Effect of various eCG doses on reproductive performance of Kohgiluyeh and Boyerahmad province native goats at during the summer and spring seasons

To investigate the effect of different doses of eCG on reproductive performance of Kohgiluyeh and Boyer-Ahmad province native goats, 75 goats (2-3 years age and 46±1.9 Kg mean weight) and 75 goats (3-4 years age and 45±2.6 Kg mean weight) were chosen during the summer season (first experiment) and during the spring season (second experiment), respectively. The estrous cycle of goats was synchronized by progesterone sponges in an 18 days period. In each experiment, one day before removing sponges, 300, 400, 500 and 600 IU of eCG were injected intramuscularly to the goats in experimental groups, and one group was assumed as control group. The results indicated that the groups which received 500 and 600 IU of eCG and the control group all had less kidding compared with the remaining groups. The fecundity rate in treatment groups that received 400 and 500 IU of eCG (1.2 and 1.13, respectively) was also more than the remain groups. During the spring season, the results indicated that all the goats which received eCG doses more than 300 IU cycled in 42 hours and in the groups, which received 500 and 600 IU of eCG doses, the onset of estrus was significantly earlier compared to other groups. The results indicated that the eCG dose up to 500 IU level, the percentage of triple kidding was increased. Fecundity and prolificacy rate among different treatment groups tended to significant difference and these characteristics were higher in the group receiving 500 IU of eCG, compared to other groups. In conclusion, the result of this study indicated that 400 and 500 IU of eCG had the most effect on increasing the pregnancy rate, twin kidding, and fecundity rate of native goats during the late summer and the beginning of spring seasons, respectively.