Effect of high doses of equine chorionic gonadotrophin (eCG) treatments on follicular developments, ovulation and pregnancy rate in boer goats

Abstract

The aim of this study was to determine the effects of the superovulatory technique using equine chorionic gonadothrophin (eCG) on follicle response, ovulation and pregnancy rate in Boer goats. Twenty nine (29) does were divided into three groups, G1 (n = 11), G2 (n = 8) and G3 (control, n = 10). All groups had their estrus synchronized by the use of controlled internal drug release (CIDR) containing 0.3 g progesterone for 18 days. Twenty-four hours prior to CIDR removal, all animals were intramuscularly injected with different eCG doses: does in G1, G2 and G3 received 600, 800 and 1000 IU eCG, respectively. Follicular activity was determined once a day for four consecutive days by ultrasonographic monitoring starting at eCG treatment (day 17) in all groups. The number of corpora lutea were assessed on day seven after estrus to calculate ovulation rate, whereas the pregnancy diagnosis was detected on 30 days post mating. Follicles response resulted in significant differences (P < 0.05) only under small size follicles but not significant difference (P > 0.05) on number of follicles under medium and large size follicles among treatments. Ovulation rate recorded a significant difference (P < 0.05) among treatments after seven days post estrus with the highest rate at 2.3 ± 0.3, 1.6 ± 0.2 and 1.4 ± 0.1 for G2, G3 and G1, respectively. Meanwhile, pregnancy rate that showed the highest recorded was 50, 45.5 and 12.5% for G3, G1 and G2, respectively. The results concluded that there was no significant difference on follicle number recorded among treatments except for small size follicle numbers on days 19 and 20. Meanwhile, we concluded that 800 IU eCG was the best treatment resulting in the highest ovulation rate. Different doses of eCG however did not influence the pregnancy rate in superovulated does.

Keywords: Equine chorionic gonadotrophin, follicular, ovulation, pregnancy, estrus synchronization, goat

African Journal of Biotechnology, Vol 13(12), 1374-1378