Influence of climatic conditions on in vitro production of bovine embryos

Abstract

Temperature and rainfall were analyzed daily during six years to evaluate their influence on in vitro production of bovine embryos. Weekly replications (n=480) were performed on 14,778 ovaries collected at slaughterhouses. Cumulus oocyte complexes (n=19,180) were fertilized with a pool of Bos taurus taurus semen in one incubator with 5% CO 2. Presumable zygotes were cultured in gasified plastic bags with 5% CO 2 , 5% O 2 , and 90% N 2 . In the first year, cleavage and embryo yield were 60.3% and 15.6%, respectively, being lower (P<0.05) than in the following years. Average cleavage rates were always lower in winter (P<0.0001), thus producing less embryos. Winter climatic conditions had a negative influence on in vitro production, when cleavage and embryo yield declined, possibly because of reduced availability and growth of native pasture.

Effect of low doses of FSH and season on the in vitro maturation, fertilization and embryo development of bovine oocytes

“…In previous research, both the fertilization of oocytes and embryonic development, had been reported to be affected by season (Rust et al 2009). In a previously conducted study, it was suggested that the cleavage rates obtained in winter season were lower than those obtained in other seasons (Pessoa et al 2010). Temperature, season and diet affect reproductive efficiency, follicular development and oocyte quality, and thus have effect on fertility (Wolfenson and Roth 2018).…”