Vermorel M, Coulon J B
Laboratoire Croissance et Métabolismes des Herbivores, Centre de Recherches de Clermont-Ferrand/Theix, St-Genès Champanelle, France.
J Dairy Sci. 1998 Mar;81(3):846-55. doi: 10.3168/jds.S0022-0302(98)75643-7.
The structure, prediction steps, and accuracy of the US (NRC), United Kingdom (ARC), Dutch (VEM), French (UFL), and German (NEL) systems for feeding high producing cows were compared. Simulations were made using 15 feeds ranging from hays to cereals. Agreement was satisfactory among European systems for the prediction of metabolizable energy and net energy for lactation (NEL) contents of feeds and the quantities of feeds in balanced diets necessary to meet the energy requirements of lactating cows. The metabolizable energy and NEL contents of feeds seemed overestimated by the US system compared with results using the European systems, and the ratio of NEL to total digestible nutrients was almost constant, unlike the other systems. Estimating the NEL content of feeds for a level three times maintenance intake allowed satisfactory rationing for the production of 20 to 25 kg of fat-corrected milk/d. However, feed allowances seemed underestimated for higher milk production, especially with diets based on hay, probably because of the overestimation of feed NEL content, the underestimation of level of feeding, and the effects associated with feeding levels > 3 and high concentrate diets.
对美国（NRC）、英国（ARC）、荷兰（VEM）、法国（UFL）和德国（NEL）的高产奶牛饲养系统的结构、预测步骤和准确性进行了比较。使用从干草到谷物的15种饲料进行了模拟。欧洲各系统在预测饲料的可代谢能量和泌乳净能量（NEL）含量以及满足泌乳奶牛能量需求所需的平衡日粮中的饲料量方面，一致性令人满意。与使用欧洲系统的结果相比，美国系统似乎高估了饲料的可代谢能量和NEL含量，并且与其他系统不同，NEL与总可消化养分的比率几乎恒定。对于维持摄入量三倍水平的饲料，估计其NEL含量可为每天生产20至25千克校正乳脂的牛奶提供令人满意的定量。然而，对于更高的产奶量，饲料供应量似乎被低估了，尤其是对于以干草为基础的日粮，这可能是由于饲料NEL含量的高估、饲养水平的低估以及与饲养水平>3和高浓缩日粮相关的影响。
