AVALIAÇÃO DA TAXA DE PRENHEZ EM PROGRAMA DE IATF USANDO SÊMENS DE DIFERENTES TOUROS DA RAÇA NELORE

Several reproductive technologies have been inserted into the production system in order to optimize the pregnancy rate, as fixed-time artificial insemination (FTAI). However, beyond the bull, others factors may interfere with the final pregnancy rate. This study was carried out to identify the variation on pregnancy rate in a FTAI program using semen from different Nellore bulls. It was collected information on 703 females raised on pasture in Goiás. To identify the variation on pregnancy rate, the binary outcome (Pregnancy) was fitted using logistic model to evaluate the effects of calving order (CO), body condition score (BCS), technician, timing of artificial insemination, batch and bull. Although there was a high variability of the pregnancy rate, the effect of the bulls was not statistically significant (P>0.05), and only BCS measured on day 0 of AI protocol was significant (P<0.05). These results reflect the importance of BCS on the reproductive efficiency of females.