RESPUESTA REPRODUCTIVA EN OVEJAS DE PELO SINCRONIZADAS CON ACETATO DE MEDROXIPROGESTERONA IMPREGNADO EN ESPONJAS INTRAVAGINALES NO COMERCIALES

Background. Intravaginal sponges impregnated with medroxyprogesterone acetate or fluorogestone acetate are routinely used in oestrus synchronization protocols in sheep, non-commercial sponges are a viable option in the reproductive control of female sheep. Objective. To evaluate the reproductive response in hair sheep synchronized with medroxyprogesterone acetate impregnated in non-commercial intravaginal sponges. Methodology. 31 adult hair sheep 5/8 Pelibuey x 2/8 Black Belly x 1/8 Dorper, average weight of 40 ± 3.2 kg and a body condition of 3-3.5 were used. They were randomly assigned to one of four treatments: T1 (n = 8 ewes), 5 mg of medroxyprogesterone acetate impregnated in non-commercial intravaginal sponges + 1 mg of estradiol cypionate + 200 IU of eCG; T2 (n = 8 ewes), synchronization similar to T1, but 500 IU of eCG were applied; T3 (n = 8 ewes), 20 mg of fluorogestone acetate impregnated in intravaginal sponges + 200 IU of eCG; T4 (n = 7 ewes), synchronization similar to T3, but 500 IU of eCG were applied. In all treatments the sponges were placed for 10 days. Blood samples were collected by jugular puncture and the concentrations of progesterone and LH were determined. Results. The sponge removal interval to estrus was different (P 0.05) between T1, T2 and T3 (54.5 ± 5.5, 46.5 ± 5.8 and 38.3 ± 2.6 h, respectively), T4 (59.3 ± 4.1 h) was similar (P> 0.05) to T1 and T2 (54.5 ± 5.5 h and 46.5 ± 5.8 h, respectively) but different (P