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)