Resumo

AKE-LOPEZ, Jesús Ricardo; CENTURION-CASTRO, Fernando Gerardo; MAGANA-MONFORTE, Juan Gabriel  e  AKE-VILLANUEVA, Jesús Ricardo. Effect of progestagen and dose of equine gonadotropin corionic on estrus sinchronization and pregnancy rate in pelibuey ewes following laparoscopic insemination. Ecosistemas y recur. agropecuarios [online]. 2014, vol.1, n.3, pp.261-268. ISSN 2007-901X.

The aim of the present study was to evaluate the effect of two progestagen and two doses of equine chorionic gonadotropin (eCG) on synchronization of estrus and pregnancy rate in Pelibuey ewes following laparoscopic insemination under tropical conditions. A total 296 Pelibuey ewes were synchronized with 40 mg of flurogestona acetate (Group Sponges; n = 150) or 0.3 g of natural progesterone (Group CIDR; n = 146) for 12 days; 200 or 250 UI of eCG were applied randomly at progestagen removal Estrus was observed during the morning and afternoon until 48 h of progestagen removal, the insemination was intrauterine with chilled semen at 54-56 h of progestagen removal. Pregnancy was diagnosed by ultrasound 35-40 days later. The results were analyzed using Chi-square. The proportion of ewes in estrus (Sponges = 89.3 % vs CIDR = 93.5 %) and pregnancy rate (Sponges = 77.3 vs CIDR = 72 6 %) was similar (p > 0.05) between groups. The dose of eCG influenced the proportion of ewes in estrus (200 UI = 86 5 % vs 250 UI = 95 9 %; p < 0.05) and the pregnancy rate (200 UI = 64 9 % vs 250 UI = 85 1 %; p < 0.05). In conclusion, results show that the progestagen did not affect synchronization of estrus or pregnancy rate. However, the proportion of ewes in estrus and the pregnancy rate were greater when applying 250 IU of eCG.

Palavras-chave : Hair sheep; intrauterine inseminated; chilled semen; tropic; fertility.

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