Casein is easily coagulated by acid or by enzyme renin while the other proteins are not. Fat Milk fat is also called butter fat and is characterised by the presence of short chain saturated fatty acids. Carbohydrate Lactose is the carbohydrate in milk which is broken down by the enzyme lactase. An absence or insufficiency of lactase causes micro-organisms to act on lactose leading to the formation of gases and thus the cramping discomfort and diarrhoea in 'lactose intolerence'. The minerals present in milk are sodium, phosphorus, sulphur, magnesium, manganese, calcium and iron.
Calcium is bound to phosphate which, with casein, forms a phosphoprotein.
It is also present with fat. The quantity of iron is low in milk, but is of an excellent quality resulting in its ready absorption. Vitamins Vitamin A - carotene present gives the milk yellowish tinge and is obtained from plant feed. The amount varies with the breed, the amount present in the feed and the fat content of milk. These nutrients are present in small amounts.