03333naa a2200253 a 450000100080000000500110000800800410001902200140006002400390007410000170011324501310013026000090026150000470027052025000031765300080281765300090282565300290283465300170286370000240288070000180290470000120292270000170293477301280295110607122020-01-29       1999    bl uuuu     u00u1 u    #d  a0921-44887 a10.1016/S0921-4488(99)00024-32DOI1 aREGUEIRO, M.  aEffect of medroxyprogesterone acetate and eCG treatment on the reproductive performance of dairy goats.h[electronic resource]  c1999  aArticle history: Accepted 27 January 1999.  aABSTRACT. The incidence of short oestrous cycles and kidding rate in dairy goats were evaluated after administering a low dose (500 IU) of equine chorionic gonadotrophin (eCG) during two breeding seasons. The first year, 46 does (Saanen, n = 10; Nubian, n = 26; and their local crossbred, n = 10) were used. The second year of the study was performed on 34 of the same does (Saanen, n = 4; Nubian, n = 19; local crossbred, n = 11). The goats were synchronised with intravaginal sponges that contained medroxyprogesterone acetate during a period of 14 days. At the time of sponge withdrawal the animals were assigned to two groups: the eCG group was injected with 500 IU of eCG i.m. and the control group was injected with 2 ml of saline solution. Oestrous detection began 12 h after sponge removal. Once a doe was detected to be on heat, it was mated twice: at the moment of detected heat and 12 h later. The animals which presented short cycles were mated again according to the same schedule. To determine the progesterone concentration, all of the animals were bled on the day of standing heat and every second day over a period of 22 days during the second year. All of the does exhibited oestrus within 4 days after sponge removal. The average time (mean ± SD) between sponge withdrawal and standing heat was significantly shorter in the eCG group than in the control group (34.5 h ± 11.9 versus 42.9 h ± 19.6). More animals in the eCG group returned to oestrus than those in the control group (62.5% versus 15%; p < 0.0001). In the eCG group 77.5% Nubian, 63.6% crossbreed and 14.3% Saanen does returned to oestrus while the corresponding percentages for the control group were 8.7, 10 and 42.9%, respectively. Seventy-six percent (n = 19) of the animals which returned to oestrus in the eCG group did so after a short oestrous cycle, while the corresponding figure in the control group was 16.7% (n = 1) (p = 0.0051). Mean progesterone levels in the mid luteal phase of pregnant and non-pregnant eCG treated animals, were higher than the levels found in the control group. Kidding rates differed significantly between eCG-treated (41.0%) and control animals (64.1%) (p < 0.05), but no significant difference was observed in the mean number of live kids born per doe. Animals weighing less had a higher incidence of short oestrous cycles and a lower kidding rate than heavier animals. In conclusion, using eCG to increase litter size in goats may be influenced by body weight and breed.  aECG  aGoat  aOestrous synchronisation  aProgesterone1 aPÉREZ-CLARIGET, R.1 aGANZÁBAL, A.1 aABA, M.1 aFORSBERG, M.  tSmall Ruminant Research, August 1999, Volume 33, Issue 3, Pages 223-230. Doi: https://doi.org/10.1016/S0921-4488(99)00024-3