The present work was carried out at Universidade Federal de Santa Maria to evaluate composition of the body and body weight gain. A experiment was conducted with 70% of corn silage and 30% of concentrate. Forty 3,5 years old Santa Gertrudis steers were used; four of them were slaughtered at the beginning of the experiment and 36 were randomly assigned to the treatments and slaughtered at the end of the experimental period. From each carcass the 9th to 11th rib section was taken and its physical and chemical composition determined, and from this the body composition was estimated. Linear equations between log of protein, fat and energy content in the empty body and log of empty body weight were fitted. It was observed that increasing empty body weight decreased the content of protein in empty body and in empty body weight gain while it increased fat and energy content. It was also observed that when body weight increased, the requirements of energy increased while those of protein decreased.
meat and bone meal; silage; urea
