Reproductive Performance in Dorper Ewes Synchronized at Estrus During non Breeding Season in Tropical Conditions

With the objective to evaluate reproductive response in Dorper ewes were studied during non-breeding season under tropical conditions of Mexico. Ewes were randomly assigned to one of three treatments: T1 (n = 20): continuous breeding; T2 (n = 15): 65 fig Medroxiprogesterone Acetate (MPA)+500 I.U. equine Chorionic Gonadotrophin (eCG) at sponge removal+controlled breeding and T3 (n = 16): 100 mu g of gonadotropin releasing hormone (GnRH) (Day 0) +7.5 mg of luprostiol (Day 5) and 100 pg of GnRH (Day 6.5). Estrus percentages were 65, 933 and 25% for T1, T2 and T3, respectively. The average pregnancy percentage was 43.7% with the higher value for T2 and the lower for T3 and the prolificacy percentage was 100% for all the treatments. It is was concluded that intravaginal sponges impregnated with 65 mg of medroxiprogesterone acetate used during 12 days, plus 500 I.U. of eCG, efficiently synchronized estrus in Dorper ewes whereas the ovsynch scheme presented low pregnancy and prolificacy percentage.