Mastitis, on account of causing serious wastage and undesirable milk quality, has emerged as a major challenge and continue to be one of the most common and costly diseases in dairy cattle across the globe accounting for around 40% of the total direct costs of the common production diseases. In India, the economic losses due to mastitis have increased about 115 folds in last five decades. Subclinical mastitis is believed to be more prevalent than clinical mastitis in most the countries. Most of dairy farmers in Jammu division are hardly aware of sub-clinical mastitis and give no importance to it. Therefore, an early detection of sub-clinical mastitis using suitable field diagnostic aid is very much essential for its successful treatment and control.This book contains the bonafide research work of the authors with special emphasis on prevalence of sub-clinical and clinical mastitis in cross bred cows, haemato-biochemical changes and electrolyte and mineral status of blood in dairy animals suffering from sub-clinical and clinical mastitis. It also contains the results of therapeutic trials in mastitic cases using antimicrobials along with supportive therapy.