UTILIZAÇÃO DO ESCT E DO GNRH COMO FERRAMENTAS PARA OTIMIZAR PROTOCOLOS DE IATF COM SEMEN SEXADO

The use of paint markers and the application of GnRH are tools that have been studied to increase the efficiency of FTAI protocols. The objective of this study was to evaluate the influence of the paint removal score (PRS) and GnRH on pregnancy rates and gestational losses of Nellore cows inseminated with sexed semen. A total of 119 Nellore cows were submitted to a 3-progesterone-based protocol (P4). At the time of insemination the PRS was evaluated (1,2 and 3), and the cows were divided into two groups: GnRH (n = 59) and Contr (n = 60). There was no significant difference between the PRS groups for pregnancy rate (PR) and gestational loss rate (GL) (PR: 46,1%, 50% and 54,3%; GL 14,3%, 16,1% and 7,89%, for PRS 1, 2 and 3). There was also no difference between the Contr and GnRH groups (PR: 54,2% and 50%; GL: 15,6% and 6,6%, for Contr and GnRH). It was concluded that under the conditions of this experiment the application of GnRH and the evaluation of PRS 60 hours after the withdrawal of P4 did not influence the pregnancy rate and gestational loss of nelore cows submitted to FTAI with sexed semen.