritis is a common and costly disease that affects dairy cows during the early postpartum period. (Figure 1). Researchers at the UBC Dairy Centre have completed a number of studies investigating the relationships between health and behaviour of cows during the transition period and have found that both feeding behaviour and dry matter intake (DMI) can be used in the early detection of disease (Research Report Vol. 10 No. 1). One of these studies characterized prepartum behaviour and DMI of cows that developed metritis after calving. Relative to the healthy cows, those that developed metritis after calving spent less time at the feed bunk and had lower dry DMI as far back as 2 weeks prior to calving (approximately 3 weeks before clinical signs of disease were evident).

Figure 1. Cows are highly susceptible to disorders like metritis during the weeks after calving.

While this work highlights that metritis can have negative consequences on the behaviour and intake of transition dairy cattle, there has been limited research investigating the long-term impact of these changes on both milk production and culling risk.

To explore the long-term consequence of metritis, data from two previous transition cow studies were combined. Using only data from multiparous cows a population of 43 healthy animals (no fever or other clinical signs of disease by 21 days post-partum) and 16 metritic animals (had a fetid, foul smelling vaginal discharge, with a fever greater than 39.5°C by 21 d postpartum) were identified. Individual animal DMI was monitored for 21 days after calving for all experimental animals using an ectronic feeding system (Insentec). During this time cows had ad libitum access to both feed and water.

Metritis during early lactation had an overall negative impact on the milk production by multiparous cows. These animals produced less milk than those that remained healthy. This reduction in milk yield was not only experienced during the metritis infection but also throughout the first 20 weeks of lactation, despite all sick cows receiving veterinary care (Figure 2).

Figure 2. Multiparious cows with metritis have lower average daily milk yields throughout the first 20 weeks of lactation compared to healthy multiparious cows. *Weekly averages are based on 7 days of data.

Cows with metritis and lower milk yield also had reduced feed intake during the first 21 days after calving (Figure 3).

Figure 3. Dry matter intake (DMI; kg/d) is lower during the 21-day period after calving for cows diagnosed with severe metritis relative to cows that remained healthy.

The reduction in feed intake during the first 3 weeks of lactation for cows with metritis may help to explain the lower daily milk yield observed in these animals over the first 20 weeks of lactation; however, it remains unknown whether these cows have decreased feed intake beyond 3 weeks after calving.

The odds of being culled were 3.8 times greater for cows with metritis compared to the odds of being culled for healthy cows. Cows that were culled produced less milk than those that were not culled during the first 12 weeks of lactation.

Culling decisions for the study farm were made prior to any indications of reproductive problems, as most of the cows with metritis that were culled were never bred. This finding indicates that culling decisions were likely based on disease status and low milk production in early lactation, rather than reproductive performance.

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Feeding Behaviour and Early Detection of Diseases (2010)

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Infectious and metabolic diseases can result in decreased milk production, poor reproductive performance, and increased culling of dairy cows. Early identification of diseases is beneficial to producers -- the sooner a disease is identified, the sooner it can be treated, and early treatment decreases the negative effects of disease on both the cow's welfare and the producer's bottom line. Monitoring social feeding behaviour has proven useful in the early identification of sick cattle.

Studies on feedlot cattle have shown that sick animals can be identified by the fact that they spend less time at the feed bunk. These reduced feeding times can be measured using a computer, which monitors how much time each animal spends at the feed bunk. What is most interesting is that these changes are evident days before experienced stockmen identify the animals as ill based on clinical signs of disease.

UBC researchers are working to apply this technology to dairy cattle. Cows are especially prone to infectious and metabolic diseases during the transition period, which covers the time period 3 weeks before to 3 weeks after calving. Metritis is a uterine infection that is common after calving, is expensive to treat, and can severely impair reproductive performance. A series of UBC studies were performed to compare the behaviour of cows that develop metritis with cows that remain healthy.

Read the complete article: Feeding Behaviour and Early Detection of Diseases

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Mastitis Vaccines (2002)

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Bovine mastitis, an inflammation of the mammary gland, is the single most important factor contributing to economic losses to the dairy industry. Several streptococcal species are capable of causing infections, which result in mastitis. The bacterium S. uberis is a significant problem due to the fact that it is found throughout the dairy environment, and is predominantly associated with sub-clinical mastitis cases, resulting in reduced, and poor quality milk yields.

The development of vaccines against mastitis-causing pathogens has been slow, partly because the infection must be controlled without causing a significant inflammatory response, since this in itself contributes to the disease condition. Currently, treatment practices including antibiotic therapy and teat disinfection are relied upon to minimize the spread of infection. However, these measures are often inadequate, simply because animals are constantly being re-exposed to infection from their surrounding environment. Therefore, there is a clear requirement for an effective vaccine to augment conventional methods of infection prevention.

Three experimental vaccines against S. uberis were developed by VIDo in Saskatoon. Immunization and bacterial challenge of lactating Holstein cows were performed at the UBC Dairy Centre. Four groups of eight animals were selected for vaccination with a placebo or one of the three experimental vaccines. Cows received two subcutaneous injections in the neck at 36 and 15 days prior to challenge with S. uberis. Six cows from each group were chosen based on antibody response to the vaccine antigens. The challenge involved infusion of inoculum containing a culture o f S. uberis into both right quarters of each animal. Milk samples were collected from all quarters, daily for seven days post-challenge, for determination of somatic cell count (SCC) and bacteriology. Daily clinical assessments of animals included measurement of rectal temperatures, presence of clots in the milk, and udder swelling (visual and palpated). A numerical score was assigned to each animal and used as a means of comparing the severity of mastitis among vaccine groups.

Challenged animals displayed signs of disease, and SCC indicated that inflammation had occurred. Between the vaccine groups, no significant differences were observed in rectal temperatures. Clinical scores indicated that there were no significant differences in the severity of infection. Although no differences in milk yield were observed, the quality of milk was slightly affected in all four groups, as discussed below.

Vaccination with vaccine-1 resulted in a significant decrease in SCC, compared to the control group, which did not receive a vaccine (Figure 1). From day three onward, SCC in the cows that received vaccine-1 were significantly lower than in the control cows. SCC in milk from cows that received vaccine-3 were slightly higher than in milk from the vaccine-1 treated animals. However, they were still clearly lower than SCC in milk from the control non-vaccinated group. The SCC in milk from cows that received vaccine-2 increased sharply immediately post-challenge, reaching a maximum at day three, before decreasing erratically over the remainder of the trial. However, the decrease in SCC was not different from that of the control group.

Following challenge with S. uberis, the time period that the quality of milk remained affected was significantly different between vaccine groups. Post-challenge, milk quality in the control, vaccine-1, vaccine-2, and vaccine-3 vaccinated groups was reduced for a total of 21, and 11 days, respectively.

According to the milk quality data, mastitis in the vaccine-2 vaccinated group was similar to that of the control group. Although vaccination with vaccine-1 did not completely prevent reduced milk quality, it did significantly reduce the length of time that milk quality was affected. Vaccination with vaccine-3 also appeared to reduce the length of time that milk quality was affected. Vaccination with vaccine-3 also appeared to reduce the length of time that milk quality was reduced, although not as long as for vaccine-1, which is in keeping with the SCC results.

These experimental results suggest that vaccine-1 is ideally suited for use as a vaccine against S. uberis mastitis. Further research and development for production, licensing and marketing remain to be done by a biologics manufacturer before a vaccine product will be available for use by veterinarians and dairy producers.

For further information about this research on mastitis vaccines, contact Dr. Jim Shelford, Professor in Animal Nutrition at shelford@interchange.ubc.ca

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Sole Lesions in Fraser Valley Dairy Cattle (2002)

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How healthy are your cows’ feet? Sole lesions are a leading cause of lameness in dairy cattle, but are difficult to see except during hoof trimming. The next time the hoof trimmer comes, observe how many of your cows are affected by sole lesions. The numbers might surprise you.

Over the past year we have been visiting farms in the Fraser Valley to determine the extent of this problem, and also to find out what factors make cows more vulnerable to sole lesions. In this article we will tell you more about sole lesions and highlight some of the results of our recent research.

Sole lesions range in severity from minor bruising to severe ulcers (see photos). Lesions are signs of inner-tissue damage in the hoof that can lead to diminished cow comfort and production losses. Injuries can be present for up to two months before lesions are visible on the surface of the hoof. Until recently, most available information on the incidence of this condition was only for European dairy herds.

Results from our study on 20 Fraser Valley dariy herds indicate that the problem is wide spread in this region (see Figure 1).

During the observations at hoof trimming, we recorded the number, severity, and location of lesions in the claws of 624 Holstein cows. Lesions were found in cows from all herds. On average per herd, 85.7% of the cows had at least one lesion. When focusing only on severe hemorrhages and ulcers, the average percentage of cows affected per herd was 34.9%. This is more than double the percentage of animals affected by hairy heel wart on the same farms – a condition often cited by producers as a significant problem.

Although sole lesions were found on every farm, some cows were more likely than others to have lesions. In particular, cows were more likely to have lesions if they had a low body condition score. Cows early in their first lactation were also at greater risk for lesions, as were older cows in mid to late lactation.

Improved management for these more vulnerable cows may help reduce these injuries. For example, cows in their first lactation will likely benefit from special care during the transition phase and in early lactation. Attention to diet and access to suitable areas for rest are especially important at this stage. Mixing with older cows and overstocking might be especially risky for these animals.

In addition to these cow factors, we also found that some farms had more problems than others. We found that cows on farms with the following characteristics were more at risk for developing sole lesions: high steps, computer grain feeders, automatic alley scrapers, imperfections in concrete floors such as holes or large cracks.

Farms with steps 10 cm or higher tended to have more lesions per cow than those with lower steps. Those using computer grain feeders had more lesions per cow than farms with total mixed rations, especially when cows were allowed to consume their daily concentrate allotment in fewer than six feedings. Farms using automatic alley scrapers to remove manure from alleys had more severe lesions than farms utilizing flush or tractor-scraper methods. More severe lesions were also associated with farms that had holes or large cracks in the concrete flooring.

The link between feeding methods and sole lesions is not surprising. Diets rich in concentrates put cows at greater risk for ruminal acidosis. This in turn leads to laminitis, which weakens the sole and makes injuries more likely. Reducing the proportion of concentrates in the diet, and spreading the intake of concentrates more evenly across the day will help reduce this risk. However, attention to diet needs to go hand in hand with attention to the cows’ physical environment, especially the flooring. Flooring imperfections obstacles make hoof injuries more likely, so facilities need to be designed and maintained with this in mind. If physical problems in your barn cannot be fixed, take special care in moving cows, as injuries are most likely to occur when cows are being rushed.

We would like to express our appreciation to the producers and hoof trimmers who participated in this study. We would also like to thank the dairy industry for their support of this research, through funding to the Animal Welfare Program by the Dairy Farmers of Canada, the BC Dairy Foundation, the Cattle Industry Development Council, Westgen, members of the BCVMA and many others listed at www.agsci.ubc.ca/animalwelfare.

This article is based on thesis research of MSc student Erin Bell. Dan Weary is Associate Professor in the Animal Welfare Program and can be contacted at danweary@interchange.ubc.ca.

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Staph and Coliform Isolation from Healthy Cow

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Mariam Dembélé, Serge Messier, Nelson Dinn and Moussa S. Diarra

The importance of milk in the nutrition of the Canadian population requires strict quality control of this product and control of mammary gland infections (mastitis) of the dairy cows. Mastitis is one of the major causes of economical loss to the dairy industry, averaging $150-$250/cow/year. This disease is mostly caused by bacteria such as Coliforms (Escherichia coli, Klebsiella spp., Enterobacter spp, Citrobacter spp), Streptococci (S. uberis, S. agalactiae, S. dysgalactiae) and Staphyloccocci [(S. aureus and coagulase negative staphylococci (CNS)]. The CNS are designated as "skin flora opportunists" since they are a part of the normal teat skin flora.

CNS bacteria can colonize the teat canal and infections are usually subclinical resulting in individual quarter somatic cell counts (SCC) increasing only about two-to three-fold above that of uninfected quarters. In recent years CNS are increasing in importance as causes of bovine intra-mammary gland infection throughout the world. The CNS can cause tissue damage and decrease milk production. Most CNS infections are transient. Cows and heifers have a higher prevalence of CNS infection after calving, with a rapid decline during the first week or two of lactation. Because CNS are commonly found on teat skin and in the streak canal, they can cause milk contamination.

Isolation and identification of mastitis pathogens including CNS is a fundamental aspect of milk quality and udder health control programs. There is an increasing demand for development and evaluation of the milk culture method and rapid and accurate identification of bacterial species.

Identification of mastitis pathogens and the determination of their antibiotic susceptibility or resistance are important when selecting appropriate antimicrobial therapy. The purpose of the work presented in this Research Report was to isolate CNS and to determine their susceptibility to antibiotics. In addition the number of E. coli and other Coliforms in healthy cow's milk was quantified.

Milk samples (20 ml) obtained during December 2004 and January 2005, were taken aseptically from all quarters of 83 healthy Holstein cows and cultured to determine the presence of CNS and total numbers of E. coli and Coliforms by standard procedures according to the National Mastitis Council. Results were expressed as number of bacteria per ml of milk. Antibiotic susceptibility testing was performed by the disk diffusion method. Isolates were categorized as susceptible, intermediate and resistant based upon interpretive criteria developed by the Clinical Laboratory Standard Institute.

Figure 1. Distribution of tested milk samples as a function of Somatic Cell Counts (SCC)

As shown in Fig. 1, the majority (85%) of the milk samples had low SCC (= 250,000 cells/ml). Staphylococci (30%) and Coliforms (26%) were isolated from the milk samples with low SCC (Fig. 2). The high environmental bacteria (coliforms and CNS) number in milk may be the result of poor milking time hygiene and poor animal cleanliness.

The staphylococcal isolates were identified as S. chromogenes, S. xylosus, S. epidermidis, and S. cohnii chonii. In addition, coagulase positive S. aureus and S. hyicus were identified. Low bacterial numbers were observed in milk samples with low SCC compared to those with high SCC (Fig. 3).

The antibiotic susceptibility or resistance essay performed with eight antibiotics using 23 random CNS showed 15 (52%) resistant strains (Table 1).

This study shows that antibiotic resistant CNS can be present in milk from dairy cows without any signs of infection. These bacteria could come from the cow's environment. Generally, the concentration of somatic cells serves as an indirect measure of the level of infection in the cow's mammary gland. Our results indicated that milk with low SCC can contain CNS and Coliforms.

Attention to good milking and barn hygiene is important to decreasing the risks of contamination of raw milk by such environmental bacteria during milking.

Figure 2. Percentage of positive milk samples to E. coli and CNS as a function of somatic cell counts (SCC)

Figure 3. Mean of the total coliforms number [colony forming unite (CFU)] per ml of milk as a function of somatic cell counts (SCC).

Table 1. Antibiotic susceptibility and resistance to 8 selected antimicrobial agents in randomly selected 23 isolates of CNS obtained from healthy dairy cow.
Antibiotic

Number of Isolates (Agar disk diffusion test) / 23

Susceptible

Resistant

Penicillin

20

3

Oxacillin

21

2

Enrofloxacin

23

0

Tetracycline

18

5

Erythromycin

22

1

Clindamycin

20

3

Penicillin + novobiocin

23

0

Trimethoprin + sulfamethoxazol

22

1

Total Resistant Strains

15


This work is part of MSc thesis research by Mariam Dembelé, who was supported by a Canadian International Development Agency Scholarship. Dr. S. Messier is a Professor at the Faculté de Médecine Vétérinaire, Université de Montréal, St-Hyacinthe, Nelson Dinn is Manager of the UBC Dairy Education and Research Centre. Dr. Moussa S. Diarra is a Research Scientist at Agriculture and Agri-Food Canada, Agassiz, BC. This study was supported by Agriculture and Agri-Food Canada.

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Feeding

Feed Sorting: Effects of Feed Composition and Management (2009)

Feed Stalls Reduce Competition at the Feed Bunk (2007)

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Trevor DeVries and Marina von Keyserlingk

Dairy cattle housed in free stall barns are normally separated from the feed delivery area by some sort of barrier. Barriers are important as they prevent cattle from walking and defecating on the feed. They have been designed to allow cows unrestricted access to feed, however, the design and management of these barriers may affect the ability of cows to access feed.

One particular management factor that can influence the ability of cows to access feed is the amount of available feed bunk space. Previous work by our group (see UBC Research Reports Vol 3 No 3 and Vol 6 No 3) has shown that increased space allowance per cow at the bunk reduces competition and improves bunk access, especially for subordinate animals. Even though decreasing stocking density at the feed bunk will reduce competition and increase feed access, competition is not eliminated at the feed bunk. This suggests that there are additional factors affecting competition for food resources by lactating dairy cows.

In our previous research we have shown that the use of a feed barrier that provides some physical separation between adjacent cows (such as headlocks) can reduce competition (displacements) at the feed bunk, and that subordinate animals experienced the greatest decreases in competition. Unfortunately, cows also show reduced feeding time when fed using a headlock feed barrier, possibly due to a learned aversion to being restrained in locking headlocks.

Interestingly, researchers have demonstrated in other species, such as pigs, that providing partitions that separate the bodies of adjacent animals can have profound effects on reducing competition and allowing animals to feed for longer periods of time. These effects had not yet been shown in group-housed dairy cattle. Therefore, the first objective of this study was to provide further evidence that increased bunk space reduces the frequency of aggressive behaviour at the feed bunk and improves feed access. The second objective was to determine if the addition of feed-stall partitions (see Figure 1) between adjacent cows even further reduces aggressive behaviour at the feed bunk and improves feed access.

Figure 1. A cow at a feed bunk with feed stalls.

Twenty-four lactating Holstein cows were subjected to each of three treatments in three successive 10-day treatment periods using a 3 x 3 Latin square design. The treatments tested were: 1) 0.64 m (~2 ft) of feed bunk space/cow, 2) 0.92 m (~3 ft) of feed bunk space/cow, and 3) feed stalls (0.92 m of feed bunk space/cow plus feed-stall partitions separating adjacent cows). Time-lapse video was used to record the feeding and standing behavior, as well as the aggressive behavior (displacements) displayed at the feed bunk by the cows. To meet our first and second objectives, we compared the data from the 0.64 m/cow to the 0.92 m/cow treatment and the 0.92 m/cow to the feed stall treatment, respectively.

Total daily feeding time increased when feed bunk space was increased from 0.64 to 0.92 m/cow (Figure 2). Further, the time spent standing in the feeding area while not feeding (not shown) and the frequency of aggressive interactions (Figure 3) at the feed bunk decreased when more bunk space was provided. The addition of the feed stalls resulted in an even further increase in feeding time and decrease in aggressive interactions for the cows compared to when they were provided with 0.92 m/cow of bunk space.

The feed stalls also forced cows to change the strategy by which they displaced others from the feed bunk. The presence of the feed stalls forced the cows to initiate contact at the rear of the animal they were displacing rather than from the front or side as in the case of the other two treatments. Further, subordinate cows experienced the greatest decreases in the number of times they were displaced per day when they were provided additional feeding space, and this effect was strongest when the feed stalls were present.

The results indicated that the provision of increased feed bunk space, particularly when combined with feed stalls, will improve access to feed and reduce competition at the feed bunk, especially for subordinate cows. We predict that this may be important for transition cows, as improved bunk access may help these animals maximize their feed intake to meet their energy demands. To verify this, our current research is directed at determining the implications of increased feed access and reduced competition at the feed bunk on the dry matter intake, milk production, and health of lactating dairy cows, particularly those in early lactation.


This report is a summary of an article published in the Journal of Dairy Science (DeVries and von Keyserlingk. 2007. J. Dairy Sci. 89:3522-3531). This article is based on Ph.D. thesis work of Dr. Trevor DeVries, who was supported by a NSERC Canada Graduate Scholarship. Dr. Marina (Nina) von Keyserlingk is an Associate Professor in the UBC Animal Welfare Program located in the Faculty of Land and Food Systems.

We thank The University of British Columbia's Dairy Education and Research Centre. In particular we thank Kiyomi Ito, Audrey Nadalin, Dan Weary, and Julie Huzzey for their assistance with this study. The project was funded by the Natural Sciences and Engineering Research Council of Canada and through contributions from many other donors who are listed at: http://www.landfood.ubc.ca/animalwelfare.

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Feeding Behaviour of Lactating Dairy Cows (2002)

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Do you know that your lactating dairy cows spend nearly six hours a day at the feed bunk? Most dairy producers are well aware that maintaining dry matter intake in lactating dairy cows is critical to their milk production and health status. However, there is little known about how cows spread their meals throughout the day. Do they eat breakfast, lunch and dinner with a few snacks thrown in between or do they just eat from the feed bunk whenever they get hungry? How do changes in feed management such as increasing the schedule of sweeping feed back into the bunk (push-up), affect when they eat? Will such a change in manage-ment cause cows to come to the feed bunk more often?

Over the past year we have been working with new equipment that allows us to monitor how often each individual cow goes to the feed bunk and allows us to determine how many minutes she spends at the bunk each trip. Each cow is fitted with a transponder that is read by an electronic mat placed directly under the feed. The information provided allows us to determine exactly when she is at the feed bunk and her position along the feed line. This equipment has allowed us to do the world’s first experiments on how changes in routine feeding management affect feeding behaviour of free-stall housed dairy cows. In this article we will highlight some of the results of our recent work, which was designed to determine the effects of the frequency of pushing up feed on the feeding behaviour of high producing lactating dairy cows housed in a free stall barn.

The objectives of our research were: 1, to describe the daily feeding patterns of lactating dairy cows, and 2, to determine the effects of increasing the frequency of feed push-ups on the cows 24 hour feeding patterns. We used 24 high producing cows housed in a free-stall barn and fed a TMR twice daily at 6:00 am and 3:30 pm. During the first week we pushed up the feed at 11:00 am and 9:30 pm. During the second week we added two more push-ups at 12:30 am and 3:30 am.

Cow fitted with a transponder at the bottom of her neck strap.

The results from our study show that during the first week, the cows consumed 7.3 meals per day and spent 5.8 hours per day at the feed bunk. Interestingly, only 8% of the total time spent at the feed bunk occurred between 12 midnight and 6:00 am. Most importantly, our study showed that milking and delivery of fresh feed clearly had a much greater effect on increasing the percentage of cows present at the feed bunk over the course of a day than did the feed push-ups themselves (see Figure 1). The added feed push-ups did not change the number of meals, and resulted in only an additional 12.4 minutes at the feed bunk per day.

