Estimation of chemical carcass composition from 8th rib characteristics with Belgian blue double-muscled bulls

Characteristics from the 8th rib cut: chemical composition, tissue composit ion after dissection, specific gravity (SG) and m. longissimus thoracis (LT ) composition, collected on 17 Belgian Blue double-muscled fattening bulls were used to generate equations for predicting chemical carcass composition . Carcass composition was best predicted from chemical analysis of the 8th rib cut and the empty body weight (EBW) of the bull. Carcass chemical fat c ontent (CCF, kg) was predicted from the 8th rib cut fat content (ether extr act, 8RF, kg) by the following regression: CCF = 1.94 + 27.37 8RF (R-2 = 0. 957, RSD = 9.89%). A higher coefficient was found for carcass water (CCW, k g) predicted from 8RF and EBW: CCW=-2.26+0.28 EBW-34.28 8RF (R-2=0.997, RSD =1.48%). No parameter was found to improve the prediction of CCP from EBW s olely: CCP= -0.86+0.08 EBW (R-2 = 0.992, RSD=2.61%). Prediction equations b ased solely on LT composition had low R-2 values of between 0.38 and 0.67, whereas no significant equations were found using SG. However, equations ba sed on EBW had R-2 values between 0.78 and 0.99. Chemical components of the 8th rib cut in combination with EBW are most useful in predicting the chem ical composition of the carcass of Belgian-Blue double-muscled bulls. (C) 1 998 Elsevier Science Ltd. All rights reserved.