Effects of Long and Short-Term Progestagen Treatments Plus GnRH Followed by TAI on Fertility Parameters in Lactating Hair Goats during the Transition Period

Summary The aim of this study was to determine the efficiency of the progestagen containing intravaginal sponges used for 6 or 12 days at timed artificial insemination (TAI) in Hair Goats during the transition period, the effect of GnRH administrations at the time of TAI on fertility was also investigated. In this study 104 lactating hair goats aged between 2-5 years old minimally primiparous was used as animal materials. All of the goats received 30 mg fluorogestone acetate (FGA) impregnated vaginal sponges. The sponges were inserted into vagina for 6 days in the short-term (ST, n=52) group also for 12 days in the long-term (LT, n=52) group. The goats received 400 IU PMSG and 0.075 mg of cloprostenol at the time of sponge removal. The goats in both the ST and LT groups timed artificially inseminated 48 h after sponge withdrawal with fresh cooled semen. At the time of artificial insemination, the subgroups ST1 (n=24) and LT1 (n=22) were maintained as controls, the subgroups ST2 (n=24) and LT2 (n=23) received 5 mcg of buserelin acetate. Pregnancy and twinning rates of the ST1, ST2, LT1 and LT2 groups were 37.5%, 41.6%, 40.9%, 47.8% and 22%, 30%, 11%, 18%, respectively. The litter sizes were 122%, 130%,111% and 118% in the ST1, ST2, LT1 and LT2 groups, respectively. The parturition rates were 100% in all treatment groups. Pregnancy rates, twinning rates and litter sizes were not statistically different among the groups (P>0.05). The results of this study indicated that, a TAI protocol without detection estrus seems to be a suitable administration for short and long progesterone sponges aplications in lactating hair goats during the transition period. In addition, progesteron and AI without estrus detection procedure may be useful alternative to traditional synchronization program using progesteron and AI after estrus detection. Also, GnRH addition to progesterone sponges did not improve reproductive paramaters.