i8o GUIDE TO DAIRYING IN SOUTH AFRICA 



Nutrients described. 



The principal nutrients in feed stuffs which give 

 them their value are known as protein, carbohy- 

 drates, and fat. These are technical terms, but 

 they are few and not hard to follow. 



Protein is the principal of the nutrients, and 

 should always be considered first when we talk of 

 feeding stuffs ; white of egg is a good example, 

 also the gummy substance which we find in wheat 

 if we chew a few grains at a time. Protein is 

 usually the most expensive item in feeding and 

 the one most thoroughly needed for milking-cows, 

 as it is necessary for building up the foetal calf and 

 for forming the albumin and casein in the milk. 



The carbohydrates are next in importance. 

 Sugar and starch are pure carbohydrates, and when 

 dissolved in the digestive process serve the animal 

 for production of fat, body heat and energy, and 

 also help form the milk sugar. Oats, wheat, 

 barley, mealies are all rich in carbohydrates as 

 they are composed chiefly of starch. 



The fats in feeding stuffs have the same work 

 as carbohydrates. When fats are burned they give 

 off 2\ times as much heat as starch, hence by multi- 

 plying the fats present in a given food by 2^ we are 

 able to find their value in terms of carbohydrates. 



Thus a feed containing 



Fat or 



Protein. Carbohydrates. ether extract. 



12 % 45 % 6 % 



