Hristov A N, Price W J, Shafii B
Department of Animal and Veterinary Science, College of Agricultural and Life Sciences, University of Idaho, Moscow 83844.
J Dairy Sci. 2005 Aug;88(8):2860-9. doi: 10.3168/jds.S0022-0302(05)72967-2.
Previously observed strong relationships between dry matter (DM) intake and milk yield in dairy cows were the basis for this meta-analysis aimed to determine the influence of intake of specific dietary nutrients on milk yield and milk protein yield in Holstein dairy cows. Diets (563) from feeding trials published in the Journal of Dairy Science were evaluated for nutrient composition using 2 diet evaluation programs. Intake of nutrients was estimated based on DM intake and program-derived diet composition. Data were analyzed with and without the effect of stage of lactation. Models based on intake of nutrients improved prediction of milk yield and milk protein yield compared with DM intake alone. Intake of net energy of lactation was the dominant variable in milk yield prediction models derived from both diet evaluation models. Milk protein yield models also improved prediction over the DM intake model. These models were dominated by ruminally undegradable protein intake and included a number of energy-related intake variables. In most models, incorporating stage of lactation improved the model fit.
先前观察到的奶牛干物质摄入量与产奶量之间的强相关性是本荟萃分析的基础，该分析旨在确定特定膳食营养素摄入量对荷斯坦奶牛产奶量和乳蛋白产量的影响。使用2种日粮评估程序对发表在《乳品科学杂志》上的饲养试验中的日粮（563种）进行了营养成分评估。根据干物质摄入量和程序得出的日粮组成估算营养素摄入量。在考虑和不考虑泌乳阶段影响的情况下对数据进行了分析。与仅使用干物质摄入量相比，基于营养素摄入量的模型改善了对产奶量和乳蛋白产量的预测。泌乳净能量摄入量是两种日粮评估模型得出的产奶量预测模型中的主导变量。乳蛋白产量模型也比干物质摄入量模型改善了预测效果。这些模型以瘤胃不可降解蛋白摄入量为主导，并包括一些与能量相关的摄入量变量。在大多数模型中，纳入泌乳阶段可改善模型拟合度。
