Department of Animal and Poultry Science, University of Guelph, Kemptville Campus, 830 Prescott Street, Kemptville, ON, K0G 1J0, Canada.
J Dairy Sci. 2012 Feb;95(2):850-5. doi: 10.3168/jds.2011-4509.
The objective of this study was to determine if feed sorting can be reduced and if nutrient consumption can be limited in late-lactation cows through water addition to a nutrient-dense total mixed ration (TMR) with a dry matter (DM) content greater than 60%. Twelve lactating Holstein cows (214.8±28.5 d in milk) were exposed to 2 diets in a crossover design with 28-d periods. Diets had the same ingredient composition and differed only in DM percentage, which was reduced by the addition of water. Treatment diets were (1) dry TMR (61.7% DM) and (2) wet TMR (51.9% DM). Dry matter intake and milk production (4% fat-corrected milk; FCM) were recorded for the last 14 d of each treatment period. For the final 4 d of each period, fresh feed and orts were sampled for particle size analysis and subsequent calculation of sorting activity (expressed as a percentage of predicted intake). Adding water to the diet tended to decrease the amount of DM in the fine particle fraction, increase starch concentration in the longer ration particles, and reduce starch concentration in the shortest ration particles. All cows sorted against long ration particles; the extent of this sorting did not differ between the dry and wet treatments (72.9 vs. 77.6%). There tended to be more sorting for fine ration particles on the dry diet compared with the wet (106.3 vs. 104.0%). Water addition had no effect on production, with similar DMI (27.9 vs. 26.5 kg/d), 4% FCM (28.7 vs. 27.6 kg/d), and efficiency of production (0.98 vs. 1.00 kg of 4% FCM/kg of DMI) between the dry and wet treatments. Adding water to a TMR with greater than 60% DM containing primarily haylage and corn silage forage sources may change ration particle DM distribution and particle starch content, possibly contributing to less sorting for the smallest ration particles. This research does not provide evidence that water addition to such a TMR can effectively limit DMI in late-lactation cows and, thus, improve efficiency of milk production.
本研究旨在确定通过向干物质（DM）含量大于 60%的高营养全混合日粮（TMR）中添加水，是否可以减少泌乳后期奶牛的饲料分类，并限制其营养物质的消耗。12 头泌乳荷斯坦奶牛（泌乳天数 214.8±28.5 天）采用交叉设计进行了 2 种日粮处理，每个处理期为 28 天。日粮具有相同的成分组成，仅 DM 百分比不同，通过添加水降低了 DM 百分比。处理日粮分别为（1）干 TMR（DM 含量 61.7%）和（2）湿 TMR（DM 含量 51.9%）。在每个处理期的最后 14 天记录干物质采食量和牛奶产量（校正 4%乳脂的牛奶；FCM）。在每个时期的最后 4 天，采集新鲜饲料和剩料进行颗粒大小分析，并随后计算分类活动（以预测采食量的百分比表示）。向日粮中添加水会降低细颗粒部分的 DM 量，增加较长日粮颗粒中的淀粉浓度，并降低最短日粮颗粒中的淀粉浓度。所有奶牛都对长料颗粒进行了分类；干处理和湿处理之间的分类程度没有差异（72.9%比 77.6%）。与湿处理相比，干处理中对细料颗粒的分类似乎更多（106.3%比 104.0%）。添加水对生产没有影响，干处理和湿处理的干物质采食量（27.9 比 26.5kg/d）、校正 4%乳脂的牛奶产量（28.7 比 27.6kg/d）和生产效率（1.00kg 校正 4%乳脂的牛奶/kg 干物质采食量）相似。向主要含有青贮干草和青贮玉米饲料的 TMR 中添加超过 60% DM 的水可能会改变日粮颗粒 DM 分布和颗粒淀粉含量，从而减少对最小颗粒的分类。本研究没有提供证据表明，向这样的 TMR 添加水可以有效地限制泌乳后期奶牛的干物质采食量，并提高牛奶生产效率。
