Comparison of Estrus, Breeding and Pregnancy Rates in Goats During the Non-Breeding Season Using a Short P4 Protocol with and Without GnRH or hCG

The purpose of this project was to compare induction of estrus and pregnancy rates in goats bred during the non-breeding season using a short progesterone priming protocol with either gonadotropin releasing hormone (GnRH) or human chorionic gonadotropin (hCG) to induce ovulation. Previous work on a small number of animals suggested that the use of hCG (stimulates ovary directly) resulted in good estrus and increased willingness to be bred as well as a slightly better pregnancy rate compared to using GnRH (stimulates anterior pituitary). Our hypothesis was that during the non-breeding season using hCG vs. GnRH would increase the percentage of animals coming into estrus and breeding rate, as well as increasing pregnancy rates. A larger study was performed to test this hypothesis. [...]