THE ESTIMATION OF BEEF CARCASS MUSCLE USING CROSS-SECTIONAL AREA OF M-LONGISSIMUS-DORSI AT THE 5TH RIB

The improvements in the accuracy of prediction of side muscle (weight and proportion) using measurements of eye muscle area at the 10th rib (EMA10) and eye muscle area at the 5th rib (EMA5), were compared in 48 steers, grain-fed for the Japanese market. For side muscle proportion the addition of EMA10 to hot side weight and a fat thickness measurem ent did not improve prediction but the addition of EMA5 did. P8 fat th ickness together with hot side weight and EMA5 (each, P<0.001) predict ed side muscle proportion with an SEE of 2.05% and an R2 of 61%, while the values for 10th rib thickness together with hot side weight and E MA5 (each, P<0.001) were 2.09% and 68%, respectively. For the predicti on of side muscle weight a fat thickness measurement and hot side weig ht (both, P<0.001) explained 77-84% of variance; the addition of an ey e muscle area measurement further improved prediction with the most ac curate being P8 fat thickness together with hot side weight and EMA5.