Induction of synchronized estrus in dairy goats with different gonadotrophins1
J.F. Fonseca, J.H. Bruschi, F.N. Zambrini, E. Demczuk, J.H.M. Viana, M.P. Palhão
Anim Reprod, vol.2, n1, p.50-53, 2005
Abstract
The objective of this study was to evaluate the efficiency of two gonadotrophins in induction of estrus in dairy goats. A total of 47 dairy goats were randomly divided according to breed into two treatments (T1 and T2). In both treatments, goats received intravaginal sponges containing 60 mg medroxy-progesterone acetate for six days and subvulvar administration of 22.5 μg of d-cloprostenol at the time of sponge insertion. In T1 (n=23) and T2 (n=24), animals received intramuscular administration of 200 IU and 250 IU of eCG and hCG, respectively. After sponge removal, goats were monitored twice daily (06:00 a.m. and 18:00 p.m.) with bucks. Animals were bred at the start of estrus and at each 12 hours interval until the end of estrus. Pregnancy was checked by ultrasonography 63 days after breeding. Percentage of animals in estrus did not differ (P>0.05) between T1 (95.6%) and T2 (78.3%). There was no effect (P>0.05) of treatment on interval from sponge removal to the start of estrus (IE) and duration of estrus (DE). The average IE was 48.0 ± 9.4h and 46.2 ± 8.4h for eCG and hCG, respectively. The average DE was 20.7 ± 11.9h and 18.8 ± 9.0h for eCG and hCG, respectively. Pregnancy rate did not differ (P>0.05) between eCG (77.3%) and hCG (61.1%). Results of this study showed that estrus can be efficiently induced in female goats outside the breeding season with both eCG and hCG.
Keywords
eCG, goat; hCG, progestagen; reproductive performance