Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta T6G 2P5, Canada.
J Anim Sci. 2013 Jun;91(6):2846-57. doi: 10.2527/jas.2012-5564. Epub 2013 Mar 18.
The objectives of this study were to examine the impact of corn- or wheat-based dried distillers grains with solubles (CDDGS or WDDGS) on enteric methane (CH4) emissions from growing beef cattle and determine if the oil in CDDGS was responsible for any response observed. Effects of CDDGS or WDDGS on total N excretion and partitioning between urine and fecal N were also examined in this replicated 4 × 4 Latin square using 16 ruminally cannulated crossbreed heifers (388.5 ± 34.9 kg of initial BW). The control diet contained (DM basis) 55% whole crop barley silage, 35% barley grain, 5% canola meal, and 5% vitamin and mineral supplement. Three dried distillers grains with solubles (DDGS) diets were formulated by replacing barley grain and canola meal (40% of dietary DM) with CDDGS, WDDGS, or WDDGS plus corn oil (WDDGS+oil). For WDDGS+oil, corn oil was added to WDDGS (4.11% fat DM basis) to achieve the same fat level as in CDDGS (9.95% fat DM basis). All total mixed diets were fed once daily ad libitum. Total collection of urine and feces was conducted between d 11 and 14. Enteric CH4 was measured between d 18 and 21 using 4 environmental chambers (2 animals fed the same diet per chamber). Methane emissions per kilogram of DM intake (DMI) and as percent of GE intake (GEI) among heifers fed WDDGS (23.9 g/kg DMI and 7.3% of GEI) and the control (25.3 g/kg DMI and 7.8% of GEI) were similar (P = 0.21 and P = 0.19) whereas heifers fed CDDGS (21.5 g/kg DMI and 6.6% of GEI) and WDDGS+oil (21.1 g/kg DMI and 6.3% of GEI) produced less (P < 0.05) CH4. Total N excretion (g/d) differed (P < 0.001) among treatments with WDDGS resulting in the greatest total N excretion (303 g/d) followed by WDDGS+oil (259 g/d), CDDGS (206 g/d), and the control diet (170 g/d), respectively. Compared with the control diet, heifers offered WDDGS, CDDGS, and WDDGS+oil excreted less fecal N (P < 0.001) but more (P < 0.001) urinary N. Results suggest that high-fat CDDGS or WDDGS+oil can mitigate enteric CH4 emissions in growing beef cattle. However, to completely assess the impact of DDGS on greenhouse gas emissions of growing feedlot cattle, the potential contribution of increased N excretion to heightened NH3 and nitrous oxide emissions requires consideration.
本研究的目的是检验玉米或小麦基干酒糟及其可溶物（DDGS 或 WDDGS）对生长肉牛肠道甲烷（CH4）排放的影响，并确定 DDGS 中的油是否是观察到的任何反应的原因。在这项重复的 4×4 拉丁方试验中，还检查了 DDGS 或 WDDGS 对总氮排泄和尿氮与粪氮之间分配的影响，该试验使用了 16 头瘤胃插管杂交小母牛（初始体重 388.5±34.9kg）。对照日粮以（DM 基础）包含 55%整株大麦青贮、35%大麦粒、5%菜籽油和 5%维生素和矿物质补充剂。通过用 CDDGS、WDDGS 或 WDDGS+玉米油（WDDGS+油）替代大麦粒和菜籽油（日粮 DM 的 40%）来配制三种 DDGS 日粮。对于 WDDGS+油，将玉米油添加到 WDDGS（4.11%脂肪 DM 基础）中，以达到与 CDDGS（9.95%脂肪 DM 基础）相同的脂肪水平。所有总混合日粮均自由每日一次饲喂。在第 11 天至第 14 天之间进行尿液和粪便的总收集。在第 18 天至第 21 天之间使用 4 个环境室（每个环境室饲喂相同饮食的 2 头动物）测量肠道 CH4。WDDGS（23.9g/kg DMI 和 7.3%的 GEI）和对照（25.3g/kg DMI 和 7.8%的 GEI）中 WDDGS 喂养的小母牛的甲烷排放量（g/kg DMI）和占总可消化能（GEI）的比例（%）相似（P=0.21 和 P=0.19），而 CDDGS（21.5g/kg DMI 和 6.6%的 GEI）和 WDDGS+油（21.1g/kg DMI 和 6.3%的 GEI）喂养的小母牛产生的 CH4 较少（P<0.05）。氮总排泄量（g/d）因处理而异（P<0.001），WDDGS 导致最大的氮总排泄量（303g/d），其次是 WDDGS+油（259g/d）、CDDGS（206g/d）和对照日粮（170g/d），分别。与对照日粮相比，WDDGS、CDDGS 和 WDDGS+油喂养的小母牛排出的粪便氮量较少（P<0.001），但尿液氮量较多（P<0.001）。结果表明，高脂肪 CDDGS 或 WDDGS+油可以减少生长肉牛的肠道 CH4 排放。然而，要全面评估 DDGS 对生长育肥牛温室气体排放的影响，需要考虑增加氮排泄对升高的氨和氧化亚氮排放的潜在贡献。