In conclusion, our work with this new technology has shown that both milking and delivery of fresh feed have dramatic effects on feeding behaviour in lactating dairy cattle. In comparison, increasing the number of feed push-ups has only a minor effect on time cows spend at the feed bunk.

In new work, we hope to determine how other changes in feeding practices, such as providing fresh feed once a day or more often, affects feeding time, and ultimately how these changes in feeding practices relate to feed intake, cow health and milk production.

Figure 1. Percentage of cows present at the feed bunk over the course of a day.

We thank Lorna Baird and the staff of the UBC Dairy Centre for their help with this research. We also thank Dr. Karen Beauchemin and Agriculture and Agri-Food Canada, for loaning us the feed bunk monitoring equipment. We are grateful to the dairy industry for their support of this research, through funding of the Animal Welfare Program by the Dairy Farmers of Canada, the BC Dairy Foundation, and many others listed at www.agsci.ubc.ca/animalwelfare.

NEXT MONTH: Cow Comfort II

This article is based on thesis research of graduate student Trevor DeVries, who is supported by a NSERC postgraduate scholarship. Dr. Marina (Nina) von Keyserlingk is an Assistant Professor in the Faculty of Agricultural Sciences, Animal Welfare Program. Nina grew up on a farm in the Okanagan Valley region of British Columbia. She recently joined the Faculty after obtaining her Ph.D. in animal nutrition followed by several years experience as a research scientist working in the animal feed industry. Nina has a strong interest in understanding the links between nutrition, behaviour and animal health as related to animal welfare issues. She can be contacted at nina@interchange.ubc.ca.

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Feeding Calves More Milk (2002)

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On a typical dairy farm calves are separated from their mothers within 24 hours of birth. These young dairy calves are usually moved to individual pens or hutches and fed about 2 litres of milk by bucket twice a day. Recent work at the UBC Dairy Education and Research Centre have shown that even small changes in these calf rearing practices can produce big improvements in calf growth and well being.

Our research started by asking what we can learn from the cow. When kept with her calf, the cow allows it to nursed about 10 times a day. On each occasion, the calf sucks for several minutes consuming about 1 litre of milk.

Over the day, this amounts to approximately 10 litres, or over twice as much milk as is typically provided to calves on commercial dairy farms. Not surprisingly, this increased intake of milk allows the calves to grow rapidly.

As illustrated in Figure 1, calves kept with the cow for the first 2 weeks of life gain weight at nearly four times the rate of bucket-fed calves during the first 2 weeks of life.

While keeping calves with their mothers may not be practical on most dairy farms, the benefits of consuming more milk in smaller but more frequent meals can still be achieved. In several experiments we have provide calves with free access to milk through a nipple drinker (Figure 2)

Calves fed in this way consume twice as much as they are normally given (Figure 3), allowing them to gain weight about twice as fast as those calves fed in conventional manner. The calves fed more milk were no more likely to scour than the traditionally fed calves. The calves fed more milk also made an excellent transition to solid food at weaning, allowing them to maintain their weight advantage over the conventionally fed calves.

Producers can also achieve higher calf weight gains using buckets to feed more milk, more often, but we have fount that nipple based systems are labour efficient, and they allow calves to express their natural desire to suck for their milk. Like calves kept with the cow, those with access to a nipple also tend to divide their daily milk consumption into about 10 meals.

Using nipple systems to provide more milk also facilitates group housing. If properly managed, calves direct their sucking to the nipples, and not to pen mates. Group housing of calve will be the topic of a future Research Report.

In a summary, there can be advantages to the calves and to the producers in giving calves more milk. With increase access to milk calves grow faster, permitting weaning at an earlier age. Under well-managed conditions, increased milk intake does not lead to increased scouring or problems in making the transition to solid feed at weaning. Calves also call when they are hungry, so feeding more milk helps to keep the calf barn much quieter.

Changes in feeding methods can require new equipment and new management skills. Producers interested in feeding their calves more milk should start slowly with just a few calves to develop procedures that work well on their farm. As with feed for any animal, keep a careful eye on the quality and avoid sudden changes in the feeding program. We have found that even very young calves (within their first week of life) can take advantage of more milk. Consider starting off with the youngest calves, after having ensured that they have received colostrum.

To find out more about recent work on dairy calf rearing, please look up this web based article:

http://www.afns.ualberta.ca/hosted/wcds/wcd2001/proceedings/Chapter%2009....

Thanks to the dairy industry and others for their support of this research through funding to the Animal Welfare Program by the Dairy Farmers of Canada, the BC Dairy Foundation, the Cattle Industry Development Council, Westgen, members of the BCVMA, the BC SPCA and many others listed at : www.agsci.ubc.ca/animalwelfare.

This article is based on research by Mike Appleby, Erin Bell, Bev Chua, Eveline Coenen, Frances Flower, Tamiko Thomas and Joyce van Delen. Dan Weary is Associate Professor in the Animal Welfare Program and can be contacted at: danweary@interchange.ubc.ca

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Feeding Management Strategies for Growing Heifers (Nov 2011)

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Click here to view this article in pdf format: Feeding Management Strategies for Growing Heifers

Replacement heifers are the future of the dairy herd, but very little research is focused on these animals. Researchers at the University of British Columbia's Dairy Education and Research Centre have recently completed three experiments designed to determine the effects of different methods of feeding weaned 5-8 month old Holstein heifers.

For all three experiments, electronic feed bins were used that identify individual heifers housed in a group pen and record the timing and amount of feed eaten during each visit to a feed bin (Figure 1). Feed samples were also taken to determine if heifers preferentially selected certain components of a total mixed-ration.

Figure 1. Electronically controlled feed bins used to study the feeding behaviour of growing heifers.

There are different strategies used to feed replacement heifers. One approach is limit feeding, where they are fed a restricted amount of a nutrient-rich diet. But limit fed heifers typically spend less time eating than they would under natural grazing conditions and spend more time standing (not eating) and may show higher rates of vocalization associated with hunger. An alternative to limit feeding is to provide unlimited feed that is less nutrient-dense so that the heifers can eat as much as they like, when they like. A less nutrient-dense diet is achieved by diluting the diet with a low-quality feedstuff, such as straw.

In the first experiment we tested the effect of adding rye straw to TMR on the intake and behavior of heifers. After a week of adaptation, six heifers were fed three different diets for 1 week each. The three diets were the control diet (corn silage, grass silage and concentrates), the control diet plus 10% straw and the control diet plus 20% straw.

Adding straw to the diet changed the feeding behavior of heifers in several ways. Adding straw increased average meal times from 38 minutes on the control diet to 41 and 43 minutes, for 10% and 20% straw, respectively. This translated into more time spent feeding each day. Heifers consuming the 10% straw ration spent 13 minutes longer eating each day and those on the 20% straw ration ate for an extra 19 minutes. Heifers fed with 20% added straw also decreased feeding rate, meal size and number of meals consumed per day.

These changes in feeding behavior were due in part to an increase in time spent sorting. Heifers sorted their feed preferentially for concentrate and smaller particles (corn silage) and selected against long particles (straw). Heifers consuming the control and 10% straw diets showed similar body weight gains averaging 1.0 kg per day, but heifers on the 20% straw diet gained 0.9 kg per day.

These results suggest that adding 10% straw may be optimal in terms of reducing feed costs and satisfying natural feeding behavior without slowing growth.

Our second study focused on the effects of feeding methods on feed-sorting behavior in heifers. After a week of adaptation, six heifers were tested on each of the three treatments for 1 week each. Treatments consisted of 2 kg of grain concentrate and unlimited grass hay provided in three different ways; separately (grain and hay), as a top-dressed ration or as a total mixed ration (TMR).

When heifers were fed grain and hay in separate bins or the grain was top-dressed on the grass hay, heifers quickly ate the grain in a few large meals before they began eating the hay. When the two feed components were mixed together (i.e. TMR) the feed intake of each component was more balanced throughout the day and feed sorting behavior was reduced.

Given the high forage component of growing heifer diets it is expected that feeding times will be longer than 3 hours per day. Moreover, given that heifers are fed and tend to eat at the same time, it is important to consider how much competition there is for access to feed and how this affects their feeding behavior. These factors were investigated in the third experiment.

Thirty-six heifers were tested during two treatments. In the "non-competitive" treatment each heifer could access feed from a single feed bin. In the "competitive" treatment pairs of heifers had to each share a feed bin. The groups were balanced for age and weight.

Competition did not change feed intake or feed-sorting behavior but the treatment did alter feeding patterns, especially during peak feeding times. Figure 2 shows how competitively fed heifers spent less time eating, especially during peak feeding times in the morning and evening.

Heifers in the competitive treatment spent about 15 minutes less time feeding each day, had 9% fewer meals per day and ate larger, longer meals. To maintain the same intake, they ate faster to compensate for the shorter feeding times in the competitive situation. The day-to-day variation in feeding behavior also tended to be higher in the competing heifers.

In conclusion, providing the diet in the form of a TMR minimizes sorting behavior by heifers, and diluting this with some low-quality feed such as straw increases feeding time. Providing adequate feed bunk space for each heifer is also essential as it will allow all animals access to feed at peak feeding times, when they are highly motivated to feed.

Figure 2. Hourly averages for feeding time (min) for growing dairy heifers fed noncompetitively (1 heifer/feed bin) or competitively (2 heifers/feed bin). Data are averaged per feed bin (expressed on a per animal basis) over 7 d and the 12 feed bins on each treatment. Arrows show feeding times.


We are grateful to Hanna Miedema for help preparing this report. For further information, please email marina.vonkeyserlingk@ubc.ca or dan.weary@ubc.ca. This report is based on three published papers in the Journal of Dairy Science (Greter et al., 2008. J. Dairy Sci. 91:2786-2795; DeVries and von Keyserlingk, 2009. J. Dairy Sci. 92:1161-1168 and DeVries and von Keyserlingk, 2009. J. Dairy Sci. 92:3922-3929). We thank the researchers and staff of the UBC Dairy Education and Research Centre for their hard work on the studies described in this report. This research was funded by the NSERC Industrial Research Chair in Animal Welfare with contributions from the Dairy Farmers of Canada and many others listed at www.landfood.ubc.ca/animalwelfare/.

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Feeding Pasteurized Milk to Dairy Calves

Waste Milk
All dairy farms have a supply of milk that is not saleable, typically referred to as waste milk. Waste milk may consist of excess colostrum, non-saleable transition milk from the first six milkings, abnormal milk, mastitic milk and hospital milk including milk from antibiotic treated cows. Historically, raw waste milk has been fed to calves a means of economic efficiency and alleviating disposal challenges and associated environmental concerns. However, one major concern with this practice is that waste milk is often contaminated with potential pathogens. Bacterial counts in raw milk are variable and can be extremely high. The increased risk of transmission of infectious pathogens shed directly from the mammary gland can pose serious health issues with the animal. Bacteria load can proliferate due to post-milking contamination (e.g. manure) and milk that is not collected, stored or cooled properly. These concerns of bacterial contamination with Salmonella, Lysteria monocytogenes, E.coli, Mycobacterium paratuberculosis (the organism responsible for Johnes disease), etc. through feeding waste milk have led to a general recommendation not to feed waste milk to calves.

Pasteurization
Pasteurization of waste milk for calves is one option to reduce the transmission of disease to calves. The heating of milk to a specific temperature for a specified time has been used to destroy pathogenic bacteria and reduce spoilage bacteria to negligible levels. While pasteurization destroys major pathogens, it does not sterilize milk and some spoilage bacteria may survive. Temperature and time should be carefully monitored during the pasteurization process. Standard written protocols should be set up for using and maintaining waste milk pasteurizers.

Benefits
Feeding pasteurized waste milk has been demonstrated to improve calf health as compared to feeding raw waste milk. Waste milk is pasteurized to destroy pathogens and reduce the risk of disease transmission to calves. Research trials have shown that feeding calves pasteurized milk lessens the severity and duration of scours and pneumonia when compared to calves consuming non-treated milk. Also, average daily gains are significantly greater with pasteurized milk when compared to raw milk. Other related advantages include fewer sick days, lower mortality rates, lower health associated costs and higher weaning weights.

Considerations
When Feeding Pasteurized Milk A pasteurized milk feeding program requires more intensive management than a milk replacer feeding program. Initial capital costs are significant and hot water capacity is critical. A separate designated hot water source to accommodate the pasteurizer may be required.

Success in a pasteurized milk feeding program is also related to the ability to control the milk before and after pasteurization. Time must be taken to clean the pasteurization equipment thoroughly and maintain the equipment for optimum operation efficiency. Poor cleaning procedures result in inefficient or ineffective pasteurization as milk protein, fat and inorganic films can buildup and interfere with heat transfer and may further inoculate milk with bacteria. Personnel capable of managing and monitoring the pasteurization system should be assigned the task of operating it.

The supply of non-saleable milk may not always be adequate to feed all calves. To be practically effective a dairy farm must have a stable supply of waste milk. Alternatively, dairy farm operators must have a strategy for periods when waste milk supplies are inadequate. Options may be using saleable milk, milk from higher somatic count cows or adding milk replacer solution to pasteurized milk.

Higher than required temperatures during the pasteurization process (the required time and temperature varies depending on whether the pasteurizing unit is batch or HTST continuous flow) actually makes the feeding value of the milk worse. When milk is overheated, the high temperatures can break down or denature milk proteins, rendering them indigestible to the calf. Indigestible proteins pass through the digestive tract and end up in the feces. Calves may actually become protein deficient, even though there was plenty of protein in the milk. Symptoms may be small, unthrifty calves with sunken eyes and rough hair coats. In batch pasteurizers, hot spots in milk can occur if agitation is not adequate or not functioning properly. Again, protein denaturing may arise.

Good management practices in the handling and storage of both pre-pasteurized and post-pasteurized milk should be adhered to. With pre-pasteurized milk, excessively high bacteria counts or inadequate cooling will cause milk to ferment and sour. Producers should not pasteurize soured milk because this can result in coagulation (curd formation).

Pasteurizers should be equipped to rapidly cool the milk after pasteurization is complete. Any remaining spoilage bacteria can double their numbers every 20 minutes at 38º Celcius. Post-pasteurized milk that is not being fed immediately should be chilled in a clean, covered container and later reheated to feeding temperature at feeding time.

Pasteurization provides no protection against antibiotic residues in waste milk and calves fed pasteurized waste milk may be contaminated with antibiotic residue, therefore producers need to consider appropriate meat withholding times. Post-pasteurization contamination of milk negates the advantages of the whole process so careful attention to regular and thorough sanitization of all milk holding, transfer and feeding equipment is required.

Heat Treating Colostrum
Untreated colostrum can pose a risk of exposing dairy calves to pathogenic bacteria when they are most vulnerable. Pasteurizing colostrum at temperatures traditionally used for pasteurizing milk presents two significant challenges. First, regular pasteurization temperatures have shown to decrease the availability of immunoglobulin G (IgG) resulting in lower serum IgG levels in calves that were fed pasteurized colostrums. Secondly, colostrum tend to thicken with increased viscosity as it is heated resulting in handling problems. More recent research has shown that these challenges may be overcome by heat treating colostrum using a lower temperature, longer time approach (e.g. 60º Celcius for 60 minutes instead of 63º Celcius for 30 minutes in a batch pasteurization system). Heat treating colostrum at temperatures above 60º Celcius will result in denaturing of IgG. Feeding heat treated colostrum to calves increases IgG absorption and serum IgG concentration when compared to feeding raw colostrum.

Summary
Success in pasteurizing milk is related to the ability to control the milk before and after pasteurization. When managed correctly, pasteurized milk is a calf liquid feeding option for larger farms. The main advantages are utilization of non-saleable milk and reduced disease transmission resulting in improved calf health and growth rates compared to calves consuming raw waste milk. Disadvantages include initial capital cost, required detailed pasteurization management, inadequate non-saleable milk supply and possible antibiotic residue concerns. Heat treating colostrum using a lower temperature, long time approach can be successful to reduce or eliminate major pathogens while maintaining available immunoglobulins and retaining physical fluidity for easier handling.

When compared to feeding raw waste milk to calves, the advantages of feeding pasteurized milk are clear. However, the feeding of premium quality milk replacers also offer several benefits including day to day consistency, ease and flexibility of storage, mixing and feeding along with good calf performance. Research has shown when calves are raised solely on premium quality milk replacer formulated with optimal blends of essential fatty acids and amino acids growth rates are improved. Equipment, space, time and handling requirements should be considered in evaluating the milk feeding program to use on your farm.

References:
Akey Replacement Report; Milk Replacer Research, Comparison of Feeding Pasteurized Milk to an Akey and NRC Formulated Milk Replacer, Akey Nutrition and Research Center, Lewisburg, Ohio.

Akey Replacement Report; Research Review, Pasteurized Waste Milk, Akey Nutrition and Research Center, Lewisburg, Ohio.
A Review of Issues Surrounding the Feeding of Pasteurized Non-Saleable Milk and Colostrum; S. Godden, DVM, DVSc, J. Fetrow, DVM, MBA, DACVPM, J. Feirtag, MS, PhD, S. Wells, DVM, PhD, DACVPM, L. Green, MS, Center for Animal Health and Food Safety, University of Minnesota, St. Paul, Minnesota 55108

Feeding Heat-Treated Colostrum to Neonatal Dairy Heifers: Effects on Growth Characteristics and Blood Parameters; J.A. Elizondo-Salazar and A.J. Heinrichs, Department of Dairy and Animal Science, The Pennsylvania State University, University Park 16802

Heat-Treatment of Bovine Colostrum. I: Effects of Temperature on Viscosity and Immunoglobulin G Level & II: Effects of Heating Duration on Pathogen Viability and Immunoglobulin G; S. Goyal, USDA,ARS, National Animal Diseases Center, Ames, Iowa 50010, S. Godden, S. McMartin, J. Feirtag, R. Bey, J. Stabel, L. Metzger, J. Fetrow, S. Wells, H. Chester-Jones, University of Minnesota, St. Paul 55108

Glenn Smith, Dairy Nutritionist

Feeding calves more milk: A practical approach (2006)

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Marina von Keyserlingk and Dan Weary

Rearing healthy milk-fed heifers is one of the many challenging tasks facing dairy producers. Calves normally provided milk at 10% of their body weight (~ 4 kg / day), are vulnerable to disease, often fail to gain adequate weight and can sometimes experience high levels of mortality. However, research has shown that some of these problems can be avoided by providing pre-weaned dairy calves with more milk.

Continuous access to milk results in greater milk intake and higher weight gains. Providing access to milk via a teat allows the calf to express normal sucking behaviour, while reducing non-nutritive sucking and increasing secretion of hormones important in the digestion process. However, improving access to milk raises practical problems, such as maintaining milk quality throughout the day, especially in warm weather.

An alternate approach to continuous access is to provide unlimited access to milk but only for a few hours each day. Previous research has found that calves provided unlimited access to milk spend just 45 minutes per day drinking milk, and that the largest meals occur just after the delivery of fresh milk. In a recent study we tested the effects of limited access to milk (4 hours per day, (h/d) versus continuous (24 h/h) access on milk intake, weight gain and behaviour of dairy calves.

Figure 1. Calf drinking milk through a teat-based feeding station.

In our 4 week long experiment we housed 28 female Holstein calves individually and provided milk through a rubber teat. Calves also had access to calf starter and water from a bowl drinker.

Pre-weaned calves were assigned to one of two treatment groups: one group of calves had access to milk for 24 h/d. The second group had access to milk twice per day for 2 hours each time.

Calves in both treatment groups gained weight rapidly (approximately 1.1 kg/day). In fact there was no difference in average daily gain between the two treatment groups, despite a modest decline in milk consumption by calves on the 4 h/d treatment (intakes of approximately 10.0 kg/day versus 11.2 kg/day). Our behavioural observations showed that during the 4 h/d when milk was available to all, the calves on the 4 h/d treatment spent more time at the teat than the 24 h/d calves. (Figure 2)

Figure 2. Mean time calves spent sucking on the teat, shown separately for
calves that had access to milk 24 h/d and those that had access twice a day
for 2 h each, a total of 4 h/d. Both groups spent most time at the teat when the
fresh milk was provided twice daily.

Calves on the 4 h/d treatment almost never visited the teat during the 20 h/d that milk was not available to them, suggesting that the calves were not unduly disturbed by milk unavailability. Similarly, the calves fed milk 4 h/d appeared to have no trouble adjusting their time spent at the teat to times when milk was accessible to them.

In conclusion, our results show that feeding calves milk during only a few hours each day allows for similar performance to when calves have access 24 h/d.

With restricted periods of free access to milk, calves can adjust their milk feeding behaviour with no detrimental effects on weight gain. Calves provided milk for only 4 h/d spend slightly less time drinking and tend to consume less milk, but are able to maintain similar weight gains as calves provided with continuous access to milk. These results apply well for calves housed individually. In other work we have found that group-housing calves can result in competition for milk and for teats. New work is now required to determine if restricted periods of milk access would also be suitable for group-housed calves.


This article is based on research conducted by M. von Keyserlingk, F. Wolf, M. Hötzel and D.M. Weary and published in the Journal of Dairy Science in 2006. We thank the staff and students at the University of British Columbia's Dairy Education and Research Center and Animal Welfare Program. We are grateful to Nicole Fenwick for help preparing this report. Drs. Marina (Nina) von Keyserlingk and Dan Weary are professors with the UBC Animal Welfare Program located in the Faculty of Land and Food Systems. Funding was provided by the NSERC Research Partnership Support Program made possible by contributions from the Dairy Farmers of Canada and the many others listed at the Animal Welfare Program website at http://www.landfood.ubc.ca/animalwelfare.

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How Many Times a Day Should You Feed Your Cows? (2005)

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Trevor DeVries and Marina von Keyserlingk

Previous research by our group has shown that the delivery of fresh feed is the primary driver stimulating dairy cows to get up and eat. Traditionally most dairy producers provide a total mixed ration (TMR) to their lactating dairy cattle twice per day (2x). However, many producers are electing to feed their cows only once per day (1x), as a means of reducing labour costs.

There has been some concern that providing feed 1x may result in slug feeding, which could predispose a cow to sub-acute ruminal acidosis. Alternatively, more frequent offerings of feed may result in cows spreading out their feeding time more evenly throughout the day. Further, a steady input of nutrients into the rumen over the course of the day should benefit rumen function, which in turn may reduce the risk for sub-acute ruminal acidosis.

