Efeitos da suplementação estratégica com metionina protegida da degradação ruminal sob parâmetros fisiológicos e produtivos de vacas Nelore

Abstract

The difficult to control high temperature and humidity index on bovines raised on pasture can affect the productive and reproductive efficiency of these animals, being necessary strategies to mitigate these effects. The aim of this dissertation was to evaluate the effects of rumen-protected methionine (RPM) supplementation on physiological and productive parameters of Nelore cows. On the study was used 563 multiparous Nelore cows, divided on two groups with three repetitions each, the control group (CG) and methionine group (MG), both were kept on tropical pastures with access to mineral supplementation, the MG had added to its supplementation 3g of RPM to 100g of supplement. The supplementation period was 77 days, 31 before the d0 of the fixed-time artificial insemination (FTAI) protocol, 11 during the protocol, and 35 until the pregnancy diagnosis. On protocol d0, accoupled to the intravaginal dispositive of progesterone, was put a datalogger on 142 animals, that measured the vaginal temperature each 30 minutes for eight days, the pregnancy rate was calculated by the number of pregnant cows/inseminated cows. The RPM supplementation did not affect the pregnancy rate (CG = 64.83% vs. MG = 60.01%) and had modulated the internal temperature (median CG = 39.63ºC vs. MG = 39.38ºC) in the moments that the environmental temperature increased. In conclusion, 3g of rumen-protected methionine modulate the internal temperature of Nelore cows submitted to high temperatures and humidity environments, but do not affect the pregnancy rate.