Hopkins D L, Roberts A H
Department of Primary Industry and Fisheries, PO Box 46, Kings Meadows, Tasmania 7249, Australia.
Meat Sci. 1995;41(2):137-45. doi: 10.1016/0309-1740(94)00077-k.
The percentage saleable meat yield was determined for 42 carcasses from grass-fed steers representing a range of breed types purchased in Australia for the Japanese market. Their mean (s.d.) carcass weight and P8 fat depth were 329 (28.1) kg and 17.3 (4.3) mm, respectively. All measures of subcutaneous fat depth were significantly (P < 0.05) and moderately correlated with percentage saleable meat yield, with measures in the loin region showing a stronger association than those taken in the rump region. The association between P8 fat depth and the loin measures of subcutaneous fat were low and there was a significant (P < 0.05) association only between P8 and fat depth at the 10th rib (FD 10). The use of fat depth measurements from the loin region reduced the error associated with predicting saleable meat yield more than those from the rump region and significantly increased the amount of variation (R(2)) in saleable meat yield that was explained. Hot carcass weight (HCW) did not significantly (P > 0.05) improve prediction models when combined with subcutaneous fat depth measurements and overall, the R(2) values were low ranging from 0.19 to 0.42. The models indicated that fat depth measures and carcass weight are poor predictors of percentage meat yield in heavy-weight carcasses from mixed breed cattle as produced and processed in Australia. The prediction of percentage yield was in general significantly (P < 0.05) improved when measures of M. longissimus thoracis et lumborum (LD) area were added as independent variables to models based on hot carcass weight and subcutaneous fat depth measurements. With LD area added the amount of variation in yield that could be explained by the models increased by as much as 28%. Overall, the best model was based on fat depth at the 12th rib and LD area measured at the 5th rib for which the R(2) was 0.58 and the residual standard deviation was 1.63%. The next most accurate prediction of yield was provided by a model which included the independent variables used in the Australian Chiller Assessment Scheme namely HCW, FD10 and LD area at the 10th rib upon which breed type had no significant (P > 0.05) effect.
测定了42头来自澳大利亚为日本市场采购的不同品种类型的草饲阉牛胴体的可售肉产量百分比。它们的平均（标准差）胴体重和第8肋处脂肪厚度分别为329（28.1）千克和17.3（4.3）毫米。所有皮下脂肪厚度测量值与可售肉产量百分比均呈显著（P<0.05）且中等程度的相关性，腰部区域的测量值比臀部区域的测量值显示出更强的关联。第8肋处脂肪厚度与腰部皮下脂肪测量值之间的关联较低，仅第8肋与第10肋处脂肪厚度（FD 10）之间存在显著（P<0.05）关联。与臀部区域的测量值相比，使用腰部区域的脂肪厚度测量值可减少与预测可售肉产量相关的误差，并显著增加可解释的可售肉产量变化量（R²）。热胴体重（HCW）与皮下脂肪厚度测量值结合时，对预测模型没有显著（P>0.05）改善，总体而言，R²值较低，范围为0.19至0.42。这些模型表明，在澳大利亚生产和加工的混合品种牛的重胴体中，脂肪厚度测量值和胴体重是肉产量百分比的较差预测指标。当将胸腰段最长肌（LD）面积测量值作为自变量添加到基于热胴体重和皮下脂肪厚度测量值的模型中时，产量百分比的预测通常会得到显著（P<0.05）改善。添加LD面积后，模型可解释的产量变化量增加了多达28%。总体而言,最佳模型基于第12肋处脂肪厚度和第5肋处测量的LD面积，其R²为0.58，剩余标准差为1.63%。产量的次准确预测由一个模型提供，该模型包括澳大利亚冷却器评估计划中使用的自变量，即热胴体重、FD10和第10肋处的LD面积，品种类型对其没有显著（P>0.05）影响。
