286 ELEMENTS OF AGRICULTURE 



of ash, they may be fed lime or wood-ashes, tankage 

 or bone meal. If fed on corn and alfalfa, the shortage of 

 ash is made up. Hens always require more lime than is 

 contained in their feeds. The striking reason for this is 

 seen when we compare the composition of eggs and corn. 

 The eggs contain 12.2 per cent ash, the corn only 1.5 

 per cent. Hens are, therefore, commonly fed cracked 

 oyster shells. Possibly one reason why the Kentucky 

 horses have such good bones and feet is the high ash 

 content of the feed that they get in the blue-grass pastures. 

 It is very probable that the ash food of colts in the corn- 

 belt should be given more consideration. 



260. Protein. There are a large number of compounds 

 that are classed together as protein. The gluten of wheat, 

 lean meat, white of egg, the curd of milk, are protein com- 

 pounds. All the protein compounds contain nitrogen. 

 They are not all of equal feeding value. 



The protein compounds make the basis of the bones, 

 muscles and other tissues. They are also used, to a limited 

 extent, as fuel to keep the body warm, but this is not 

 their important function. 



261. Fats. The fats in food serve the same purpose 

 to the animal as do the carbodydrates. Fat is more effec- 

 tive than carbohydrate. It has been found that if a pound 

 of fat is burned it gives 2.25 times as much energy as is 

 furnished by burning a pound of carbohydrates. We 

 therefore say that a pound of fat is approximately equiva- 

 lent to 2.25 pounds of carbohydrates as food for a seed 

 or as food for animals. 



262. Carbohydrates. The starch and sugar compounds 

 are the most important carbohydrates. Crude fiber or 



