1. The composition of rumen gas , properties of rumen liquor, digestibilities of feeds, and nitrogen balance were compared when two goats, Nos. 3 and 4, were fed three rations, L, M, and H, which differed in crude protein content. 2. Basal ration L was composed of 300g of hay and 400g of concentrate consisting of wheat bran and starch. The content of crude protein of ration L was 7.60 per cent in dry matter. Ration M was ration L plus 6g of urea and contained 10.54 per cent crude protein in dry

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... matter. Ration H, which differed from ration M in the combination ratio of wheat bran and starch, contained 12.61 per cent crude protein in dry matter. 3. The ratios of CO2/CH4 in the rumen gas collected 2 hours after feeding (at 3 P. M.) with rations L, M, and H were 1.37, 2.57, and 3.54, respectively. The results indicate that the larger the nitrogen content of a ration, the higher this ratio became. The composition of rumen gas, however, was almost alike 22 hours after feeding (at 11 A. M.), regardless of the kind of ration. 4. The properties of rumen liquor collected 22 hours after feeding (at 11 A. M.) were compared when rations L. and M were given. The values of pH were nearly equal, but the concentration of volatile fatty acids was higher when ration M was given than when ration L was fed, the difference between the two rations being of high statistical significance. When ration M was given, the concentration of ammonia-nitrogen in the rumen liquor was about twice as high as that when ration L was fed. The concentrations of reducing and non-reducing sugars in the rumen liquor were almost the same, regardless of the ration given. 5. The digestibility coefficients of dry matter of the all rations used were nearly 53 per cent when determined in goat No. 3. When determined in goat No. 4, however, the digestibility was 55 per cent in the case of ration L and 60 per cent in the case of both rations M and H. 6. By comparing rations L and M in digestibility, it was proved that the addition of urea to a ration promoted the digestihilities of crude protein and crude fiber. 7. Nitrogen balance in both goats was nigative in the period of ration L feeding and positive in that of ration H feeding. In the period of ration M feeding, nitrogen balance was slightly negative in goat No. 3 and positive in goat No. 4.