INFLUÊNCIA DOS FATORES AMBIENTAIS E FISIOLÓGICOS NA TAXA DE CONCEPÇÃO DE RECEPTORAS BOVINAS DE CORTE

Abstract

The conception rate after embryo deposition in the female bovine is considered a crucial factor for the efficiency of a property that adopts this type of biotechnique. The importance of the dynamics between the environment and the animal at this time is generally seen as an obstacle for those who wish to adopt this biotechnology. The aim of this study was to verify whether the temperature and humidity index (ITU), wind and temperature of the Nelore recipient, at the time the embryo is deposited in the uterine environment, influence the conception rate at 30 and 55 days of gestation throughout the year. Data was collected from the Samvet Embriões laboratory, located in the rural area of Morrinhos, Goiás, from March 2023 to March 2024. 23 Nelore cattle recipients were evaluated, with an average age of 4.0 years and a body condition score of 4.0 to 6.0 (scale of 1.0 to 9.0), raised in an extensive system. A transrectal temperature measurement was taken at the time of embryo deposition. Pregnancy was diagnosed by transrectal ultrasound at 30 and 55 days. Environmental data was retrieved from the Meteorological Station of the Instituto Federal Goiano. Statistical analysis used logistic regression to evaluate conception rates at 30 and 55 days, considering transrectal temperature, UTI and wind speed, with significance established at P ≤ 0.05. The conception rate for recipients with a rectal temperature of up to 38.1oC was 50.00% and 0.00%, between 38.1oC and 39.2oC was 40.90% and 27.27%, and greater than 39.2oC was 27.58% and 24.13%, at 30 and 55 days of gestation, respectively. Conception rates were 32.43% and 18.91% for UTIs under 74, and 37.50% and 37.50% for UTIs equal to or greater than 74, at 30 and 55 days, respectively. With regard to wind, conception rates were 30.55% and 19.44% at speeds of less than 5 km/h, 70.00% and 60.00% between 5 and 8 km/h, and zero when the speed was greater than 8 km/h. There was no significant difference for any of the variables evaluated and conception rates. It can be concluded that, for the conditions of the property evaluated throughout the year, there was no significant difference in conception rates at 30 and 55 days of gestation in relation to the cow's temperature at the time of embryo deposition, UTI and wind speed.