Visual marbling score and chemical fat content of the M. longissimus in beef carcasses.

The visually assessed marbling score and the intramuscular fat content at the 5th rib and the 10th rib positions were determined for M. longissimus samples from 48 beef carcasses of 4 breeds. The carcasses were heavy (mean side weight of 195 kg), relatively fat (mean P8 fat thickness of 18 mm), had mean marbling scores of 2.6 at the 5th rib and 2.4 at the 10th rib and mean intramuscular fat contents of 8.63% at the 5th rib and 7.97% at the 10th rib. The correlation coefficient between marbling score and intramuscular fat content at the 5th rib was 0.68 and at the 10th rib was 0.49, with some pronounced breed differences occurring at the 10th rib but not at the 5th rib. Marbling scores assessed at either the 5th rib or the 10th rib did not provide a useful prediction of intramuscular fat content.