Provimi Holding B.V., Research Centre De Viersprong, Veilingweg 23, NL-5334LD, Velddriel, The Netherlands.
J Dairy Sci. 2011 Mar;94(3):1445-54. doi: 10.3168/jds.2010-3635.
Two experiments were conducted to assess the effects of a mixture of dietary additives on enteric methane production, rumen fermentation, diet digestibility, energy balance, and animal performance in lactating dairy cows. Identical diets were fed in both experiments. The mixture of feed additives investigated contained lauric acid, myristic acid, linseed oil, and calcium fumarate. These additives were included at 0.4, 1.2, 1.5, and 0.7% of dietary dry matter, respectively (treatment ADD). Experimental fat sources were exchanged for a rumen inert source of fat in the control diet (treatment CON) to maintain isolipidic rations. Cows (experiment 1, n=20; experiment 2, n=12) were fed restricted amounts of feed to avoid confounding effects of dry matter intake on methane production. In experiment 1, methane production and energy balance were studied using open-circuit indirect calorimetry. In experiment 2, 10 rumen-fistulated animals were used to measure rumen fermentation characteristics. In both experiments animal performance was monitored. The inclusion of dietary additives decreased methane emissions (g/d) by 10%. Milk yield and milk fat content tended to be lower for ADD in experiment 1. In experiment 2, milk production was not affected by ADD, but milk fat content was lower. Fat- and protein-corrected milk was lower for ADD in both experiments. Milk urea nitrogen content was lowered by ADD in experiment 1 and tended to be lower in experiment 2. Apparent total tract digestibility of fat, but not that of starch or neutral detergent fiber, was higher for ADD. Energy retention did not differ between treatments. The decrease in methane production (g/d) was not evident when methane emission was expressed per kilogram of milk produced. Feeding ADD resulted in increases of C12:0 and C14:0 and the intermediates of linseed oil biohydrogenation in milk in both experiments. In experiment 2, ADD-fed cows tended to have a decreased number of protozoa in rumen fluid when compared with that in control cows. Total volatile fatty acid concentrations were lower for ADD, whereas molar proportions of propionate increased at the expense of acetate and butyrate.
进行了两项实验，以评估日粮添加剂混合物对泌乳奶牛肠道甲烷生成、瘤胃发酵、饲料消化率、能量平衡和动物生产性能的影响。两项实验均使用相同的日粮。所研究的饲料添加剂混合物含有月桂酸、肉豆蔻酸、亚麻籽油和富马酸钙。这些添加剂分别以日粮干物质的 0.4%、1.2%、1.5%和 0.7%（处理 ADD）添加。对照日粮中用一种瘤胃惰性脂肪源替代了实验性脂肪源，以维持等脂日粮（处理 CON）。奶牛（实验 1，n=20；实验 2，n=12）限制采食量，以避免干物质采食量对甲烷生成的混杂影响。在实验 1 中，使用开路间接测热法研究甲烷生成和能量平衡。在实验 2 中，使用 10 头瘤胃瘘管奶牛测量瘤胃发酵特性。在两项实验中均监测动物生产性能。日粮添加剂的添加降低了甲烷排放量（g/d）10%。实验 1 中，添加 ADD 会降低牛奶产量和乳脂含量。实验 2 中，添加 ADD 不影响牛奶产量，但降低了乳脂含量。两项实验中，添加 ADD 均降低了脂肪校正奶和蛋白校正奶。实验 1 中，添加 ADD 降低了牛奶尿素氮含量，实验 2 中，牛奶尿素氮含量也有降低的趋势。添加 ADD 提高了脂肪和蛋白质校正奶的表观全肠道消化率，但不影响淀粉和中性洗涤纤维的消化率。处理间能量保留没有差异。当以每千克产奶量表示时，甲烷生成量（g/d）的减少并不明显。在两项实验中，添加 ADD 增加了牛奶中 C12:0 和 C14:0 以及亚麻籽油生物氢化中间产物的含量。实验 2 中，与对照奶牛相比，添加 ADD 的奶牛瘤胃液中的原生动物数量减少。添加 ADD 降低了总挥发性脂肪酸浓度，而丙酸摩尔比例增加，乙酸和丁酸比例减少。
