Linear regressionswere developed to estimate the chemical empty body composition of cattle fromthree genetic groups (Caracu, CaS; Selected Nellore, NeS; and Control Nellore,NeC) using the physical and chemical compositions of the 9th-10th-11thrib section. Fifty six intact males (20 CaS, 20 NeS and 16 NeC) were slaughteredat 20-24 months of age. The content of water, protein, ether extract and asheswere determined in rib section and on samples obtained after grinding and homogenizationof all body tissues (blood, hide, head + feet, viscera and carcass). The physicalcomponents muscle, fat and bones were also determined in the rib section. Thebest estimates of empty body components were obtained using the same estimatorcomponents as in rib section. The amounts of water and ether extract of therib section accurately allowed to estimate the total water, ether extract andprotein in the empty body of animals. The amounts of muscle and fat in the ribsection allowed estimating with efficiency the total of water, ether extractand protein in the empty body of animals. To estimate the empty body total ashesthree multiple equations were developed (one for each genetic group) with satisfactorycoefficients of determination. These equations included as estimators the amountsof muscle and fat in the rib section. The physical and chemical compositionsof the rib section can satisfactorily estimate the chemical components of theempty body of animals. Equations described in the literature can estimate withprecision the amounts of ether extract and water in the body empty of animalsof this study.
