Dinâmica folicular associada a contagem de folículos antrais em novilhas nelore submetidas a protocolo de inseminação artificial em tempo fixo

Abstract

Low reproductive efficiency limits productivity in beef cattle farming. In the reproductive process, knowing the follicular dynamics of bovine females is essential to guarantee promising results in reproductive biotechnologies. Fixed-Term Artificial Insemination is a biotechnique that consists of synchronizing the estrous cycle of bovine females using drugs that stimulate estrus at a random period in the estrous cycle, while follicular dynamics makes it possible to makes it possible to identify and analyze the evolution of antral follicles. In addition, counting antral follicles in the same individual individual makes it possible to classify bovine females as high, low or intermediate carrier of antral follicles by means of a simple transrectal transrectal ultrasound during the estrous cycle. In this study, we investigated the antral follicle count and the response to Fixed-Time Artificial Insemination (FTAI). Insemination (IATF) in Nelore heifers, using ultrasound scans, we evaluated follicular development in animals with high and low follicle counts, seeking to identify follicle count, seeking to identify factors that may influence the success of insemination, analyzing and identifying the diameter of the follicles at D8 and D10, establishing statistics for the variables of total follicles and by FAC category, as well as indicating the incidence of these follicles and measuring the ovaries. A average number of FACs in the heifers was 20 for low and 35 for high. There was greater occurrence of follicles in the right ovary, with 76% in low and 72% in high CFAS. in high CFAS. With regard to the presentation of oestrus, 72% was in heifers with CFAs and 92% in high CFAs, the data was based on the absence of the demarcation demarcation at the base of the tail on D8. A factor positively correlated with ovulation rate is the diameter of the dominant follicle. In the present study, heifers with low FACs had an average follicle size of size at D8 was 10mm, while heifers with high CFAs had an average follicle size of 9mm at D8. on D8 was 9.93mm. These data suggest that the number of antral can influence the reproductive performance of Bos taurus indicus beef cattle in artificial insemination in fixed-time artificial insemination programs