Department of Agricultural Research for Northern Sweden, Swedish University of Agricultural Sciences, SE-901 83, Umeå, Sweden.
Department of Agricultural Research for Northern Sweden, Swedish University of Agricultural Sciences, SE-901 83, Umeå, Sweden.
J Dairy Sci. 2021 May;104(5):5617-5630. doi: 10.3168/jds.2020-19644. Epub 2021 Mar 6.
This study evaluated the effects of gradual replacement of barley with oats on enteric CH emissions, rumen fermentation, diet digestibility, milk production, and energy utilization in dairy cows fed a grass silage-based diet. Sixteen lactating Nordic Red dairy cows received a total mixed ration [58:42 forage:concentrate on dry matter (DM) basis]. Grass silage (Phleum pratense) was the sole forage with canola meal (10% of diet DM) as a protein supplement. The effects of gradual replacement of barley with oats on DM basis were evaluated using a replicated 4 × 4 Latin square design with 21 d periods. The grain supplements (30% of diet DM) consisted of 100% barley, 67% barley and 33% oats, 33% barley and 67% oats, and 100% oats. In addition to intake, milk production, and digestibility measurements, CH emissions were measured by the GreenFeed system (C-Lock Inc.). The energy metabolism was estimated from the gas exchange measurements recorded by the GreenFeed unit. The last 10 d of each period were used for recordings of gas exchanges, feed intake and milk production. Dry matter intake, body weight, milk yield, and energy-corrected milk yield were not affected by gradual replacement of barley with oats in the diet. Increased inclusion of oats linearly decreased CH emissions from 467 to 445 g/d, and CH intensity from 14.7 to 14.0 g/kg energy-corrected milk. In addition, the ratio of CH to CO decreased with increasing inclusion of oats in the diet. Digestibility of organic matter, neutral detergent fiber, and potentially digestible neutral detergent fiber decreased linearly with increasing inclusion of oats. Increased inclusion of oats linearly increased fecal energy from 121 to 133 MJ/d, whereas urinary energy and heat production were not affected by dietary treatment. This resulted in a linear decrease in metabolizable energy intake. However, increased levels of oat in the diet did not significantly affect energy balance or efficiency of metabolizable energy utilization for lactation. This study concludes that barley could be replaced with oats in the diet of dairy cows fed a grass silage-based diet to mitigate CH emissions without having any adverse effects on productivity or energy balance. However, the effect of replacing barley with oats on CH emissions is dependent on the differences between barley and oats in the concentrations of indigestible neutral detergent fiber and fat.
本研究评估了在以青贮草为基础的日粮中逐渐用燕麦替代大麦对奶牛肠道 CH 排放、瘤胃发酵、饲料消化率、产奶量和能量利用的影响。16 头泌乳北欧红牛奶牛接受了全混合日粮[干物质基础上 58:42 的饲料：浓缩物]。青贮草（梯牧草）是唯一的饲料，菜籽油粕（日粮干物质的 10%）作为蛋白质补充。用重复的 4×4 拉丁方设计评估了以大麦为基础的日粮中逐渐用燕麦替代大麦的效果，试验期为 21 天。谷物补充物（日粮干物质的 30%）由 100%大麦、67%大麦和 33%燕麦、33%大麦和 67%燕麦和 100%燕麦组成。除了摄入、产奶量和消化率测量外，CH 排放还通过 GreenFeed 系统（C-Lock Inc.）进行测量。能量代谢是通过 GreenFeed 单元记录的气体交换测量来估计的。每个时期的最后 10 天用于记录气体交换、饲料摄入和产奶量。在日粮中逐渐用燕麦替代大麦不会影响干物质摄入、体重、产奶量和能量校正奶产量。随着燕麦含量的增加，CH 排放量从 467 降至 445 g/d，CH 强度从 14.7 降至 14.0 g/kg 能量校正奶。此外，随着日粮中燕麦含量的增加，CH 与 CO 的比例降低。随着燕麦含量的增加，有机物、中性洗涤纤维和潜在可消化中性洗涤纤维的消化率呈线性下降。随着燕麦含量的增加，粪便能量线性增加，从 121 增至 133 MJ/d，而日粮处理对尿能和产热没有影响。这导致可代谢能摄入的线性下降。然而，日粮中燕麦水平的增加并没有显著影响产奶的能量平衡或可代谢能利用效率。本研究得出结论，在以青贮草为基础的日粮中，奶牛可以用燕麦替代大麦来减少 CH 排放，而不会对生产力或能量平衡产生不利影响。然而，用燕麦替代大麦对 CH 排放的影响取决于大麦和燕麦在不可消化中性洗涤纤维和脂肪浓度方面的差异。
