Comparison of equations for predicting voluntary intake by dairy cows
Comparison of equations for predicting voluntary intake by dairy cows
复制标题
奶牛自愿采食量预测方程的比较
DOI：
10.1017/s0021859600043264
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发表时间：
1984
影响因子：
0.6
通讯作者：
J. Cobby
中科院分区：
文献类型：
--
作者：
H. Neal;C. Thomas;J. Cobby
奶牛的综合日粮通常使用回归方程计算的自愿采食量预测来制定。研究了七个方程预测干物质摄入量的准确性。当活重被视为观察到的每周平均值（MLW），观察到的产犊后的活重（CLW）或估计的品种重量伴随着一个概念模式的活重变化（BLW）进行比较。数据记录在英国弗里斯兰奶牛群在草地研究所饲料主要是青贮饲料和各种补充剂。每周计算均方预测误差（MSPE），并在整个实验期间进行总结。最小MSPE分别为2.1、2.8和2.4（kg D. M.）2分别使用MLW、CLW和BLW进行比较。农业、渔业和食品部（1975年）的公式只涉及活重和产奶量，效果很好，在只有有限的活重和产奶量测量数据时很有用，但Vadiveloo和Holmes（1979年）和刘易斯（1981年）的更复杂的公式始终给出最佳预测。说明了在应用预测方程时使用变量的原始定义的重要性。即便如此，在摄入量预测中发现的巨大误差表明需要进一步研究。
Summary Rations for dairy cows are often formulated using predictions of voluntary feed intake calculated from regression equations. The accuracy of the predictions of dry-matter intake by seven equations is investigated. Comparisons are made when live weight is taken to be the observed weekly mean (MLW), the observed live weight after calving (CLW) or an estimated breed weight accompanied by a notional pattern of live-weight change (BLW). Data recorded on a British Friesian dairy herd at the Grassland Research Institute fed mostly silage ad libitum and various supplements are used. The mean square prediction error (MSPE) is calculated for each week and summarized over the whole experimental period. The least MSPE's are 2·1, 2·8 and 2·4 (kg D.M.)2 for comparisons using MLW, CLW and BLW respectively. The Ministry of Agriculture, Fisheries and Food (1975) equation involving only live weight and milk yield performs well and would be useful when only the limited measurements of live weight and milk yield are available, but the more complex equations of Vadiveloo & Holmes (1979) and of Lewis (1981) give consistently the best predictions. The importance of using the original definitions of the variables when applying a predictive equation is illustrated. Even so, the large errors found in the predictions of intake points to the need for further research.