Abstract: Cattle performance and blood biochemical parameters were examined to evaluate the best treatment.24 healthy Simmental cross cattles (Simmental × local cattle), weighing (345±22) kg, were randomly divided into four groups, corresponding to 4 dietary treatments varying with the ratios of concentrate and distilled grain which were 1∶1,1∶1.5,1∶2.5,1∶3.5. All the cattle were offered the same amount of hay. The results showed that the whole experiment the lowest temperature and humidity index was 72.18, beef cattle were in the state of heat stress. With the increase of distilled grain, the total intake of dry matter increased, and had the significant difference (P＜0.05).The daily gain of 1∶1.5 group was relatively high (P>0.05), it was highest than the 1∶1 group for 11.25%. And compared with the 1∶2.5 or 1∶3.5 group, it was improved by 12.66%. And the weight gain efficiency of 1∶1.5 group was highest (P>0.05). Compared with the minimum group, it was increased by 40.64%. The total protein, albumin levels of serum in 1∶1.5 group was also highest(P＜0.05). The remaining blood parameters of each treatment had no significant difference (P>0.05).To sum up, fattening beef cattle under heat stress conditions in summer, the best proportion of concentrate and distilled grain was 1∶1.5, which improved the protein metabolism and the growth rate. When feeding high proportion of distilled grain, it reduced the weight gain efficiency of feeder cattle.

Key words: beef cattle; distilled grain; production performance; blood biochemical parameters