The objective of the research was to develop equations to predict the chemical body composition of F1 Simmental x Nellore, based on the chemical composition of rib joints. Twenty-nine F1 Simmental x Nellore bulls, averaging 17 months of age and initial live weight of 354 kg, were used. Five animals were slaughtered at the beginning of the experiment and the others were randomly allotted to the treatments designed according to the concentrate levels in the diet (25, 37.5, 50, 62.5, and 75%). Body contents of protein, fat, energy and ash were determined from the analysis of carcass joint, including the 9th, 10th and 11th ribs, according to HANKINS E HOWE (1946) (HH joint), and the remaining body tissues. The contents of protein, fat, energy and ash, except magnesium, from the HH joint, were closely correlated to the chemical empty body composition.
body composition; cattle; prediction equations
