Beauchemin K A, McGinn S M
Agriculture and Agri-Food Canada, Research Centre, Box 3000, Lethbridge, Alberta, Canada.
J Anim Sci. 2006 Jun;84(6):1489-96. doi: 10.2527/2006.8461489x.
The objective of this study was to identify feed additives that reduce enteric methane emissions from cattle. We measured methane emissions, total tract digestibility (using chromic oxide), and ruminal fermentation (4 h after feeding) in growing beef cattle fed a diet supplemented with various additives. The experiment was designed as a replicated 4 x 4 Latin square with 21-d periods and was conducted using 16 Angus heifers (initial BW of 260 +/- 32 kg). Treatments were: control (no additive), fumaric acid (175 g/d) with sodium bicarbonate (75 g/d), essential oil and spice extract (1 g/d), or canola oil (4.6% of DMI). The basal diet consisted of 75% whole-crop barley silage, 19% steam-rolled barley, and 6% supplement (DM basis). Four large chambers (2 animals fed the same diet per chamber) were equipped to measure methane emissions for 3 d each period. Adding canola oil to the diet decreased (P = 0.009) total daily methane emissions by 32% and tended (P = 0.09) to decrease methane emissions as a percentage of gross energy intake by 21%. However, much of the reduction in methane emissions was due to decreased (P < 0.05) feed intake and lower (P < 0.05) total tract digestibility of DM and fiber. Digestibility of all nutrients was also lowered (P < 0.05) by feeding essential oil, but there were no effects on ruminal fermentation or methane emissions. In contrast, adding fumaric acid to the diet increased total VFA concentration (P = 0.03), increased propionate proportions (P = 0.01), and decreased the acetate:propionate ratio (P = 0.002), but there was no measurable effect on methane emissions. The study demonstrates that canola oil can be used to reduce methane losses from cattle, but animal performance may be compromised due to lower feed intake and decreased fiber digestibility. Essential oils had no effect on methane emissions, whereas fumaric acid caused potentially beneficial changes in ruminal fermentation but no measurable reductions in methane emissions.
本研究的目的是确定可减少牛肠道甲烷排放的饲料添加剂。我们测量了饲喂添加各种添加剂日粮的生长肉牛的甲烷排放量、全消化道消化率（使用氧化铬）和瘤胃发酵（采食后4小时）。试验设计为重复4×4拉丁方，每期21天，使用16头安格斯小母牛（初始体重260±32千克）进行。处理方式为：对照（不添加添加剂）、富马酸（175克/天）与碳酸氢钠（75克/天）、精油和香料提取物（1克/天）或菜籽油（占干物质采食量的4.6%）。基础日粮由75%的全株大麦青贮、19%的蒸汽压片大麦和6%的补充料（干物质基础）组成。每个时期有四个大室（每个室饲喂相同日粮的2头牛）配备用于测量甲烷排放3天。在日粮中添加菜籽油可使每日总甲烷排放量降低（P = 0.009）32%，并使甲烷排放量占总能摄入量的百分比有降低趋势（P = 0.09）21%。然而，甲烷排放的大部分减少是由于采食量降低（P < 0.05）以及干物质和纤维的全消化道消化率降低（P < 0.05）。饲喂精油也会降低所有营养素的消化率（P < 0.05），但对瘤胃发酵或甲烷排放没有影响。相比之下，在日粮中添加富马酸可提高总挥发性脂肪酸浓度（P = 0.03），增加丙酸比例（P = 0.01），并降低乙酸:丙酸比例（P = 0.002），但对甲烷排放没有可测量的影响。该研究表明，菜籽油可用于减少牛的甲烷损失，但由于采食量降低和纤维消化率下降，动物性能可能会受到影响。精油对甲烷排放没有影响，而富马酸会引起瘤胃发酵的潜在有益变化，但对甲烷排放没有可测量的减少作用。