Questions have been raised regarding the effect of frequency of feed delivery on the quality of the TMR consumed by the cows over the course of the day. Cows have been shown to preferentially sort for the grain component of the TMR, leaving behind the longer forage components resulting in an increase in the fibre content of the remaining feed. This effect is thought to be greatest when frequency of feed delivery is low. This may result in cows that are unable to feed at the time of fresh feed delivery, possibly due to increased competition, consuming a ration that is not balanced to meet their nutritional requirements.

Figure 1. Delivery of fresh feed acts as the
primary driver stimulating cows to feed.

In reviewing the scientific literature it appears that there is little work addressing these issues surrounding the frequency of feed delivery. Therefore, we set out to investigate how the frequency of feed delivery affects the behaviour of group-housed lactating dairy cows and how it affects the extent of feed sorting. These questions were addressed in two experiments, the first comparing the effects of delivering feed 1x to 2x, and the second comparing the effects of delivering feed 2x to four times per day (4x). To ensure that feed was always available for the 1x, 2x, and 4x treatments, feed was pushed-up 3, 2 and 0 times per day, respectively. In each experiment, 48 lactating Holstein cows were split into groups of 12 and subjected to each of the two treatments for two weeks. In both experiments the same TMR (50:50 forage:concentrate ratio) was provided in equal amounts to each group, regardless of treatment.

Increased frequency of feed provision increased the time cows spent feeding each day in both experiments (see Figure 2). It also changed the distribution of daily feeding time, resulting in cows having more equal access to feed throughout the day. Frequency of feed delivery had no effect on the daily lying time of the cows or the daily incidence of aggressive interactions at the feed bunk. However, subordinate cows were not displaced from the feed bunk as frequently when all cows were fed more often.


Figure 2. Cows spend more time feeding throughout
the day as the frequency of feed delivery increases.

For all treatments, in both experiments, the fibre content of the TMR present in the feed bunk increased throughout the day, indicating that sorting of the feed had occurred for all treatment levels. Further, the amount of sorting of the feed was highest when feed was delivered 1x (see Figure 3).

Figure 3. The more rapid increase in fibre (NDF) content
of the TMR during the 1x treatment indicates that more
feed sorting occurred. Feed delivery occurred at 5:30 for the
1x and at 5:30 and 15:15 for the 2x treatment.

The increased sorting in the first experiment translated into the feed refusals (collected at 5:00) containing 8% more forage when the cows were fed 1x compared to when they were fed 2x.

In conclusion, these results indicate that more frequent delivery of feed improves access to feed for all cows. Further, delivering feed 2x compared to 1x will reduce the variation in the composition of feed consumed by the cows. This could have dramatic effects for submissive cows, which may have inadequate access to feed during peak feeding times.


This article is based on thesis research of Ph.D. candidate Trevor DeVries, who is supported by a NSERC Canada Graduate Scholarship. Dr. Marina (Nina) von Keyserlingk is an Assistant Professor in the UBC Animal Welfare Program located in the Faculty of Land and Food Systems. Thanks to Danica Olenick, Kiyomi Ito, Dineke van den Hazel and the staff of the UBC Dairy Education and Research Centre for their help with this research. We also thank Dr. Karen Beauchemin and Agriculture and Agri-Food Canada for the feed analyses. This research was made possible through funding by the Dairy Farmers of Canada, NSERC, and many others listed at www.agsci.ubc.ca/animalwelfare.

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Improving Feed Access Through Feed Bunk Design (2006)

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Juliana Huzzey, Trevor DeVries and Marina von Keyserlingk

Dairy cattle housed in free stall barns are normally separated from the feed delivery area by some sort of barrier. This barrier is important as it prevents cattle from walking and defecating on the feed. These barriers have been designed to allow cows unrestricted access to feed, however, the management and design of these systems may affect the ability of cows to access feed.

One particular management factor that can influence the ability of cows to access feed is the amount of available feed bunk space. Previous work by our group (see UBC Research Report Vol. 3 No. 3) has shown that increased space allowance per cow at the bunk reduces competition and improves bunk access, particularly for subordinate animals.

Two common feed barriers used in the dairy industry are the headlock and post-and-rail barriers (Figure 1). In a recent study we investigated how the type of feed barrier affects feeding behaviour and the level of competition at the feed bunk. We found that headlocks reduced the frequency of competitive interactions at the feed bunk by 21% compared to the post and rail; this resulted in all cows having more equal access to fresh feed. In a follow-up study, we set out to examine the relationship between feed barrier design and the amount of available space at the feed bunk.

In this study 36 lactating Holstein cows were divided into four groups. Two groups were assigned to pens with headlock barriers and two groups to pens with post-and-rail barriers.

Figure 1. Picture of a headlock (A) and post-and-rail (B) feed barrier.

Each group was then exposed to four feed bunk space treatments (0.21, 0.41, 0.61 (industry standard), and 0.81 m/cow, corresponding to 0.33, 0.67, 1.00, and 1.33 headlocks/cow), in four successive 10-d treatment periods. After these periods, the barriers were switched between groups and the four bunk space treatments were repeated.

Our results showed that when cows were provided with more space at the feed bunk they spent more time feeding per day (Figure 2). Even though 0.61 m (2 ft) of linear bunk space has traditionally been regarded by the dairy industry as adequate, the results of this study, supported by other studies completed by our group, indicate that feeding time would likely increase if cows were provided with more than 0.61 m of space per cow.

Figure 2. Average daily feeding time per cow at four different feed bunk space treatments when provided either a headlock (HL) or a post-and-rail feed barrier.

In addition, cows housed with the post-and-rail feed barrier fed on average 18 minutes longer per day than cows housed with the headlock system (Figure 2). This could be due to cows finding the post-and-rail more comfortable while feeding as there was less hardware separating them from the feed and from adjacent animals. Alternatively, cows may have a learned aversion to the headlock barrier, as this system is often used to restrain animals during uncomfortable procedures such as herd health or artificial insemination.

We found that reduced space availability increased the number of aggressive interactions, particularly at the 0.21 m/cow treatment (Figure 3). On average there was a 134% increase in the number of aggressive interactions (displacements) when cows went from the most bunk space (0.81 m/cow) to the least bunk space (0.21 m/cow). Further, aggressive interactions at the feed bunk were more frequent when using the post-and-rail barrier, suggesting that the headlocks provide some protection against competitive interactions at the feed bunk.

Figure 3. Average daily number of displacements per cow at four different feed space treatments when provided either a headlock (HL) or post-and-rail feed barrier. A displacement was recorded when a cow physically forced another cow from the feed bunk.

In conclusion, we recommend avoiding overstocking at the feed bunk to reduce competition and thus improve access to feed. Further, the use of a barrier that provides some physical separation between adjacent cows can further reduce competition at the feed bunk, particularly for subordinate animals. Future work by our group will focus on determining the long-term effects of overstocking and competition on measures such as DMI, milk production, claw health, and disease incidence.


The results discussed in this report are a summary of research completed by the authors in collaboration with Paul Valois, Marcia Endres, and Dan Weary of the UBC Animal Welfare Program (Endres et al. 2005. J. Dairy Sci. 88:2377-2380; Huzzey et al. 2006. J. Dairy Sc. 89:126-133).

Special thanks to the staff of the UBC Dairy Education and Research Centre. We also thank Nicole Fenwick for her help in preparing this research report. This research was funded by the Dairy Farmers of Canada, the BC Dairy Foundation, NSERC and the many others listed at: http://www.landfood.ubc.ca/animalwelfare.

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Mycotoxin Effects in Dairy Cattle (2012)

Mycotoxins are toxic substances produced by fungi (molds) growing on crops in the field, during handling or in storage. It is estimated that up to 25% of the worlds crops may be contaminated with mycotoxins. While over 400 mycotoxins have been chemically identified, the impact of only a few mycotoxins are known. Common types of mycotoxins include aflatoxin, deoxynivalenol (also referred to as DON or vomitoxin), zearalenone, T-2 toxin and fumonsin. Of the thousands of mold species that can grow on feedstuffs, only a small proportion produce mycotoxins.

Mold Growth and Mycotoxin Formation
Some molds proliferate while the crop is growing while others propagate during handling and storage. Field mold spores propagate in both the grain and forage parts of plants. Weather related growing conditions contribute to the onset of molds that may produce mycotoxins. Storage fungi are soilborne mold spores brought into the silo with forages. Most molds identified in silage do not produce mycotoxins.

In the fall of 2011, some of the Fraser Valley corn silage harvest picked up mycotoxin contamination from soil in lodged corn plants. The limiting factor for mold growth in stored silage is pH. If silage is stored too dry, or is insufficiently packed and covered then air allows for microbial activity which depletes silage acids allowing pH to rise with subsequent mold growth and possible mycotoxin contamination. With hay, the limiting factor for mold growth is moisture where contamination is more likely in higher moisture hay.

Mycotoxin Effects
An excess of mycotoxins cause undesirable effects when animals are exposed. Sometimes mycotoxins occur at concentrations high enough to cause major losses in health and performance of animals. However, mycotoxins are usually at lower levels that result in interactions with other stressors to cause subclinical losses in performance, increases in incidence of disease and reduced reproductive performance.

The mode of action of mycotoxin ingestion within ruminants is not clearly defined nor well understood, however it is known that mycotoxins exert their effects through three primary mechanisms:

1. Reduction in amount of nutrients available for use by animal
2. Effects on hormonal systems and subsequent reproductive performance
3. Suppression of immune system

In the past, ruminants were thought to tolerate the adverse effects of mycotoxins – perhaps due to the ability of rumen microbes to detoxify mycotoxins. However, with high producing dairy cattle increased rumen passage rates overwhelm the ability of the rumen to completely denature the toxins.

Mycotoxicosis Symptoms and Diagnosis
The diversity of symptoms make mycotoxicosis diagnosis confusing and difficult. Sypmtoms of mycotoxicosis may be vague or nonspecific but may include: reduced feed intake, feed refusal, unthriftiness, rough hair coat, poor body condition and reproductive problems. Mycotoxins have also been associated with increased transition cow problems including more substantive symptoms such as displaced abomasums, ketosis, retained placenta, metrtitis, mastitis, fatty livers and other infectious disease because of immune suppression.

A definitive diagnosis of mycotoxicosis can not usually be made from symptoms, tissue damage or feed analyses. Regardless of the difficulty of diagnosis, mycotoxins should be considered as a possible cause of production and health problems when symptoms exist and problems are not attributable to other typical causes. These same factors make it difficult to establish levels of safety for mycotoxin ingestion. Interactions with other stress factors make recommendations difficult as animals under environmental or production stress may show more pronounced symptoms. Also, partial degradation in the rumen complicates recommendations.

Mycotoxin Testing
The accurate determination of mycotoxin concentrations present in grain and forages depends on a number of factors. The largest source of error is due to sampling. Molds grow in hot spots and associated mycotoxins are not uniformly distributed within a feed making it difficult to obtain a representative sample. Analytical techniques for mycotoxins are improving but constraints exist with respect to cost of analyses and the practicality of testing for a multitude of toxins. For example, testing for one type of mycotoxin does not preclude that another mycotoxin may be prevalent. Moreover, commercial testing for some specific toxins may not be readily available. Analyzing for mold spore counts may not be useful and are only a gross indication of potential for toxicity as not all molds produce mycotoxins. Generally, where growing conditions were conducive for feeds with mycotoxin contamination it is advisable to forgo mycotoxin testing and include an economical mycotoxin binder in the ration.

Managing Mycotoxin Contamination
As we understand more about mycotoxin diagnosis, we need to determine methods for reducing or removing the adverse effects of theses compounds on livestock production. There probably are levels of mycotoxins where no adverse effects will be observed and these are probably greater for ruminants than non-ruminants. However, it is prudent to lower concentrations as much as possible and manage mycotoxins that are present.

Prevention of mycotoxicosis begins in the field with good agronomic practices as the most commonly diagnosed mycotoxins found in forages are produced in the field prior to ensiling. Irrigation, reduction of conditions conducive to mold growth and minimizing soil contamination are all practices that will reduce the incidence of mycotoxin contamination in the harvested crop.

Choosing varieties that have resistance to fungal disease and insect damage can reduce field produced mycotoxins. Crop stressors such as wind, bird, hail, flood or insect damage increase the chances for mold growth. Mycotoxins increase with delayed harvest, late season rain and cool periods. Mold spore levels may be higher with no-till management. Deep disking is advised to facilitate the degradation of crop debris that contribute to mold growth. Optimizing soil fertility to improve plant health can reduce mold activity. Producing healthy plants helps to diminish plant stresses such as stalk lodging. Anything that helps improve plant health will help reduce disease lesions and pest damage, thus suppressing mold invasion and mycotoxin production. Planting corn year after year on the same ground creates the opportunity for increasing mold levels. Most plant pathologists advise crop rotation in an attempt to break the cycle.

A timely harvest at proper moisture and maturity levels not only ensures that molds will be minimized in the field, but also that storage mold activity will be minimized in the silo. Other silo management considerations that promote optimal fermentation will also minimize molds and associated mycotoxins during storage. These include: filling the silo rapidly, proper chop length, packing the silo sufficiently, covering the silo completely to reduce exposure to oxygen. Ensuring a clean silo prior to filling and that mud and manure is eliminated during the ensiling process will minimize the mold spore load entering during filling of the silo.

Feeding practices that reduce deterioration of the feeding face and reduce heating in the feed bunk should be implemented. Silo size should be matched to herd size to ensure daily removal of silage at a rate faster than deterioration. In warm weather, remove at least 15 cm of silage daily from the feeding face. The feeding face of silos should be cleanly cut and disturbed as little as possible to prevent aeration into the silage mass. Silage and other wet feeds should be fed immediately after removal from storage. Feed bunks should be cleaned regularly.

Although silage inoculants do not detoxify mycotoxins, they are recommended to help ensure optimal fermentation, rapid pH drop and stable silage. Reducing silage pH rapidly will reduce mold growth and subsequent mycotoxin formation.

When feeding high moisture byproduct feeds (e.g. brew mash), handle in quantities that will allow them to be fed out within 7 to 10 days. Discard any spoilage. High moisture grains should be avoided. Most molds need free water activity to grow and produce toxins so storing grain below 15% moisture helps reduce the infection rate.

Mycotoxins reduce feed consumption therefore manage the feeding regime to maximize intake. Acidic diets intensify the effects of mycotoxins. For that reason, ensure that adequate dietary fibre and buffers are fed. Dry cows, springing heifers and calves should receive the cleanest feed possible. Specific transition rations can reduce stress in fresh cows and reduce effects of mycotoxins.

Adsorbents
When animals are exposed to mycotoxins, favourable results have been seen if adsorbent materials and complex indigestible carbohydrates are added to the ration. Responses to some of these products in dairy cattle have been encouraging.

The concept of mycotoxin adsorbents added to the diet is to bind mycotoxins to prevent toxicity in the gastro-intestinal tract and prevent absorption across the gut wall. For best results an adsorbent should: effectively adsorb mycotoxins, reduce mycotoxin availability and activity, reduce animal toxicity and tissue residues, not be detrimental to the animal or food product, be resistant to the physical effects of feed manufacturing and be cost effective.

There are several natural based mycotoxin adsorbents on the market. Contact your Hi-Pro Feeds representative for advice on what fits the best on your farm.

Conclusion
Mycotoxins and molds occur in many feed types including grain, hay and silage, and can be the root cause of animal disorders. Chronic symptoms such as low performance and reduced immune status can be the result of mycotoxin ingestion. Most molds do not produce known mycotoxins. Proper crop management from field to feedout will reduce opportunities for mold growth and subsequent toxin production. Even after implementing good agronomic and feeding management practices, it may not be possible to completely eliminate mycotoxins from the diet. Many adsorbent type products are used in the feed industry to help minimize the effects of mycotoxins.

Glenn Smith, Dairy Mill Nutritionist, Hi-Pro Feeds, Chilliwack

Why cattle graze the bunk: effects of variation in TMR quality on feeding behaviour (2012)

Why this matters…

A total mixed ration (TMR) should provide a nutritionally balanced diet with all nutrients that cattle need to grow and function well. However, on farms the quality of the TMR may vary between days (in relation to inputs and mixing), within days (due to sorting by cows or environmental exposure), and along the feed bunk (due to improper mixing or uneven feed distribution and usage). Recent research at UBC has shown that this variability can have profound affects on dairy cattle feeding behaviour.

Animals generally search for the most profitable feeding sites (i.e. locations with the highest nutrient density) in order to make the most efficient use of feeding time. Often these sites are also associated with highly palatable feed which makes these locations even more desirable. Searching behaviour allows animals to locate higher quality feeding sites, but this exploration also requires time during which animals are not feeding. High levels of searching may make feeding behaviour less efficient by decreasing the time spent at the bunk and increasing competitive behaviour over access to preferred feeding locations.

The aim of this study was to measure how variation in TMR quality affects the feeding behaviour of dairy heifers.

non-uniform distribution of feed ingredients

What we did…

Thirty-two, 7-month old Holstein heifers were divided into 4 groups each consisting of 8 animals. All animals in each group pen had free access to 8 feeding stations (bins). Three different TMR qualities were used in this study: low energy, moderate energy and high energy. The TMR was a mix of fescue hay, corn silage, grass silage and grain concentrate. The energy density of the TMR was modified by adjusting the amount of grain in the mix. The grain component made up 0, 24 or 39 % of the total dry matter of the Low, Moderate and High diets, respectively.

The study lasted 9 days. To simulate variation in TMR quality along the length of the feed bunk, 7 feed bins were filled with the low quality TMR and 1 bin, positioned at random on days 1, 2, 4, 5, 7, and 8 of the study, was filled with the high quality TMR. On days 3, 6 and 9, all 8 feed bins were filled with either Low, Moderate or High quality TMR to simulate unexpected changes in TMR quality between days. By the end of the 9-day study period all 4 groups of animals experienced a TMR change to each of the 3 different qualities of TMR. The average quality of the TMR (across all 8 bins) on these 3 test days was either higher (Moderate and High TMR) or lower (Low TMR) than what the heifers experienced on the day previous, when TMR distribution was non-uniform along the length of the feed bunk.

To determine how variation in TMR quality affected feeding behaviour, heifers within each of the 4 groups were arranged into pairs for observation. Before the morning feed delivery all heifers were moved to the back of the pen and then 1 pair at a time was allowed access to the fresh feed for 15 minutes. Feed bins were refilled after each 15-minute period. The number of times heifers switched between bins and the average time spent at each bin was recorded. The number of competitive interactions (displacements and attempts to displace) that occurred between the heifers was also recorded.

What we found…

Heifers explored their feeding environment more (more switches between bins) when offered a lower energy density TMR than what they experienced the previous day (i.e. during the non-uniform period; Figure 1). In contrast, switching decreased when TMR was changed to a higher quality than what was experienced on the previous day (Figure 1). This change in sampling behaviour was likely driven by sensory cues from the diet (i.e. taste, texture, smell) more so than by how the animal felt after feeding (e.g. feeling satiated) since the observations occurred within a short period following exposure to fresh feed.

quality of TMRalong feed bunk

The time spent at each feed bin was 47 % shorter on the day heifers were switched to lower quality TMR relative to the day before when they received the non-uniform TMR. The average time spent at each bin increased by 27 % and 74 % on the days the TMR was switched to a higher quality than experienced on the previous day (Moderate and High TMR qualities, respectively).

Competitive interactions at the feed bunk occurred most frequently when TMR quality was non-uniformly distributed among bins at the feed bunk (Figure 2). When TMR quality was the same in all bins (regardless of quality level) competition for feed was reduced (Figure 2). During the days heifers were fed the non-uniform TMR, only one heifer could occupy the high quality feed bin at a time. The other heifer was forced to either wait for access to high quality feed bin or eat a lower energy diet. In general, one heifer in each pair was more successful at maintaining access to this high quality bin, spending on average 11 minutes feeding at this location compared to only 2 minutes for her pen mate.

 competitive interactions

Take Home Messages

  • Cattle respond to variation in TMR quality by changing the way they explore their feeding environment.
  • When TMR quality is lower than previously experienced heifers spend more time ‘grazing’ the feed bunk. They move more between feeding locations and spend less time at each location.
  • Competitive interactions between heifers are more frequent when TMR quality is not uniformly distributed along the length of the feed bunk. Cattle are highly motivated to obtain access to the highest quality feed locations.
  • Minimizing variation in TMR energy density between and within days will help promote more efficient feeding behaviour.

UBC Dairy Education & Research Centre
Faculty of Land and Food Systems Nelson Dinn, Manager Email dinn@shawbiz.ca
6947 No. 7 Highway, P.O. Box 202, Agassiz, BC V0M 1A0 Telephone 604-796-8410 Fax 604-796-8413
www.landfood.ubc.ca/dairy_centre

We are grateful to Julie Huzzey for help preparing this report. For further information please Email marina.vonkeyserlingk@ubc.ca or dan.weary@ubc.ca. This report is based on a paper recently accepted for publication in the Journal of Dairy Science (Huzzey et al. In Press. J. Dairy Sci.). We thank the researchers and staff of the UBC Dairy Education and Research Centre and especially Jose Fregonesi who collaborated in the work described in this report. This research was funded by NSERC. The UBC Animal Welfare is also supported by the Dairy Farmers of Canada and many others listed at http://awp.landfood.ubc.ca/   

 

Industry Leaders

Abbotsford Dairy Farmer and Entrepreneur Wins Award of Excellence for Innovation (2011)

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January 26, 2011, Abbotsford, B.C. - The Investment Agriculture Foundation of B.C. (IAF) announced today that Bill Vanderkooi, president of Abbotsford's Bakerview Eco-Dairy Association and CEO of Nutriva Group, is the recipient of the 2011 Award of Excellence for Innovation in Agriculture and Agri-Food.

"This award celebrates the innovators who help B.C.'s agriculture and agri-food industry stay on the cutting edge, for the benefit of all British Columbians," said IAF chair Stuart Wilson. "We are very pleased to honour Mr. Vanderkooi for his commitment to innovative, environmentally responsible and sustainable dairy farming practices."

Bakerview EcoDairy is the first demonstration farm of its kind in Canada. Through the EcoDairy's interactive tours, the public can access a fully operational dairy farm that showcases a number of innovations, including an on-site anaerobic digester, robotic milker, cow brush, comfort stall systems, lighting and ventilation.

"We appreciate the recognition for the Bakerview EcoDairy's contribution to innovation and education," says Vanderkooi. "The EcoDairy promotes technology that integrates cow comfort and sustainability and is uniquely positioned to deliver a valuable experience for the B.C. school curriculum that will help increase exposure to where our food comes from."

