Pregled Protokola Superovulacije Malih Preživača Na Klinici Za Porodništvo I Reprodukciju

The overview of small ruminant superovulatory protocols performed at Faculty of Veterinary Medicine Zagreb

Silvijo Vince, Branimira Ževrnja, Ivan Folnožić, Martina Karadjole, Ozren Smolec, Maja Belić, Marija Lipar, Tomislav Dobranić, Juraj Grizelj* [email protected]

Faculty of Veterinary Medicine University of Zagreb, Croatia

This article examined two different superovulation protocols for goats. The high variability of superovulatory response is a major limiting factor in goat embryo transfer programs. This variability is due to extrinsic and intrinsic factors. Two protocols were compared: standard and „Day 0“ protocol of superovulation on 30 goats of Boer breed in each group during the breeding season. The purpose of „Day 0“ protocol is to minimize the ovarian status influence on superovulation response by starting the administration of gonadotrophins after ovulation, concurrently with the 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by 11 days progestagen sponges and superovulated with 6 decreasing doses of pFSH, during 3 days before the pessary was withdrawn. The oestrous in Day 0 protocol was synchronized by vaginal 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 in order to obtain luteolysis of corpus luteum (CL) created during oestrous synchronization. The ultrasonic exam of ovaries in both groups of animals was performed in order to follow up the status of ovaries before and during the superovulation procedures until ovulation. The females in standard protocol were mated 24h after vaginal pessary has been withdrawn. In „Day 0“ protocol goats were mated 24h after luteolysis have been induced. Seven days after being mated, the uterus in both groups 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. The “Day 0” protocol didn’t improve superovulatory success partly because only 54 % of goats in the 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 superovulatory response in „Day 0“ protocol is smaller number of follicles with ø3.5-5 mm at the onset of superovulation treatment which positively correlate with the number of the transferable embryos.

Key words: goat, superovulation protocol, follicles, ultrasound