The Efficacy of Three Different Estrus Synchronization Protocols on Reproductive Performance in Chinese Hu Sheep

Background: The estrous synchronization has become a worldwide available solution for modern management and large-scale cultivation of sheep. The objective of the present study was to compare the efficacy of three estrus synchronization protocols, CIDR9+PGF(2 alpha)+eCG; CIDR14+eCG and GnRH+PGF(2 alpha) in Hu sheep. Methods: This study was conducted on 80 multiparous ewes, which were assigned into four groups: CIDR9+PGF(2 alpha) +eCG; CIDR14+eCG; GnRH+PGF(2 alpha) and control. Behavioral estrus was checked with teaser rams. Percentage of ewes behaving estrus at different time (0-24 h, 24-48 h, 48-72 h, respectively) was recorded. Pregnancy diagnosis was implemented on day 28 and confirmed on day 60 after insemination. Result: The results suggested that the estrus rate, pregnancy rate, conception rate, lambing rate and prolificacy in three treatment groups have no significant difference compared with control group. Most notably, CIDR9+PGF(2 alpha)+eCG and CIDR14+eCG have significantly shorter duration of pregnancy than control. While CIDR14+eCG and GnRH+PGF(2 alpha) did not dramatically change the fecundity of ewes, still CIDR9+PGF(2 alpha)+eCG significantly decreased the fecundity of that compared with the control. Estrus responses in CIDR9+PGF(2 alpha)+eCG, CIDR14+eCG and GnRH+PGF(2 alpha) groups rose gradually to attain their significantly higher percentages (56.3%, 52.9% and 66.7%, respectively) during 24-48 h post-estrous detection, afterwards, they fell down.