Comparative studies of inducing estrus in suffolk breed sheep, as the choice of the optimal receptor synchronization scheme, in vivo embryotransfer protocol

Abstract

Reproductive biotechnologies in sheep, are important tools for genetic improvement because they enable to increase the gene frequency of individuals with superior genotype. The techniques for AI and ET of sheep and goats differ from those normally used in other farm animals mainly due to their anatomical peculiarities. Embryo transfer biotechnology (ET) is applied to females of superior genotype (like the Suffolk race) and aims to increase the frequency of their genes by increasing their progeny. ET allows the transference of embryos from superior females (donors) to matrices with low genetic value (recipients). In this study we followed the protocol for the induction and stimulation of estrus in Suffolk sheep. Also, the reactivity of the sheep to different schemes for the treatment of estrus synchronization was followed. The purpose was to obtain, test and recommend a certain treatment for the synchronization of embryos donors and receptors, part of ET. Therefore, a number of 60 Suffolk sheep were treated with different hormones, divided into 3 groups of 20 each. Group A received P12-PGF; group B, P12-PGF-GnRH; and group C, P12-PGF-PMSG. Following treatment, the sheep were monitored on days 1-3 for signs of estrus, which were observed in most sheep. Thus: at Gr A, 16/20 (75%), at Gr.B, 18/20 (90%) and at Gr C, 20/20 (100%). Regarding ovarian response and synchronization of estrus for the anticipation of ovulation, (after the time of onset), the most favorable response was obtained in group B. Following treatment with P12-PGF-GnRH, estrus was manifested on the second day. For the synchronization of embryo receptors in sheep of the Suffolck breed, we recommend scheme B, because it synchronizes the ovulation in most sheep.