222 COMPARISON OF COMMERCIAL IN VITRO EMBRYO PRODUCTION OF BRAHMAN DONORS UNDER BRAZILIAN v. PANAMANIAN MANAGEMENT

Abstract

Brazil is a leading country in the world in commercial use of in vitro-produced bovine embryos, with approximately 200 000 transfers per year (IETS; Thibier, 2009). This model of large-scale commercial in vitro bovine embryo production is now available for Panamanian producers. Because of the tropical environment in Panama, the most popular breed is the Brahman, a Zebu type of cattle that has been shown to have more follicles emerging per follicular wave than Bos taurus type of cattle and, consequently, that produce more oocytes per session of follicular aspiration. This characteristic, added to the embryo production results, permits such a biotechnology to be implemented on a commercial scale and incorporated into the reproduction management of a herd. A comparison of oocyte number and quality, cleavage, and embryo production was made using the same in vitro production system (InVitro Brazil, Mogi Mirim, São Paulo, Brazil) for Brahman donors, both in Brazil and in Panama. Data were compared using a z-test analysis (Table 1). The percentage of cleaved zygotes was greater (P < 0.001) with the Panamanian Brahman donors as compared with the Brazilian Brahman donors (73 v. 69%, respectively). However, the percentage of blastocysts/cleaved zygotes was greater (P < 0.01), indicating a higher blastocyst production rate from the Brazilian donors. No other differences were observed. Thus, in vitro embryo production with Brahman donors could be used as a tool to improve and spread superior genetics within a Panamanian herd and could also serve as a model for other Central American and Caribbean countries under similar management systems.

Table 1.  Panama and Brazil in vitro Brahman embryo production¹