Donaldson R S, McCann M A, Amos H E, Hoveland C S
Dept. of Anim. Sci., University of Georgia, Athens 30602.
J Anim Sci. 1991 Jul;69(7):3067-71. doi: 10.2527/1991.6973067x.
Six abomasally cannulated Hereford steers (12 mo of age, 300 +/- 10 kg) grazing annual ryegrass (Lolium multiflorum Lam.) paddocks were used in a replicated 3 x 3 Latin square design to determine effects of ruminal escape protein (EP) supplementation on forage intake, fiber digestion, and protein flow to the intestine. Steers were fed one of three isoenergetic supplements: high ruminal escape protein (HEP), low ruminal escape protein (LEP), or corn, which supplied an estimated .25, .125, or 0 kg of EP/d in addition to EP supplied by corn. Fish meal (FM) and distiller's dried grains with solubles (DDGS) were sources of EP; FM provided 66.7% and DDGS provided 33.3% of estimated EP. Steers were adjusted to each supplement for 7 d before a 4-d collection period. Both total and forage DMI responded quadratically (P less than .03 and P less than .07, respectively) to EP supplementation. Total tract DM digestion tended (P less than .13) to increase linearly with EP supplementation. Abomasal total CP flow increased linearly (P less than .10) as supplemental EP increased. Crude protein flow in steers receiving HEP, LEP, and corn was 1,137, 1,027, and 844 g/d, respectively. Likewise, abomasal nonammonia N (NAN) tended to be greater (P less than .15, linear) for steers receiving HEP. Nonammonia N flows were 1,044, 955, and 771 g/d for steers receiving HEP, LEP, and corn, respectively. Abomasal ammonia flow did not differ (P less than .20) among treatments, nor did reticuloruminal fiber digestion (P less than .20). These data indicate that EP can increase postruminal protein flow and will not negatively affect fiber digestion in steers grazing annual ryegrass pastures.
选用6头安装了真胃瘘管的赫里福德阉牛（12月龄，体重300±10千克），让它们在多年生黑麦草（多花黑麦草）牧场上放牧，并采用重复3×3拉丁方设计，以确定瘤胃逸出蛋白（EP）补充剂对采食量、纤维消化以及蛋白质向肠道流动的影响。给阉牛饲喂三种等能量补充剂之一：高瘤胃逸出蛋白（HEP）、低瘤胃逸出蛋白（LEP）或玉米，除了玉米提供的EP外，它们每天还分别提供约0.25、0.125或0千克的EP。鱼粉（FM）和干酒糟及其可溶物（DDGS）是EP的来源；FM提供估计EP的66.7%，DDGS提供33.3%。在为期4天的收集期之前，让阉牛对每种补充剂适应7天。总干物质采食量和牧草干物质采食量对EP补充剂均呈二次响应（分别为P<0.03和P<0.07）。随着EP补充剂增加，全消化道干物质消化率呈线性增加趋势（P<0.13）。随着补充EP增加，真胃总粗蛋白流量呈线性增加（P<0.10）。接受HEP、LEP和玉米的阉牛的粗蛋白流量分别为1137、1027和844克/天。同样，接受HEP的阉牛的真胃非氨氮（NAN）含量往往更高（P<0.15，线性关系）。接受HEP、LEP和玉米的阉牛的非氨氮流量分别为1044、955和771克/天。各处理之间真胃氨流量没有差异（P<0.20），瘤网胃纤维消化率也没有差异（P<0.20）。这些数据表明，EP可以增加瘤胃后蛋白质流量，并且不会对在多年生黑麦草牧场放牧的阉牛的纤维消化产生负面影响。
