Efficacy of Second Prostaglandin F2 Alpha Treatment during Ovsynch Protocol on Pregnancy Rate Inseminated with Sex-sorted Semen in Buffaloes

Abstract

Background: Ovsynch is one of the most adopted estrus synchronization protocols used for synchronization of ovulation and fixed-time artificial insemination however, new corpus luteum (CL) induced by the first GnRH treatment in Ovsynch is inappropriately regressed with a single treatment with prostaglandin F2α. Inadequate CL regression reduces fertility. Considering this rationale, present research was implemented with the effect of second prostaglandin F2 alpha treatment during Ovsynch protocol on pregnancy rate inseminated with sex-sorted semen in buffaloes. Methods: Post-partum true anestrus multiparous buffaloes (n=24) were categorized as a group I (Ovsynch; n=12) and group II (Double PG Ovsynch; n=12). Buffaloes from group I were treated with standard Ovsynch protocol (D=7; G-P-G), while additional second prostaglandin F2 alpha injection was administered on day eighth (D=7; G-P-P-G) in group II (Double PG Ovsynch). All the buffaloes were inseminated 16-20 hrs after the last GnRH injection with sex-sorted semen. Result: The estrus signs exhibited were numerically higher in group II than in group I. The first service pregnancy rate in double PG Ovsynch was higher than the Ovsynch group. The addition of a second prostaglandin F2 alpha injection in the Ovsynch protocol improves the estrus quality and increases pregnancy rate.