Existing equations to estimate empty body chemical composition were developed over 40 years ago using different cattle genetics. The objective of this analysis was to evaluate existing equations using cattle genetics from then to today. A literature search was performed to identify experiments measuring empty body chemical composition by proximate analysis resulting in 198 treatment means from 25 experiments since 1976. Three sets of equations were used to compute empty body chemical composition assuming empty body water was known: 1) Garrett and Hinman (1969; 10.2527/jas1969.2811), 2) Gil et al. (1970: 10.2527/jas1970.313459x), and 3) Ferrell et al. (1976; 10.2527/jas1976.4251158x). Mean (SD) empty body water, fat and protein were 59.91 (6.32), 17.58 (7.89), and 18.24 (2.02) % of EBW, respectively. For all equations, simultaneous testing of intercept equal to zero and slope equal to 1 indicated that the intercept and slope for fat, protein, ash and energy were different than zero and one, respectively. The concordance correlation coefficient (CCC) was high (> 0.85) for fat and energy, but low (< 0.50) for protein and ash for all equations. Mean bias for fat, protein, ash, and energy ranged from -19.58 to -3.50%, 1.62 to 15.84%, -2.22 to 14.15%, and -6.09 to -0.63%, respectively, with Eq. 1 having the MB closest to 0 for protein, and Eq. 3 having the MB closest to 0 for fat, ash, and energy. Publication year as a continuous variable was a significant predictor of the difference between observed and predicted values for all components. Fat and energy had greater overpredicted whereas, protein and ash had greater underprediction in more recent publications. In conclusion, existing equations provide similar precision, but differ in accuracy to predict empty body chemical composition. The trend for greater bias in more recent publication years indicates the need to reevaluate relationships among empty body chemical components using current cattle genetics.

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214 评估有关生长/育肥牛的空体化学成分的方程

40 多年前使用不同的牛遗传学开发了用于估计空体化学成分的现有方程。该分析的目的是评估从那时到今天使用牛遗传学的现有方程。进行了文献检索，以确定通过近似分析测量空体化学成分的实验，从 1976 年以来的 25 次实验中得到了 198 种治疗方法。假设空体水已知，使用三组方程来计算空体化学成分：1) Garrett 和Hinman (1969; 10.2527/jas1969.2811), 2) Gil 等人。(1970: 10.2527/jas1970.313459x)，和 3) Ferrell 等人。（1976；10.2527/jas1976.4251158x）。平均 (SD) 空腹水、脂肪和蛋白质分别为 EBW 的 59.91 (6.32)、17.58 (7.89) 和 18.24 (2.02) %。对于所有方程，截距等于 0 和斜率等于 1 的同时测试表明，脂肪、蛋白质、灰分和能量的截距和斜率分别不为零和一。对于所有方程，脂肪和能量的一致性相关系数 (CCC) 较高 (> 0.85)，但蛋白质和灰分的一致性相关系数 (CCC) 较低 (< 0.50)。脂肪、蛋白质、灰分和能量的平均偏差范围分别为 -19.58 至 -3.50%、1.62 至 15.84%、-2.22 至 14.15% 和 -6.09 至 -0.63%，方程式。1 具有最接近 0 的蛋​​白质的 MB，和等式。3 脂肪、灰分和能量的 MB 最接近 0。作为连续变量的出版年份是所有组件的观察值和预测值之间差异的重要预测因子。脂肪和能量被高估了，而 蛋白质和灰分在最近的出版物中被低估了。总之，现有方程提供了相似的精度，但预测空体化学成分的精度不同。最近出版年份出现更大偏差的趋势表明，需要使用当前的牛遗传学重新评估空体化学成分之间的关​​系。