An evaluation of the Australian beef carcase appraisal system

The australian Beef Carcase Appraisal System (ABCAS) which evaluates the commerical worth of carcases by scoring fat percentage, estimated from carcase weight and fat thickness, and by scoring muscle weight, estimated from rib-eye area (REA) and carcase length (CL), was used on 45 steer carcases. Scores were related to carcase components determined by total dissection. ABCAS underestimated fat percentage in 44 of the 45 carcases, the degree increasing with carcase fatness. In 26 of the 44 carcases (59.1%) fat was underestimated by over 7%. Twenty-nine of the 45 carcases (64.4%) received more points for the ABCAS estimates of fat percentage than for dissected values. Nine (20.0%) received the same score for the estimate but in 7 of these this was the minimum score for overfatness. Seven carcases only (15.6%) scored less for estimated fat percentage, 6 of these resulting from under-estimations on the ABCAS scale. Nine carcases which should have been penalised for overfatness were penalised for underfinish. ABCAS adjustments to estimated fat percentage for carcase weight were contradicted because of the small (0.03) but highly significant positive regression of fat percentage on carcase weight. ABCAS scores for carcase muscle, based on REA and CL were neither closely nor consistently related to dissected muscle percentage. The range of dissected muscle in the fat-free carcase (72-81%) was not accurately reflected by the ABCAS points score range (14-46). REA and CL were not satisfactory predictors of carcase muscle. It is concluded that differences in weight or percentage of muscle between carcases at constant fat-free carcase weight may be too small to determine accurately using current prediciton parameters. A useful estimation of the commercial value of a carcase may be based on cold carcase weight and fat thickness at the 10th rib. Two equations utilising these measurements are given for estimating fat percentage and muscle weight.