The comparison of standard and Day 0 superovulatory protocols for goats

This article examined two superovulation protocols for goats: standard and „Day 0“ on 30 goats of Boer breed in each group during breeding season. The purpose of “Day 0” protocol is to minimize ovarian status influence on superovulation response by starting the administration of gonadotrophins after ovulation, concurrently with first follicular wave, without presence of dominant follicles (ø>6mm). The animals in standard protocol group were synchronised by 11 days progestagen sponges and superovulated with 6 decreasing doses of pFSH, during 3 days before withdrawing the pessary. The oestrous in Day 0 protocol was synchronized by pessaries (11d) and eCG (9.d), with GnRH induction of ovulation (13.d). The superovulation was performed 24h after ovulation has been confirmed (14.d) by 6 decreasing dosis of pFSH (15.-17.d). Concurrently with the 3rd day pFSH, the prostaglandin was applied to obtain luteolysis of corpus luteum (CL). The ultrasonic exam was performed to follow up ovaries. The females in standard protocol were mated 24h after pessary has been withdrawn. In „Day 0“ protocol goats were mated 24h after luteolysis have been induced. Seven days after, the uterus was flushed. It was established that “Day 0” protocol significantly diminished number of animals with dominant follicle before the superovulation procedure started, but however didn't improve the superovulatory success (the number of CLs and transferable embryos were significantly lower). However, similar percentage of 1st class embryos was noticed in both protocols. “Day 0” protocol didn’t improve superovulatory success partly because only 54 % of goats in standard protocol group had dominant follicle, which has negative influence on the number of transferable embryos, especially those of 1st class. The other reason for the lower response in „Day 0“ protocol is smaller number of ø3.5-5 mm follicles at the onset of superovulation which positively correlate with the number of transferable embryos.