Preliminary results evaluating a simplified superovulation protocol in Boer goats

Abstract

This study was conducted to evaluate the use of one shot follicle stimulating hormone (FSH) plus equine chorionic gonadotrophin (eCG) (simplified) superovulation protocol in mature Boer goat does. Eighteen does used were allocated into two groups, during the natural breeding season (autumn). The two group were Group 1: the control (n=9); multiple FSH protocol and Group 2: treatment group (n=9); one shot FSH plus eCG protocol. All does were synchronised for oestrus, using controlled internal drug release dispensers (CIDR's) for 9 days. Does in the multiple FSH protocol group were superovulated with 200μg pFSH/doe, administered i.m. in 7 dosages at 12h intervals, starting 48h prior to CIDR removal. In the treatment group (one shot FSH plus eCG protocol), the superovulation treatment was administered once as 200μg FSH plus 350 IU eCG, 48h prior to CIDR removal. All does were then observed for oestrous behaviour twice daily, at 12h intervals following CIDR removal for a period of 72h. Cervical inseminations (with 0.1ml fresh undiluted Boer goat semen) were performed 36h and 48h following CIDR removal. Embryos were then surgically flushed on day 6 following the second artificial insemination. The time interval from CIDR removal to onset of oestrus was not affected by treatment. The duration of the oestrous period however was significantly longer in the one shot group, compared to the multiple FSH protocol. Does from the one shot FSH plus eCG protocol recorded a significantly (p<0.05) lower mean number of CL's, structures (unfertilised ova plus embryos) and (p<0.01) embryos recovered. A significantly (p<0.01) higher number of unfertilised ova were observed from the one shot FSH plus eCG group (4.06±0.9), compared to the multiple FSH group (0.24±0.1). However, the number of degenerated embryos was not affected by treatment. The total number of transferable embryos was significantly lower in the one shot FSH plus eCG protocol (0.22±0.2), compared to the multiple FSH protocol (9.56±1.9). The size of follicles was not affected by treatment, however the total number of follicles at CIDR removal was significantly lower in the one shot FSH plus eCG group (11.67±0.7), compared to the multiple FSH group (14.83±0.7). AI might have been performed at the wrong time, because of the duration of the oestrous period being longer in Group 2. The multiple FSH superovulation protocol overall seemed to be more efficient in the Boer goat. More research is needed on the doses of gonadotrophins administered and the time of AI, in order for the simplified protocol (Group 2) to be effective.