Based on domestic experience and many years of personal research, modern data on the morphology and physiology of the breast of cows are presented , Biological value of milk , chemical composition , Environmentally friendly milk hygiene and veterinary and sanitary control , breast disease and mastitis research methods, prevention and treatment in large farms and industrial complexes. The training manual is intended for veterinary doctors, zooengineers, mid-level specialists in veterinary medicine, students of higher and secondary specialized educational institutions, students of faculties of advanced training, graduate students .