Influência da estação do ano na produção de embriões in vitro de bovinos

Abstract

This study aimed to assess the quality of oocytes recovered from donor females and survival of embryos produced in vitro inovulated on recipient females during the summer and winter and the quality of bodiesluteum produced by female recipients in these two seasons. The bioclimatic data demonstrated consistency between the summer and winter with the relative humidity values for the summer of 82.52 ± 7.03 % and for winter 81.06 ± 10.18 % (P > 0.05); maximum temperature of 33.07 ± 1.84 and 27.76 ± 2.16 degrees C (P <0.05) for the summer and winter, respectively, and minimum temperature of 20.57 ± 1.60 and 18 , 02 ± 1.58 ° C (P < 0.05) , for summer and winter, respectively. Even the summer period presenting values being above the maximum temperature limits for thermal comfort , there was no difference in the total number of oocytes collected (21.40 ± 10.91 and 22.26 ± 13.22 , for summer and winter, respectively) , number of viable oocytes (11.26 ± 6.94 and 13.40 ± 10.08 , for summer and winter, respectively) and embryos (4.07 ± 3.23 and 3.80 ± 3.26 , summer and winter, respectively) produced between the two groups (P> 0.05). There was no difference in stage of embrionary development between the summer season and winter (P > 0.05) and was observed in both seasons the expanded blastocyst stage (84.40 % and 84.09 %, respectively for summer and winter), and there was no difference in pregnancy rates between groups (55.25% and 56.89% , for summer and winter, respectively) (P > 0.05) . Was no difference in the quality of the corpus luteum between groups (P < 0.05), with the largest number of CL Grade 1 produced in summer (41.01% and 28.97% for summer and winter, respectively). The process of in vitro production of bovine embryos of the Gir breed dairy can be performed in both seasons without any difference in results in the Reconcavo region of Bahia and maximum ambient temperature of up to 33, 07 o C.