The effect of roughage level on milk yield, milk fat content, and lice weight were studied by using 3×3 latin square experimental design. Three different roughage levels have been tested with the following proportions of roughage per body weight in forage basis: Treatment A(3%), Treatment B(5%), Treatment C(7%). The results obtained are as follows: 1. Dry matter intake per day during the experimental period among three treatments showed little difference. 2. The animals in treatment A tended to give higher fat content than those in treatment B or C, but the difference was not significant statistically. 3. The cows in treatment C gave the milk of higher fat content than those in treatment A or B, but the difference was not significant statistically. 4. Cows did not show any difference in the solids-not-fat content of the milk they produced. 5. Treatment A gave the mast increase in body weight followed by treatment B, and treatment C gave the least increase in body weight during the experimental period, but the difference was not significant.