Productive performance and carcass characteristics of dairy crossbred bulls fed different concentrate and broiler litter levels

Twenty-four Holstein crossbred young bulls, with initial average weight of 75 kg and final average weight of 215 kg, under feedlot, were used to evaluate the intake, average weight gain, feed:gain ratio, carcass and basic cuts yield and physical carcass composition. The animals were fed elephantgrass with 30 to 45 days of age, soybean meal, corn meal, meat meal and mineral mix basal concentrate, and broiler litter, that constituted the treatments: 1 = 50% forage and 50% concentrate, 2 = 50% forage, 35% concentrate and 15% broiler litter, 3 = 25% forage and 75% concentrate and 4 = 25% forage, 52.5% concentrate and 22.5% broiler litter, as dry matter basis. A completely randomized blocks experimental design, with six blocks and four treatments, was used. There was no effect of treatment for dry matter intake (DMI) in kg/day. The neutral detergent fiber intake (NDFI) was smaller for treatment 3 and crude protein intake (CPI) was larger for treatment 4. The DM, CP and NDF feed:gain ratios were better, the average daily weight gain (ADWG) and the hot and cold carcass weights of the animals of the treatment 3 (75% concentrate) were higher than the other treatments. The 22.5% broiler litter proportion of total dry matter decreased the ADWG in the diet with 75% concentrate, but it was not observed the same behavior to the 15% proportion. The hot and cold carcass dressing percentages, the acem, needle point, spare ribs, round, front, special back and total back yields, the carcass length, the loin eye area, the carcass physical composition and the muscle/bone relationship were not affected by the treatments. The animals of treatment 3 had the largest fat thickness and, consequently, the smallest break in cold carcass dressing percentage absolute value.