Repeated superovulation treatments in Kivircik ewes during breeding and nonbreeding seasons

Abstract

The present study compared superovulation and embryo recovery rates applied repeatedly during breeding and nonbreeding seasons in the same 20 Kivircik sheep. Trials 1 and 3 were performed during the breeding season and the trial 2 was performed in the nonbreeding seaSon. We synchronized the sheep's estrus cycles and induced a superovulatory response with porcine follicle stimulating hormone (pFSH) injections. Natural mating took place 12 h after the last FSH injection: The embryos were collected by laparotomy 7 days after natural mating. There was no significant difference between the number of corpora lutea (CL) counted following the 1st (breeding) and 2nd (nonbreeding) superovulatory treatments (P > 0.05). However, the number Of CL in the 3rd (breeding) treatment was dramatically lower than that in the other groups (P < 0.001). Recovery rates showed significant differences among embryo flushing treatments (P < 0.001). The number of morulae + blastocysts and freezable-quality embryos decreased considerably for the 3rd flushing treatment (P < 0.001), while no significant difference was observed between the 1st and 2nd flushing treatments (P > 0.05). In conclusion, our study demonstrated that 2 consecutive in vivo embryo production programs can be successfully applied in Kivircik ewes with suitable superovulation treatments and operation techniques, irrespective of the season.