Ovulation and fertility in goats after intravaginal device-PMSG treatment

Abstract

Three experiments were conducted in the breeding season to examine the effects of intravaginal device and PMSG treatments on the time and synchrony of ovulation and on fertility after artificial insemination. Administration of PMSG stimulated ovulatory activity in females treated with Controlled Internal Drug Release (CIDR) devices. The time of ovulation was advanced by injection of PMSG before rather than at CIDR removal and by increased doses of PMSG. Kidding rates for Cashmere does after laparoscopic insemination with frozen-thawed semen were indistinguishable for CIDR and fluorogestone acetate sponge treatments when PMSG was injected at their removal (48.8% and 56.1%) or 48 h before removal (61.0% and 52.5%). The fertility of does weaned 25 days before insemination was lower than for animals weaned 3 months earlier (46.9% and 65.2% does kidded; P<0.05). Kidding rates for dairy does after cervical insemination with fresh-diluted semen were not different when PMSG was administered 48 h before or at removal of intravaginal sponges (77.3% and 68.8%). Time of insemination after sponge removal (40 or 48h) had no effect on the fertility. Uterine deposition of semen was performed in 40% of females, and the kidding percentage was higher after intra-uterine (via cervix) than cervical deposition (84.0% and 66.1%; P<0.01).