Little boy drink milk with zest. Milk is a very healthy food, recommended both children as well as adults due to its composition. Milk composition varies greatly between different mammals. Human breast milk for example contains much lactose, sugar main of them. In contrast, cow’s milk contains less sugar and fat. Cow’s milk fat is composed of 3.5%, 9% milk solids and 87.5% water. Main protein (80%) is casein. The milk of certain mammals, such as cows, sheep, goats, buffaloes and horses, is collected to be consumed by humans directly, usually after pasteurization or processed milk products such as cream, butter, yogurt, ice cream or cheese.recommended both children as well as adults due to its composition. Milk composition varies greatly between different mammals. Human breast milk for example contains much lactose, sugar main of them. In contrast, cow’s milk contains less sugar and fat. Cow’s milk fat is composed of 3.5%, 9% milk solids and 87.5% water. Main protein (80%) is casein. The milk of certain mammals, such as cows, sheep, goats, buffaloes and horses, is collected to be consumed by humans directly, usually after pasteurization or processed milk products such as cream, butter, yogurt, ice cream or cheese.