Effect of breed and follicular status on response to superovulation in South African goats

This study evaluated the effect of breed and follicular status of Boer and indigenous goats on response to superovulation and embryo yield. The oestrous cycles were synchronized with progestagen for nine days and superovulated with porcine follicle-stimulating hormone. Does were cervically inseminated and embryos were surgically flushed on day six following artificial insemination. The oestrous activity, ovarian response, embryo yield and quality, did not differ significantly between breeds. The number and size of follicles at the onset of superovulation treatment and during oestrus did not differ significantly between breeds. The follicles 2–3 mm, 4–5 mm and total number of follicles at the onset of superovulation treatment were positively correlated with the number of structures, embryos and transferrable embryos recovered. The number of medium follicles (4−5 mm) at the beginning of superovulation treatment increased the number of transferable embryos. The total number of follicles >6 mm at the onset of superovulation was positively correlated to the number of unfertilized ova. Although limited number of animals was used, the results suggest that breed has limited effect on superovulation response. Instead, the quality and yield of embryos are dependent on number and size of follicles present at the beginning of a superovulation treatment