Measurement of total body electrical conductivity in beef and its correlation with carcass composition
Abstract
Two groups of carcasses were used in this experiment. Left beef carcass sides were used for carcass quality and quantity evaluation. Right sides were quartered and/or separated into primal cuts (eleven primal cuts for group 1 and four major primal cuts for group 2) for measurement of total body electrical conductivity (TOBEC). The best equations for dissected and fat-free side lean weights using the USDA yield grade factors showed R$\sp2$ =.916 and.869 (RSD = 3.23 and 3.79 kg) for group 1 and R$\sp2$ =.929 and.859 (RSD = 3.30 and 4.20 kg) for group 2. The TOBEC index (phase curve peak) of beef quarters was highly correlated with lean content of beef sides (r over.820, p $<$.001). Lean prediction equations developed from scanning beef hindquarters were better predictors than obtained from forequarters. The best equations for dissected and fat-free side lean weights based on TOBEC index of hindquarters had R$\sp2$ values.950 and.933 (RSD = 2.42 and 2.56 kg) for group 1 and R$\sp2$ =.919 and.906 (RSD = 3.53 and 3.41 kg) for group 2. Regression analysis of the lean content of the eleven primal cuts was estimated from the TOBEC index. Larger lean mass cuts (chuck and round) showed higher R$\sp2$ (.930-.980 vs.589-.933) and lower coefficient of variation (CV) values (2.48-5.01% vs 4.35-13.01%) than smaller lean mass cuts in the estimation of primal cut lean mass. Equations for fat-free lean weight of the four major primal cuts using the TOBEC index and cut measurements showed higher R$\sp2$ (.843 and.897 vs.741 and.874) and lower CV (4.97 and 5.49% vs 9.26 and 6.02%) values for chuck and primal round than rib and full loin. Biases due to differences in warm carcass weight were not significant in equations including MQ-25 TOBEC readings (group 1). However, equations using either yield factors or TOBEC measurements to predict lean content of carcasses from single sex or extremely fat populations may result in a bias problem (p $<$.05).
Degree
Ph.D.
Advisors
Forrest, Purdue University.
Subject Area
Food science
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