Predicting percentage of retail yield from carcass measurements, the yield grading equation, and closely trimmed, boxed beef weights

• Published in: Journal of animal science Vol. 70; no. 7; p. 2151
• Main Authors: Reiling, B.A. (Animal Sciences Laboratory, Urbana, IL), Rouse, G.H, Duello, D.A
• Format: Journal Article
• Language: English
• Published: United States 01.07.1992
• Subjects: Abattoirs; Adipose Tissue - anatomy & histology; Animals; Body Weight; BOEUF; BOVIN DE BOUCHERIE; BUEY; CARNE DE RES; Cattle - anatomy & histology; COMPOSICION DE LA CANAL; COMPOSITION DE LA CARCASSE; Female; GANADO DE CARNE; Male; MATEMATICAS; MATHEMATIQUE; Meat - standards; MUSCLE; Muscles - anatomy & histology; MUSCULOS; PIECE DE VIANDE; PIEZAS DE CARNE; Regression Analysis; RENDEMENT EN VIANDE; RENDIMIENTO CARNICO; Sex Factors; SEXE; SEXO; TAUREAU; TECHNIQUE DE PREVISION; TECNICAS DE PREDICCION; TEJIDO ADIPOSO; TISSU ADIPEUX; TORO; VACA; VACHE; VIANDE BOVINE
• ISSN: 0021-8812; 1525-3163
• DOI: 10.2527/1992.7072151x

Over the past 3 yr, 100 carcasses (64 steers, 24 bulls, and 12 heifers) were fabricated into closely trimmed (6 mm maximum fat cover), boxed beef and further evaluated for percentage of retail yield at the Iowa State University Meat Laboratory. Hot carcass weight ranged from 235 to 399 kg with a least squares mean (LSM) and standard error across all sex classes of 318 +/- 3 kg. Additionally, fat cover ranged from 0.30 to 1.78 cm with an average of 0.91 +/- 0.05 cm. The LSM for longissimus muscle area (LMA) across all sex classes was 81.6 +/- 1.0 cm2. Bulls had significantly less subcutaneous fat (P 0.01) and greater LMA (P 0.01) than did either steers or heifers. Retail yield from the boxed chuck, expressed as a percentage of cold carcass weight, was 19.2 for bulls and 14.8 for steers. This difference was due primarily to a reduction of intermuscular fat. Similarly, bulls had a greater yield (P 0.01) of the boxed round than did steers. When cattle of differing frame sizes were compared, only percentage of retail yield of the boxed round was significant (P 0.01): large-framed cattle yielded 14.3 +/- 0.2%, compared with 12.8 +/- 0.2% for the small-framed cattle. When all possible regression analyses were run, sex class differences accounted for 25.7% of the variation in retail yield. The current USDA retail yield equation accounted for only 37.2% of the variation. Percentage of closely trimmed, boneless round had an R2-value of 0.57. When sex class and percentage of round were added to the USDA yield grading factors, R2 improved from 0.48 to 0.70. Simple correlations of 0.68 for both the USDA equation and a newly developed equation from this data set showed that unless new variables such as sex class or percentage of round are added to the equation, the current equation seems to be adequate