Ativação e maturação folicular e produção embrionária em ovelhas da raça Santa Inês em diferentes condições climáticas

Abstract

In order to evaluate different situations of heat stress on the activation and follicular development, oocyte maturation and embryo production for Santa Inês ewes, four experiments were conducted. In the first, the influence of climatic conditions on the activation and development of preantral follicles, through in vitro culture of ovarian cortex fragments. The results showed that climatic conditions the season with higher temperatures did not prevent the activation and growth of preantral follicles. Then, it was evaluated follicular development and oocyte retrieval puncture of sheep ovarian maintained under conditions of heat stress and comfort. The results were reduction in the number of follicles and oocytes retrieved in the first section of aspiration in sheep under heat stress. In the third, we evaluated the influence of heat stress on viability and in vitro maturation of oocytes retrieved in the previous experiment. In this, no differences were found between treatments (comfort and warmth). In the fourth experiment, we evaluated if the supply of artificial shade on the superovulatory response and embryo production in two seasons. No differences were found between presence and absence of shade. However, we found lower mean ovulations for superovulated ewes at the time of higher temperatures. In conclusion, heat stress affects the final growth and ovulation rate of Santa Inês sheep.