Abstract Total mixed ration (TMR) quality depends on feed levels and values, and appropriate diet formulation, but also on diet preparation practice. We examined the accuracy and homogeneity of rations, as affected by the machinery used for TMR preparation, and their effects on dairy cow performance. Multiparous Israeli-Holstein cows (n = 216) were stratified into 2 groups, according to milk yields, days in milk, parity, and body weight; they were fed the same formulated TMR, prepared by either a trailer mixer (TM) or an self-propelled loading mixer (SPLM). To examine the accuracy of diet preparation we have recorded and analyzed 10 times the difference between the programmed and the actual loaded content (as fed matter) of each feed ingredient. For evaluation of the accuracy and homogeneity of the ration contents, the TMRs from 6 spots along the feeding trough were sampled at 10 time-points, and the samples were analyzed for DM, protein, ADF, aNDF and ash contents; the results were compared with the programmed values. On another 7 occasions, samples of the TMRs were taken from 3 spots along the feeding trough for evaluation of the particle sizes distribution using the Penn State Particle Separator. The mean difference – in percentage units – between the programmed and actual, loaded concentrate feeds was similar (∼ 5.7%) for both TMRs (SEM = 1.5; P = 0.98), but for forage feeds it was +17.6 and - 0.6% (SEM = 3.7; P = 0.001), for TM and SPLM TMR, respectively. The mean differences of contents (in percentage units; DM basis) between the programmed and prepared diets, were: for protein – 1.1 and 0.9% (SEM = 0.2, P = 0.25), for ADF – 2.7 and 1.3% (SEM = 0.2, P 19 mm was 2.9 percentage units greater (P = 0.04), and that of particles ≤ 8 mm was 3.3 percentage units less (P = 0.04) in the TM than in the SPLM ration. The milk yield was 1.2 kg/d greater (2.7%) in cows fed the SPLM than in those fed the TM TMR (P

中文翻译：

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拖车式搅拌机或自走式搅拌机加工的总混合日粮的准确性和均匀性，以及对高产奶牛产量的影响

摘要 全混合日粮 (TMR) 质量取决于饲料水平和价值，以及适当的日粮配方，还取决于日粮准备实践。我们检查了受用于 TMR 制备的机器影响的日粮的准确性和同质性，以及它们对奶牛生产性能的影响。根据产奶量、产奶天数、胎次和体重，将经产的以色列荷斯坦奶牛 (n = 216) 分为 2 组；它们被喂以相同配方的 TMR，由拖车搅拌机 (TM) 或自走式装载搅拌机 (SPLM) 制备。为了检查日粮制备的准确性，我们记录并分析了每种饲料成分的编程和实际装载含量（作为饲料）之间的 10 倍差异。为评估日粮含量的准确性和均匀性，在 10 个时间点对进料槽沿线 6 个点的 TMR 进行采样，并分析样品的 DM、蛋白质、ADF、aNDF 和灰分含量；将结果与编程值进行比较。另外 7 次，从沿进料槽的 3 个点采集 TMR 样品，以使用宾夕法尼亚州立大学粒子分离器评估粒度分布。两种 TMR（SEM = 1.5；P = 0.98）的程序化和实际装载精料饲料之间的平均差异（以百分比为单位）相似（~5.7%），但对于草料饲料，它是 +17.6 和 - 0.6%（ SEM = 3.7；P = 0.001)，分别为 TM 和 SPLM TMR。程序化日粮和预制日粮之间含量的平均差异（以百分比为单位；DM 基础）为：蛋白质 - 1.1 和 0.9%（SEM = 0.2，P = 0.25），ADF - 2.7 和 1.3%（SEM = 0.2） , P 19 mm 比 SPLM 配给中的 P 19 mm 大 2.9 个百分比单位（P = 0.04），TM 中≤ 8 mm 的颗粒比 SPLM 配给中的小 3.3 个百分比单位（P = 0.04）。饲喂 SPLM 的奶牛的产奶量比饲喂 TM TMR 的奶牛高 1.2 kg/d（2.7%）（P