Características do ciclo estral de éguas pertencentes ao setor de equideocultura da Universidade Federal de Uberlândia

Abstract

Equine production is a growing activity in the country and, with this, equine breeding has advanced, with more and more studies about factors intrinsic to the estrous cycle of the mares, in order to improve biotechniques and increase reproductive efficiency, which allows the production of animals with higher zootechnical value. About the estrous cycle, equine females show cyclicity in periods of days with highest luminous incidence, despite this, the study of specifics reproduction characteristics is still scarce. In this context, the aim of this study was to assess characteristics of the estrous cycle of mares from the Equine Production and Breeding Sector of the Federal University of Uberlândia, evaluating the existence of correlations between each other. Nine mares were monitored for 1 to 3 cycles, during 74 days between the months of September and November 2023, totalizing 13 estrous analyzed. The mares were submitted to transrectal ultrasound for the analysis of pre-ovulatory follicles, days and intensity of uterine edema and diameter of the corpus luteum 5 and 12 days post-ovulation. As a result, a significant positive correlation was observed between the maximum size of the pre-ovulatory follicle and the days of edema for both the variations correlated with the CL diameter on D5 (r = 0.7134; p = 0.006) and on D12 (r = 0.9149; p = 0.0005). For the other variables, no relationships were noticed. In conclusion, we found that a larger pre-ovulatory follicle has a greater estrogenic capacity, influencing the duration of endometrial edema. However, due to the low number of variables, more studies are needed, allowing assessments that are more conclusive on the topic.