In addition to his work on the Bakerview EcoDairy, Vanderkooi is CEO of Nutriva Group, a multi-faceted group of agri-businesses that focuses on developing and managing whole food value chains. Vanderkooi lives with his wife Helinda and five children in Abbotsford.

This year's honourable mention is Abbotsford's Catalyst One On-Farm Anaerobic Digester, a facility currently under development to process manure and other organic waste streams to produce biogas and high quality fertilizer. This project will be the first in British Columbia to produce raw biogas that is upgraded to biomethane (a carbon-neutral fuel) and injected into the existing natural gas system.

"This facility shows that technology and innovation can offer solutions to problems, such as how to deal with organic waste materials," says Chris Bush, president of Catalyst Power Inc. "It is our hope that B.C. will build on the foundation we provide by progressively developing new solutions."

The IAF Award of Excellence for Innovation in Agriculture and Agri-Food celebrates innovative ideas, products, projects and programs generated by the agriculture and agri-food industry that deliver economic, environmental or social benefits to British Columbia. The award is open to individual B.C. residents and Canadian-based organizations and businesses operating in B.C. This year's honourees were announced on January 26 at the B.C. Agriculture Council's annual Agri-Food Industry Gala in Abbotsford.

The Investment Agriculture Foundation is a not-for-profit organization that strategically invests funds on behalf of the federal and provincial governments in support of innovative projects that benefit the agriculture and agri-food industries in British Columbia.

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Dairy Centre Attracts Four New Researchers (2005)

In Memory of Dr. James A. Shelford (March 4, 1944-April 6, 2002)

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The agricultural industry and the academic community lost a respected researcher, teacher and friend with the untimely death of Dr.Jim Shelford. Jim was well known to the dairy community for his industry relevant research and his participation in various associations. He was a man of optimism, dedication, and hard work, with a lifelong commitment to advancement of agricultural science. Jim ’s courageous struggle with cancer during the past four years has been a source of strength to many. He faced death as he faced life: with dignity, courage, and hope.

A large congregation of family, colleagues, industry associates and friends attended the funeral service on April 10 at St.Augustine ’s Catholic Church in Vancouver. Jim is survived by his loving wife Helen, and their three sons: Timothy, Jeremy and Mark.

Jim was born to a pioneer ranching family of Francois Lake near Burns Lake, BC. He attended the University of British Columbia and received his PhD in 1974.Since then, he has been a professor in the Faculty of Agricultural Sciences, specializing in ruminant nutrition. He enjoyed teaching and research, and his many interactions with the dairy industry.

Throughout most of his life, Jim expended enormous effort and time helping young people. As an undergraduate student, Jim worked for the BC Ministry of Agriculture with young people in 4-H programs on Vancouver Island and in the Fraser Valley during the summers. Later, as his sons grew up ,he was a leader in the Scouts Canada movement. In the Faculty, Jim was the Animal Science professor students most often sought for academic advice. He obviously enjoyed helping students achieve their goals. Jim also dedicated a great deal of time helping students obtain financial aid, and for years served on, or chaired, scholarship committees, both within the Faculty and at the university-wide level.

In recent years, Jim gave much time and energy to the establishment of the UBC Dairy Education and Research Centre in Agassiz, BC. This facility,a unique partnership of UBC and Agriculture &Agri-Food Canada, was developed to serve both the dairy industry and UBC students. The Centre is fast becoming a leading international dairy research facility for animal behavior, nutrition and reproduction.

Jim ’s research activities covered a broad range of topics related to dairy and forage production in which he mentored many Canadian and international students, post-doctoral fellows and visiting scientists. His research was often collaborative with industry and was supported by numerous agencies including NSERC,Agriculture &Agri-Food Canada,and various industries. Jim was a valued member of the BC Institute of Agrologists and will be dearly missed by his professional colleagues. Brief tributes from a few of his university and industry friends follow on page two.

In consultation with Jim and his family, the Faculty has arranged to establish an endowed scholarship that will provide financial assistance to undergraduate and graduate students whose studies are related to dairy production. All donations to the scholarship will be matched dollar for dollar by the Faculty. Tax receipts will be provided to donors. Further details are provided on page two.

The James A Shelford Fund

Individuals and organizations interested in donating to this scholarship (cheques payable to UBC – Shelford Memorial Scholarship),or seeking additional information, are encouraged to contact:

Jim Thompson, Associate Dean Graduate Programs/Research

Faculty of Agricultural Sciences, The University of British Columbia

Room 270, 2357 Main Mall, Vancouver,BC V6T 1Z4

604-822-2794 jim.thompson@ubc.ca

Tributes to Jim Shelford

“Jim was a great academic and people person, who took the time to understand our dairy industry. Jim was extremely well liked and respected.His pleasant manner and ability to get practical research done and communicated to producers and other industry people were unique. We will miss Jim …God bless.”

Ron Barker, Dairy Specialist, BCMAFF

“Jim played a major role in my studies at UBC.He was always ready and willing to help both as my academic advisor and as my undergraduate research supervisor. Since beginning to work under Jim as a graduate student last fall, I became even more appreciative of his dedication and compassion for students and their research. I will always remember him as my mentor and as an inspiration to my education.”

Trevor Devries, Grad Student, UBC

“Up to the end of his life,Jim was a tireless campaigner for the betterment of students. His keen interest and enthusiasm in improving efficiencies in milk production, through nutrition research, will have a lasting impact on the dairy industry. The development of a dairy research and education facility, with ties to the dairy industry, was Jim ’s dream that was realized with the UBC Dairy Education &Research Centre at Agassiz.”

Nelson Dinn, Manager, UBC Dairy Centre

“Jim Shelford may have left us,but his work lives on. It will continue to benefit dairy producers from across the province, the country and beyond.”

Andy Dolberg, Sec-Manager, BC Milk Producers Assn.

“Jim Shelford exerted an indelible and invaluable influence on my scientific education. But more then that,the phrase, ‘a gentleman and a scholar ’will always refresh the fond memories I hold for Jim ’s ability to bring both his scientific and personal contributions to our society.”

David Dyble, Nutritionist, Unifeed

“Jim Shelford committed many hours of his time to advising undergraduate and graduate students, and it is only fitting that we contribute to a scholarship fund in his memory for the support of students.”

Lorne Fisher, Dairy Research Scientist (retired), Agassiz

“Dr Jim Shelford was a sincere, successful dairy researcher and advocate. He will be missed by many.”

Bill Klop, Dairy Farmer and Member, Advisory Committee

“This is a big loss to agriculture,and particularly to the dairy industry. Jim, in his quiet manner encouraged much change and advancement, both to the industry and the people who worked within it. I was privileged to have worked with, and to be encouraged by Jim throughout my career. He will be highly missed.”

Annette Moore, BCMAFF

“Jim ’s dedication and passion for the dairy industry will be greatly missed. His research and relentless efforts to improve and promote the understanding of dairy nutrition, benefited us all. His work and research goals were never questioned, because we all knew where his heart was!”

Louis Schurmann, Dairy Farmer, and Chair, SCDEA

“The Pacific Agri-Food Research Centre has lost a valuable link with the UBC Dairy Centre. Jim provided that link through his research collaboration and through his concern for the success of both Centres.Jim ’s knowledge,never-ending willingness to help, and trustworthiness earned him a place in the hearts of many. I miss Jim, my dear brother-in-law, who helped me throughout my career, and who is loved by my family. I miss him as a colleague, my family member, and especially my friend.

Valerie Stevens, Deputy Director, PARC, Agassiz

“No one lights a lamp and hides it under a bed. Instead he puts it on a stand, so that those who come in can see the light.

(Luke 8:16).Jim Shelford lived his life as a shining light quietly giving friendship and support to all that crossed his path. I count myself as blessed to have had the privilege of working with Jim, as a graduate student and a research associate. May we all endeavor to live by his example.”

Marylou Swift, Nutritionist, Abbotsford Veterinary Clinic

“Jim was a tireless advocate for the dairy industry and was dedicated to helping students in the Faculty of Agricultural Sciences achieve their academic goals.”

Jim Thompson, Professor and Associate Dean

“What I remember most about Jim is the perpetual twinkle in his eye and his ready smile. These welcoming traits,which I will never forget, reflect the great warmth that this fine man gave to others.”

Brian Upper, UBC Herd Veterinarian

“Jim had a major effect on me as a new dairy researcher. He was very open and approachable, full of positive feedback and helpful suggestions, and made me feel like a welcome addition to the team. I am particularly grateful for the great research and teaching environment that Jim helped foster at the Dairy Centre. Jim’s quiet, respectful and supportive manner helped make the Centre an excellent place to work, and thus helped it attract some of the top students and researchers to work in British Columbia.”

Dan Weary, Associate Professor, Faculty of Ag Sciences

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Management

Assessing Cow Comfort on Dairy Farms (2009)

BC Dairy Hoof Health Group (2011)

The BC Dairy Hoof Health Group Founded in 2009 with six members from industry, university and government, the Group has evolved quickly to encompass reps from every possible niche – producers, hoof trimmers, veterinarians, BCMPA, university researchers (UBC), AAFC researchers, CAHA (Canadian Animal Health Association), DHI, government extension staff and external expert advisors. Recent expansion will bring the total to 18 enthusiastic, motivated and knowledgeable members, focused on improving the state of hoof health on BC dairies.

Read entire article in pdf format.

Brisket Boards: Preventing More Than Forward Movement? (2005)

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Cassandra Tucker, Gosia Zdanowicz and Dan Weary

In building a new barn, or in renovating an existing facility, we aim to create a comfortable and relatively clean environment for the cow to lie down. The brisket board is thought to help keep the stall clean by preventing cows from moving forward in the stall. However, like other hardware used to position the cow in free stalls, we need to understand the effects of the brisket board on cow comfort.

To understand how the brisket board affects cow behaviour, we housed cows with access to two stalls: one stall had a wooden brisket board (2”x8” installed at a 30 degree angle) and the second stall did not contain a brisket board. We measured how much dry cows used each stall when they could choose between the two options (preference test) and how their behaviour changed when they could only use a single option.

UBC Researchers performed an experiment to “ask” cows which stall
they prefer, a stall with a brisket board (right), or without a board (left).
Cows preferred to lie down in stalls without a brisket board.

Cows spent more time lying down per day in a stall without a brisket board (1.2 hours per day more; Figure 1). They also had longer lying bouts in the stall without a board. This result is similar to the effect of free-stall width, where cows have longer lying bouts in wide stalls compared to narrow stalls. Cows may shorten their lying bouts in narrow stalls and stalls with brisket boards because both stall partitions and boards may be uncomfortable to lie against. The presence of the brisket board also influenced cow placement in the stall. Cows lay farther forward in the stall without a brisket board (Figure 2). The brisket board particularly affected the placement of long cows (> 125 cm between wither and tail head), pushing these cows closer to the curb than shorter animals.


Figure 1. Cows spent more time lying down in stalls without a brisket board.

Figure 2. Cows lie closer to the curb when there is a brisket board in the stall.
By preventing the forward movement, brisket boards may help keep stalls clean.
Distance to the curb was measured by recording the location of the withers
relative to the neck rail (125 cm high and placed 160 cm from curb).

When given a choice between using a stall with or without a brisket board, we found that cows spent 68% of their time lying in the stall without a brisket board.

Cows prefer stalls without brisket boards, and when they are forced to use stalls with brisket boards they spend less time lying down in total, and lie down for shorter periods of time.

It is possible that other designs of brisket board disturb cows less. For example, brisket boards that are rounded, lower or softer may represent less of a barrier to lying behaviour. Judging if any barrier is necessary requires better information about how effective these are in improving stall cleanliness. To date, no research is available to judge the effects of brisket board design or placement on stall cleanliness. It is important to note that, like the neck rail, the effects of the brisket board will depend upon cow size. Also the negative effects on cow comfort might be especially important for the more vulnerable cows in the herd, such as those that are lame.

Other research from our laboratory has shown that barriers to stall use (such as aggressive neck rail placement) are in general a poor way of keeping stalls clean, in much the same way that losing your keys to the pickup is probably not the smartest way to save gas. We recommend that producers experiencing difficulties with cow comfort consider removing the brisket board from at least some of the stalls in their free stall barn.


Watch for future research reports on the topic of alternative flooring surfaces for free-stall barns.

Thanks to industry for supporting this research. Supporters are listed at: www.agsci.ubc.ca/animalwelfare

This article is based on post doctoral research of Cassandra Tucker and research assistant Gosia Zdanowicz. Dan Weary is a Professor in the Animal Welfare Program and can be reached at danweary@interchange.ubc.ca

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Cow Comfort and stall Maintenance (2006)

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Michelle Drissler, Marek Gaworski, Cassandra Tucker and Dan Weary

In previous Research Reports, we have reported how stalls can be built or modified to improve comfort. However, regardless of how well your stalls are designed and built, comfort will be limited by how well stalls are maintained.

There are many advantages to using well-bedded freestalls. Cows choose these stalls over bare surfaces or those covered with a thin layer of bedding, even when stalls also contain a thick mat or mattress. Cows housed with well-bedded stalls spend more time lying down, are less likely to become lame and fewer have hock injuries.

Unfortunately, maintaining bedding in stalls can be a challenge. Soon after filling stalls with fresh bedding, cows move the bedding to the outer edges of the stall and into the alley. The resulting changes to the depth and shape of the bedding may make the stalls less attractive for cows. To make better decisions about how often to add bedding to stalls, we studied how sand bedding depth declines with time after fresh bedding is added, and how these changes in bedding level affect cow comfort.

Our ‘head-to-head’ stalls had a total bed length of 8' and were 4' wide between Artex Y2K dividers. Bedding was river sand, sieved over a 2-mm screen and washed with water to remove silt. We measured changes in 24 stalls (housing 24 lactating dairy cows), from the day they were filled with sand (to the height of the rear curb) and over the next 9 days.

As illustrated in Figure 1, sand bedding depth declined rapidly with time and stall surface became increasingly concave or 'bathtub' shaped.

Figure 1. Contour diagrams of the average stall on 0, 3, 6, and 9 days after stalls were filled and levelled to the height of the rear curb. Contours represent decreases in sand depth, with darker colours indicating decreasing depth. Each colour change represents an average decline of 2 cm. Greater sand loss in the centre of the stalls creates a bath-tub like shape.

The most sand was lost during the first day after the stalls were filled but sand levels continued to decline over the following 9 days. Also, those stalls that were in the locations preferred by cows tended to lose sand more rapidly than stalls that were used less.

To determine how these changes in bedding depth and shape affect cow use of stalls, we experimentally imposed treatments by digging out stalls to match these conditions. In this way we determined how cows respond to stalls representing different amounts of stall maintenance.

In the first experiment we tested stalls filled to the level of the curb (like a well maintained stall), and what they looked like 3, 6 and 9 days with no maintenance (having lost up to 6 cm of sand at the deepest point).

In a second experiment we imposed levels like those seen in the stalls that lost the most bedding over the same period. In this case stalls varied from bedding level with the curb to losing as much as 14 cm of sand. To measure the effects of these conditions on lying time we again used 24 cows, and monitored behaviour using electronic sensors attached to the cows’ hind legs. These sensors automatically recorded whether the cows were lying or standing every 30 seconds.

As shown in Figure 2, cows spent less time lying down in stalls that contained less sand. On average, lying time declined by about 11 minutes per day for every 1 cm decline in bedding. In the stalls with the least bedding, cows spent 2.3 hours less time lying down each day. These differences in lying time were due to cows lying down for shorter periods each time they lay down, suggesting that the reduced bedding depths made the stall less comfortable to be lying in.

These differences in lying time associated with decreased bedding levels are as large or larger than any other stall feature we have tested in previous research on cow comfort. Thus any improvements in cow comfort associated with building or renovating freestall barns can be completely undone by poor stall maintenance.

Figure 2. Changes in daily lying time as stalls lose bedding. In Exp.1 bedding levels tested represented the average stall sand depth after 0, 3, 6, and 9 days with no stall maintenance. Exp. 2 tested levels representing the stalls that had lost the most bedding on each of those days.

This research demonstrates that comfort is improved by frequent stall maintenance, such as daily raking when cows are moved to the milking parlour. In addition to improved cow comfort, better stall maintenance will help keep cows cleaner, reducing the risk of environmental mastitis.


This research was part of a project designed by visiting researcher Marek Gaworski and research assistant Michelle Drissler. Cassandra Tucker is currently a scientist at AgResearch in New Zealand and Dan Weary is a professor in the UBC Animal Welfare Program. This research was made possible through funding by the Dairy Farmers of Canada, NSERC, and many other donors listed on our web site at . www.agsci.ubc.ca/animalwelfare.

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Dehorning Depression? (2014)

UBC RESEARCH REPORTS - pdf version of this article

Anyone who has dehorned a calf will tell you this is painful. Pain control for this procedure is now required in the new Code of Practice for Dairy Cattle. Pain during hot-iron dehorning can be controlled easily and inexpensively using a local nerve block like lidocaine.

Unfortunately, burn injuries can be painful for many hours after they occur, and long after the effects of lidocaine have worn off. Other researchers have shown pain-related behaviours in the hours after dehorning, like head shaking, head rubbing and ear flicking, and we know that this pain can be reduced using anti-inflammatory drugs like meloxicam. Some producers treat post-operative pain, but other producers do not treat for pain at all. To help producers and their veterinarians make better decisions about pain control protocols, UBC researchers set out to ask just how much does this post-operative pain really affect the calves.

Years of research on humans have shown that our emotional state influences the way we think and interpret information. For example, depressed patients are more likely to anticipate negative future events and are less willing to take risks. They also interpret ambiguous events more negatively, classifying a glass as "half empty" rather than "half full".

Similarly, humans experiencing pain associated with diseases such as arthritis tend to choose pain-related meanings rather than neutral meanings of ambiguous sentences. For example, patients in pain are more likely to infer that “growth” refers to a tumor rather than to height when reading the sentence "The doctor examined the child's growth". These negative interpretations of ambiguous information are judgement biases.

To find out if calves experiencing pain from dehorning have the same pessimistic judgement biases seen in humans, they were first trained to perform a simple task. If a calf approached a computer screen in its pen when the screen was red it received a few sips of milk. However if the calf approached the white screen, no milk was given and instead the calf received a one minute "time-out" with no colour on the screen. In this way the calves quickly learned to only approach the screen when it was showing red.

Once trained, calves were tested with ambiguous colours: three different shades of pink (blends between red and white: dark pink, mid pink, and light pink). As expected, calves tended to approach the dark pink screen (like it was red), and avoided the light pink screen (like it was white); the mid pink shade was approached about half the time.

Calves were then hot-iron dehorned (at 6 weeks of age) with lidocaine used to block the pain during dehorning (4 mL per bud). We then retested the calves with the ambiguous colours 6 and 22 hours after dehorning when we expected that they would still experience pain and that the lidocaine would have worn off.

After dehorning calves continued to approach the red and avoid the white screens, showing that they remembered their training and that they were still motivated to drink the milk reward. However, calves were much less likely to approach the ambiguous pink screens in the hours after dehorning (Figure 1).

These results indicate that, when experiencing pain in the hours after hot-iron dehorning, calves responded as if they were feeling unlucky – they treated the ambiguous pink screens as if these were more likely to signal a ‘time-out’ than a milk reward. This pessimistic judgement bias is similar to a depressed patient seeing the glass as "half empty".

The researchers concluded that these pessimistic responses indicate a negative emotional state in calves, similar to depression or anxiety in humans. What's more, this bias persisted for at least 22 hours after dehorning. Thus, despite receiving lidocaine to treat the immediate pain during the procedure, the post-operative pain occurring hours after dehorning has an emotional impact on the calves.

This research highlights the importance of considering the pain that follows a procedure like dehorning, and argues in favour of treating this post-operative pain using an anti-inflammatory drug. Your veterinarian can advise you on a specific treatment protocol appropriate for your farm.

More generally, this work shows how we can ask calves and cows how they ‘feel’ about the housing and management decisions we make. This research using judgment bias tasks provides a new scientific method to better understand and improve the welfare of cattle.

Check out this link to a short video of a trained calf in the judgement bias task:  http://tinyurl.com/km28fx9

UBC Dairy Education & Research Centre
Faculty of Land and Food Systems
Nelson Dinn, Manager
Email:  dinn@shawbiz.ca

Effects of Bedding Quality on Lying Behavior of Dairy Cows (2008)

Effects of Regrouping Dairy Cows (Aug 2011)

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UBC Dairy Research Report

Click here to view this article in pdf format: Effects of Regrouping Dairy Cows

Dairy cows are often grouped according to age, days in milk, feed requirements and health status. To create these groupings cows, are often moved to new groups four or more times per lactation. At each regrouping, cows are mixed with unfamiliar herd mates resulting in changes in group composition and dynamics. In the new group each cow must re-establish social relationships through threats, butting and other physical and non-physical interactions (Figure 1).

Figure 1: A cow being displaced at feed bunk

A series of recent studies at UBC have assessed the effects of regrouping on dairy cows. For example, in one study mid-lactation cows were initially observed in their home pen to monitor baseline behaviour and milk production. After the baseline period, 12 different cows were introduced individually (one at a time) into different established group of 11 cows. Feeding time, social behaviour (displacements from the feed bunk and lying stall) and lying behaviour were monitored using video cameras. Data loggers were attached to one hind leg of the each animal to measure standing and lying time.

When these cows were introduced to the new group they spent less time feeding, especially in the hour after fresh feed delivery when competition for food is typically at its peak. Newly regrouped cows were also displaced from the feeder by other cows much more frequently than before regrouping (see Figure 2). Cows also tended to spend less time lying down after regrouping, likely because cows entering a new group were often displaced from freestalls by other cows. These disruptions set back milk production; on the day after regrouping cows produced 39.7 kg/d compared with an average production of 43.4 kg/d before regrouping.

Group changes frequently occur around calving. For example, cows are often placed into a new group to facilitate dry off, moved to another group once dry, moved yet again 3 weeks before calving, moved into a maternity pen to calve, and then moved again to a lactating pen.

Cows are especially vulnerable to disease during the ‘transition’ period around calving, so a second UBC study investigated the effects of regrouping during the dry period. 48 cows were housed in groups of 6. After a baseline-recording period cows were moved in groups of 3 into a new group. In total, 8 groups of 3 were moved to a new pen with 3 cows in it, while the other 8 groups of 3 remained in their home pen and had 3 new cows introduced to them. Feeding behaviour (feeding time, feeding rate), social behaviour (displacements) and lying behaviour were monitored. In addition dry matter intake was measured using electronic feed bins and rumination time was monitored using electronic collars.

