A variação climática afeta a produção in vitro de embriões bovinos (Bos taurus) na região de Uberlândia, MG, Brasil?

Abstract

IVEP (in vitro embryo production) is a reproductive biotechnology that provides a high genetic gain by multiplying characteristics of a product that would be generated from just one gestation. There are several factors that can influence the efficiency of IVEP, including environmental and climatic factors. Climate can affect the quality of oocytes, semen, and the laboratory stages of IVEP. With the present study, the aim was to identify how climatic variation influences the in vitro production of bovine embryos (Bos taurus) in the region of Uberlândia, MG, Brazil, minimizing the effects from the bull. For this purpose, the Spearman correlation test was conducted between climatic factors (total precipitation, relative air humidity, air temperature, atmospheric pressure, and global radiation on the day and during the 31 days prior to oocyte collection) and the results of IVEP routines (cleavage rates, embryonic development, and blastocyst rates) performed in the years 2019, 2020, 2021, and 2022 in a laboratory in Uberlândia. All IVEP routines were performed with ejaculate from the same bull, collected in the same month. The results of the analysis using data from the 31 days prior to oocyte collection showed a significant positive correlation with relative air humidity regarding blastocyst rate and embryonic development. There was also a trend of positive correlation with precipitation on the day of oocyte collection and embryonic development. These results can be justified because when relative humidity is very low, there may be stress due to faster evaporation processes, which can result in skin irritation and dehydration. In the rainy season, when air humidity is higher in the Uberlândia region, temperatures are not as high because they are mitigated by cloudy weather. It is concluded that in the Uberlândia region, climatic factors have little influence on the results of in vitro embryo production when minimizing the bull effect. However, oocyte collection during periods with higher levels of air humidity and rainfall can benefit IVEP efficiency.