Effect of supplementation of hCG or GnRH on ovulation and subsequentembryo production of eCG superovulated goats

Abstract

The aim of this study was to enhance the ovulation and subsequent embryo production of equine chorionic gonadotrophin (eCG) superovulated goats by supplementing with human chorionic gonadotrophin (hCG) or gonadotrophin releasing hormone (GnRH). Thirty crossbred donor does were oestrus synchronized using controlled internal drug release (CIDR) device and superovulated using 1500 IU eCG. Then all the donor does were randomly divided into 3 groups. Group 1 were administered 500 IU hCG each at 2 successive days starting from 24 hours after CIDR removal; Group 2 received a single dosage of 20 μg GnRH and Group 3 was control. Ovulation and embryo production responses were evaluated during laparotomy session on Day 7 after CIDR removal. Does in Group 1 showed higher number of CL (10.90) than the Group 2 (1.90) or Group 3 (0.90). The number of ovarian stimulation and number of anovulatory follicles had no significant (P>0.05) differences among the treatment groups. Average number of structure recovered was significantly (P<0.05) higher in Group 1 (3.10) than Group 2 (0.70) or Group 3 (0.00). Moreover, average number of embryo production was higher in Group 1 (0.90) than Group 2 (0.50) and Group 3 (0.00), but no significant difference was observed between Group 1 and Group 2. Results indicated that using hCG hormone would be an effective means for increasing ovulation in eCG superovulated crossbred goats, although it was unable to enhance the embryo number due to increase number of unfertilised ovum.