Figure 2: Newly regrouped cows were displaced from the feeder (Reactor) much more frequently on the day of regrouping (Day 0) and the day after (Day 1), but there was no difference in the number of times these cows displaced other cows (Actor).

Cows that were introduced to a new pen decreased feed intake by 9% compared to the days before regrouping; cows that remained in their home pen did not change intake.

Cows that were moved to a new pen were more likely to be displaced from the feed bins, especially during the 3 hours after fresh feed delivery. These cows also spent less time ruminating, returning to baseline values only 2 days after regrouping (Figure 3).

Both studies show the negative effects that regrouping can have on dairy cows. A comparison of these studies indicates that regrouping cows in small groups can decrease these effects. Regrouping cows at quiet periods of the day (and not close to peak-feeding times) may help to decreases the frequency of aggressive interactions. Regrouping can provide producers with some benefits but comes at a cost to the cow – this cost should be kept in mind when considering when and how often cows should be regrouped.

Figure 3: After regrouping, cows that remained in the same pen (black bars) spent less time ruminating the day they were regrouped (Day 0), but returned to normal (i.e. the pre- regrouping baseline) the day after (Day 1). Cows that were also moved to a new pen spent less time ruminating on both Day 0 and Day 1.


We are grateful to Lori Vickers for help preparing this report. For further information please email marina.vonkeyserlingk@ubc.ca or dan.weary@ubc.ca. This report is based on two published papers in the Journal of Dairy Science (J. Dairy Sci. von Keyserlingk et al., 2008. 91:1011-1016; Schirmann et al., 2011. J. Dairy Sci. 94:2312-2319 ). We thank the researchers and staff of the UBC Dairy Education and Research Centre for their hard work on the studies described in this report. The research was funded by the NSERC Industrial Research Chair in Animal Welfare with contributions from the Dairy Farmers of Canada and many others listed at www.landfood.ubc.ca/animalwelfare/.

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Free Stall Dimensions Right For Your Cows (2002)

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Producers are faced with a wide range of recommendations when installing new housing facilities or renovating an existing barn. In previous Research Reports, we have discussed the effects of providing a comfortable environment for dairy cattle to lie down and have reported information concerning the choice of bedding. In addition to the lying surface, the configuration of the free stall can affect cow comfort and stall cleanliness.

Unfortunately, there has been very little scientific research on free-stall design and dimensions, and the existing recommendations to producers are highly variable. For example, one recent producer-oriented article suggested that stalls for adult Holsteins should be between 47” – 51” wide and 8’4” – 8’10” long, but another recent article recommended a width of only 44” and a length of 7’3”.

In this report we describe some of our latest research at the UBC Dairy Centre that will provide a scientific basis to such recommendations, by testing how various free stall dimensions affect both cow comfort and stall cleanliness. In one experiment we looked at both free-stall length and width, and compared some of the recommendations described above. Cow behaviour was video recorded 24 hours per day using ‘time-lapse’ recorders developed for the security industry. Cows were tested with four types of stalls:

1) 44” wide, 7’6” long (NS; Narrow Short),

2) 44” wide, 9’ long (NL: Narrow Long),

3) 52” wide, 7’6” long (WS: Wide Short), and

4) 52” wide 9’ long (WL: Wide Long).

Cows spent an additional 1.5 hours per day lying down in the two wide stalls compared to the narrow ones. In addition, both length and width affected the amount of time spent standing with only the front hooves in the stall. We found animals with access to the largest stall (52” wide, 9’ long) spent 2 hours per day standing half-in-half-out, while animals with access to the smallest stall (44” wide, 7’6” long) spent nearly 3 hours standing in this position (see Figure 1).

Figure1. Cows spend more time standing half-in

and -half-out of stalls as the total area available

decreases.

Figure 2.Cows spend more time lying down

in wider stalls.

In a second experiment, we compared three free-stall widths: 41.5”, 45.5”, 49.5”. As in the first experiment, we found that cows spent more time lying down in the wider stalls (Figure 2), and less time standing half-in-half-out.

Thus providing wider stalls increases lying time and reduces the time cows spend standing half-in-half-out. Prolonged standing in this way may be a sign of discomfort, and has negative health consequences for the animals. While standing with the back hooves in the alley, the hooves are exposed to moisture and fecal material that can increase the risk of hoof health problems like digital dermatitis and sole lesions. Lying down is also important for cow health. Reducing lying time results in physiological changes, such as reduced secretion of growth hormone and an increase in the stress hormone cortisol. In addition, cows that spend less time lying down spend more time standing outside of the stall, and increased standing time on concrete floors increases lameness.

In the second experiment we also measured stall cleanliness by collecting and weighing the fecal material in the stalls. We found that the wider stalls contain more fecal material, but this was simply because cows spent more time in these stalls. Thus some poorly designed stalls will stay relatively clean because cows are less likely to use them. In other experiments we have tested the effect of neck rail placement, a feature of stall design that can help improve stall cleanliness without reducing lying time. We will describe our findings from these experiments in a future Research Report.

This article is based on thesis research of Ph.D. student Cassandra Tucker. Dan Weary is an Associate Professor in the Animal Welfare Program and can be reached at danweary@interchange.ubc.ca

Thanks to DFC, BCDF, Westgen and many others in the dairy industry for their support of this research. Supporters are listed at www.agsci.ubc.ca/animalwelfare.

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Group Housing Calves (2004)

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Dan Weary

Dairy cattle are naturally group-living animals, and almost all aspects of modern dairy production systems are based on keeping cattle in groups. This raises the questions; why are young calves normally housed in individual pens or hutches from birth until weaning, and if the calves were kept in groups, what would be the potential advantages and disadvantages? The aim of this Research Report is to describe some positive aspects of group rearing, especially associated with improved calf feeding methods, as well as some of the potential pitfalls.

Challenges of calf rearing

Caring for the milk-fed calf is one of the most challenging aspects of dairy production. At no other stage of life are our animals so vulnerable to disease, and far too many calves fail to survive until weaning. However, many dairymen are able to achieve very high levels of calf health by following several key practices including: 1) ensuring that all calves receive generous amounts of high-quality colostrum within the first few hours after birth, 2) providing that they have free access to clean water, 3) making sure they receive a high quality and quantity of milk from a clean feeding system, and 4) providing the calves with a clean, dry and well-bedded resting area, protected from drafts but with good air quality. Farm bio-security procedures, like keeping a closed herd and ensuring that boots and equipment from other farms are properly washed before arrival on your property, can be used to further prevent the spread of diseases. In situations with frequent outbreaks of disease, the factors listed above should be considered before attempting group housing, which may otherwise simply increase the spread of disease among the calves.

However, for those producers with excellent calf management procedures in place and a good record of calf health, group housing may provide further advantages for both the calves and those who care for them.

Why keep calves in groups?

Group rearing allows for early social interactions that have been shown to be important in the development of normal social responses later in life. Group housing provides improved access to space, allowing for more vigorous activity and play. Grouping calves also reduces the labor associated with cleaning calf pens and calf feeding.

Figure 1. Housing calves in small groups can provide advantages over individual housing, but is only recommended for good calf managers.

Despite these apparent advantages of group housing, North American dairy calves are typically housed in individual pens or calf hutches, in part due to concerns about reduced weight gains, increased incidence of disease, and behavioral problems such as cross-sucking. Research in now showing that for a well-managed calf unit these problems can be avoided.

Feeding calves more milk

When calves are fed limited amounts of milk by bucket, as in conventional practice, calves remain highly motivated to suck, and will spend time sucking on anything available especially during the first half hour after each milk meal. When housed alone, calves will suck on pen fixtures such as the empty milk bucket, but if kept in groups calves fed this way will often suck each other, sometimes leading to injury. The good news is that this abnormal behaviour can easily be prevented by feeding calves in a more natural manner.

The advantages of feeding calves more milk are becoming widely recognized, in part because of UBC research on this topic (see Research Reports "Feeding Calves More Milk", Vol. 2, No.4). We also recommend providing this milk from a teat to encourage more natural drinking behaviour. Calves fed this way spend about three-quarters of an hour drinking milk each day, compared to just a minute or two when limit fed (4-6 litres per day) from a bucket. This also provides a natural outlet for the calves sucking behaviour, and essentially eliminates sucking on fixtures, or other calves. Thus feeding calves more milk and using a teat to deliver the milk can address problems with cross-sucking, but what about calf health and performance?

Growth rates of group housed calves

In a recent study at the UBC Dairy Research and Education Centre in Agassiz, we showed that calves could be reared in small groups with excellent health and rates of growth. In this study, we created ‘group’ pens by simply removing partitions between pairs of conventional pens to create space for two calves. Half of the pens in the calf barn were kept as individual pens for comparison, and all calves were provided with free access to milk by teat. Calves were gradually weaned at approximately 5 weeks of age and remained on the experiment until 8 weeks old.

As illustrated in Figure 2, calves gained weight steadily with no differences between treatments. During the week of weaning, pair-housed calves continued to gain weight normally but the individually housed calves experienced a slight growth check. There were no differences between groups in the amounts of milk, starter or hay consumed, or in the incidence of scouring or other disease. Aggressive behaviour and cross-sucking were almost never observed. These results show that dairy calves can indeed be reared successfully using small groups.

Figure 2. Weight gains of calves housed in either individual pens or as a pair.

For the past 2 years we have reared all calves at the UBC Dairy Centre in small groups (usually about 5 calves per group) as part of our standard procedures, and this method continues to work well for us.

With funding from Dairy Farmers of Canada we are also pursuing new research on how to further improve management and housing for group-housed calves fed in this way. In one new project we are working with automated calf feeders, specifically designed to manage the feeding of calves kept in groups. Watch for future Research Reports for updates on this research about improved methods of housing and managing the young dairy calf.

To find out more about recent work on dairy calf rearing and other topics, look the at the Dairy Centre’s web site at http://www.agsci.ubc.ca/dairy_centre/ .

Thanks to the dairy industry for their support of this research through funding to the Animal Welfare Program by the Dairy Farmers of Canada, the BC Dairy Foundation, BC Milk Producers Assn, Westgen, and many others listed on our web site.

This article is based on research by graduate students Bev Chua, Eveline Coenen, and Joyce van Delen. Dan Weary is a Professor in UBC’s Animal Welfare Program.

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Improving cow comfort at the feed bunk (2003)

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Attention to cow comfort by producers and researchers alike has usually focused on improving conditions for lying down in the stall (see previous UBC Research Reports dealing with this subject). This focus is appropriate, as cows spend about half the day lying down in the stall, and problems with stall design are known to contribute to health problems such as lameness.

Another important activity for cows is feeding. Housed lactating cows spend about 5 hours a day at the feed bunk. Access to feed is important in maintaining health and high levels of milk production. Despite the importance of this activity, very little research has been done on how to design a comfortable environment for feeding.

Figure 1. Cows spend about one-quarter of their day at the feed bunk. Creating comfortable environments for feeding is one important focus of current UBC Dairy Centre research.

This report describes two recent UBC studies designed to improve the feeding environment. In the first study, we examined the surface that cows stand upon when eating. In the second study, we tested how the density of cows at the feed bunk affects feeding behaviour and social competition.

Concrete is a popular flooring surface in dairy barns due to its durability, availability, cost and ease of cleaning. Unfortunately, use of concrete flooring is known to contribute to the risk of cows developing hoof injuries and lameness. Concrete floors may also affect the comfort of cows, reducing important behaviours such as time spent eating and displays of estrus. Alternative flooring surfaces such as rubber are becoming popular with some producers, but no previous research has tested if these surfaces provide real improvements in comfort for cows.

The objective of this experiment was to test if rubber flooring in the area where the cow stands at the feed bunk increased feeding time and time spent standing at the feed bunk. Four groups of 12 cows each were tested with both 1” solid rubber flooring and grooved concrete in this area. Each group was observed for a 3-week period on each surface, and individual cow behavioural responses were recorded with time-lapse video equipment.

We found that providing rubber flooring for the cows to stand on did not affect the amount of time they spent eating. However, cows showed a slight increase in time standing without eating when they were provided the rubber surface.

In conclusion, access to rubber flooring at the feeder has little affect on cow behaviour. However, softer surfaces may provide longer-term benefits in terms of hoof health and lameness. Current research at the Dairy Centre is focusing on these issues.

Regardless of how well we design and build barns for cows, the ability of animals to benefit from the design is limited by the space made available to them. When grazing, cattle often synchronize their behavior such that many animals in the group feed, ruminate, and rest at the same times. This synchronization is normally reduced when cattle are housed indoors, likely because of competition for space or food. If feeding space is limited, increased competition among cows at the feeder may prevent access to feed during peak-feeding times, especially for subordinate cows.

The objective of the second study was to determine if increasing space availability at the feed bunk improves access to feed and reduces social competition. Twenty-four lactating Holstein cows were each tested under two conditions: with 0.5 m or 1.0 m of feeding space per cow. Time-lapse video and an electronic feed alley monitoring system were used to monitor cow behaviour. When animals had access to more space we observed 57% fewer aggressive interactions while feeding. This reduced aggressive behaviour allowed cows to increase feeding activity throughout the day (see Figure 2). The increase in feeding activity was especially noticeable during the 90 minutes after fresh feed was provided. During this period, cows with access to more feeding space, increased time at the feeder by 24%, and this effect was strongest for subordinate cows.

In conclusion, providing more space at the feed bunk increases feeding time and reduces competition among lactating dairy cows.

Figure 2. Percentage of cows present at the feed bunk over the course of the day for both 0.5 m and 1.0 m feeding space per cow treatments.

This article is based on research of by visiting Professor Jose Fregonesi and Ph.D. student Trevor DeVries. Dan Weary and Nina von Keyserlingk are faculty members in UBC’s Animal Welfare Program.

Nina and Dan thank the Dairy Farmers of Canada, BC Dairy Foundation, BC Milk Producers, Westgen and many others in the dairy industry for their support of this research. Supporters are listed at www.agsci.ubc.ca/animalwelfare.

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Individual housing of dairy calves leads to learning deficits (2014)

Pdf version of article:  Individual housing of dairy calves leads to learning deficits

Want smarter cows? Try raising calves with social companions.

Previous work from the UBC Dairy Education and Research Centre demonstrated that calves raised in individual pens had more difficulty adapting to a group pen with five other calves after weaning than calves raised in pairs did. The more barren environment of the individual pen seemed to result in calves that were more fearful of anything new, including new environments and other calves. Perhaps because of this increased fearfulness, these calves took nearly 2 days to begin eating grain from automated feeders in their new pens, while their pair-reared peers began eating normally within hours (see Research Report Vol. 13, No. 1, 2013). These results made us wonder if socially-reared calves were ‘smarter’ than calves raised in individual pens.

A new study completed at the UBC Dairy Centre has shown that individual housing of calves during the milk-feeding period results in learning difficulties. These cognitive deficits help explain the delay these calves show in adapting to new technology like automated feeders.

This new work used innovative methods to train calves and to test their ability to learn new rules. Eight calves were housed individually and eight were housed in pairs starting at 4 days old. Learning abilities were tested in two ways, beginning with ‘reversal learning’. The calves were trained to perform a simple task: they entered a test pen in which they could go in one of two directions. If they approached a side with a black bottle, they received milk. If they went to a side with a white bottle they did not receive a reward, and instead were ‘punished’ with a brief time out period during which they were not allowed to return to either bottle. Calves from both housing conditions quickly learned to approach only the black bottle.

calves

Unfortunately, in real life, rules rarely remain the same. For example, a cow may become used to entering the parlour from the left side of the barn, but one day she is regrouped, meaning that she now must enter from the right side. Successful cows (and calves) must be able to adapt to changes in their environment.

To test how the housing treatments affected the calves’ ability to adjust to new rules, we simply reversed the contingencies for the learning task. Now when calves approached the white bottle, they were rewarded with milk, and when they approached the black bottle they were ‘punished’ with a time out.  As illustrated in Figure 1, at first all the calves made mistakes, continuing to visit the now unrewarded black bottle, but after a few sessions, the pair housed calves began approaching the correct bottle. The individually-housed calves were more persistent in making the previously learned (and now incorrect) choice. These results are very similar to what has previously been found for laboratory rodents raised in social isolation: all animals can learn an initial task, but the socially reared animals do much better in coping with changes in a learning task when these occur.

Figure 1

Figure 1. The per cent of choices made correctly by individually-and pair-housed calves in “reversal learning” tests. Figure is redrawn from Gaillard et al. 2014.

A very simple type of learning is called habituation. This is the natural tendency of animals to become used to things after prolonged or repeated exposure; they typically show less interest in a stimulus over time. To assess this, we tested how quickly the same calves as above were able to habituate to an object they have never seen before.

Each calf was tested eight times over a two-day period by placing a red bin in the centre of their pen for 5 minutes each time. The first time calves from both housing conditions encountered the bin, they initially appeared to be fearful but eventually approached the object and began sniffing and touching it. During subsequent tests, the pair-housed calves did exactly as expected. They showed less and less interest in the bin over the multiple exposures. In other words, these calves showed a classic habituation response. In contrast, the individually-housed calves seemed to treat each new exposure to the bin as if it was their first encounter; they showed no decline in the amount of time spent sniffing and investigating the bin over the multiple exposures. In other words, the individually-housed calves failed to habituate to what to us seemed like a fairly innocuous addition to their pen.

Why should these learning deficits matter to dairy farmers? Learning difficulties that result in trouble adjusting to changes in routine and environment are likely to cause problems for both farmers and the animals. As calves mature, they are housed in groups, and must learn to adjust to new pens, group mates, and new types of feed. Researchers at the UBC Dairy Centre are continuing to investigate these effects, looking at different levels and durations of social housing. However, these results indicate calves benefit from social contact.

Lame cows improve when given access to pasture (2008)

Lameness Workshop for Producers, Hoof-trimmers and Veterinarians

Lameness: A Transition Cow Disease (2012)

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Lameness: A Transition Cow Disease - pdf format.

Lameness is the number one animal welfare issue facing the North American dairy industry. Lameness is painful, and cases can last from weeks to months. Severe cases that do not improve can result in the cow being culled from the herd. Cows experiencing pain are less likely to show signs of estrus, such as mounting and standing for mounting, since these behaviors are likely to induce further pain.

A growing body of research is showing that problems with cow comfort can increase the risk of lameness. In particular, increased time spent standing outside stalls on wet concrete and in manure slurry is associated with higher rates of lameness.

There is also now increasing evidence that lameness may be triggered during the transition period (generally accepted as the period beginning 3 weeks before and ending 3 weeks after calving). Physiological and behavioral changes during transition can damage the corium (the tissue that produces healthy hooves). This damage is not immediately apparent but results in poor hoof growth. The natural cycle of hoof growth and wear means that the damaged sections take 2-3 months before they become visible on the surface of the sole as hemorrhages and ulcers. This means that lameness cases that emerge during mid-lactation may have been triggered by changes that occurred during the transition period months earlier.

Two recent studies at the University of British Columbia’s Dairy Education and Research Centre were designed to investigate behaviors during transition associated with lameness and hoof lesions in lactating dairy cows. All of the cows in these studies were housed in free stalls.

In one study we measured the standing behavior of Holstein cows for 2 weeks before calving. We used video cameras to score where cows were standing (feeder, the feed alley, the alley adjacent to the stalls or in the stall). When cows were in the stall, we recorded if they were perching with two fore feet in the stall (see Figure 1) or standing fully in the stall. We also scored their hoof health for 3 months after calving.

Figure 1. Cows that spend more time perching (standing with two feet in the stall) are more likely to become lame.

Any cows that were lame before calving or had other clinical disease were excluded from the study. Cows that only had moderate lesions at the end of the study were also excluded, leaving 13 cows with no visible lesions and 13 cows with severe lesions (5 sole ulcers and 8 severe sole hemorrhages). We compared the behavior of these two groups during transition.

Cows that spent 2 hours a day longer standing idle during the 2 weeks before calving were at higher risk for having either a sole ulcer or severe hemorrhage later in lactation. Most interesting was that this time was almost entirely spent perching with the two front feet in the stall (Figure 2).

Figure 2. Standing behavior of cows, during the 2 weeks before calving, diagnosed as healthy or with a lesion at 15 weeks after calving.

In the second experiment we measured standing behavior during the transition period again, but this time focused on the weeks immediately after calving. Holstein cows (n = 48) were housed in groups of 12 in four identical pens with sand-bedded stalls and solid concrete flooring. We recorded their lying, feeding and standing behavior using video cameras, for 3 weeks after calving. Hoof health was also followed for 3 months after calving.

In this study we also found that cows that spent more time perching with two feet in the stall during the first 3 weeks after calving were more likely to develop sole hemorrhages. Both the average and maximum time spent perching in the stall were associated with more serious and higher numbers of sole hemorrhages. Time spent feeding or lying was not associated with changes in hoof health.

Both studies show the negative effects of perching in the stall during the transition period. Longer perching times are associated with problems in the cows’ environment. For example, cows housed in stalls with restrictive neck rails spend more time perching because the neck rail placement prevented them from standing comfortably in the stalls.

Moving the neck rail further from the curb reduces perching behavior and can therefore reduce the risk of lameness. However, this change comes at a hygiene cost (because cows standing with all four feet in the stall are more likely to defecate and urinate in the stall) so extra effort in stall maintenance is needed.

Is this extra effort worthwhile? Changes in stall layout and management that reduce perching during the transition period will help to reduce lameness. Another option could be to create a lame cow pen with less restrictive neck rails. This would allow lame cows to stand with all four feet in the stall and give them a chance to recover.


We are grateful to Hanna Miedema for help preparing this report. For further information please email marina.vonkeyserlingk@ubc.ca or dan.weary@ubc.ca. This report is based on two published papers (Proudfoot et al., 2010. Journal of Dairy Science 93:3970-3978 and Dippel et al., 2011. Applied Animal Behaviour Science 134:16-22). We thank the researchers and staff of the UBC Dairy Education and Research Centre for their hard work on the studies described in this report. This research was funded by the NSERC Industrial Research Chair in Animal Welfare with contributions from the Dairy Farmers of Canada and many others listed at www.landfood.ubc.ca/animalwelfare/.

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Measuring Cow Comfort (2002)

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Dairy cattle require a comfortable environment in order to enhance their welfare and to maximize production. Since cows spend 40-50% of their day lying down, a comfortable space for lying is particularly important. There are also important health benefits associated with adequate rest. Reduced lying time results in physiological changes, such as a decreased secretion of growth hormone and an increase in circulating levels of the stress hormone, cortisol. Finally, increased standing time on concrete floors increases lameness. In addition to the heath benefits of adequate rest, cows are highly motivated to lie down. For example, after 3 hours away from both food and a place to lie down, cows will chose to lie down instead of feeding. Poor stall design can be one cause of a reduction in lying time.

