Serum progesterone concentrations associated with superovulation and premature corpus luteum failure in dairy goats

The incidence and cause of premature corpora lutea failure and the response to luteinizing hormone treatment was investigated in superovulated dairy goats. Does were treated with 1000 IU pregnant mare serum gonadotropin intramuscularly, followed by either luteinizing hormone (treated group) or saline (control group). Serum progesterone concentrations were used to monitor corpus luteum function. The dose of pregnant mare serum gonadotropin used induced superovulation in a majority of the does, but the responses varied depending on the time of year. Premature regression of the corpora lutea occurred in 4 of 18 does after pregnant mare serum gonadotropin treatment, but there was no difference in the incidence of corpora lutea failure between treated and control groups. Decreases in serum progesterone concentrations were evident by day 3 after ovulation in does that experienced corpora lutea failure indicating this to be the critical time for premature regression of the corpora lutea in superovulated does.