Influencia De La Raza Del Embrión Y El Ambiente Ecológico en La Sobrevivencia De Embriones Ovinos Congelados Por Transferencia Directa

Abstract

In Peru, there has been an introduction of new sheep breeds in order to reorient the production of this species, towards products of greater value and demand, which has taken on greater importance in the last 10 years. Thus, for the importation of these embryos it is required to comply with the strict sanitary regulations and quality control in the process. The objective of the study was to evaluate the embryonic survival of cryopreserved ovine embryos and transferred in one step to recipients located in two ecological environments. The ovine embryos (n = 190) cryopreserved were imported from Australia and used using the one-step freezing method for direct transfer. The number of embryos per breed were Dohne Merino (n = 70), East Friesian (n = 70) and Dorper (n = 50). The embryos were transferred surgically (ventral laparotomy with laparoscopic help) into the uterine horn ipsilateral to the ovary with the functional corpus luteum. Crossbred recipient ewes (East Friesian x Barbados Black Belly and Corriedale x Criollo) were synchronized in two ecological environments; Peruvian Coast (Trujillo, at sea level) and central Andean mountains (Ayacucho, 3 704 masl) respectively. The sheep embryos were distributed according to the number of recipients available in each ecological environments; Peruvian Coast (n = 150) and central Andean mountains (n = 40). Our criterion for determining embryonic survival was based on the birth of a live lamb. The results were analyzed by the Chi square test in the contingency table and subdivision of the contingency table. The overall rate of pregnant recipients was 43.15%. The survival rate of the embryos in the two ecological environments was statistically different (p <0.05) between Peruvian coast (37.33%) and central Andean mountains (50.98%). The East Friesian breed showed the highest birth rates in two ecological environments, Peruvian coast (50%) and central Andean mountains (80%). The cryopreservation of embryos for direct transfer in sheep, is a repeatable and simple technique and with very good efficiency to achieve birth lambs in two ecological environments of Peru. Therefore, it allows the introduction of new breeds of sheep with high productive potential, minimizing costs.