Lu C D, Jorgensen N A, Satter L D
American Institute for Goat Research, Langston University, Oklahoma 73050.
J Dairy Sci. 1988 Mar;71(3):697-704. doi: 10.3168/jds.S0022-0302(88)79608-3.
In vivo and in situ trials were conducted to investigate the utilization of alfalfa protein concentrate as a protein supplement for lactating dairy cows. In the in vivo trial, four Holstein cows fitted with ruminal, duodenal, and ileal cannulae were used in a crossover experiment to measure site and extent of nutrient digestion. Isonitrogenous and isoenergetic diets containing alfalfa protein concentrate or soybean meal were fed four times daily. Sixty percent of dietary total N was provided by the test proteins. Ruminal ammonia and total VFA concentrations were lower in cows fed alfalfa protein concentrate. Fractional digestion coefficient of organic matter (52 vs. 43%) and degradation of dietary protein (57 vs. 47%) in the rumen were slightly lower in cows fed alfalfa protein concentrate. The ratio of amino acid flow to the small intestine to dietary intake of amino acid was higher in cows fed alfalfa protein concentrate. In the in situ trial, rate of N disappearance (2.4 vs. 9.5%.h-1) and potential protein degradability (35 vs. 68%) were lower for alfalfa protein concentrate. Results suggest that alfalfa protein concentrate may be more resistant to ruminal degradation than soybean meal and could be utilized as a relatively undegradable protein source for milk production.
进行了体内和原位试验，以研究苜蓿浓缩蛋白作为泌乳奶牛蛋白质补充剂的利用情况。在体内试验中，四头安装了瘤胃、十二指肠和回肠套管的荷斯坦奶牛用于交叉试验，以测量养分消化的部位和程度。每天四次饲喂含苜蓿浓缩蛋白或豆粕的等氮等能日粮。日粮总氮的60%由试验蛋白质提供。饲喂苜蓿浓缩蛋白的奶牛瘤胃氨和总挥发性脂肪酸浓度较低。饲喂苜蓿浓缩蛋白的奶牛瘤胃中有机物的消化系数（52%对43%）和日粮蛋白质的降解率（57%对47%）略低。饲喂苜蓿浓缩蛋白的奶牛小肠氨基酸流量与日粮氨基酸摄入量的比值较高。在原位试验中，苜蓿浓缩蛋白的氮消失率（2.4%对9.5%·h-1）和潜在蛋白质降解率（35%对68%）较低。结果表明，苜蓿浓缩蛋白可能比豆粕更耐瘤胃降解，可作为相对不易降解的蛋白质来源用于牛奶生产。
