The objective of this work was to evaluate the effects of sex class and concentrate allowance level on performance and digestibility of the nutrients in Nellore cattle. Thirty five animals were used, 12 young bulls, 11 steers and 12 heifers, from the same contemporary group, were randomly allotted into two treatments: concentrate allowance levels of 0.6 and 1.2% BW, respectively. The animals were individually fed during 112 days, and slaughtered at the end of the trial with a reference group slaughtered at the beginning of the trial. The young bulls were more efficient and had heavier body weight (BW) and empty body weight (EBW), as a result of their increased growth rate in relation to the heifers, with the steers presenting intermediate values. The relative intakes (% BW) of dry matter and of all other nutrients were superior in the heifers in relations to the young bulls, while the steers showed intermediate values. The digestibilities, except EE, were unaffected by sexual class. The digestibilities of dry matter and organic matter were higher for the diet with concentrate allowance of 1.2% BW. Sexual class affected the growth and the intake capacity of the animals, however with no effect on the digestibility of the nutrients of the diet. Concentrate allowance levels of 0.6 and 1.2% BW were not sufficient to elicit difference in the performance of Nellore cattle, independently of sex class.
