Abstract: Two experiments were conducted to investigate the effect of different dietary concentrate to forage ratios (C/F) on the growth performance,serum biochemical indexes and economic benefits of Dorper sheep.TestⅠ:40 weaned lambs with the 20 to 35 kg body weight were divided into 4 groups with 10 sheep in each group and provided 4 different C/F diets:group A (40:60),group B (50:50),group C (60:40),group D (70:30) and the experiment lasted for 70 d;TestⅡ:40 growing sheep with the 30 to 45 kg body weight were divided into 4 groups with 10 sheep in each group and provided 4 different C/F diets:group E (35:65),group F (45:55),group G (55:45),group H (65:35) and the experiment lasted for 70 d.The results showed as follows:In the testⅠ:①With the increase of C/F,the ADG of rams increased,but that of ewes was increased initially and then decreased,the ADG of group A in male and female were significantly lower than other three groups (P<0.05),and there were no significant differences in group B,C and D (P>0.05);ADFI of male and female were reduced significantly (P<0.05);F/G was decreased significantly of ram (P<0.05),while that of group B was significantly lower than the other three groups of ewe (P<0.05).②There were no significant differences of TP,TG and Glu in 4 groups (P>0.05),but C/F had different effects on other serum components.③The average net profit in group D of rams was 53.03% higher than group B,and 35.33% higher than group C,while that in group B of ewes was 61.76% higher than group C,and 54.49% higher than group D.In the testⅡ:①With the increasing of the C/F,the ADG of the growing rams was increased gradually,but group G of ewe was significantly higher than group E (P<0.05),and there were no significant differences in group F,G and H (P>0.05).ADFI of male and female was reduced significantly (P<0.05);F/G was decreased significantly of ram (P<0.05),while that of ewes was decreased initially and then increased,group G was significantly lower than the other three groups (P<0.05).②There were no significant differences in TP,TG and Glu in 4 groups (P>0.05),but C/F had different effects on other serum components.③The average net profit in group H of ram was 69.49% higher than group F and 52.13% higher than group G.While that in group G of ewe was 1 282.61% higher than group F.Under the conditions of this experiment,the appropriate C/F was 60:40 to weaned male lambs,while 50:50 to weaned female lambs,and the appropriate C/F was 50:50 if they were mixed fed.TestⅡ showed that the appropriate C/F was 55:45 to both male and female growing sheep.

Key words: Dorper sheep; concentrate to forage ratios; growth performance; serum indexes; economic benefit