ABSTRACT Respiration experiments with high-yielding dairy cows in Northern Ireland have shown higher energy maintenance requirements than those used in the requirements standards of, e.g. France, UK, USA and Germany. Therefore, the current net energy for lactation (NEL) system of Germany was tested by comparing measured NEL intake with calculated NEL requirements based on a comprehensive dataset from feeding trials conducted at nine research institutions in Germany, Austria and Switzerland. The relationship between NEL requirements and NEL intake is described by the equation: The equation indicates a systematic over-estimation of NEL requirements in the lower performance range and an under-estimation at higher energy intake levels. A multiple regression analysis was conducted by calculating metabolisable energy (ME) requirements [MJ/d] using metabolic body size (MBS) [kg0.75], milk energy performance (LE) [MJ/d] and body weight change (BWC) [kg/d]: These results indicate that the energy maintenance requirements are markedly higher than presumed in the feed evaluation systems commonly in use but confirm the results from Northern Ireland (0.600–0.660 MJ ME/kg0.75 MBS). ME efficiency for lactation is also higher (kL = 1/1.37 = 0.73) than that used in the systems and is also similar to the results of Northern Ireland with 0.64–0.69. The energy contribution of BWC derived by this equation is 12.1 MJ/kg (16.6 · 0.73) and distinctly lower than that of 21–25 MJ/kg presumed by the feeding standards, e.g. in Germany. Further, maintenance requirements were linked to milk yield (energy corrected milk (ECM) [kg/d]), as is practiced in the standard Australian energy system: These results demonstrate that maintenance energy requirements are partly dependent on milk yield. A differentiated analysis by stage of lactation showed that the regressions coefficients for MBS, LE and BWC change with lactation month; however, these findings apply especially to the first lactation months (i.e. in phases of intensive mobilisation).

中文翻译：

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基于饲喂试验综合分析的泌乳系统净能量评估和奶牛能量需求估算

摘要 北爱尔兰高产奶牛的呼吸实验表明，能量维持要求高于法国、英国、美国和德国等国的要求标准中使用的能量维持要求。因此，根据在德国、奥地利和瑞士的九个研究机构进行的喂养试验的综合数据集，通过比较测量的 NEL 摄入量与计算的 NEL 需求量来测试德国当前的净泌乳能量 (NEL) 系统。NEL 要求和 NEL 摄入量之间的关系由以下公式描述： 该公式表明系统性高估了较低性能范围内的 NEL 要求，而在较高能量摄入水平上低估了 NEL 要求。通过使用代谢体大小 (MBS) [kg0.75]、牛奶能量性能 (LE) [MJ/d] 和体重变化 (BWC) 计算代谢能 (ME) 需求 [MJ/d] 来进行多元回归分析[kg/d]：这些结果表明能量维持要求明显高于常用饲料评估系统中的假设，但证实了北爱尔兰的结果 (0.600–0.660 MJ ME/kg0.75 MBS)。泌乳的 ME 效率也高于系统中使用的 (kL = 1/1.37 = 0.73)，并且也与北爱尔兰的结果相似，为 0.64–0.69。由该方程推导出的 BWC 的能量贡献为 12.1 MJ/kg (16.6 · 0.73)，明显低于饲喂标准所假定的 21-25 MJ/kg，例如在德国。更多，维持需求与产奶量有关（能量校正牛奶 (ECM) [kg/d]），正如在标准澳大利亚能源系统中所采用的那样：这些结果表明维持能量需求部分取决于产奶量。按泌乳阶段的差异分析表明，MBS、LE 和 BWC 的回归系数随泌乳月而变化；然而，这些发现尤其适用于最初的泌乳月（即在强化动员阶段）。