Thirty two Santa Gertrudis bulls with ten months of age and 245 kg average live weight were fed 88% concentrate diets with corn silage or sugarcane bagasse and dry corn or high moisture corn. Four animals were slaughtered in the beginning of the experiment for initial body composition determination. Other 28 animals were distributed on four treatments. The experimental design was randomized blocks in 2 X 2 factorial (two roughage X two corn sources) with seven replicates. Regression equation of log body energy content as a function of log empty body weight (EBW) provided estimation of body energy content at any EBW range included in this research: for weight gain of 1 kg, an animal of 300 kg requires 3.64 Mcal/day of energy and 129.5 g of protein.
bulls; energy requirements; feedlot; sugarcane bagasse; high moisture corn
