Efeitos da utilização do dispositivo intra-uterino (diu) sobre o ganho de peso e o rendimento de carcaça de novilhas nelore destinadas ao abate

Abstract

This experiment was conducted to evaluate the effectiveness of intra-uterine device to suppress estrus activity and improve weight gain and carcass yield in Nelore heifers. 41 Nelore heifers, from thirteen to fifteen months of age, were divided in two groups: control group (GC, n=19) and intra-uterine device group (GT-DIU, n=22). They were raised in Brachiaria brizantha cv. Marandu pasture, receiving mineral mix during raining period and mineral plus protein supplementation in dry season. The animals were weighed at the beginning of the experiment and every 28 days until the end of the study, when they were slaughtered. When the heifers were weighed, blood was collected from jugular vein to measure testosterone levels. For carcass measurements, the heifers were weighed 24 hours before slaughter and the total carcass weight were obtained in order to calculated the yield. The fore and hind quarters were weighed separately to evaluate yield. There were no difference between the two groups in all characteristics studied (P>0.05), and heifers continue to show signs of estrus. The results of this experiment suggest that the intrauterine device was no effective in suppress estrus activity and improve weight gain and carcass yield.