Time of ovulation in goats (Capra hircus) induced to superovulate with PMSG

• Published in: Journal of reproduction & fertility Vol. 83; no. 2; pp. 747 - 752
• Main Authors: Cameron, A.W.N, Battye, K.M, Trounson, A.O
• Format: Journal Article
• Language: English
• Published: England Society for Reproduction and Fertility 01.07.1988
• Subjects: Animals; duration; Female; goats; Goats - physiology; Gonadotropins, Equine - pharmacology; induction; Laparoscopy; Ovulation; Ovulation Induction - methods; Ovulation Induction - veterinary; Pituitary Hormone-Releasing Hormones - pharmacology; pregnant mare serum gonadotropin; Superovulation; Time Factors
• ISSN: 0022-4251; 1470-1626; 1741-7899
• DOI: 10.1530/jrf.0.0830747

The timing of ovulation in feral goats treated with 1200 i.u. PMSG ± 50 μg 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 GnRH synchronized ovulation, leading to 91% of ovulations appearing between 36 and 48 h after sponges were withdrawn.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 < 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. Keywords: goats; PMSG; ovulation; laparoscopy; progesterone