Superovulation and egg recovery in goats in the tropics

The superovulatory response to gonadotrophin treatment during different months of the year was investigated in Kambing kacang goats, a tropical breed, in Malaysia. Sixty-three cycling does, fitted with progesterone impregnated intravaginal sponges for 17 days, received two days before sponge withdrawal, an intramuscular injection of either 10, 15 or 20 mg of follicle stimulating hormone (FSH) or 500, 1000 or 1500 iu of equine chorionic gonadotrophin (eCG). The dose of FSH was divided into four decreasing daily doses and each daily dose was subdivided into two and administered at 07.00 and 19.00. Fifty-four does detected in oestrus were mated with fertile bucks. The ovarian response was determined by laparoscopy and eggs were recovered surgically five or six days after oestrus. The ovulatory response (mean +/- standard deviation) based on corpora lutea was higher in the FSH (13.4 +/- 8.4 corpora lutea per doe, n = 20) than the eCG-treated groups (6.4 +/- 5.1 corpora lutea per doe, n = 25) but the difference was not significant (P greater than 0.05). Does responded to gonadotrophins throughout the year with more than 50 per cent of does responding during the rainy months compared with less than 35 per cent responding during the dry months. This difference was statistically significant (P less than 0.05). Egg recovery was better in the FSH (6.8 +/- 5.3 per doe, n = 20) than the eCG groups (3.0 +/- 3.8 per doe, n = 21) but the difference was not significant (P greater than 0.05).