Department of Animal Science, and.
Department of Animal Science, and.
J Dairy Sci. 2013 Apr;96(4):2356-2365. doi: 10.3168/jds.2011-5239. Epub 2013 Feb 15.
The purpose of this experiment was to study the effect of the physical form of rapeseed fat on methane (CH4) mitigation properties, feed digestion, and rumen fermentation. Four lactating ruminal-, duodenal-, and ileal-cannulated Danish Holstein dairy cows (143 d in milk, milk yield of 34.3 kg) were submitted to a 4×4 Latin square design with 4 rations: 1 control with rapeseed meal (low-fat, CON) and 3 fat-supplemented rations with either rapeseed cake (RSC), whole cracked rapeseed (WCR), or rapeseed oil (RSO). Dietary fat concentrations were 3.5 in CON, 5.5 in RSC, 6.2 in WCR, and 6.5% in RSO. The amount of fat-free rapeseed was kept constant for all rations. The forage consisted of corn silage and grass silage and the forage to concentrate ratio was 50:50 on a dry matter basis. Diurnal samples of duodenal and ileal digesta and feces were compiled. The methane production was measured for 4 d in open-circuit respiration chambers. Additional fat reduced the CH4 production per kilogram of dry matter intake and as a proportion of the gross energy intake by 11 and 14%, respectively. Neither the total tract nor the rumen digestibility of organic matter (OM) or neutral detergent fiber were significantly affected by the treatment. Relating the CH4 production to the total-tract digested OM showed a tendency to decrease CH4 per kilogram of digested OM for fat-supplemented rations versus CON. The acetate to propionate ratio was not affected for RSC and WCR but was increased for RSO compared with CON. The rumen ammonia concentration was not affected by the ration. The milk and energy-corrected milk yields were unaffected by the fat supplementation. In conclusion, rapeseed is an appropriate fat source to reduce the enteric CH4 production without affecting neutral detergent fiber digestion or milk production. The physical form of fat did not influence the CH4-reducing effect of rapeseed fat. However, differences in the volatile fatty acid pattern indicate that different mechanisms may be involved.
本实验旨在研究菜籽脂肪的物理形态对甲烷（CH4）减排特性、饲料消化和瘤胃发酵的影响。选用 4 头泌乳期、十二指肠和回肠瘘管丹麦荷斯坦奶牛（产奶 143d，产奶量 34.3kg）进行 4×4 拉丁方设计，共 4 个日粮：1 个对照日粮含菜籽粕（低脂，CON），3 个脂肪补充日粮分别为菜籽饼（RSC）、全破碎菜籽（WCR）或菜籽油（RSO）。CON 日粮的脂肪浓度为 3.5%，RSC 日粮为 5.5%，WCR 日粮为 6.2%，RSO 日粮为 6.5%。所有日粮的无脂菜籽量保持不变。饲草由青贮玉米和青贮黑麦草组成，饲草与精料比为 50:50（干物质基础）。收集十二指肠和回肠食糜及粪便的日排样。在闭路呼吸室中测量甲烷产生量 4d。额外添加脂肪使每干物质采食量和总能采食量的甲烷产量分别减少 11%和 14%。处理对全肠道和瘤胃有机物（OM）或中性洗涤纤维的消化率均无显著影响。将甲烷产生量与全肠道消化 OM 相关联，表明与 CON 相比，脂肪补充日粮的 OM 每千克消化甲烷产生量有减少的趋势。与 RSC 和 WCR 相比，RSO 使乙酸/丙酸比增加，但对 CON 无影响。日粮对瘤胃氨浓度无影响。脂肪补充对奶和校正奶产量无影响。总之，菜籽是一种合适的脂肪来源，可以减少肠道 CH4 产生，而不影响中性洗涤纤维消化或产奶量。脂肪的物理形态不影响菜籽脂肪的 CH4 减排效果。然而，挥发性脂肪酸模式的差异表明，可能涉及不同的机制。
