Yang Y, Ferreira G, Teets C L, Corl B A, Thomason W E, Griffey C A
Department of Dairy Science, Virginia Tech, Blacksburg 24061.
Department of Dairy Science, Virginia Tech, Blacksburg 24061.
J Dairy Sci. 2017 May;100(5):3576-3583. doi: 10.3168/jds.2016-12241. Epub 2017 Mar 16.
The objectives of this study were to evaluate production performance, milk fatty acid composition, and nutrient digestibility in high-producing dairy cows consuming diets containing corn and hull-less barley (cultivar Amaze 10) in different proportions as the grain source. Eight primiparous and 16 multiparous Holstein cows were assigned to 1 of 4 diets in a replicated 4 × 4 Latin square design with 21-d periods. Cows were fed once daily (1200 h) by means of a Calan gate system (American Calan Inc., Northwood, NH). All diets contained ∼20% grain (dry matter basis). Treatments consisted of 100% corn (0B), 67% corn and 33% hull-less barley (33B), 33% corn and 67% hull-less barley (67B), and 100% hull-less barley (100B) as the grain sources. Total-tract nutrient digestibility was estimated using lanthanum chloride (LaCl) as an external marker. Dry matter intake differed quadratically among treatments, being lowest for 67B and highest for 0B and 100B. Feeding hull-less barley did not affect milk yield, and milk fat concentration differed cubically among treatments. The cubic response was attributed to the higher milk fat concentration observed for the diet containing 67B. Neither the concentrations in milk of protein and lactose nor the yields of protein and lactose differed among treatments. The proportion of de novo synthesized fatty acids in milk did not differ among treatments. The apparent total-tract digestibility of dry matter, crude protein, and neutral detergent fiber did not differ among treatments. Although a quadratic effect was observed, starch digestibility was minimally affected by treatments. In conclusion, this study indicates that hull-less barley grain is as good as corn grain as an energy source when formulating diets for high-producing dairy cows.
本研究的目的是评估高产奶牛采食不同比例玉米和无壳大麦（品种Amaze 10）作为谷物来源的日粮时的生产性能、乳脂肪酸组成和养分消化率。将8头初产和16头经产荷斯坦奶牛按照重复4×4拉丁方设计分配到4种日粮中的1种，试验期为21天。通过Calan门系统（美国Calan公司，新罕布什尔州诺斯伍德）每天一次（12:00）给奶牛投喂。所有日粮含约20%谷物（干物质基础）。处理组日粮分别采用100%玉米（0B）、67%玉米和33%无壳大麦（33B）、33%玉米和67%无壳大麦（67B）以及100%无壳大麦（100B）作为谷物来源。使用氯化镧（LaCl）作为外源指示剂估计全消化道养分消化率。干物质采食量在各处理组间呈二次方差异，67B组最低，0B和100B组最高。饲喂无壳大麦不影响产奶量，乳脂肪浓度在各处理组间呈三次方差异。三次方反应归因于含67B日粮的乳脂肪浓度较高。各处理组间乳中蛋白质和乳糖浓度以及蛋白质和乳糖产量均无差异。乳中从头合成脂肪酸的比例在各处理组间无差异。干物质、粗蛋白和中性洗涤纤维的表观全消化道消化率在各处理组间无差异。虽然观察到二次方效应，但淀粉消化率受处理的影响极小。总之，本研究表明，在为高产奶牛配制日粮时，无壳大麦作为能量来源与玉米一样好。