At UBC Dairy Centre, we have begun to apply modern techniques to the study of cow comfort. Three of the most promising techniques are: 1) testing cow preferences for different housing options, 2) assessing how much cows actually use various stall designs, and 3) assessing the effects of housing options on factors such as cow injuries and stall cleanliness. We have performed a series of experiments to determine the effects of stall dimensions, stall surfaces, bedding types and other features on cow behavior and health. The results of these experiments will be described in future Research Reports. In this Report, we will illustrate these methods in the science of cow comfort, and then describe examples from recent experiment on the effects of amount of bedding.

How can we determine what kinds of stall features are important to dairy cattle? Until recently, industry specifications have been based on a ‘best guess’ approach, as few people realized that we could put the question directly to the cow. We “ask” cows about their preferences by providing them with a number of options, for example three bedding types, and monitor which option they choose to lie down on. In essence, we let them vote with their feet for their favorite bedding type. This approach, called preference testing, has proven to be a powerful technique in studying animal behavior in order to design better environments for animals.

Preference tests can be used to identify what cows like, but what are the practical implications of these preferences on your farm? For example, when cows are limited to a single bedding type, as is usual on a farm, will they spend less time lying down in the stalls bedded with the material they my not prefer? To answer this question we performed tests of stall usage, in which cows had access to only a single type of stall and simply had to decide how much to use it. To get a complete and accurate record of the time cows spent standing and lying down in the stall, we used video cameras and time-lapse recorders from the surveillance industry. With this equipment we have records of the cows’ behaviour for every minute of the day and night, and can watch the tapes to measure stall usage.

We are now testing new technology that will allow us to perform this type of experiment more efficiently. Electronic sensors have been developed that can be taped to a cow’s leg to continuously record if she is standing or lying. With this technology, we need only download the information from the sensor when the cow comes into the parlour for milking, thus freeing up time that researchers would otherwise have to spend watching video surveillance tapes.

In addition to finding out which stall features cows prefer, and how access to these preferred stalls increases stall usage, we need to know the effects of stall design on stall maintenance, cow health and cow productivity. For example, neck-rail placement can affect stall cleanliness, and stall bedding can affect udder health (as described in Research Reports Vol 2, No 1). Another area we’ve focused on is how stall designs can be improved to reduce injuries, such as skin lesions on the legs.

We have used all three techniques (measures of preference, stall usage and health) to address the issue of how much bedding should be used on geotextile mattresses. We started by measuring preference. Cows were allowed to choose between stalls bedded with 0, 1, or 7/5 kg of kiln-dried shavings spread on top of individual geotextile mattresses. These three levels represent the variation in mattress management seen in the industry: bare, a little bedding to absorb leaking milk or heavily bedded. In our study, all cows chose the heavily-bedded stall.

We measured stall usage when cows had access to only one level of bedding, and found that cows spent about two hours more lying down when they had access to the heavily-bedded stalls, compared to stall with bare mattresses (see Figure 1).

Finally, we looked at how the amount of bedding on mattresses affects cow health. In one experiment, we compared the development of hock lesions on mattresses with and without a bedding retainer. We found that cows were less likely to develop lesions when using stalls with a bedding retainer, probably because of the increase in effective bedding depth. Thus cows not only prefer and spend more time lying down on mattresses with more bedding, additional bedding also reduces the number and severity of hock lesions.

This three-step approach, (measures of preference, usage and health), provides a set of proven tools in our work to identify better housing systems for dairy cattle.

Watch for upcoming Research Reports in which we show how these techniques have been applied to other questions in stall design, such as appropriate stall width and neck rail placement.

Thanks to the dairy industry for their support of this research. Supporters are listed at www.agsci.ubc.ca/animalwelfare.

This article is based on thesis research of Ph.D. student Cassandra Tucker. Dan Weary is an Associate Professor in the Animal Welfare Program and can be contacted at danweary@interchange.ubc.ca

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Moving the Neck Rail Helps Lame Cows Recover

Neck Rails: Raising the Bar for Cow Comfort (2003)

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In building a new barn, or renovating an existing facility, one key aim is to create a comfortable environment for the cow to lie down. A second important goal is to create an environment that stays relatively clean and dry, thus minimizing the risks of foot and udder infections that can result from contact with urine or feces in the bedding or on the floor. The free-stall neck rail is thought to help achieve this second aim, by discouraging cows from defecating or urinating in the stall. However, neck-rail placement is a balancing act – place it too low or too close the curb and the cow may have difficulty in entering the stall, place it too high or too far from the curb and cows may be more likely to soil the stall. Achieving this balance requires research.

In one study we housed animals either with or without a neck rail, and examined the difference in stall cleanliness. Cattle can defecate in the stall when they are lying down and when they are standing up. We found no effect of the presence or absence of a 49” neck rail on the number of times animals defecated in the stall while lying down, but when the neck rail was absent, the animals were 58% more likely to defecate while standing in the stall. This is because the neck rail prevented most animals from standing with all four hooves on the stall surface. (picture to the right)

In other work we have determined how neck-rail placement affects the cow’s use of the stall. Correct placement of neck rails involves both the height from the surface of the stall and the distance from the curb. We’ve completed experiments determining how both these factors affect the cow’s lying and standing behavior in the stall.

In the experiments described in this report animals were free-stall housed with geotextile mattresses covered by either sand or sawdust bedding. Behavioral results are based on at least 24 hours of continuous monitoring, using time-lapse video recording.

In the first experiment, we monitored stall usage when the neck rail was 40”, 45”, or 50” above the stall surface or if the neck rail was absent. Neck rail height had no effect on how much time cows spend lying down in stalls. However, the cows spent more time standing with all four hooves in the stall when the neck rail height was 50”. Standing with four hooves in the stall increased 2-4 times when the neck rail was absent (see Figure 1). This research indicates that neck rail height affects the comfort of the cow while standing, but not while lying down.

In the second experiment, neck rail height was held constant at 49.5” and we compared two distances from the curb: 60” or 67”. Again, neck rail placement did not affect how much time cows spend lying down, but it did affect the type of standing performed in the stall. Cows spent more time standing half-in-half-out when the neck rail was closer to the curb (60”), and less time standing with all four hooves in the stall (see Figure 2). p>

Lowering the neck rail and placing it closer to the curb helps keep the stall clean without affecting lying times. However, installing the neck rail in this way will increase the time the cows spend standing on the concrete flooring outside of the stall. Although we typically think about the free stall as a place for cows to lie down, the stall is also used for standing, and the less time cows spend standing on concrete, the lower the risk of hoof injuries. Higher neck rails placed further from the curb allow cows to use the free stall as a relatively dry, non-concrete standing surface. Thus neck rail placement involves a trade off between allowing cows access to a more comfortable standing surface and increased stall maintenance.

If neck rails are positioned so as to discourage cows from standing in the stall, it becomes all the more important to provide improved standing surfaces elsewhere in the pen, such as rubber flooring in front of the feeder.

Watch for future Research Reports on the topic of alternative flooring surfaces for free-stall barns.

Thanks to industry for supporting this research. Supporters are listed at: www.agsci.ubc.ca/animalwelfare

This article is based on thesis research of Ph.D. student Cassandra Tucker. Dan Weary is an Associate Professor in the Animal Welfare Program and can be reached at danweary@interchange.ubc.ca

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Overstocking: At the Stall and the Feed Bunk (2010)

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UBC Dairy Research Report

Overstocking typically occurs in two areas of the barn: at the freestall and at the feed bunk. Producers overstock dairy cattle to save building costs, or because herds grow before barns can be expanded to accommodate more cows. Overstocking can also occur unintentionally; even when each cow has access to a freestall (i.e. one-to-one, or 100% stocking rate, for cows-to-stalls). Differences in barn layout can mean that cows have adequate feeding space in barns with two rows of freestalls but too little feeding space in barns with three rows of stalls in each pen. This is because two-row pens have to be longer in order to house the same number of cows as a three-row pen, providing approximately 50% more bunk space per cow.

Open complete pdf: Overstocking: At the Stall and the Feed Bunk

In summary, these studies illustrate the effects of overstocking at the freestalls and the feed bunk; overstocking reduced the time cows (especially subordinate animals) can access the resource (i.e. lying space or feed), and increases unwanted behaviours (i.e. standing and competition for feed). Transition cows are more vulnerable to these effects, especially in terms of reductions in feed intake (that increase the risk of transition diseases) and increased standing time (that increase the risk of lameness). The effects of overstocking at both the freestalls and the feed bunk on displacements are also more harmful for submissive cows. Submissive cows may be especially at risk for disease during the transition period because they show reduced intakes, stand more and lie down less. Whether these cows are submissive by nature, or temporarily submissive due to their ill health, is not known and is a focus of future research.

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Reducing Pain Due to Caustic Paste Dehorning (2006)

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Dan Weary

Dairy cattle are typically dehorned to reduce the risk of injuries to humans and other animals. To prevent horn growth, tissue is destroyed using a variety of methods including heat cauterization with a hot-iron and chemical cauterization with caustic paste. Choice of method has depended largely upon the producer’s experience and preference. Both methods require skill to use correctly, and misapplications can result in unintended injuries (Figure 1).

Figure 1. (A) Well-healed scabs after caustic paste dehorning
(B) Over-application of caustic paste can damage the calf.

Both methods are also painful for the calf. Previous work by our research group and others has shown that during hot-iron dehorning calves experience distress associated with physical restraint, pain during the dehorning process, and post-operative pain during the hours that follow. Research has also shown this pain and distress can be decreased by use of a sedative, a nerve block or anti-inflammatory drugs.

Much less is known about pain associated with caustic paste dehorning. With caustic paste tissue damage continues as long as the active chemical is in contact with the tissue, so it cannot be assumed that the time course, pain response and pain treatment methods would be the same as for hot-iron dehorning. The aims of our study were to; 1) examine the time course of the pain in response to caustic paste dehorning, 2) examine methods of treating this pain, and 3) compare the calf’s responses to caustic paste with responses to hot-iron dehorning.

Holstein heifer calves between 10-35 days old were dehorned as part of two experiments. Experiment 1 examined the effects of using caustic paste and a sedative with and without a local anesthetic. In our procedure calves received 0.2 mg/kg of the sedative xylazine by intramuscular injection. Once sedation took effect the hair surrounding the horn bud was clipped. Half the calves then received 9 mL of the local anesthetic lidocaine by subcutaneous injection around the horn bud and 10 minutes later a thin film of caustic paste was applied to each horn bud surrounded by a ring of petroleum jelly to prevent the paste from spreading. Several days before the actual dehorning all calves acted as their own control in a “sham dehorning” procedure during which they received the identical treatment as they did during dehorning except petroleum jelly was used instead of caustic paste.

Experiment 2 compared the responses of calves to hot-iron dehorning with the sedative and local anesthetic (xylazine and lidocaine) versus caustic paste dehorning with the sedative only (xylazine). In both experiments calf behaviour was monitored for 12 hours following the dehorning. To measure the pain response we recorded the frequencies of behaviours such as head shaking and head rubbing.

We found that pain-related behaviours increased in calves that were; 1) dehorned with caustic paste versus those sham dehorned and 2) dehorned with a hot-iron versus those dehorned with caustic paste. These results indicate that dehorning with caustic paste causes pain but that the pain is less than that caused by dehorning with a hot-iron, even when using lidocaine (see Figure 2).

HEADSHAKES

HOURS

Figure 2. Calves dehorned with caustic paste and a sedative show less pain
response than calves dehorned using a hot-iron with both a sedative and local
block. Other behavioural measures (not shown) demonstrate the same response.

Interestingly there did not seem to be a benefit to using lidocaine with the caustic paste. This may be because the effect of lidocaine is inhibited by the low pH of the caustic paste. However, the sedative was very important - it eliminated the need for physical restraint during the procedure, and any associated distress, and also provides some pain relief.

In summary, caustic paste dehorning with an xylazine sedative provides a relatively simple procedure for dehorning calves with a minimum of pain. At the UBC Dairy Centre we follow the procedure outlined below. Producers are encouraged to work with their veterinarians to develop a method of dehorning and pain treatment that works well for their herd.

Example Procedure for Dehorning:

  • 10 min before dehorning calves are sedated with xylazine (0.2 mg/kg IM).
  • Hair is clipped around each horn bud, a thin film of caustic paste (2 cm diameter) is rubbed into the scalp until each horn bud is evenly coated, and a ring of petroleum jelly is applied around the paste to prevent spreading.
  • Calves are allowed to rest sternally until recovered from sedation.

The results discussed in this report are a summary of a paper by K. Vickers, L. Niel, L. Kiehlbauch and Dan Weary (J. Dairy Sci. 88: 1454-1459). Special thanks to the staff of the UBC Dairy Education and Research Centre and to Nicole Fenwick for her help in preparing this research report. This research was funded by the Dairy Farmers of Canada, the BC Dairy Foundation, NSERC and the many others listed at: http://www.landfood.ubc.ca/animalwelfare.

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Reducing Pain Due to Dehorning (2001)

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Paul Faulkner and Dan Weary

Dairy producers recognize that dehorning is painful for calves. New research has methods of reducing the pain and distress calves experience during this procedure. Horn buds of calves are removed to reduce the risk of injuries to farm workers or to other cattle that can be caused by horns. Canada’s Recommended Code of Practice for the Care and Handling of Dairy Cattle, and the Canadian Veterinary Medical Association recommend that dehorning done during the first few weeks of like. Horn buds of young calves are typically removed using a caustic pasted or a hot iron. Both methods cause calves pain as evidenced by physiological ad behavioral responses. Physiologically, increased levels of stress hormones (corticosteroids) are commonly found in the blood after hot-iron dehorning. Behavior responses include head movements, ear flicking, tripping and rearing. Use of a local anesthetic such as lidocaine can reduce both the physiological and the immediate behavioural responses. This is why the use of a local anesthetic is recommended in the Dairy Code of Practice, and why in countries such as the UK, it is required by law.

The use of a local anesthetic is an obvious first step in reducing pain at dehorning, but other interventions may also help. Calves respond to both the pain of the procedure and the physical restraint. Calves dehorned using a local anesthetic still require restraint, and calves often struggle in response to the restraint itself. Calves must also be restrained while the local anesthetic is administered, as well as during the actual dehorning. One way to avoid the effects of physical restraint is to use a systemic sedative, such as xylazine. Our work has shown that a systemic sedative can eliminate calf response to the injection of the local anesthetic and the need for physical restraint during this injection and during dehorning.

A second consideration is that the local anesthetic does not provide pain relief in the hours following dehorning. The most popular local anesthetic, lidocaine, is effective for only 2 to 3 hours, but the response to burn injury may persist for 24 hours or more. This post-operative pain response can be seen in the results of a study done at the UBC Dairy Centre, published in the Journal of Dairy Science.

Under normal circumstances calves rarely shake their heads or flick their ears, but these behaviours are common after dehorning. As you can see in Figure 1, the control calves show these behaviours in the hours after hot-iron dehorning. However, when we give calves ketoprofen in their milk (similar to the ibuprofen you take for a headache), these pain responses are greatly reduced.

Behavioural responses (head shakes and ear flicks) during 20 minute observations 1-24 hours after hot-iron dehorning. The ‘Ketoprofen’ calves received this drug in their milk before and after dehorning, while the ‘Control’ claves did not. Note that there is little response during the first few hours by either group, as all animals in this experiment received both a sedative and a local anesthetic before dehorning. This study involved 10 calves per treatment group. From Faulkner & Weary, 2000. J. Dairy Sci. vol. 83: 2037-2041.

Three objectives to consider in improving dehorning methods are:

1. Reducing the distress associated with restraining the calf

2. Reducing the immediate pain associated with dehorning

3. Reducing the pain calves experience in the hours that follow

Consult with your veterinarian to determine what types of interventions will work best on your farm.

Ongoing work at the Dairy Centre is aimed at finding practical but effective ways of reducing the pain associated with dehorning. In a current experiment we are investigating methods of reducing pain during caustic-paste dehorning. Watch for future editions of this newsletter to find out more about this work and other research on animal welfare at the UBC Dairy Education and Research Centre .

This article is based on thesis research by MSc student Paul Faulkner. Dan Weary is Associate Professor in the Animal Welfare Program and can be contacted at danweary@interchange.ubc.ca.

Next Month: Mastitis Vaccines

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Sand or Sawdust? Bacterial Counts in Bedding and on Teat Ends (2001)

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Gosia Zdanowicz and Jim Shelford

Increasingly, dairy producers are turning to inorganic types of bedding, mainly sand, in an attempt to decrease the rates of environmental mastitis in their herds. Is sand bedding really decreasing the numbers of pathogenic bacteria in the cows’ environment? This is the question addressed in our research project.

Environmental mastitis is caused by bacteria found in the soil, manure and bedding. Dairy cows are constantly exposed to them; therefore, reducing the concentrations of those pathogens in the barn is one of the ways to minimize the rates of intramammary infections. Mastitis is a very costly disease as it leads to reduced milk production and quality, treatment and medication costs, loss of animals and premature culling of animals. Therefore, a lower incidence of mastitis in the herd has an enormous economic impact.

It is commonly believed that inorganic bedding does not support the growth of bacteria as well as organic bedding does. However, the effects of sand bedding on the bacterial populations in the bedding and on the teat ends have not been well researched, so there is a need to determine if there is a relationship between bacterial counts and bedding. The objectives of our project were to determine and compare bacteria populations of mastitis-causing organisms in tow different kinds of bedding materials and on teat ends.

Two groups of eight cows each were housed in the Centre’s free-stall barn, one group with sand bedding and the other with sawdust bedding. Cows were assigned to each treatment group balanced by parity, stage of lactation, intramammary-infection status at the beginning of the trial and teat ends score. Each group of cows was moved to the other treatment after 3 weeks. Fresh bedding was added every 7 days but manure was removed daily as needed to keep stalls visibly clean and dry. Cow activities were recorded for 24 hours prior to the sample collection on a time-lapsed video recorder to estimate the time spent lying down for each treatment pen and for each stall.

Bedding samples were collected four times a week from the back one-third of each stall. Teat swabs and milk samples were taken three times a week during the morning milking. Bedding samples were analyzed for dry matter content and pH. All collected samples (bedding, teat swabs, and milk) were analyzed for the concentrations of three major groups of mastitis-causing bacteria: coliforms, Streptococci spp., and Klebsiella spp. Our results showed that there are more coliforms and Klebsiella bacteria in sawdust bedding than in sand bedding. Surprisingly, sand bedding contained as many Streptococci as sawdust bedding. Also, the pattern of bacterial counts over time was different for the two kinds of bedding.

Bacterial populations in sawdust increased steadily for the first 2 days after adding fresh bedding and then stabilized. However, there was no defined pattern for the bacterial counts in sand bedding. Figure 1 illustrates the differences in bacterial counts in sand and sawdust bedding for the three classes of bacteria.

Test swab samples showed very similar results to bedding samples. We found more coliforms and Klebsiella bacteria on the teat ends of cows housed on sawdust bedding than those housed on sand bedding. However, cows housed on sand had more Streptococcus bacteria on their teat ends than cows housed on sawdust. Over the period of a week, as stalls became increasingly wetter and dirtier, ‘sawdust’ cows had higher bacterial counts on their teat ends. Bacterial populations were steadily increasing on teat ends of animals housed on sawdust. However, this was not the case for cows housed on sand bedding. Again, there was no clearly defined pattern here, similar to the bedding samples.

Milk samples were collected to determine the bacterial populations in the milk in the teat canal of a cow. However, we did not find any significant bacterial counts in milk samples. One of the reasons is that our study was a short-term project with only 6 weeks of data collection and only 16 animals used.

In summary, our work shows that there are higher counts of Coliforms and Klebsiella bacteria in sawdust bedding and on the teat ends of cows housed on sawdust than in sand and on teat ends of cows housed on sand. We have found similar levels of Streptococcus in sand and in sawdust bedding. Moreover, Streptococcus populations were higher on the teat ends of cows housed on sand than on sawdust.

Watch this newsletter for information about this research and other work from the UBC Dairy Centre. Contact Dr. Jim Shelford, Professor in Animal Nutrition at shelford@interchange.ubc.ca. This article is based on thesis research by MSc. Student Gosia Zdanowicz.

Next Month: Dehorning Dairy Calves

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Update on Lameness Research (2004)

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Dan Weary and Nina von Keyserlingk

Lameness is now identified as the most common malady of dairy cows. Much of the current research at the UBC Dairy Research Centre relates to lameness and ways of preventing injuries leading to lameness by designing better environments and management strategies for dairy cattle. This year’s BC Dairy Expo will focus on this important and costly problem for dairy farmers and their cows.

At this meeting, researchers from the UBC Dairy Research Centre, along with invited guests, will host a workshop on improving methods for identifying injuries and gait abnormalities, and provide an update on the recent and on-going research projects in this area. For those of you who are not able to attend this event, here is a brief overview of our work in this area, together with some key findings and recommendations.

Assessing lameness

Although lameness is commonly recognized as a major problem faced by dairy cattle, there has been almost no work on describing the problem in BC, and little research on developing more accurate tools for identifying lame cows. Cows become lame as a result of injuries and diseases of the hooves and legs. In this article, we summarize data on prevalence of hoof injuries, describe work looking at changes in gait and report on recent research findings about facility design and management that may help prevent lameness.

Sole lesions are signs of tissue damage in the hoof and can range in severity from minor bruising to severe ulcers. M.Sc. student Erin Bell measured lesions in 20 local herds and found that 86% of the cows had at least one hoof lesion (see Research Reports Vol. 2, No. 2). Lesions can be assessed easily at hoof trimming.

Sometimes a direct assessment of injuries will not be possible, for example, between scheduled visits by the hoof trimmer. In these cases we need to look for other, indirect signs of the problem. We all have some understanding of the obvious changes in the way cows walk when they are lame – a reluctance to bear weight on one limb, an arched back, bobbing of the head and short strides. When these signs are exaggerated or combined, most of us would be able to recognize a cow as lame, but what about when these changes are subtle? Many of us do not do well in picking out these cows.

One study found that producers were able to identify only one out of every four clinically lame cows. Clearly, work is needed to improve our assessment techniques. Gait scoring methods, similar to body condition scoring, provide ways of not just picking out the severely lame cows but also the intermediate cases. Those interested in learning these scoring systems should attend one of our workshops or speak to their vet.

