MILK The principal constituents of milk are water, fat, proteins, lactose (milk sugar) and minerals (salts). Milk also contains trace amounts of other substances such as pigments, enzymes, vitamins, phospholipids and gases. The residue left when water and gases are removed is called the dry matter(DM) or total solids content of the milk. Milk is defined as the lacteal secretion of the mammary glands of mammals which is obtain five days after calving's. Milk is a complex biological fluid consisting of seven main components : water, fat, protein, sugar(lactose), minerals, vitamins and enzymes. The color varies from white to yellow depending on the carotene content of the fat. Milk has a pleasant, slightly sweet taste, and pleasant odour. It is an excellent source of calcium, phosphates and riboflavin. The capacity of milk is due to its content of suspended particles of fat, proteins and certain minerals. Oxytocin hormone is responsible for emptying under of cow. COMPOSITION OF MIL