Bayat A R, Ventto L, Kairenius P, Stefański T, Leskinen H, Tapio I, Negussie E, Vilkki J, Shingfield K J
Milk Production Solutions, Green Technology, Natural Resources Institute Finland (Luke), FI-31600 Jokioinen, Finland.
Animal Genomics, Green Technology, Natural Resources Institute Finland (Luke), FI-31600 Jokioinen, Finland.
Transl Anim Sci. 2017 Sep 1;1(3):277-286. doi: 10.2527/tas2017.0032. eCollection 2017 Sep.
The effects of supplementing high- or low-concentrate diets with sunflower oil (SO) on rumen fermentation, nutrient utilization, and ruminal methane (CH) emissions in lactating cows were examined. Four multiparous Nordic Red dairy cows fitted with rumen cannulae were used in a 4 × 4 Latin square with a 2 × 2 factorial arrangement of treatments and 35-d periods. Experimental treatments comprised iso-nitrogenous total mixed rations based on grass silage with forage to concentrate ratio of 65:35 or 35:65 supplemented with 0 or 50 g/kg diet DM of SO. Apparent ruminal OM and starch digestibility was greater ( < 0.05) with high- than low-concentrate diets but was unaffected by SO. Inclusion of SO in high-concentrate diet decreased ( ≤ 0.05) apparent total tract OM, fiber, and GE, and apparent ruminal fiber digestibility. High-concentrate diets and SO shifted ( < 0.05) fiber digestion from rumen to the hindgut. High-concentrate diet resulted in a lower rumen pH and elevated total rumen VFA concentration compared with low-concentrate diet, whereas SO increased rumen pH and decreased rumen VFA concentration when included in high-, but not low-concentrate diet ( < 0.05 for interaction). High-concentrate diet reduced rumen ammonia-N ( < 0.01) and molar proportion of acetate to propionate ( < 0.01), and decreased ( < 0.05) ruminal CH emissions when expressed as g/d or g/kg OM digested in the rumen. With both low- and high-concentrate diets, SO reduced ( < 0.05) daily emissions of CH as g/d or g/kg OM digested in the rumen, but SO reduced CH emissions expressed as g/kg OM intake, OM digested in total digestive tract, energy-corrected milk or % of GE intake only with low-concentrate diet ( ≤ 0.05 for interaction). In conclusion, replacing grass silage with concentrates led to a reduction in daily ruminal CH emissions that were accompanied by a shift in rumen fermentation toward the synthesis of propionate, and decreases in rumen pH and fiber digestion. Sunflower oil was effective in reducing daily CH emissions in lactating cows which was accompanied by a noticeable lower feed intake with high- but not low-concentrate diet. Overall the effects of SO and greater proportion of concentrates in the diet on daily CH emissions were additive but the additivity declined or vanished when different indices of CH emission intensity were considered. Consequently, SO was more effective in reducing CH emissions when low-concentrate diet was fed.
研究了在泌乳奶牛的高浓缩或低浓缩日粮中添加向日葵油（SO）对瘤胃发酵、养分利用和瘤胃甲烷（CH）排放的影响。选用4头装有瘤胃瘘管的经产北欧红牛奶牛，采用4×4拉丁方设计，处理采用2×2析因排列，试验期35天。试验处理包括以青贮饲料为基础的等氮全混合日粮，饲草与精料比例为65:35或35:65，并添加0或50 g/kg日粮干物质的SO。高浓缩日粮组的瘤胃表观有机物质和淀粉消化率高于低浓缩日粮组（P<0.05），但不受SO的影响。在高浓缩日粮中添加SO降低了（P≤0.05）表观全消化道有机物质、纤维和总能，以及瘤胃表观纤维消化率。高浓缩日粮和SO使纤维消化部位从瘤胃转移到后肠（P<0.05）。与低浓缩日粮相比，高浓缩日粮导致瘤胃pH值降低，瘤胃总挥发性脂肪酸浓度升高，而在高浓缩日粮中添加SO可提高瘤胃pH值，降低瘤胃挥发性脂肪酸浓度，在低浓缩日粮中添加SO则无此作用（交互作用P<0.05）。高浓缩日粮降低了瘤胃氨氮（P<0.01）和乙酸与丙酸的摩尔比例（P<0.01），以g/d或g/kg瘤胃消化有机物质表示时，降低了瘤胃CH排放（P<0.05）。在低浓缩和高浓缩日粮中，SO均降低了以g/d或g/kg瘤胃消化有机物质表示的CH日排放量，但只有在低浓缩日粮中，SO降低了以g/kg有机物质摄入量、全消化道消化有机物质、能量校正乳或总能摄入量百分比表示的CH排放（交互作用P≤0.05）。总之，用精料替代青贮饲料可降低瘤胃CH日排放量，同时瘤胃发酵向丙酸合成方向转变，瘤胃pH值和纤维消化率降低。向日葵油能有效降低泌乳奶牛的CH日排放量，高浓缩日粮组的采食量明显低于低浓缩日粮组。总体而言，日粮中SO和较高比例的精料对CH日排放量的影响具有相加性，但考虑不同的CH排放强度指标时，相加性降低或消失。因此，饲喂低浓缩日粮时，SO对降低CH排放更有效。
