目的 研究不同饲粮营养水平对杂交肉牛育肥效果和经济效益的影响，优化杂交肉牛的营养配方和育肥方案。 方法 选择体重相近、体况相近且健康的西杂公牛90头，将其随机平均分为试验Ⅰ组、Ⅱ组、Ⅲ组，分别饲喂高营养水平、中等营养水平、低营养水平日粮，开展为期300 d的饲养试验，测定肉牛的体重，核算饲料成本，分析经济效益。 结果 试验Ⅰ组、Ⅱ组、Ⅲ组的肉牛总增重达到277.7~337.1 kg，平均日增重达到925.7~1 123.6 g，其中试验Ⅰ组和试验Ⅱ组育肥期肉牛总增重与平均日增重差异不显著（P＞0.05），但均显著高于试验Ⅲ组（P＜0.05）。育肥期间试验Ⅲ组投入的饲料成本最高，达到6 558元/头，其次是Ⅱ组和I组，分别为5 796和5 298元/头；试验Ⅱ组的净利润为1 242元/头，在3个试验组中最高，分别高于Ⅰ组和Ⅲ组543、519元/头。 结论 综合各组育肥期增重效果和经济效益，可以确定试验Ⅱ组的营养水平为杂交肉牛育肥最适宜营养水平。

Objectives The effects of different levels of nutrition in feed on the performance of fattening and economic benefits of hybrid beef cattle were studied to optimize the nutrition formula and fattening plan for hybrid beef cattle. Methods 90 Simmental crossbred bulls with similar body weight, physical condition, and health were randomly divided into the experimental group Ⅰfed with high level of protein in diet, the group Ⅱ fed with medium level of protein in diet and the group Ⅲ fed with low high level of protein in diet. The feeding experiment lasted 300 days. The body weight, the cost of feed, and the economic benefits of beef cattle were measured and analyzed. Results The total weight gain in the group I, group Ⅱ and group Ⅲ reached 277.7-337.1 kg, with an average daily gain of 925.7-1 123.6 g. The difference in total weight gain and average daily weight gain during the period of fattening between the experimental group I and the experimental group Ⅱ was not significant (P>0.05), but both were significantly higher than that in the experimental group Ⅲ (P<0.05). The cost of feed in the experimental group Ⅲ during the period of fattening was the highest, reaching 6 558 yuan/head, followed by that in the experimental group Ⅱ and the experimental group I, at 5 796 yuan/head and 5 298 yuan/head, respectively. The net profit in the experimental group Ⅱ was 1 242 yuan/head, which was the highest among the three experimental groups, higher than that in the experimental group I and the experimental group Ⅲ at 543 yuan/head and 519 yuan/head, respectively. Conclusions It can be determined that the level of nutrition in the experimental group Ⅱ is most suitable for fattening hybrid beef cattle based on comprehensively analyzing the weight gain and economic benefits in each experimental group during the period of fattening.