Abstract: The experiment was conducted to investigate the effect of non-protein nitrogen supplementation on the grazing cattle. Thirty Chinese Simmental bull Taihang (weighted 150 to 170 kg) were chosen and divided into 3 groups, which were control group, experiment group 1 and experiment group 2. One kilogram corn flour was supplemented in experiment group 1 and 0.25 kg NPN supplementation was added at the basis of experiment group 1 in experiment group 2. The experiment was conducted at the time before grazing, which is the late spring and early summer, and lased 100 days. Results showed that the average daily gain was 0.622,0.839 and 1.051 kg for the control group, experiment group 1 and experiment group 2, respectively. Average daily gain was increased 217 g for the experiment group 1 than the control group and increased 429 and 212 g for experiment group 2 than control group and experiment group 1, respectively. The difference among three groups was remarkable significant, and weight gain differed significantly between experiment group 2 and control group. It was concluded that small amount of concentrate supplementation has obvious effect on the grazing cattle in northern slopes and small amount of NPN supplementation would have more significant economic benefits.

Key words: Chinese Simmental bull of Taihang; NPN supplementation; grazing; feeding; weight gain; benefit