To improve treatment and prevention, work with your vet to develop ways of tracking hoof lesions and gait defects on your farm.

More sensitive methods of assessment may allow us to learn more about preventing and treating lameness at an early stage. One recent innovation is the work of Ph.D. student Frances Flower who is using computer-assisted video analysis to quantify gait measures such as stride length and hoof velocity. Another approach, by M.Sc. student Sophie Neveux, is using load cells to measure how cows favour certain legs when standing. We have also used measures of standing and lying behaviour as indicators of injury. Frances Flower has found that cows that spend more than 10% of their time standing with only their front two hooves in the stall are more likely to have hoof injuries.

Preventing lameness

Standing on concrete flooring increases the risk of hoof lesions and lameness, especially if the surface is wet, poorly maintained (e.g. large cracks or holes), or poorly designed (e.g. high steps between walking surfaces). Our research is helping design improved standing surfaces and resting areas that promote lying in the stall.

The stall surface is one of the most important features of the resting area. Softer surfaces promote lying: mattresses are better than mats, and bedded surfaces (e.g. sand or sawdust) are better than bare mattresses. Our experiments have shown that softer surfaces, like deep-bedded sand or sawdust, can increase lying times by several hours a day. These surfaces also prevent leg injuries such as hock lesions and swollen knees.

Although deep-bedded systems provide benefits for cattle, these need to be maintained. Without regular raking, stalls begin to look like bathtubs, while cement curbs, brisket boards, and stall partitions can all become obstacles for the cow. We have found that cows lie down 1-2 hours less every day when new bedding has not been added over the past week.

Other aspects of stall design can affect standing and lying times. Recent work has shown that increasing stall width from 45” to over 48” can increase the time spend lying down by about 1 hour per day (see Research Reports Vol. 2, No. 8), and decrease time spent with only the front two hooves in the stall. Placing the neck rail too low, or too close to the entrance of the stall prevents cows from standing completely on the stall surface (see Research Reports Vol. 3, No. 1). Although this helps prevent cows from defecating in the stall, it also forces cows to stand on concrete and likely increases the risk of hoof problems. It is important to recognize that the stall provides a location for cows to both lie down and to spend time standing on a non-concrete surface.

Well-designed and managed stalls improve lying times and reduce time spent standing on concrete.

The development of better standing and walking surfaces is another important research area for our group. We have found that dairy cattle spend close to 6 hours per day standing in front of the feed bunk, so this is an obvious area for improvements (see Research Reports Vol. 3, No. 3).

Some producers have now started to look for alternative flooring and walking surfaces for cows, such as rubber mats and conveyor belts. We found that cows spent slightly more time standing at the feed bunk when provided a rubber surface compared to concrete. Frances Flower has worked with Drs. Rushen and de Passillé to identify more innovative walking surfaces, and has found that soft textured rubber can provide both good comfort and good traction. The next generation of flooring surfaces may be best installed in ‘feeding stalls’ that are raised above the alley floor and provide a comfortable, dry surface for cows to stand on while eating.

Another approach is to improve management of the feed bunk. Ph.D. student Trevor DeVries has found that reducing stocking density at the feed bunk allows all cows better access to feed, reducing the amount of time cows spend standing waiting to eat. Sabine Dipple, a visiting researcher from Germany, is now studying the effect of overstocking on the development of lesions and other hoof problems, especially early in lactation when many animals first develop these injuries. Time on pasture during summer months may also reduce injuries as is currently being studied by M.Sc student Lorna Baird.

Cows benefit from using softer flooring surfaces with good traction. Management practices that reduce the time cows spend standing on wet concrete should be favoured.

In conclusion, new research projects at the UBC Dairy Centre are helping to identify improved methods of detecting and preventing lameness. Stay tuned to Research Reports for updates as these results become available. We thank our many supporters of this research (listed at http://www.agsci.ubc.ca/animalwelfare/).

Dan Weary and Nina von Keyserlingk are faculty members in UBC’s Animal Welfare Program.

Plan to attend the seminar on Hoof Care and Lameness at the Pacific Agriculture Show – Dairy Expo on Friday, February 20th at 10:00am.

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Usage of Mechanical Brushes by Lactating Dairy Cows (2007)

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Trevor DeVries, Marcela Vankova, Douglas Veira, and Marina von Keyserlingk

All farm animals, especially horses, pigs and cattle, perform grooming as part of their natural behaviour. The primary function of grooming is body care, including cleaning and sanitation. Grooming behaviour is thought to help animals remove mud, feces, urine, insects and parasites and, thus reduce their risk of disease.

Self-grooming by cattle often involves licking with the tongue, scratching with their hind feet, scratching with their horns (if present) and swatting with the tail in an effort to clean all areas of their bodies they can reach. To reach inaccessible parts, such as the head, neck, back and hindquarters, cattle will often scratch themselves on inanimate objects. In extensive production systems, cattle will often make use of environmental items to scratch on, such as branches, bushes, trees, fences and posts, particularly for areas of the body inaccessible to the mouth, tongue and feet.

In the mid 1980’s, automated mechanical brushes for dairy cows were introduced into freestall barns with the idea that they would facilitate grooming behaviour. These brushes are equipped with a mechanical switch that can be activated by the cow and allow for repeated brushing activity. Such a mechanical brush makes it easier for cows to satisfy their natural grooming behaviour. There is little previous research investigating grooming behaviour in dairy cattle housed in a free stall barn with or without the provision of mechanical grooming devices. Therefore, the objective of this experiment was to investigate how the provision of a mechanical brush affects the grooming behaviour of group-housed dairy cattle.

Figure 1. A cow using a mechanical brush.

In this study 72 freestall-housed lactating dairy cows, divided into 6 equal groups, were each exposed to a control period (1 wk) and an experimental period (2 wks) where the cows were provided a mechanical brush (Luna cow brush, Lely Industries, NV; Figure 1). We analyzed and compared the duration and frequency of scratching on pen objects (wall and water trough) or on the mechanical brush by cows in the control and experimental treatments. Furthermore, we compared the relative frequency of scratching by the cows on various parts of their body (head, neck, back, tail and thigh) between the control and experimental treatments.

Within 24 h of installation of the mechanical brush, 57% of the cows utilized the brush. Within 7 d 93% of the cows used the brush, and by the end of the experimental period, all but one of the cows had used the brush. The average length of time it took cows to commence using the brush after first exposure to it was 1.9 d, with a range of 0 to 14 d.

During the control period the cows primarily scratched themselves on the pen wall and the water trough. When the mechanical brush was added to the pen, the cows not only dramatically increased their total time spent scratching by 6x, but also increased their frequency of scratching events (i.e. number of times/d they scratched themselves) more than three fold. The huge increase in total scratching time was characterized by a decrease in time spent scratching on the wall and water trough, combined with a large amount of time scratching on the brush. Scratching on the brush represented 91% of the total scratching time. Although the increase in frequency of scratching visits was partially influenced by a decrease in scratching events on the wall, it was largely driven by a relatively large number of visits to the mechanical brush.

When cows were provided with the mechanical brush, they also changed the frequency at which they scratched the various parts of their body (Figure 2). In particular, they decreased the frequency of scratching their heads, increased the frequency of scratching on their necks, backs and tails, and tended to decrease the frequency of scratching their thighs. These changes can be explained by the increase in scratching using the brush and decrease in scratching on other pen objects. These results indicate that the mechanical brush allows for more scratching of hard to reach places on the cows’ body (i.e. neck, back and tail), which the cow has difficulty accessing by either her tongue, feet or tail or by rubbing on pen objects. Although we did not record cow cleanliness, farm staff did note that the cows appeared to be much cleaner when they had access to the brush. Further research in this area is needed as improved cleanliness may help decrease diseases.

Figure 2. Relative grooming frequency at the head, neck, back, tail, and thigh
of cows housed in pens without and with access to a mechanical brush.

In conclusion, the results of this study show that the use of a mechanical brush makes it easier for cows to groom themselves, particularly in places that are hard to reach by the cow. This may help satisfy this natural behaviour and improve cow cleanliness.


This report is a summary of an article recently accepted for publication in the Journal of Dairy Science. We thank the staff at The University of British Columbia’s Dairy Education and Research Centre. Special thanks also to Valley Genetics of Chilliwack, BC and Lely Canada for the provision of the Luna cow brushes and Audrey Nadalin for help in running this project. The project was funded by the Natural Sciences and Engineering Research Council of Canada, through the Industrial Research Chair in Animal Welfare, and through contributions from the Dairy Farmers of Canada and many other donors who are listed at http://www.landfood.ubc.ca/animalwelfare.

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Water Quality Affects Cattle Drinking Behaviour and Consumption (2002)

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Water forms the largest component of an animal’s body and is an essential nutrient required for all biological functions including temperature regulation, digestion, fetal development, and milk production. Dairy cattle require an adequate supply of fresh water – from 75 to over 100 L per day. We know that water consumption is closely tied to feed dry-matter intake and that milk production is dependent upon access to large volumes of water. Thus, if water intake declines due to restricted access or inferior quality, both feed consumption and milk production can be negatively impacted.

It is well established that water quality is one of the most important factors affecting water intake which in turn can affect herd health and milk production. There are two further aspects to consider regarding water quality: what causes water quality to decline, and what happens when cows only have access to poor quality water?

Water quality is reduced when it contains either biological or inorganic contaminants. One of the main biological contaminants found in water available to dairy cows is manure. Manure may contain pathogenic bacteria and when it contaminates drinking water disease can easily spread between animals drinking from the same trough. Inorganic contaminants such as sulphates, which occur naturally in many water sources, also decrease water quality and can lead to nutritional disorders.

Previous research has shown that cattle do not like “bad smelling” water and, not surprisingly, find it unpalatable. We also know that they can learn to associate illness with water flavour. Once cattle establish this link it has been shown that they will actually refuse to continue drinking the water.

Water quality is an issue that affects both the beef and dairy industries. All cattle are sensitive to decreasing water quality whether it is through biological or inorganic contamination. Our research was conducted using beef heifers and steers but the findings apply equally to dairy cattle. We conducted several trials to examine the effect of contaminated water on intake and drinking behaviour of cattle.

Our research has shown that cattle respond to decreases in quality by changing their drinking behaviour and reducing their water consumption. In particular, cattle given water containing sulphate compounds such as sodium sulphate and magnesium sulphate found it unpalatable and reacted to their presence in water by changing their drinking patterns, drinking more often at night when compared to the animals that had access to good quality water. Additionally, as sulphate concentration in the water increased, cattle reduced their water consumption (Figure 1).

Figure 1. Average water intake per drink, when drinking twice daily, declines as concentration of sulphate (in the form of MgSO4) in drinking water increased.

Other researchers have demonstrated that the presence of manure in water also drastically reduces how much cattle will drink. As manure is one of the most common water contaminants in a dairy barn, it is important to recognize the potential for reduced water intake and impaired milk production.

Additionally, our research demonstrated that some cattle are particularly sensitive to declining water quality and that water intake was reduced when cattle had access to water only twice daily as compared to free access (Figure 2).

Figure 2. Cattle drink less water per day when it contains sulphate compared to tapwater, and less water when access is restricted to twice daily compared to unrestricted access.

If cattle do not have access to good quality water, their behaviour is affected. When cattle were forced to drink sulphate-contaminated water, we saw a shift towards more aggressive encounters. This could result in even lower water intakes in some animals, negatively impacting milk production and decreasing animal welfare.

Not only is it important that good quality water be provided to dairy cattle, but this clean water must be available at all times. Even if water troughs are dirty only part of the day, cattle may refuse to drink enough water to maintain milk production. The quality of the water supplied to the herd must be carefully monitored, which can be done through visual inspection for manure and simple chemical testing for minerals. Contamination can result in herd health problems or cause cattle to drink less water, negatively impacting feed intake and milk production.

We thank Lavona Liggins and the staff of Agriculture and Agri-Food Canada - Kamloops Range Research Unit for the use of their facilities and their assistance with this research. We are grateful for the financial support of the Beef Cattle Industry Development Fund, the British Columbia Cattlemen’s Association, and the dairy industry through the funding of the Animal Welfare Program by the Dairy Farmers of Canada, the British Columbia Dairy Foundation, and the many others listed at www.agsci.ubc.ca/animalwelfare.

This article is based on thesis research of graduate student Amanda Zimmerman. Dr. Veira is an adjunct professor at The University of British Columbia and works closely with the UBC Animal Welfare Program. He is based at the AAFC Kamloops Range Research Unit. Dr. von Keyserlingk is an assistant professor, Dr. Weary an associate professor, and Dr. Fraser a professor in the UBC Animal Welfare Program. For more information on this research, please contact Amanda at amandaz@interchange.ubc.ca.

Best Wishes for a Wonderful Christmas and a Prosperous New Year from the Faculty, Students and Staff of the UBC Dairy Education and Research Centre.

NEXT MONTH: Neck Rail Placement

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What Cows Prefer: Pasture and Access to the Barn (2010)

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UBC Dairy Research Report

Click here for a complete pdf copy of this report: What Cows Prefer: Pasture and Access to the Barn

Lameness is widely regarded as a problem for both dairy cows and dairy producers. Lack of access to pasture has been linked with higher rates of lameness. Pasture is also perceived as providing a more natural environment for cows, so lack of access to pasture is often viewed as a welfare concern and organic standards typically require some pasture access. That said, many producers prefer housing systems based on zero access to pasture as free stall barns are designed to provide a high degree of comfort for cows. To provide access to pasture could be a challenge on many dairy farms. A well-designed barn provides cows with a comfortable place to lie down, protection from the elements, and free access to a well-balanced diet that helps maintain high levels of milk production. If cows can use a well-designed freestall barn do they really prefer or need access to pasture, and what are the advantages and disadvantages of pasture access?

Continuous access to pasture is not an option for many Canadian producers given our climate, but can even temporary access provide benefits? In one study, UBC researchers compared lameness in cows restricted to a freestall barn with cows restricted to pasture for 5 weeks.

Gait scoring was used to assess lameness: cows with a gait score of one were considered healthy and cows scored five were considered severely lame. Seventy-two multiparous dairy cows in mid to late lactation were gait scored and divided into 18 groups of four animals. Nine groups of cows were restricted to each treatment for five continuous weeks sometime during July through October. The average gait scores for the pasture and freestall treatments were both three at the beginning of the trial. Cows on pasture grazed and were fed concentrate after each milking before returning to pasture. Cows kept in the barn were fed a total mixed ration (TMR). All cows were gait scored weekly and lying time was measured using a data logger attached to each cow’s hind leg.

Average gait score improved for cows on pasture, despite reduced lying time, but the scores of cows in freestalls remained stable or worsened. Improvement in gait was most apparent for cows with the highest initial gait scores, suggesting that pasture access is particularly beneficial for the more severely lame cows (see UBC Research Reports Vol 8 No 3 for more details).

This study indicates that cow lameness can be improved by providing even temporary access to pasture, but this might not be true for other aspects of cow welfare. Pasture access is perceived to be more natural than keeping cows inside, but most pasture provides little or no access to shade potentially increasing the risks of heat stress in the summer. Indoor housing provides shelter from direct sunlight and may help cows cope with higher temperatures.

To better understand if and how cows value access to pasture, UBC researchers simply allowed animals to vote with their feet. In this study, 25 late-lactation cows, tested in groups of five, had free access to either a freestall barn or to pasture immediately adjacent to the barn. At the start of the experiment cows were kept inside the barn or outside on pasture for 2 days each, after which cows were given free access to both options for 3 days. Each group of cows was tested three times from May through July under a range of climatic conditions.

When cows had the choice, they spent about 46% of the day indoors, especially on warmer days. They spent the majority of their time outside during the night between afternoon and morning milkings (Figure 2). Cows were most likely to prefer to be indoors on warm days (i.e. more than 20ºC).

This study indicates that cows do not have an overall preference for either a well-designed freestall barn or for pasture; instead preference varies depending on the time of day and environmental conditions. From the cow’s perspective, the best option may be to simply keep the barn doors open, allowing cows to access pasture when they choose.

One potential disadvantage of using pasture is that cows have access to a less energy dense diet, making it difficult to maintain high levels of milk production. However, when cows were allowed free choice between pasture and the freestall barn they continued to eat just as much TMR as when they were kept indoors continuously. These results suggested that cows could spend their nights on pasture and still maintain intake (and production) relative to cows that are not allowed outside. However, the study was designed to measure shorter-term behavioural effects, not the longer-term effects on intake and production.

To provide a better test of the effects of overnight access to pasture on production and intake, a third study was conducted. Fifty cows were assigned to one of two treatments: continuous freestall housing versus freestall housing during the day and pasture from 2000 h in the evening 0800 h the next morning. These treatments were applied from 4 weeks pre-calving to 8 weeks post-calving

Cows were fed TMR in the freestall barn and feed intakes were recorded. Body condition scores, body weights, and milk production were recorded throughout the experiment. None of these measures were affected by pasture access; both groups of cows had high daily intakes of TMR (averaging 11.9 kg/d) and high milk production (averaging 38.3 kg/d).

Previous research has shown that cows kept only on pasture typically show reduced intakes and reduced milk production. However, by keeping cows in the barn during the day and on pasture at night, cows were able to consume their full daily intake of TMR during the day. Cows still graze the pasture at night, but this grass intake did not displace intake of the energy dense TMR or reduce production.

In summary these studies show that:

1) even temporary pasture access can be good for cow health, helping lame cows recover,

2) cow preferences for pasture access depend upon time of day and climatic factors – cows prefer pasture at night and during cool days, and

3) cows with access to pasture can maintain very high levels of TMR intake and milk production.

Together these three studies indicate that partial access to pasture is a practical management option for producers wanting to promote cow health and welfare while maintaining high levels of milk production.


We are grateful to Lindsey Reich for help preparing this report. For further information please Email marina.vonkeyserlingk@ubc.ca or dan.weary@ubc.ca. This report is based on the following UBC papers: Hernandez- Mendo et al., 2007 (J. Dairy Sci. 90:1209-1214), Legrand et al., 2009 (J. Dairy Sci. 92:3651-3658) and Chapinal et al., 2010 (Livest. Sci., 129:104–110). We thank the researchers and staff of the UBC Dairy Education and Research Centre for their hard work on the studies described in this report.

This research was funded by NSERC Industrial Research Chair in Animal Welfare with contributions from the Dairy Farmers of Canada and many others listed at www.landfood.ubc.ca/animalwelfare/.

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Reproduction

Comparison of Two Estrus Synchronization Protocols for Fixed-Time Breeding to Increase Pregnancy in Lactating Dairy Cows (2008)

Cow Comfort at Calving (2015)

Click here for this report in pdf format.

Anyone who works in the dairy industry will be aware that there is tremendous variation in maternity pen design. Part of the reason for this variability is a lack of research on what types of environments are best for the cow while she is giving birth. Research at UBC has now recruited the cows’ help in designing more appropriate maternity pens, by conducting a series of ‘preference’ experiments in which we allow the cows to vote with their feet. Below we describe the results of three different preference experiments designed to determine what features are important in the design of maternity pens.

Earlier work on feral and extensively managed cattle tells us about the choices cows make in the natural environment. Cows typically will leave the herd to find a secluded area to give birth; for example, an area of tall grass, or bushes with soft ground cover. From these observations, we hypothesized that indoor-housed cows are motivated to seek seclusion from herd mates (and other perceived threats), and will use a ‘hide’ if given the choice.

To test if cows are motivated to ‘hide’ at calving, we reconfigured our pens at the UBC Dairy Centre in Agassiz, BC. The experimental maternity pens gave cows the choice between an 18 m2 open sawdust bedded pack, and 15 m2 sawdust bedded pack surrounded by 1.5 m high wall that provided a visual barrier between the cow and the rest of the barn (Photo 1). This design was not intended to be practical (we will get to that question later), but to provide a test of the idea that cows want to ‘hide’ around the time of calving.

 barn

Photo 1: The experimental maternity pen that gave cows the option between a hide and open pack.

Cows entered the experimental maternity pen at least 2 days before calving to ensure that they were familiar with both areas. Using video cameras, we recorded where the cows spent their time before and during calving (24 hours per day). Cows calving at night, when the lights in the barn were off and no staff were present, showed no preference between the two packs. However, cows calving during the daytime showed a strong preference for calving inside the hide. Of the 16 cows that gave birth during daylight hours, 13 chose the seclusion of the hide. Cows that calved in the hide started to use it about 8 hours before calving, likely near the start of labour.

Given these promising results, we wanted to test if cows would seclude themselves from herd mates when housed under more practical conditions. We used more conventionally sized individual maternity pens that were directly adjacent to a close-up group pen (this study was in collaboration with researchers at the University of Arhus, and took place in Denmark). To create both a ‘covered’ and ‘uncovered’ side to the maternity pen, we attached a 1.5 m high piece of plywood to half of the front of the pen (facing the close-up group), as well as to both sides (Photo 2). Again we video recorded where cows chose to calve, and again, the preference was clear: of the 19 cows used in this experiment, 15 (79%) calved in the covered side of the pen and only four calved on the uncovered side.

 maternity pen

Photo 2: Individual maternity pen retrofitted with a covered ‘corner’ that gave cows the option to hide. 

The final preference study examined flooring properties that are important to cows at the time of calving. More than a decade of research, much conducted at UBC, has shown that the bedding surface is the most important determinant of cow comfort for lactating cows. Cows strongly prefer dry, deep-bedded surfaces, regardless of the type of bedding used. Dry, deep-bedding is also the most powerful protective design feature in reducing lameness and especially hock lesions on dairy farms. Based on this information, we decided to ask indoor-housed Holstein dairy cows which surface they preferred during calving.

In this experiment, we created a maternity pen with three flooring options: 1) concrete, 2) pebble-top rubber mats, and 3) 10 cm of sand, each covered with a 15 cm layer of straw. We made a large maternity pen that was divided into three sections partitioned with wooden boards; each section had a different flooring surface. Cows were moved into this pen at least 2 d before calving to ensure that they had previous experience with each of the flooring types. After every third cow, the location of each surface was alternated to control for the chance that cows had a preferred side of the pen. Using video cameras, we recorded where cows spent their time the day before calving, and where they chose to calve.

Of the 17 cows in the study, 10 calved on sand, six calved on concrete and one calved on the rubber mats. Cows also generally avoided the rubber mats on the day before calving. These results tell us that rubber mats were the least preferred flooring option for dairy cows when housed in the maternity pen, despite being bedded with a thick layer of straw.

