Abstract: To study the effect of different diet levels of energy complex enzyme on the Holstein male calf growth performance and blood biochemical index. Twenty health Holstein male calves that were 6 months old and had a （185.20 ± 21.30） kg (P>0.05) of body weight were randomly divided into five groups. The treatments were high energy with enzymes, high energy, low energy with enzymes, low energy and control. The five NEml levels were 35.26，35.26，30.63，30.63，32.83 MJ. Each group with the same content of crude protein diet. The results showed that in high energy feeding conditions, the average daily gain of groups with complex enzyme was not significant, and in low energy feeding conditions, the average daily gain of groups with complex enzyme was 0.14 kg, that was significant (P<0.05); with the same level of energy conditions, groups with complex enzyme in the carcass weight, muscle weight, net beef rate and slaughter rate are all higher than groups without complex enzyme. The five diets have same effect on the Holstein male calf’s biochemical serum indexes, both the compound enzyme preparation and the level of energy have equally enhance the AKP, DLH and CT in the blood tendency under the low-energy level. The results of the study indicated that the effect of compound enzyme preparation is more obvious under the low-energy level, through biochemical serum indexes and slaughter rate correlation analysis, alkaline phosphatase and lactate dehydrogenase could be the important index to reflect and monitor the Holstein male calf’s growth performance and digestion metabolism.

Key words: energy level; compound enzyme preparation; Holstein male calf; growth performance; biochemical serum indexes