In the presentwork we aimed to compare intake, performance, feed efficiency and carcass traitsof cattle from three genetic groups (GG) fed two concentrate levels in the diet.Forty-eight steers (16 Nellore, 16 Nellore-Red Angus and 16 Nellore-Simmental)were used. Twelve steers were slaughtered at the beginning of experiment asa reference group and for the remaining 36 animals, the concentrate mixtureof the ration was offered as 1 and 2% of body weight basis in a 3 × 2 factorialarrangement in a completely randomized design, with six repetitions. The valueof significance defined was 0.05. Isoprotein diets were composed of corn silageand concentrate. The trial was comprised of 3 periods of 28 days each and allanimals slaughtered at the end. The dry matter and nutrients intake was higherin diets with high concentrate level of steers, except for neutral detergentfiber. The dry matter intake of crossbred steers was higher than that of Nelore,however Nellore-Angus presented greater intake as compared with Nellore-Simmental.No differences were observed for animal performance among concentrate levels.Conversely carcass and empty body weight gain were higher as 2% of body weightconcentrate was offered. The crossbreds performance was higher than that ofNelore, although no differences were verified among crossbreds. No differenceswere found in the bionutritional index between the two concentrate levels, infeed efficiency to both carcass and empty body weight gain. Animals consumingconcentrate mixtures at the level of 2% of body weight presents greater intakeand performance than those that receive level of 1% of body weight basis, butwith no differences in feed efficiency. The Nelore-Simental is more efficientthan the Nelore-Angus, but both crossbreds are more efficient than Nelore.
