May S G, Mies W L, Edwards J W, Williams F L, Wise J W, Morgan J B, Savell J W, Cross H R
Department of Animal Science, Texas A&M University, College Station 77843-2471.
J Anim Sci. 1992 Aug;70(8):2431-45. doi: 10.2527/1992.7082431x.
Commercial slaughter steers (n = 329) and heifers (n = 335) were selected to vary in slaughter frame size and muscle thickness score, as well as carcass adjusted 12th-rib fat thickness. After collection of USDA carcass grade data, one side of each carcass was fabricated into boneless primals, subprimals, and minor tissue components. Cuts were trimmed to 2.54, 1.27, and .64 cm of external fat, except for the knuckle, tri-tip, and tenderloin, which were trimmed of all fat. Forced four-variable regression equations were used to predict the percentage (chilled carcass weight basis) yield of boneless subprimals at the three fat trim levels as influenced by sex class, frame size, muscle score, and adjusted 12th-rib fat thickness. Independent variables that had the most influence on percentage yield of primals and boneless subprimals were adjusted 12th-rib fat thickness and sex class. Within the same phenotypic group, percentage of trimmable fat increased by 2.32% as 12th-rib fat thickness increased by .75 cm. Estimated percentage yield of the major subprimals from the loin and round tended to be higher or relatively equal for heifer carcasses at all trim levels compared with those subprimals from steer carcasses. Holding frame size, sex class, and fat thickness constant, there was a higher percentage yield of chuck roll, rib eye roll, and strip loin for carcasses from thick-muscled cattle than for those from average- and thin-muscled cattle. Frame size had little effect on percentage yield of boneless subprimals.
选取了329头商品屠宰公牛和335头小母牛，使其在屠宰体格大小、肌肉厚度评分以及胴体第12肋调整后的脂肪厚度方面存在差异。收集美国农业部胴体等级数据后，将每具胴体的一侧加工成去骨的主要切块、次主要切块和次要组织部分。除了指关节肉、三角肌和里脊肉需去除所有脂肪外，其他切块的外部脂肪均修剪至2.54厘米、1.27厘米和0.64厘米。使用强制四变量回归方程来预测在三种脂肪修剪水平下，去骨次主要切块的产量百分比（以冷却胴体重量为基础），该产量受性别类别、体格大小、肌肉评分和第12肋调整后的脂肪厚度影响。对主要切块和去骨次主要切块产量百分比影响最大的自变量是第12肋调整后的脂肪厚度和性别类别。在同一表型组内，随着第12肋脂肪厚度增加0.75厘米，可修剪脂肪的百分比增加2.32%。在所有修剪水平下，小母牛胴体腰部和后腿主要次主要切块的估计产量百分比往往高于公牛胴体的相应切块，或与之相对持平。在体格大小、性别类别和脂肪厚度保持不变的情况下，与平均肌肉和瘦肌肉牛的胴体相比，厚肌肉牛的胴体在肩胛卷肉、肋眼卷肉和里脊条肉的产量百分比更高。体格大小对去骨次主要切块的产量百分比影响较小。
