Casper D P, Schingoethe D J
Dairy Science Department, South Dakota State University, Brookings 57007-0647.
J Dairy Sci. 1988 Jan;71(1):164-72. doi: 10.3168/jds.S0022-0302(88)79538-7.
Formulation of diets using barley and soybean meal should result in a diet that supplies less methionine than conventional corn and soybean meal diets. To evaluate this further, 28 high producing Holstein cows (10 primiparous and 18 multiparous) were fed a barley soybean meal diet without or with 15 g of added DL-methionine as 50 g of ruminally protected methionine product during wk 4 to 16 postpartum. Cows were fed a 15% CP total mixed diet consisting of (dry matter basis) 50% concentrate mix, 45% corn silage, and 5% chopped alfalfa hay. Yields of milk (30.3 and 29.8 kg/d), 4% fat-corrected milk (26.0 and 25.6 kg/d), and solids-corrected milk (26.3 and 25.9 kg/d) were similar for cows fed diets without or with added methionine. Percent of milk fat (3.08 and 3.16%) and solids-not-fat (8.66 and 8.71%) were similar, but percent protein (2.75 and 2.87%) was higher, from cows fed ruminally protected methionine. Methionine concentrations in arterial and venous serum were not significantly elevated by feeding ruminally protected methionine. Supplemental ruminally protected methionine did not increase milk production but did increase milk protein percentages in cows fed barley-based diets.
使用大麦和豆粕配制日粮应能提供比传统玉米和豆粕日粮含蛋氨酸更少的日粮。为进一步评估这一点，在产后第4至16周，给28头高产荷斯坦奶牛（10头初产牛和18头经产牛）饲喂不添加或添加15克DL-蛋氨酸（以50克瘤胃保护蛋氨酸产品形式）的大麦豆粕日粮。奶牛饲喂一种15%粗蛋白的全混合日粮，该日粮由（干物质基础）50%精料混合料、45%玉米青贮和5%苜蓿干草组成。饲喂不添加或添加蛋氨酸日粮的奶牛，其产奶量（30.3和29.8千克/天）、4%乳脂校正乳产量（26.0和25.6千克/天）以及固形物校正乳产量（26.3和25.9千克/天）相似。乳脂百分比（3.08和3.16%）和非脂固形物百分比（8.66和8.71%）相似，但饲喂瘤胃保护蛋氨酸的奶牛的乳蛋白百分比（2.75和2.87%）更高。饲喂瘤胃保护蛋氨酸并未显著提高动脉和静脉血清中的蛋氨酸浓度。补充瘤胃保护蛋氨酸并未增加奶牛的产奶量，但确实提高了饲喂大麦型日粮奶牛的乳蛋白百分比。
