In recent years, many researches are actively undertaken for environmental-friendly animal production according to the increased understanding about food safety because of the outbreak of various diseases such as mad cow disease, Foot and mouth disease and Poultry Influenza virus. However, high quality(higher safety)-animal production may not be successful without increasing of disease resistance of animal and the improvement of feeding environment. To increase the disease resistance is able to be accomplished by stimulating the immune function. The present study was undertaken to investigate the effects of enzyme mixture reinforced with β-glucanase activity which degrade polysaccharide to release β-glucan known as stimulator of immune function on the change of milk production and somatic cell count. After 12weeks of experimental feeding, milk production tended to be increased and somatic cell count was decreased from average 227×10⁴ to 37.1×10⁴. Milk protein and solid-fat content were tended to increase but milk fat showed decreasing tendency by the feeding of enzyme mixture. All together, it has been suggested that the improvement of high quality milk production may be possible through the dietary addition of immune modulating enzyme mixture in lactating dairy cows.