Hill G M, Boling J A, Bradley N W
Int J Vitam Nutr Res. 1985;55(4):439-46.
One-hundred-twenty calves were utilized in a 2 X 3 factorial design experiment of 140 days to determine the effects of dietary urea (U) or soybean meal (SBM) with added sulfur (S) plus corn silage on growth and plasma constituents. Total dietary crude protein (CP) of SBM-supplemented diets averaged 9.06%, and U-supplemented diets averaged 9.16% CP. Within each nitrogen source, S was added to supplements to provide 0.0, 0.15, or 0.30% added S based upon predicted intake. Calves fed SBM-supplemented diets had higher (P less than 0.05) gains and lower (P less than .05) plasma urea nitrogen levels compared to calves fed U-supplemented diets. The addition of S to SBM-supplemented diets did not significantly affect growth, efficiency or plasma nitrogen constituents. Calves fed the U-supplemented diets with added S had higher (P less than .10) gains and a trend toward improved efficiency compared with those supplemented with no added S. On day 28 plasma aspartic acid, threonine, serine, glutamic acid, glycine, methionine, total nonessential and total amino acid concentrations were increased (P less than .01 to P less than .10) by the addition of S to U-supplemented diets compared to the basal U diet. Isoleucine was higher (P less than .05) in calves fed SBM-supplemented diets compared to those fed U-supplemented diets. On day 140 higher (P less than .05) plasma threonine, valine, isoleucine, leucine, phenylalanine, lysine and total essential amino acids were observed in calves fed SBM compared to U-supplemented diets.(ABSTRACT TRUNCATED AT 250 WORDS)
120头犊牛被用于一项为期140天的2×3析因设计实验，以确定添加硫（S）的日粮尿素（U）或豆粕（SBM）加玉米青贮对生长和血浆成分的影响。补充SBM的日粮总粗蛋白（CP）平均为9.06%，补充U的日粮平均CP为9.16%。在每种氮源中，根据预测摄入量向补充剂中添加S，使添加S的量分别为0.0%、0.15%或0.30%。与饲喂补充U日粮的犊牛相比，饲喂补充SBM日粮的犊牛增重更高（P<0.05），血浆尿素氮水平更低（P<0.05）。向补充SBM的日粮中添加S对生长、效率或血浆氮成分没有显著影响。与未添加S的犊牛相比，饲喂添加S的补充U日粮的犊牛增重更高（P<0.10），且有效率提高的趋势。与基础U日粮相比，在补充U的日粮中添加S可使第28天的血浆天冬氨酸、苏氨酸、丝氨酸、谷氨酸、甘氨酸、蛋氨酸、总非必需氨基酸和总氨基酸浓度升高（P<0.01至P<0.10）。与饲喂补充U日粮的犊牛相比，饲喂补充SBM日粮的犊牛异亮氨酸含量更高（P<0.05）。在第140天，与补充U日粮的犊牛相比，饲喂SBM的犊牛血浆苏氨酸、缬氨酸、异亮氨酸、亮氨酸、苯丙氨酸、赖氨酸和总必需氨基酸含量更高（P<0.05）。（摘要截短至250字）
