Wessels R H, Titgemeyer E C
Department of Animal Sciences and Industry, Kansas State University, Manhattan 66506-1600, USA.
J Anim Sci. 1997 Dec;75(12):3278-86. doi: 10.2527/1997.75123278x.
In Exp. 1, six steers (254 kg) were used in a 6 x 4 incomplete Latin square to determine the effects of solvent-extracted soybean meal alone or in combination with rumen-protected methionine and lysine on N balance in steers limit-fed a high-corn diet to gain 1.1 kg/d. The basal diet contained (DM basis) 80% rolled corn, 15% alfalfa, and .9% urea (13.9% CP), and 2 or 4% soybean meal replaced corn to give CP concentrations of 14.8 and 15.6%, respectively. Each diet was fed with and without 5 g/d of Smartamine-ML (.75 and 2.0 g of rumen-protected methionine and lysine, respectively). Nitrogen retention increased linearly (P = .09) with level of soybean meal. Rumen-protected methionine and lysine had no effect on N balance. In Exp. 2, seven steers (233 kg) were used in a 7 x 4 incomplete Latin square experiment to investigate optimal levels and sources of CP for steers limit-fed to gain 1 kg/d. Treatments included a negative-control diet (urea; 11.7% CP) and six diets containing either 13.5, 15.4, or 17.2% CP with either solvent-extracted or expeller-processed soybean meal. Diets provided 75, 87.5, 100, or 112.5% of estimated CP requirement for a gain of 1 kg/d. The basal diet contained 83% rolled corn, 15% alfalfa, and .2% urea. Nitrogen retention increased linearly (P = .006) with soybean meal addition, and no differences were observed between CP sources. The CP system underpredicted the protein requirements of limit-fed steers under our conditions.
在实验1中，选用6头体重254千克的阉牛，采用6×4不完全拉丁方设计，以确定单独使用溶剂萃取豆粕或其与瘤胃保护性蛋氨酸和赖氨酸组合，对限饲高玉米日粮以每日增重1.1千克的阉牛氮平衡的影响。基础日粮（干物质基础）包含80%的压片玉米、15%的苜蓿和0.9%的尿素（粗蛋白含量13.9%），用2%或4%的豆粕替代玉米，使粗蛋白含量分别达到14.8%和15.6%。每种日粮分别在添加和不添加5克/天的Smartamine-ML（分别含0.75克和2.0克瘤胃保护性蛋氨酸和赖氨酸）的情况下投喂。氮保留量随豆粕水平呈线性增加（P = 0.09）。瘤胃保护性蛋氨酸和赖氨酸对氮平衡无影响。在实验2中，选用7头体重233千克的阉牛，进行7×4不完全拉丁方实验，以研究限饲以每日增重1千克的阉牛的粗蛋白最佳水平和来源。处理包括一个负对照日粮（尿素；粗蛋白含量11.7%）和六个分别含有13.5%、15.4%或17.2%粗蛋白的日粮，这些日粮分别使用溶剂萃取豆粕或压榨豆粕。日粮提供了每日增重1千克所需估计粗蛋白量的75%、87.5%、100%或112.5%。基础日粮包含83%的压片玉米、15%的苜蓿和0.2%的尿素。添加豆粕后氮保留量呈线性增加（P = 0.006），且未观察到粗蛋白来源之间存在差异。在我们的条件下，粗蛋白体系低估了限饲阉牛的蛋白质需求。
