OVULATION RATE, ZYGOTE RECOVERY AND FOLLICULAR POPULATIONS IN FSH-SUPEROVULATED GOATS TREATED WITH PGF(2-ALPHA) AND OR GNRH/

Follicular development and ovulation were examined in superovulated Nu bian and Nubian-cross dairy goats following prostaglandin F-2 alpha (P GF(2 alpha)) and/or gonadotropin releasing hormone (GnRH) treatment. E strus was synchronized with Synchromate-B(R) implants. Superovulation was induced with follicle stimulating hormone (FSH) and augmented with GnRH and/or PGF(2 alpha). The PGF(2 alpha) treatment was administered on Day 2 of superovulation. Implants were removed from all goats on D ay 3 of superovulation. The GnRH treatment was administered 24 h after implant removal. All does were exposed to fertile males for 48 h at t he time of GnRH injection. Surgical embryo recovery and ovarian respon se evaluation were conducted 64 to 78.5 h after implant removal. The n umber of ovulations was higher with GnRH treatment (18.5 +/- 7; X +/- SEM) than that in the controls (5.3 +/- 4.1; P < 0.05). There were few er follicles in the GnRH-treated does than in the untreated does (10.9 +/- 2.9 vs 22.1 +/- 3.2; P < 0.05. The number of follicles smaller th an 4 mm in diameter (5.8 +/- 0.8) did not differ between treatments. T he GnRH-treated does had fewer 4- to 8-mm follicles (4.2 +/- 2.0 vs 9. 1 +/- 1.6; P < 0.01) than the controls. Predicted times for 1- and 2-c ell embryo recoveries were 68.5 and 73.7 h following implant removal, respectively. This study demonstrates that GnRH is an effective supple ment used with FSH superovulation regimens in dairy goats. Moreover, G nRH provides for enhanced early embryo collection for DNA microinjecti on studies.