Wedegaertner T C, Johnson D E
J Anim Sci. 1983 Jul;57(1):168-77. doi: 10.2527/jas1983.571168x.
Six 300-kg steers were each fed a 70% cracked corn plus corn silage diet at two levels of intake above maintenance with and without 3 mg monensin/kg.75 body weight (W.75). A changeover design was used. Dietary energy and nitrogen were partitioned by duplicate, 22-h indirect respiration calorimetry measurements of heat and methane production on each animal concurrent with 7-d total feces and urine collection trials. Feed and feces were analyzed for energy, N, starch and neutral detergent fiber (NDF). The partial efficiency and(or) heat increment of metabolizable energy (ME) used for gain and maintenance was partitioned by regression of energy storage vs intake. At equalized gross energy intakes (adjustments made by covariance), monensin improved (P less than .01) the apparent digestibilities of energy, from 71.8 to 74.8%; NDF, from 50.5 to 57.5%, and crude protein, from 61.6 to 65.8%. Methane production averaged 5.7% of the control gross energy (GE), but was reduced by 26% (P less than .01) by monensin additions. Metabolizable energy was increased (P less than .01) from 63.3 to 66.8% of gross energy intake by monensin, resulting in an increase (P less than .01) in retained energy (64.7 to 72.3 kcal/W.75). Heat production was increased (P less than .05) by monensin, but only in proportion to the increased ME. Daily energy retentions adjusted to equal ME intake were similar with or without monensin (69.9 vs 67.1 kcal/W.75). No significant effects of monensin on the heat increment of ME use for maintenance or gain were observed. Both NEm and NEg were improved by approximately 7% by monensin; however, the relative effect on NEm vs NEg depends on method of calculation. At equalized GE intakes, approximately one-third of the improved energy utilization was explained by the reduced methanogenesis caused by monensin and two-thirds by reduced fecal losses.
选用6头体重300千克的阉牛，每头阉牛均饲喂由70%破碎玉米和玉米青贮料组成的日粮，设置两个高于维持水平的采食量水平，分别添加和不添加每千克0.75体重（W.75）3毫克的莫能菌素。采用转换设计。通过对每头动物进行重复的22小时间接呼吸测热法测量热量和甲烷产生量，同时进行为期7天的粪便和尿液总收集试验，对日粮中的能量和氮进行分配。分析饲料和粪便中的能量、氮、淀粉和中性洗涤纤维（NDF）。用于生长和维持的代谢能（ME）的部分效率和（或）热增量通过能量储存与采食量的回归进行分配。在总能量摄入量均衡（通过协方差进行调整）的情况下，莫能菌素提高了（P<0.01）能量的表观消化率，从71.8%提高到74.8%；NDF的表观消化率从从50.5%提高到57.5%，粗蛋白的表观消化率从61.6%提高到到65. .8%。甲烷产量平均为对照总能量（GE）的5.7%，但添加莫能菌素后降低了26%（P<0.01）。莫能菌素使代谢能占总能量摄入量的比例从63.3%提高到6 .8%（P<0.01），导致保留能量增加（P<0.01）（从64.7千卡/W.）。莫能菌素使产热增加（P<0.05），但仅与增加的ME成比例。在调整为相等ME摄入量的情况下，无论有无莫能菌素，每日能量保留量相似（分别为69.9千卡/W.75和67.1千卡/W.75）。未观察到莫能菌素对用于维持或生长的ME热增量有显著影响。莫能菌素使净能维持值（NEm）和净能生长值（NEg）均提高了约7%；然而，对NEm和NEg的相对影响取决于计算方法。在总能量摄入量均衡的情况下，能量利用率提高的约三分之一可归因于莫能菌素导致的甲烷生成减少，三分之二可归因于粪便损失减少。
