FACTORS AFFECTING ESTIMATION OF MARBLING IN CATTLE AND THE RELATIONSHIP BETWEEN MARBLING SCORES AND INTRAMUSCULAR FAT

The aim of this study was to investigate the relationships between various estimates of marbling in Jersey and Limousin crossbred steers with intramuscular fat percentage (IMF%) as determined by solvent extraction. The correlations between IMF% and various marbling scores ranged from 0.67 to 0.79. AUS-MEAT, MSA or USDA scoring systems were correlated, and ranked animals similarly. However, the best correlation with IMF% was found to be with the AUS-MEAT marbling score. When the range of IMF% was assigned to different scores within each system, the AUS-MEAT and USDA systems were similar whereas MSA scores had a higher concentration of fat per score and a broader range of concentrations. The only factors influencing assessment of marbling were IMF% and breed. Other traits, such as loin temperature, eye muscle area, melting point, fat colour and meat colour were not significant. Jersey cross steers had higher marbling scores (1.9 vs 0.8) and IMF% (6.4 vs 4.4%) than Limousin cross. A breed by sire interaction in marbling was also detected.