Ganho de peso e rendimento de carcaça de bovinos de corte confinados com acesso a sombra

Abstract

CHAPTER 2: It evaluated itself the effect of the shade, in commercial feedlot beef cattle, about the average weight gain (AWG) and performance of carcass. They were utilized 156 animals Nelores (Bos Indicus) and Nelore-cross, with average initial weight 396 kg, divided in two pens, a shading with 90 animals (handling) and another not shady with 66 (witness); counts on occurred in two moments to the 77 days and to the 118 days of confinement. The food composed itself of a feed with urea, crumb of soy and supplement premix of a commercial brand, that was placed on top to the sorghum tillage and added of lump of cotton and sorghum in grain shredded and supplied "ad-libitum". It determined itself the extreme temperatures (maximum and most minimum); temperature of the dry bulb and wet bulb; temperature of the Black Globe Thermometer in the shade and to the sun; speed of the wind and precipitation. These facts were utilized in the determination of four indices of thermal environment (Temperature-Humidity Index - THI; Wet Bulb Globe Temperature - WBGT; Equivalent Temperature Index - ETI and Heat Load Index - HLI) for verification of the possibility of thermal stress. The animal performance was obtained by the weighing in the beginning of the confinement and when the animals were sold; also was considered the performance of carcass to the 118 days, in the second counts on. It applied analysis of variance and Tukey´s Test at 5%, being the variable I earn of weight corrected by the co-variance by means of the initial weight. Bovines Nelore and Nelore-cross, confined commercially with access in the shade, gains more of weight with 77 days. With 118 days the difference in earn of weight was not significant, but the performance of carcass of the animals of the shady pen was bigger.