Fifteen Korean native cattle, averaging 128㎏ of initial body weight, were utilized to evaluate the effects of SMS on growing performance and digestibility of nufrients, protozoal population in the rumen and some mineral balance in sheep. The concentrates were given the amount of 1% of body weight and each roughage (SMS, rice straw, rice straw-pellet) of 2%o of body weight. NaCl and water were available at all times. After 48weeks of experimental peroid, the final body weight of SMS group was significantly higher compared with the other roughage groups (P $lt; .05). Daily weight gain of SMS, rice straw and pellet group was 0.90, 0.69, and 0.81㎏, respectively. In sheep experiment, the nutrient utilization for SMS tended to increase mostly, while the crude protein digestibility for the pellet group was significantly decreased. The rumen pH value for SMS group tended to be slightly lower compared to the other groups, and the concentration of individual VFAs was higher at the SMS group. Especially, the butyric acid for SMS was doubled in value than that of other roughage. Total protozoal count in the rumen fluid was higher at SMS group, followed by straw and pellet group (P $lt; .01). And Entodiniomorphs was predominated species, especially Entodinium. SMS But Holotrichs in me or straw was more frequently observed. Absorption% of intake of Mg, Na, K for the SMS were 48.18, 64.37, and 61.83, and these of the other groups were lower. As compared to the high intake of Na for pellet group, the retained amount was fairly low as were the other minerals. Nitrogen retention for pellet group was lower than that of the other groups (P $lt; .01).