Kim Y K, Schingoethe D J, Casper D P, Ludens F C
Dairy Science Department, South Dakota State University, Brookings 57007-0647.
J Dairy Sci. 1993 Jan;76(1):197-204. doi: 10.3168/jds.s0022-0302(93)77338-5.
Holstein cows (n = 33) were assigned to one of three diets containing soybean meal, supplemental fat from extruded soybeans, or supplemental fat from Ca soaps of fatty acids. Total mixed diets containing (DM basis) 25% corn silage, 25% alfalfa hay, and 50% of the respective concentrate mixtures were fed wk 4 through 15 postpartum. Milk production (29.2, 32.4, and 31.8 kg/d) was higher for cows fed supplemental fat diets. Milk protein percentages (2.99, 2.93, and 2.81) were higher for cows fed the soybean meal diet and were higher with extruded soybeans than with Ca soaps of fatty acids. Milk fat percentages (3.20, 2.69, and 3.47) were higher for cows fed Ca soaps of fatty acids than for cows fed extruded soybeans. Milk fat from cows fed supplemental fat was more unsaturated than from those fed soybean meal and was most unsaturated from cows fed extruded soybeans. Dry matter intakes (17.8, 18.4, and 16.6 kg/d) were not significantly different among diets. Extruded soybeans and Ca soaps of fatty acids were equally effective in increasing milk production, but milk fat content was reduced, and the proportion of unsaturated fatty acids in milk fat was increased, with extruded soybeans.
33头荷斯坦奶牛被分配到三种日粮之一，日粮分别含有豆粕、膨化大豆提供的补充脂肪或脂肪酸钙皂提供的补充脂肪。从产后第4周到第15周，给奶牛饲喂全混合日粮（以干物质计），其中包含25%的玉米青贮、25%的苜蓿干草以及50%各自的精料混合物。饲喂补充脂肪日粮的奶牛产奶量（分别为29.2、32.4和31.8千克/天）更高。饲喂豆粕日粮的奶牛乳蛋白百分比（分别为2.99、2.93和2.81）更高，且饲喂膨化大豆的奶牛乳蛋白百分比高于饲喂脂肪酸钙皂的奶牛。饲喂脂肪酸钙皂的奶牛乳脂百分比（分别为3.20、2.69和3.47）高于饲喂膨化大豆的奶牛。饲喂补充脂肪的奶牛所产乳脂比饲喂豆粕的奶牛所产乳脂更不饱和，且饲喂膨化大豆的奶牛所产乳脂最不饱和。不同日粮间的干物质采食量（分别为17.8、18.4和16.6千克/天）无显著差异。膨化大豆和脂肪酸钙皂在提高产奶量方面同样有效，但膨化大豆会降低乳脂含量，并增加乳脂中不饱和脂肪酸的比例。
