This trial was conducted to study the effects of replacing corn with increasing levels of cassava starch by-products on carcass and meat characteritics for fedlot young bulls. Percentages of substitution were 0, 25, 50, 75, and 100, in dry matter basis. Forty crossbred bulls (½ and ¾ Bos taurus x Bos índicus), averaging 21 months old and 363 kg of initial body weight and 570 kg of final body weight were assigned to a block design with eight replicates by treatment. No effect of treatment on carcass traits was detected. The averages were as follows: carcass yield, 54.79%; conformation, 12.32 (good +); carcass length, 132.5 cm; cushion thickness, 28.12 cm; ribeye area, 79.25 cm²; porcentages of bone, 15.51%, of muscle, 64.12%, and of fat, 20.85%; muscle + fat/bone relation , 5.52; edible portion percentage, 85.07%; fat thickness, 4.02 mm; and marbling, 3.9 (light -). No effect of treatment on chemical composition of meat was detected, with averages of 1.01; 19.16 and 2.24%, respectively, for ash, protein, and fat. There was significant difference for humidity, with higher percentage for 50% replacement diet (74.67%) and lower for 25% replacement diet (72.89%). The other treatments had intermediate values. No treatment effects were observed and mean values for the studied traits indicate that the obtained carcasses fulfill the expected requirements of market.
beef cattle; cassava by-products; animal feeding; nutritive value; meat quality
