Stock R A, Laudert S B, Stroup W W, Larson E M, Parrott J C, Britton R A
Department of Animal Science, University of Nebraska, Lincoln 68583-0908.
J Anim Sci. 1995 Jan;73(1):39-44. doi: 10.2527/1995.73139x.
A trial involving four commercial feedlots and an individual feeding trial evaluated the effect of monensin and monensin/tylosin on intake variation and deaths from digestive disorders. Four commercial feedlots in Texas and Colorado fed 2,904 yearling crossbred steers (340 kg) high-grain diets containing approximately 82% grain, 8% silage and alfalfa hay, 4% fat, and 6% supplement (DM basis). Steers were allotted randomly to one of three monensin/tylosin levels: 1) no monensin or tylosin (control); 2) 22 mg/kg of monensin and 11 mg/kg of tylosin; or 3) 33 mg/kg of monensin and 11 mg/kg of tylosin. Monensin/tylosin reduced DMI (P < .05) and improved ADG (P < .05) and feed efficiency (P < .01). Intake variation associated with dry matter offered per pen was not different among treatments. In the individual feeding trial, feeding 27 mg/kg of monensin reduced (P < .10) DMI variation during grain adaptation and during d 57 to 70 and d 97 to 110 compared with the control (no monensin) diet. The magnitude of intake variance was 5 to 10 times greater with individually fed steers than with steers fed in the commercial feedlot pens. When the DMI of the individually fed steers were averaged and treated as a pen of steers, DMI variance was reduced drastically and was not different between treatments. We interpret these data to indicate that monensin and monensin/tylosin reduce feed intake variation among individual steers within a pen of steers. Pen means mask individual animal variation to the point that it is difficult to detect treatment differences.
一项涉及四个商业饲养场的试验以及一项个体饲养试验评估了莫能菌素和莫能菌素/泰乐菌素对采食量变化及消化系统疾病死亡情况的影响。得克萨斯州和科罗拉多州的四个商业饲养场用高谷物日粮饲喂2904头一岁杂交阉牛（体重340千克），日粮含约82%谷物、8%青贮饲料和苜蓿干草、4%脂肪以及6%补充料（干物质基础）。阉牛被随机分配到三种莫能菌素/泰乐菌素水平之一：1）不添加莫能菌素或泰乐菌素（对照）；2）22毫克/千克莫能菌素和11毫克/千克泰乐菌素；或3）33毫克/千克莫能菌素和11毫克/千克泰乐菌素。莫能菌素/泰乐菌素降低了干物质采食量（P < 0.05），提高了平均日增重（P < 0.05）和饲料效率（P < 0.01）。各处理间每栏提供的干物质相关的采食量变化并无差异。在个体饲养试验中，与对照（不添加莫能菌素）日粮相比，饲喂27毫克/千克莫能菌素可降低谷物适应期以及第57至70天和第97至110天期间的干物质采食量变化（P < 0.10）。个体饲养阉牛的采食量方差幅度比商业饲养场栏舍中饲养的阉牛大5至10倍。当将个体饲养阉牛的干物质采食量进行平均并当作一栏阉牛处理时，干物质采食量方差大幅降低，各处理间无差异。我们对这些数据的解读是，莫能菌素和莫能菌素/泰乐菌素可减少一栏阉牛中个体阉牛间的采食量变化。栏舍平均值掩盖了个体动物的差异，以至于难以检测到处理差异。
