Determination of the efficacy of human Chorionic Gonadotropin (hCG) administrations on reproductive performance, placentation, parturition, and neonatal parameters on different post–mating days in Kangal ewes sexually induced during anestrus

Abstract

This study aimed to determine the efficacy of post mating human Chorionic Gonadotropin (hCG) during anestrus on the formation of the accessory corpus luteum and some reproductive parameters. For this purpose. after synchronization of all the animal were divided into group 1 (n=100), group 2 (n=100), and group 3 (n=100) by applying 600 IU of hCG 6 d after sponge removal, 600 IU of hCG 8 d after sponge removal, and no hCG application (Control), respectively. The difference between groups in terms of reproductive parameters such as estrus, pregnancy, multiple pregnancy, litter size, and productivity was not statistically significant. The live birth weight of lambs was evaluated for singletons, twins, and triplets. The difference between group 1 and the control group was statistically significant in singleton lambs (P=0.04). The difference between group 1 and control (P<0.001) and between group 2 and control (P<0.001) was statistically significant for twins. In triplets, group 1 was different from both groups (P<0.001) and group 2 was different from the control group (P<0.001). In addition, when the placenta weight and the daily body weight gain of singleton lamb in the neonatal stage were examined, the values of both groups that were administered with post mating hCG were higher than the control group (P<0.001). The Progesterone (P4) level in blood samples taken on the 21st d of pregnancy was found to be different between all groups. Furthermore, P4 levels were found to be higher in group 1 compared to the other two groups (P<0.001). In the light of these findings, it was determined that hCG administration after mating contributed to placenta and offspring development by elevating P4 levels. It was concluded that hCG should be administered 6 d after the sponge will be removed (on d 5 postmating) for optimal efficacy.