Inclusão de volumoso para bovinos de corte terminados com dietas de alto grão

Abstract

The study aimed to evaluate three diets with 0%, 2.5%, and 5% roughage offered to cattle in 4 the finishing phase on feedlot. We used 1800 male Nellore animals divided into 12 pens in a 5 randomized block design with 150 animals each. Average daily gain, carcass yield, and 6 efficiency were calculated for all animals, and data were collected throughout the 7 experimental period. The finishing characteristics, loin eye area, fat thickness, and croup’s fat 8 thickness were obtained using an ultrasound device. Thermal welfare and production of 9 enteric heat were evaluated daily, and blood samples were collected at the beginning and the 10 end of the experimental period. Dry matter intake differed linearly in an increasing way 11 (P<0.001), with an average of 10.34 kg of dry matter in the treatment with 100% concentrate 12 and 11.88 kg for the diet with 5% roughage. The average daily gain followed the increasing 13 linear behavior (P<0.001) of intake, with averages of 1.34, 1.5, and 1.74 kg per day, 14 respectively, for treatments with 0, 2.5, and 5% roughage. The welfare index showed 15 increasing linear behavior (P<0.001) between the roughage levels. The number of standing 16 animals photographed at 6 am, moments before the morning meal, showed decreasing linear 17 behavior, i.e., the lower the roughage level, the greater the number of standing animals. 18 Regarding heat production, this characteristic presented a statistical difference (P<0.001) 19 when comparing the right and left flank temperatures and the period in which the 20 measurements were performed. Furthermore, concerning the experimental diets, the P-value 21 was 0.0003. The levels of globulin, albumin, and total proteins were not significant (P>0.001). 22 Urea levels in the blood showed increasing linear behavior, whereas glycemia showed 23 quadratic behavior, reaching the highest value for the treatment with 2.5% roughage. Thus, 24 the roughage proportion in high-grain diets positively influences the intake, weight gain, and 25 welfare of cattle in feedlot.