Avaliação do estágio fisiológico de fêmeas bovinas

Abstract

The present research aimed to evaluate the fertility rate in Nellore heifers submitted to ovarian evaluation before the beginning of the Fixed Time Artificial Insemination protocols and its impacts on the productive system. Therefore, the animals were divided into three groups after the Reproductive Tract Assessment (ATR1): anestrus (ATR1), follicle (ATR2) and corpus luteum (ATR3). and all were submitted to the same FTAI protocol. The ovarian evaluation was performed using a Mindray 2200 ultrasound device, with a frequency of 5.0 MHz. The experimental design was completely randomized and the information obtained in the field work was edited in electronic spreadsheets. After data collection, analyzes of variance were performed (p<0.05) and when significant, the chi-square test (X²) was performed at 5% probability. After analyzing the data, a significant difference was observed between the pregnancy rate of animals in anestrus compared to those with follicle and corpus luteum. Given the results of the present study, it was possible to verify that the pregnancy rate in the corpus luteum group was higher than in the other groups (ATR1 and ATR2) and obtained the best/lowest pregnancy cost (efficiency + pregnancy rate / fertility). The best strategy to optimize the fertility of bovine females was the corpus luteum group.