Authors : Mustafa Kemal Saribay, Fikret Karaca, Gokhan Dogruer, Yasar Ergun, Ilker Yavas and Cafer Tayyar Ates
Abstract: The present study was aimed at oestrus synchronization by applying progestagen-impregnated intravaginal sponges for either 7 or 12 days to lactating goats during the breeding season and at the determination of the effects of post-mating GnRH injection on fertility. The study was conducted in 80 hair goats aged between 2-5 years. The goats were allocated to two equal groups, one of which was applied short-term intravaginal sponge treatment and the other long-term treatment. The duration of intravaginal sponge treatment was 7 days in the short-term group (ST, n = 40) and 12 days in the long-term group (LT, n = 40). Furthermore, on the day of intravaginal sponge removal, the goats received intramuscular injections of 400 IU of PMSG and 0.075 mg of cloprostenol. In both groups, 12 h after the removal of the vaginal sponges, 10 fertile bucks were introduced into the flock for oestrus detection twice a day and goats which were determined to be in oestrus were hand-mated to the assigned bucks. Immediately after mating, the goats included in each of the ST and LT groups were randomly assigned to two subgroups, referred to as ST1 (n = 18), ST2 (n = 18), LT1 (n = 18) and LT2 (n = 18). The subgroups ST1 and LT1 were maintained as controls whilst the subgroups ST2 and LT2 were administered with 5 mcg of bucerelin acetate immediately after mating. In the present study, the times of oestrus onset and oestrus rates in the ST and LT groups were determined as 33.3±1.4 and 35.0±1.4 h and 94.7 and 97.2%, respectively. The differences observed between the two groups for the time of oestrus onset and oestrus rate were statistically insignificant (p>0.05). In the subgroups ST1, ST2, LT1 and LT2, pregnancy rates were determined as 55.5, 50, 50 and 55.5%, respectively whilst the parturition rate of all four subgroups was 100%. Furthermore, litter sizes were detected as 150, 200, 188 and 170% in the subgroups ST1, ST2, LT1 and LT2, respectively. The differences observed between the subgroups for pregnancy rate, parturition rate and litter size were statistically insignificant (p>0.05). In conclusion, it was demonstrated in the present study that GnRH administrations immediately after mating to lactating goats in which oestrus synchronization was performed by means of short and long-term intravaginal sponge treatment during the breeding season did not improve pregnancy rate, parturition rate and litter size.
Mustafa Kemal Saribay, Fikret Karaca, Gokhan Dogruer, Yasar Ergun, Ilker Yavas and Cafer Tayyar Ates, 2011. Oestrus Synchronization by Short and Long-Term Intravaginal Sponge Treatment in Lactating Goats During the Breeding Season: The Effects of GnRH Administrations Immediately after Matings on Fertility. Journal of Animal and Veterinary Advances, 10: 3134-3139.