Submitted to: American Society of Animal Science
Publication Type: Abstract Only
Publication Acceptance Date: 2/21/1997
Publication Date: N/A
Citation: Interpretive Summary:
Technical Abstract: The objective of this research was to quantify the proportions of subcuta- neous and intermuscular fat of beef carcasses fabricated to two fat trim levels. Carcasses from one side of 610 steers born from 1988 to 1990 in Cycle IV of the Germ Plasm Evaluation research program were fabricated into roast and steak meat trimmed to two levels (.76 and .00 cm), lean trim standardized to 20% fat, bone and fat trim. Weights of subcutaneous and intermuscular fat were recorded separately at each trim level. All fat in the plate was considered to be intermuscular fat. Quadratic or linear re- gression curves were plotted for percentages of retail product and fat trim components relative to incremental changes in USDA yield grade. Trimming to .00 cm of fat resulted in about a 5.5% lower percentage of retail pro- duct compared to trimming to .76 cm. The proportions of both subcutaneous and intermuscular fat increased nearly linearly from yield grade 1 through yield grade 5 carcasses. The average percentages of subcutaneous fat ex- pressed as percentages of carcass weight for a yield grade 3.0 carcass were 5.2% and 7.4%. The average percentages of intermuscular fat were 9.8% and 11.6%. When boneless roast and steak meat was trimmed to .00 cm fat cover, subcutaneous fat expressed as a percentage of the sum of subcutaneous fat plus intermuscular fat was 38%, whereas percentage of intermuscular fat expressed the same way was 62% for a yield grade 3.0 carcass. The latter does not include intermuscular fat in the lean trim. The percentage of subcutaneous fat expressed as a percentage of the sum of subcutaneous plus intermuscular fat increased as yield grade number increased, but the percentage of intermuscular fat was higher for all yield grades than the percentage of subcutaneous fat.