The results of our preference tests indicate that even our modern, indoor housed dairy cows are looking for a secluded place to calve, perhaps especially in busy barns and during busy times of the day. It was also clear that rubber flooring is not preferred by cows at calving. The next steps are to determine if there are other benefits to allowing cows to have a preferred maternity pen, such as reduced calving problems like dystocia or stillbirths. For now, we encourage producers to look with fresh eyes at their maternity housing, keeping cow preferences for seclusion in mind.

We are grateful to Magnus Campler and Katy Proudfoot for their help in preparing this report. For further information please Email marina.vonkeyserlingk@ubc.ca or dan.weary@ubc.ca. This report is based on research published in the Journal of Dairy Science and the Journal of Animal Science. We thank the researchers and staff of the UBC Dairy Education and Research Centre and Aarhus University who collaborated in the work described in this report.  The research by members of UBC’s Animal Welfare Program was funded by NSERC, the Canadian Dairy Commission, Dairy Farmers of Canada and many others listed at http://awp.landfood.ubc.ca/.    

Decreased Fertility with Increasing Parity in Lactating Dairy Cows (2005)

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Anusha Balendran, Jeff Nimmo, Nelson Dinn, and Raja Rajamahendran

Fertility has become a major problem for many dairy producers. Researchers in the UK and USA have reported very low pregnancy rates (PR) in high producing dairy cows. Moreover, high incidences of reproductive abnormalities such as cystic ovarian disease, delayed ovulation, and reduced length and/or intensity of behavioural estrus have been observed in high producing cows.

The PR for heifers bred by AI have not markedly changed during the past 50 years. However, reproductive statistics for heifers have not been published recently and would be a valuable tool for assessing changes in PR associated with parity that occur independent of lactation.

Reduced PR have been associated with low, or abnormal progesterone levels after AI. Progesterone is a hormone necessary for uterine function and embryonic development. It also influences maternal recognition of the embryo. The landmark events in progesterone production after AI include the beginning of the luteal phase with the formation of the corpus luteum (CL) and associated initial rise in progesterone levels. This is followed by either the end of the luteal phase (in the case of an unsuccessful AI) with a decline in progesterone production or prolongation of the luteal phase (if the AI is successful and the embryo is recognized) and continued elevated progesterone levels. A positive relationship between progesterone levels at the beginning of the luteal phase and pregnancy has been observed. Progesterone levels at the end of the luteal phase have also been reported as differing between pregnant and non-pregnant cows. Parity's effect on peripheral progesterone production is as yet unclear.

Therefore, the objectives of this study were to a) compare PR between cows of different parity and heifers and b) describe differences between cow’s and heifer’s progesterone levels as a means of examining reasons for decreased PR with increasing parity.

Beginning in April of 2004, pregnancy rates for 163 Holstein cows and heifers bred at the UBC Dairy Education and Research Centre in Agassiz were recorded. AI services and pregnancy diagnosis results were recorded until at least 30 animals were included in each of four groups; heifers (14 to 16 months), 1st parity, 2nd parity, and 3rd or 4th parity. In addition, the luteal function (progesterone levels) of 10 heifers, and 10 cows in each of three parity groups; 1st parity, 2nd parity and 3rd or 4th parities were assessed. The experimental time period spanned April until mid-September, 2004.

Animals were housed in free stall barns and fed a total mixed ration of corn silage, hay and concentrates. Animals were bred as part of the routine management of the herd, and pregnancy diagnosis was performed around 35 days post AI by ultrasonography. Progesterone levels in blood from heifers and whole milk from cows were measured to assess luteal function among animals.

In total, 11 samples were taken every other day from each animal, from the day of AI (day 0) until 22 days post AI. Blood samples were taken from the tail vein, centrifuged, and the plasma frozen for subsequent progesterone analysis. Milk samples were obtained during milking time in the parlour and frozen for subsequent progesterone analysis.

Pregnancy rate following first insemination was 67.9%, 42.9%, 20.0%, and 11.9% among heifers, and 1st parity, 2nd parity, and 3rd/4th parity cows, respectively (Figure.1). Statistical analysis showed that PR was greater in heifers following first insemination (p

Figure 1. Pregnancy Rates following first insemination. Columns with different superscripts differ significantly (p

Figure 2. Pregnancy Rates Following second insemination. Columns with different superscripts differ significantly (p

Our study clearly demonstrates that parity has a significant effect on PR. Markedly lower PR was observed in animals of higher parity. Progesterone levels were not affected by parity, and therefore are likely not directly involved in the mechanism of parity's influence on PR. Areas that could be further researched to learn why PR is reduced in animals with higher parity are parity’s effect on egg quality and uterine environment.


This research was conducted at the UBC Dairy Education and Research Centre in Agassiz. Anusha Balendran is a graduate student in Animal Science at UBC. Jeff Nimmo was a NSERC undergraduate summer student in Dr. Rajamahendran’s lab. Nelson Dinn is the Manager of the Dairy Centre in Agassiz and, Dr. Raja Rajamahendran is a Professor of Animal Science at UBC.

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Estrus Synchronization and Timed Breeding (Heat Detection Not Required) (2001)

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by: M. Hirad and R. Rajamahendran *

Dairy producers are well aware that reproductive efficiency in their herds has a marked influence on profitability. A calving interval of 12 to 13 months is generally considered to be economically optimal, but often difficult to achieve. Key factors in achieving this goal are the incorporation of efficient and accurate heat detection, proper semen handling and servicing techniques, and timely insemination relative to ovulation of the egg. Estrus (heat) detection has been cited as the most important factor affecting the reproductive success of artificial insemination programs. However, proper control of the time of estrus is difficult, since peak estrus activity often occurs at night, and determination of the actual onset of standing estrus may be difficult without 24 hour observation. In work underway at the UBC Dairy Education & Research Centre at Agassiz, we have demonstrated estrus synchronization and timed breeding as a method that could eliminate the need for estrus detection altogether.

To understand estrus synchronization, we need to review the hormonal control of reproduction. During a normal estrous cycle, gonadotropin releasing hormone (GnRH) is produced by the hypothalamus resulting in the release of follicle stimulating hormone (FSH) and luteinizing hormone (LH). These hormones act to cause the growth and development of follicles, which are structures on the ovary housing the developing eggs. Most of the follicles will regress, but one will become dominant and eventually ovulate. After ovulation, a corpus luteum (CL) is formed in place of the follicle. The CL is responsible for the production of progesterone, which is a hormone necessary to maintain pregnancy. If pregnancy does not occur, another hormone, prostaglandin, is released and acts to regress the CL, thereby initiating another cycle. By understanding these events, it is possible to develop ways to control the estrus phase of the cycle. For instance, various methods to synchronize estrus have been developed. If the approximate time of estrus is known, then estrus detection rates will be higher. Estrus synchronization followed by timed inseminations, can even avoid the need for estrus detection.

We recently compared two such protocols, "Ovsynch" vs "Prostaglandin". Forty-six cows in the "Ovsynch" group were given an injection of GnRH followed by an injection of prostaglandin after 7 days. Kamar heat detectors were placed on the tail-head to aid in estrus detection. Forty-eight hours after prostaglandin, the animals were again treated with GnRH. Timed artificial insemination was done 12 and 36 hours later. Cows in the "Prostaglandin" group (also 46) received two injections of prostaglandin 14 days apart and Kamar heat detectors were put in place at the time of the second injection. Timed AI was done 60 and 84 hours after the second injection.

For both groups, milk samples were obtained on the day of breeding and 7, 14, and 21 days after breeding. The concentration of progesterone in the milk was measured over time using a technique called radioimmunoassay. Progesterone levels, which are low during estrus, can be used to confirm whether the animal was in estrus on the day of breeding. Progesterone levels will rise if ovulation and the formation of the CL occurred but will decrease again if conception did not occur. Pregnancy diagnosis was done on all animals using ultrasound 35 days after insemination.

Our work showed that estrus synchrony was equally good in both groups. In addition, we found that milk progesterone concentrations were a much more reliable indicator of estrus than the Kamar heat detectors. Milk progesterone levels 7, 14, and 21 days after breeding were not different between the two groups, indication that the estrus synchronization method did not affect the function of the CL. Most improtantly, we found that animals in the "Ovsynch" group had a significantly higher pregnancy rate than those in the "Prostaglandin" group (62% vs 40%).

Therefore, although both methods of estrus synchronization resulted in the same degree of synchrony, the "Ovsynch" method resulted in higher pregnancy rates in lactating cows. This method also eliminates the need for estrus detection. It could help to improve reproductive management of dairy cattle and achieve that optimum 12 to 13 month calving interval.

Watch this newsletter for further information about this research and other work from the Animal Reproduction and Reproductive Technologies Program at the UBC Dairy Education & Research Centre, located in Agassiz.

* Dr R. Rajamahendran, Professor in charge of the Animal Reproduction and Reproductive Technologies Program

* M. Hirad, Masters of Science student - thesis research project.

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New Protocols for Fixed - Time Breeding in Dairy Heifers (2003)

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Dairy heifers must be inseminated at 14 to 15 months of age in order to achieve the target age of 24 months at calving. Sure sounds easy, but is this always possible in real life? Dairy producers have many chores involving the milking herd leaving little time for reproductive management of replacement heifers. As a result, timely detection of estrus and insemination do not occur in many heifers. A controlled breeding protocol that allows fixed-time breeding without estrus detection is therefore desirable.

The Ovsynch protocol for synchronizing ovulation is popular and effective for fixed-time breeding programs in dairy cows. In this 10-day protocol, GnRH (gonadotropin releasing hormone) is given on Day 0 (e.g. Monday), followed by Prostaglandin F2a (PGF) a week later on Day 7, (next Monday). A second GnRH is given two days later (on Day 9, Wednesday) and the cows are bred 16 hours later (on Day 10, Thursday). Despite being effective in cows, the average pregnancy rate is only around 40% in heifers, considerably lower than what could be achieved with breeding at detected estrus. In addition, some heifers display estrus during the period of the Ovsynch protocol. Consequently, timed-breeding is often performed after ovulation has occurred, thereby reducing the chances of pregnancy.

A practical method of preventing the early onset of estrus in heifers is to include progesterone in the Ovsynch protocol. An intravaginal progesterone device, known as the Controlled Internal Drug Release device (CIDR, Vetrepharm Inc.), is currently on the market but little information is available on the efficacy of CIDR-based protocols for fixed-time breeding in dairy heifers.

We have recently completed a research project to determine if cheaper or more efficient alternatives to GnRH are available for use in CIDR-based controlled breeding protocols. We compared pregnancy rates in heifers treated with: GnRH (Fertiline, Vetoquinol NA Inc.), porcine luteinizing hormone (pLH; Lutropin-V, Vetrepharm Inc.), estradiol cypionate (ECP, Pharmacia Animal Health), or a GnRH/ECP combination in a CIDR-based Ovsynch protocol.

We used 240 13-14 month old cycling heifers in two research herds, to compare pregnancy rates in the four different CIDR-based fixed-time breeding protocols as described in Table 1. Results are presented in Figure 1.

Table 1. Protocol schedule for the four experimental treatments.

Treatment (no. of heifers) Day of Protocol
0 7 8 9 10
GnRH/GnRH(63) CIDR insertedGnRH, 100mg PGF, 25 mg CIDR removed GnRH, 100mg A.I.
ECP/ECP(56) CIDR inserted ECP, 0.5 mg PGF, 25 mg CIDR removed ECP 0.5 mg None A.I.
GnRH/ECP(60) CIDR insertedGnRH, 100mg PGF, 25 mg CIDR removed ECP 0.5 mg None A.I.
pLH/pLH(61) CIDR insertedpLH,12.5 mg PGF, 25 mg CIDR removed pLH, 12.5 mg A.I.

Though a greater proportion of heifers assigned to the ECP/ECP protocol was determined pregnant, the pregnancy rate did not differ significantly from that of the GnRH/GnRH treated heifers. However, pregnancy rate of heifers in the ECP/ECP group was higher than that in the GnRH/ECP (P=0.05) and pLH/pLH (P=0.02) groups.

Under our experimental conditions, a CIDR-based Ovsynch/fixed-time breeding protocol using ECP at a low dose of 0.5 mg yielded pregnancy rates comparable to those obtained with GnRH, with lower costs and with heifers handled four times instead of five. Though the incorporating of a CIDR device into the Ovsynch protocol looks attractive, it adds significantly to the cost of the protocol. There is a cost advantage to using ECP, but extreme caution must be exercised with this product because in doses higher than the 0.5 to 1.0 mg range, it could lead to excessive (and prolonged) estrogen levels in the blood of heifers. This could impair reproductive function, at least temporarily. This new protocol needs further testing with a larger number of heifers.

Figure 1. Pregnancy rates to fixed-time insemination of dairy heifers after synchronization of ovulation with four different CIDR-based protocols.

This research was conducted simultaneously at the Dairy Research and Technology Centre, Edmonton and at the UBC Dairy Education and Research Centre, Agassiz. Dr. Divakar Ambrose is a Dairy Research Scientist with Alberta Agriculture, Food and Rural Development in Edmonton. Dr. John Kastelic is a Research Scientist at the Lethbridge Research Centre of Agriculture and Agri-Food Canada. Muhammad Aali is a graduate student in Animal Science at UBC, Nelson Dinn is the Manager of the Dairy Centre and Dr. Raja Rajamahendran is a Professor of Animal Science at UBC.

Financial support for this research was provided by Alberta Milk Producers and Alberta Agricultural Research Institute. In kind contributions by Pharmacia Animal Health (Lutalyse, ECP), Vetoquinol NA Inc. (Fertiline) and Vetrepharm Inc. (CIDR, Lutropin-V) are acknowledged.

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Ovulation Synchronization and Fixed-time Artificial Insemination in Dairy Cows (2004)

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Raja Rajamahendran, Jeff Nimmo, Divakar Ambrose, Muhammad Aali, and Nelson Dinn

Improved reproduction in dairy herds has a marked effect on profitability. Many recent studies have shown that, under modern management and housing systems, delay in the onset of postpartum cycling, inaccurate detection of estrus, and early embryonic mortality are the major reproductive problems. It is generally agreed that estrus detection efficiency is around 50% in most dairy herds. Therefore, there is an urgent need to develop and apply new technology that will eliminate the need for estrus detection.

Recent research findings have provided a greater understanding of ovarian follicular and corpus luteum (CL) dynamics, and based on this understanding, new protocols to synchronize ovulation that allow fixed-time artificial insemination without the need for estrus detection have been developed. In the Ovsynch protocol, two injections of gonadotropin releasing hormone (GnRH) are given 9 days apart, with a Prostaglandin F2a (PGF2a) injection given 7 days after the first GnRH treatment. The first GnRH treatment initiates the growth of a new follicular wave, and potentially ovulates a large follicle that is present. The PGF2a injection causes corpus luteum regression, and the second GnRH synchronizes ovulation. Fixed-time artificial insemination is performed about 16 h after the second GnRH injection. Although pregnancy rates after Ovsynch and fixed-time insemination have been shown to be comparable to that after artificial insemination at detected estrus, premature ovulation has been reported to negatively affect pregnancy rates in some trials.

The inclusion of a Controlled Intra-vaginal Drug Release (CIDR) device, releasing Progesterone (P), in Ovsynch-type protocols can prevent premature ovulation. A CIDR-based protocol that allows fixed-time insemination has been successfully used in beef cattle and dairy heifers and approved for commercial use. This protocol consists of initial injections of estrogens (ECP) and progesterone to cause regression of large follicles present and to initiate the growth of a new follicular wave, with concurrent insertion of a CIDR device. Seven days later PGF2a is injected to cause the regression of an existing or induced corpus luteum. The CIDR, which has acted as an artificial corpus luteum, blocking ovulation, is removed after the PGF2a injection. A second estrogen injection is given 2 days after the PGF2a to synchronize ovulation. Fixed-time artificial insemination is performed approximately 28 h after the second injection. See Table 1 for a detailed schedule of the Ovsynch and CIDR-based protocols adopted for the present study.

At the UBC Dairy Education and Research Centre in Agassiz, we used 227 postpartum lactating Holstein cows to compare ovulation synchronization rate, corpus luteum function and pregnancy rates of the two different timed breeding protocols described above. Ovulation was determined to have occurred in cows with milk progesterone levels less than 1ng/ml on day of insemination, and greater than 1ng/ml on Day 7 post insemination. Milk progesterone levels were used to assess response rate to ovulation synchronization protocols and corpus luteum function. Pregnancy rate was determined by ultrasound on Day 35, and then verified by rectal palpation on Day 60. The treatments were initiated regardless of the stage of the oestrous cycles of the experimental animals.

Table 1. Ovulation Synchronization Protocol Schedules

Protocol

Day -10

Day -3

Day -2

Day -1

Day 0

Ovsynch

100 micrograms GnRH injection

25mg PGF2a injection

None

100 micrograms GnRH injection

AI

CIDR

100mg P injection
0.5mg ECP injection
CIDR inserted

25mg PGF2a injection

CIDR removed

0.5mg ECP injection

AI

The results of our study are shown in Figure 1. The data show that ovulation in cows receiving CIDR-based protocol tended to be more synchronized than in cows receiving the Ovsynch protocol. Similarly, the overall pregnancy rate and the pregnancy rate among cows that responded to ovulation synchronization treatment were also greater in the cows receiving the CIDR-based protocol. Among the multiparous cows studied, the pregnancy rates obtained were higher (P

Even though both protocols were effective for ovulation synchronization and fixed-time artificial insemination, the CIDR-based protocol numerically outperformed Ovsynch in this experiment. Both protocols can be initiated regardless of the stage of the oestrous cycle of the animals. Although the overall pregnancy rates of 31% and 41% obtained for Ovsynch and CIDR- based protocols, respectively, were comparable to those seen in lactating cows in many dairy herds today, pregnancy rates were higher (P

This research was conducted at the UBC Dairy Education and Research Centre in Agassiz. Dr. Raja Rajamahendran is a Professor of Animal Science at UBC, and Jeff Nimmo is Dr. Rajamahendran’s undergraduate research assistant. Dr. Divakar Ambrose is a Dairy Research Scientist with Alberta Agriculture, Food and Rural Development in Edmonton. Dr. Muhammad Aali was a graduate student in Animal Science at UBC, and Nelson Dinn is the Manager of the Dairy Centre in Agassiz.

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Preserving Superior Genetics from Culled Cows (2001)

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An inexpensive laboratory technique has been developed at the UBC Dairy Education & Research Centre to produce embryos from eggs obtained from culled cows headed to slaughter. On a typical dairy farm, it is estimated that up to 30% of cows are culled every year and sent to the slaughter house. Although their milk production days are over, culled cows are still potential embryo donors. This is especially significant with cows of superior genetics.

In order to extend the genetics of superior dairy cows beyond the 5 or 6 calves a typical cow will produce in her lifetime, a number of reproduction technologies have been developed to increase the number of calves. The in-vivo embryo production technique has become practically feasible at the farm level. It involves hormone treatment to increase the number of eggs released and artificial insemination, followed by embryo removal and transfer to host recipients. But this technique is expensive and the number of embryos obtained is quite variable.

In the past decade, work in our lab at UBC and elsewhere has perfected an inexpensive technique to produce embryos in the laboratory from eggs obtained from slaughterhouse ovaries. The procedure involves maturation, fertilization and embryo culture in the laboratory. (Figure 1)

An important factor is to determine the optimal time for ovary removal to maximize the number of eggs aspirated for embryo production from culled cows. Eggs grow and develop in fluid-filled structures on the ovary called follicles. During each estrous cycle (21 days), a certain number of follicles are stimulated to grow by follicle stimulating hormone (FSH), which is produced by the pituitary gland in the brain. Normally one of these follicles is selected for ovulation and the rest will regress. By using ultrasound to follow the growth of follicles, we have shown that a higher number of follicles are present in the ovaries approximately 2 days after standing estrus. We have also shown that treatment with additional FSH at estrus can increase the number of follicles in the ovaries.

The present study was designed to investigate the feasibility of producing transferable embryos in the laboratory from ovaries removed from culled cows, before they are sent for slaughter. We also tested the hypothesis that removing ovaries from culled cows 2 days after standing estrus would result in a greater number of eggs being recovered and that treatment with FSH would increase this yield resulting in a greater number of embryos being produced.

Twenty-one cows earmarked for culling by the UBC Dairy Education & Research Centre were randomly assigned to three treatment groups. In Treatment !, seven cows were treated with prostaglandin to induce estrus, and ovaries were removed 2 days after standing estrus. Seven cows in Treatment 2 were treated with prostaglandin and given FSH at standing estrus. The ovaries were removed 2 days later. The seven cows in Treatment 3 were not treated and the ovaries were removed irrespective of the day of the cycle. In all cases, ovaries were surgically removed through the cow's vagina. Within 4 hours of collection, the ovaries were brought to the embryo biotechnology lab at UBC in a thermos flask containing sterile physiological saline at 30-35 degrees Celsius. The eggs were removed from the follicles, graded by quality, and only good quality eggs were used for maturation. After maturing for 24 hours, eggs were transferred to semen droplets for fertilization. Successful fertilization was recorded at 72 hours, and embryo production rates recorded on the 8th day of culture.

Based on this study, using our laboratory technique 6 to 8 transferable embryos can be economically obtained from ovaries removed from culled cows, irrespective of the stage of the cycle. The benefit to the dairy industry is the extending of genetic value to future generations.

* Dr. R. Rajamahendran, Professor in charge of the Animal Reproduction and Reproductive Technologies Program.

* G. Giritharan, Masters of Science student - thesis research project.

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Strategies to Improve Ovulation and Pregnancy in Ovsynch treated Cows and Heifers (2010)

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In response to poor estrus detection and low fertility in lactating dairy cows, reproductive management tools such as estrus synchronization programs are increasingly used on dairy farms. One tool, the Ovsynch timed artificial insemination (AI) protocol offers producers potential freedom from estrus detection difficulties. The Ovsynch protocol involves injecting gonadotropin-releasing hormone (GnRH), followed 7 days later by injecting prostaglandin F2a (PGF2a), and then 48 hours later by a second injection of GnRH. Animals are then inseminated 14 to 16 hours later. The economical benefits of Ovsynch are based on reducing the interval from calving to first AI, reducing the number of days animals are open, and reducing culling of cows because of reproductive problems. While cows treated with Ovsynch have similar pregnancy results to cows bred at natural estrus (~30%), this is still far from satisfactory.

Strategies to Improve Ovulation and Pregnancy in Ovsynch treated Cows and Heifers (entire article in pdf format)

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