Studies of fat distribution in the bovine carcass. III.* Influence of intramuscular fat on the weight of total dissected muscle, muscle/bone ratio and the growth coefficients of muscle groups

Abstract

The influence of intramuscular fat weight on total dissected muscle weight, muscle/bone ratio and the growth coefficients of 'standard muscle groups' was examined in 55 cattle (including foetuses and calves) with total dissected fat contents ranging from 1.3 to 38.9%.

Intramuscular fat weight was significantly correlated with total dissected muscle weight (r = 0.97, P < 0.01), percentage total dissected fat weight (r = 0.82, P < 0.01) and age (r = 0.72, P < 0.01).

Comparison of two regressions of total muscle weight on total muscle plus bone weight, one based on dissected muscle weight and the other on dissected muscle weight less intramuscular fat weight, showed that neither the slopes nor the intercepts differed significantly.

Comparison of two regressions of muscle/bone ratio on muscle plus bone weight, one based on dissected muscle weight and the other on dissected muscle weight less intramuscular fat weight, showed that neither the regression coefficients nor the intercepts differed significantly. Intramuscular fat varied from 0.71 to 7.46% of chilled side muscle weight in carcasses which had total dissected fat contents ranging from 1.3 to 35.1 %. The increase in muscle/bone ratio attributable to intramuscular fat weight over this fatness range varied from 0.02 to 0.38.

Comparison between pairs of growth coefficients for each 'standard muscle group', one based on dissected muscle weight and the other on dissected muscle weight less intramuscular fat weight, showed that there were no significant differences.

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*Part II, Aust. J. Agric. Res., 24: 287 (1973).