Hess B W, Krysl L J, Judkins M B, Holcombe D W, Hess J D, Hanks D R, Huber S A
School of Veterinary Medicine, University of Nevada, Reno 89557-0104, USA.
J Anim Sci. 1996 May;74(5):1116-25. doi: 10.2527/1996.7451116x.
Two experiments were conducted with beef steers (Exp. 1, average BW of 580 kg; Exp. 2, average BW of 247 kg) to evaluate the use of no supplements (CON) or daily supplementation with (OM basis) .34% of BW of cracked corn (CORN), .34% of BW of wheat bran (WBBW), or .48% of BW of wheat bran (WBISO; calculated to be isocaloric to CORN) on digestive responses (Exp. 1) and live weight gain (Exp. 2). In Exp. 1, type of supplement did not affect (P > .10) the dietary fiber or N constituents, but in vitro OM disappearance of the forage differed (P < .10) with supplementation and type of supplement fed. Supplemented steers consumed less (P < .05) forage and total OM. Particulate passage, fluid passage, and ruminal pH were not affected (P > .10) by supplementation. Ruminal NH3 N concentration showed (P < .05) a treatment x sampling time interaction and, in general, WBBW and WBISO steers had greater ruminal NH3 N than CORN and CON steers. Total VFA concentrations and molar proportions of propionate were lower (P < .10) in CON steers than in supplemented steers; no differences were noted (P > .10) among supplemented steers. Molar proportions of acetate were lower (P = .01) in supplemented steers than in CON steers and were greater (P = .03) in WBBW steers than in WBISO steers. Butyrate molar proportions were lower (P < .05) in CON steers than in supplemented steers and differed (P < .10) with type and quantity of supplement supplied. In situ forage NDF disappearance at 6, 9, and 24 h after feeding and rate of disappearance were greater (P < .05) in CON steers than in supplemented steers. In Exp. 2, CON steers weighed less (P = .01) than supplemented steers, CORN steers weighed more (P = .08) than wheat bran-supplemented steers, and WBISO steers weighed more (P = .02) than WBBW steers; ADG for 90 d followed a similar response. Results suggest that supplementation of wheat bran rather than corn did not seem to stop the reduction in forage intake or OM digestion associated with corn supplementation.
用肉用公牛进行了两项试验（试验1，平均体重580千克；试验2，平均体重247千克），以评估不添加任何补充料（对照组）或每日补充（以干物质计）体重0.34%的碎玉米（玉米组）、体重0.34%的麦麸（麦麸体重比组）或体重0.48%的麦麸（等热量麦麸组，计算得出其热量与玉米组相等）对消化反应（试验1）和体重增加（试验2）的影响。在试验1中，补充料类型对膳食纤维或氮成分没有影响（P＞0.10），但补充料和所喂补充料类型会使饲草的体外干物质消失率有所不同（P＜0.10）。补充了饲料的公牛消耗的饲草和总干物质较少（P＜0.05）。颗粒通过率、液体通过率和瘤胃液pH值不受补充料的影响（P＞0.10）。瘤胃液氨氮浓度呈现出处理×采样时间的交互作用（P＜0.05），总体而言，麦麸体重比组和等热量麦麸组公牛的瘤胃液氨氮浓度高于玉米组和对照组公牛。对照组公牛的总挥发性脂肪酸浓度和丙酸摩尔比例低于补充了饲料的公牛（P＜0.10）；补充了饲料的公牛之间未观察到差异（P＞0.10）。补充了饲料的公牛的乙酸摩尔比例低于对照组公牛（P = 0.01），且麦麸体重比组公牛的乙酸摩尔比例高于等热量麦麸组公牛（P = 0.03）。对照组公牛的丁酸摩尔比例低于补充了饲料的公牛（P＜0.05），且丁酸摩尔比例因补充料的类型和数量不同而有所差异（P＜0.10）。采食后6、9和24小时的饲草中性洗涤纤维原位消失率和消失速率在对照组公牛中高于补充了饲料的公牛（P＜0.05）。在试验2中，对照组公牛体重低于补充了饲料的公牛（P = 0.01），玉米组公牛体重高于麦麸补充组公牛（P = 0.08），等热量麦麸组公牛体重高于麦麸体重比组公牛（P = 0.02）；90天的平均日增重呈现类似的反应。结果表明，补充麦麸而非玉米似乎无法阻止因补充玉米而导致的饲草摄入量减少或干物质消化率降低。
