The time and rate of ovulation, and preovulatory release of LH [luteinizing hormone] were examined in Angora goats after treatment with progestagen-impregnated intravaginal sponges with or without PMSG [pregnant mare serum gonadotropin] during the anestrous and breeding seasons. The administration of PMSG was necessary to stimulate a satisfactory ovulatory response in lactating and non-lactating females, and in the anoestrous and breeding seasons. Increasing doses of PMSG increased the ovulation rate in non-lactating goats and advanced the time of ovulation in lactating and non-lactating females. The advancement of time of ovulation and of the preovulatory LH surge was most pronounced when PMSG was administered 48 h before rather than at sponge removal.