Subclinical mastitis is almost asymptomatic in nature, with no visible signs detected on the udder and most prevalent disease in dairy cows incuring a huge economic loss in the dairy industry. The treatment and prevention of this disease employing antibiotics are not always effective and have adverse effects in public health. The present study aims to measure the effectiveness of application of a probiotic (Bacillus coagulans MTCC 25250) feed additive in subclinical mastitis cows on improvement of body condition, blood parameters, milk yields and milk composition apart from mitigation of the disease. A total of 20 subclinical mastitis cows were randomly assigned into four groups with various probiotic doses comprising T1 (15 g/d/cow), T2 (30 g/d/cow), T3 (45 g/d/cow) and control (without probiotic) in a trial of 60 days. All four groups received a total mixed diet. Cows' body conditions and their bloods, milk yields and composition were investigated on the day of 0, 30 and 60. The results demonstrated that body conditions score, milk production, and compositions were improved in the T2 and T3 groups. Additionally, T2 and T3 groups showed a lower somatic cell and total bacterial counts in milk. The blood analyses showed that red blood cell, hemoglobin, lymphocyte, and monocyte counts were significantly higher for T1, T2 and T3 groups, however, white blood cell and neutrophil counts were decreased. The data suggest that application of a probiotic Bacillus coagulans MTCC 25250 as a feed supplement might be beneficial in milk yields and composition in subclinical mastitis cows. This potential probiotic strain would be useful for the mitigation of subclinical mastitis and improves the productivity of dairy cows.