Simple linear regressions to estimate empty body chemical composition of Santa Gertrudis young bulls were obtained, using the physical and chemical composition of the 9-10-11th ribs cut. Fifteen intact males, from nine to fifteen months of age and from 220 to 505 kg of liveweight, were kept confined. They were slaughtered after 18 hours without water and food, and six of them were slaughtered after adaptation period. The content of water, protein, lipid and ash were determined on the ribs cut and on the blood, hide, head + feet, visceras and carcass, and samples were obtained after quantitatively grinding and homogenizing the entire tissue. The physical composition of the ribs was determined by manual separation of bone, lean and fat. Empty body weight was closely related to hot carcass weight (r² = 0.99). Percent water and lipid of the 9-10-11th ribs cut were closely related to the empty body chemical composition, but not to the percent protein and ash, that can be calculated from their proportions on the empty body without fat. The physical composition of the ribs cut was a good estimator of the empty body composition, mainly for the equations using separable ribs fat to estimate the contents of water, ether extract and ash, but not protein content. Despite the good results with the ribs cut physical composition, chemical composition was a more efficient estimator of empty body chemical composition, because the coefficients of determination were higher and the standard errors were lower. As the percentage of water in empty body was closely related to the water percent on 9-10-11th ribs (r² = 0.95) and the percentages of ether extract and water in the empty body (r² = 0.94) were closely related each other, the water in the 9-10-11th ribs cut alone can be used to estimate empty body composition.
bovines; empty body composition; indirect determination
