Time of ovulation in goats (Capra hircus) induced to superovulate with PMSG.
The timing of ovulation in feral goats treated with 1200 i.u. PMSG +/- 50 micrograms GnRH was studied by repeated laparoscopy. Experiment 1 established that superovulation began as early as 30 h after withdrawal of progestagen-impregnated sponges and was not completed at 54 h if goats received PMSG alone. GnRH synchronized ovulation, leading to 91% of ovulations appearing between 36 and 48 h after sponges were withdrawn. Experiment 2 established that superovulation continued until up to 77 h in goats treated only with PMSG. The stress of repeated laparoscopy appeared to delay or abolish ovulation in some females. The mean (+/- s.e.) ovulation rate was greater in goats treated with GnRH (12.7 +/- 1.3) than in those that received PMSG only (9.7 +/- 1.1; P less than 0.05). Out of 47 of the females in Exp. 1, 43 had one or more corpora lutea at laparoscopy 24 h after withdrawal of progestagen. These early corpora lutea were associated with an increased concentration of plasma progesterone during the periovulatory period. Experiment 3 provided evidence that these corpora lutea arose before the withdrawal of progestagen-impregnated sponges.
Cameron
A W
AW
Centre for Early Human Development, Monash Medical Centre, Clayton, Victoria, Australia.
Battye
K M
KM
Trounson
A O
AO
D000818:Animals; D005260:Female; D006041:Goats / Q000502:physiology*; D006064:Gonadotropins, Equine / Q000494:pharmacology*; D010535:Laparoscopy; D010060:Ovulation; D010062:Ovulation Induction / Q000379:methods / Q000662:veterinary; D010906:Pituitary Hormone-Releasing Hormones / Q000494:pharmacology; D013480:Superovulation; D013997:Time Factors
D006064:Gonadotropins, Equine; D010906:Pituitary Hormone-Releasing Hormones