从营养角度探讨不同蛋白浓缩料对肉牛育肥效果和胴体性状的影响
Nutrient Effects of Different Protein Concentrate on Performance of Beef Cattle Fattening and Carcass Traits

采用单因子设计，按照组间体质量和年龄相近原则，将48头周岁以内和体质量相近（383.9 kg±38.0 kg）的杂交肉牛随机分为4个试验组，探讨不同蛋白浓缩料对肉牛育肥效果、血液生化指标和胴体性状的影响。试验肉牛饲喂4组饲料，分别来自添加量相同的自配蛋白浓缩料和3种商品蛋白浓缩料。结果显示，经过120 d育肥试验，饲喂高能量的饲料可提高肉牛体质量的增量、改善料重比和降低单位增量的饲料成本（P<0.05，P<0.01），且肉牛宰前活体质量、胴体质量、屠宰率和净肉率呈上升趋势，但差异均不显著（P>0.05），饲料氨基酸高质量分数似乎有提高净肉率趋势；饲喂高能量和高氨基酸的肉牛背膘厚、眼肌面积大、骨质量小、肉块质量高，并表现出良好的肉色亮度和红色值（P<0.05）；饲喂低能量和低氨基酸的肉牛除获得最差的育肥性能和胴体性状外，血清碱性磷酸酶活性和甘油三酯浓度最高，血液尿素氮浓度最低（P<0.05，P<0.01）。说明，能量是肉牛体质量增量的重要因子；与蛋白质比较，饲料中氨基酸的质量分数对净肉和肉块产量更为敏感；高能量和高氨基酸有助于改善肉牛胴体肉色。
A single factorial design trial was used to divide into four experimental random groups with 48 crossbred yearling beef cattle (average body mass= 383.9 kg±38.0 kg) with close body mass,The different self-made protein concentrates and three commercial protein concentrates was fed to evaluate the nutrient effects of the concentrates on performance of beef cattle fattening,biochemical index of blood and carcasstraits of finishing beef cattle. The actual chemical composition of four diets were slightly various mainly in energy, protein, acid detergent fiber and amino acids due to the source of different concentrates. After 120 d finishing period, the trial beef cattle fed with high energy concentration of diets was increased in daily gain and feed efficiency and was reduced in feed cost per kg gain (P<0.05, P<0.01), slaughter mass, carcass mass, dressing percent and lean percent were on upward trend , but the difference was non-different (P>0.05) while lean percent might be related to the amino acid concentration of the diets. The trial beef cattle fed with both high energy and amino acid concentrations of diets not only had the thicker back fat, larger ribeye area, smaller bone mass and higher prime cut mass, but also were shown the better lean color values (P<0.05). The trial beef cattle fed with both low energy and amino acid concentrations of diets were demonstrated the worst finishing performance and carcass traints while that was measured both the highest serum concentrations of alkaline phosphatase and triglyceride and the lowest concentration of BUN (P<0.05, P<0.01). In conclusion, dietary energy is an important factor in daily gain, dietary amino acids seem to be sensitive to increasing lean and prime cut yield referred to protein, both high energy and amino acid concentrations of diets can also be helpful in improving lean color of beef carcass.