68 A STUDY OF FARM ANIMALS 



The most of the stalk of corn, or any growing plant, consists 

 of carbohydrates. Common rice and potatoes are rich in 

 this substance. Many of our hays contain from 60 to 70 

 per cent. This is, therefore, the cheapest as well as the most 

 common constituent of animal feeds. Animals can not sub- 

 sist on carbohydrates alone, although they are very valuable 

 as a source of heat and energy. The farmer must depend 

 largely, however, on materials rich in these substances to 

 supplj' the great bulk of the feed for his stock. 



The fat in the plant is composed of carbon, oxygen, and 

 hydrogen in different combinations from which we find them 

 in the carbohydrates. Fat, or ether extract, as it is also 

 called, is not usually abundant in plants. One to 3 per cent 

 is the usual amount with many plants. The seeds ordinarily 

 contain the most, some of these like cottonseed, soy beans, 

 and flax having large quantities, so that it is extracted for 

 commercial purposes, and the by-product rich in protein is 

 sold as cake or meal. Fat is of special value in the food, as 

 it furnishes the animal both heat and energy. 



The words roughage and concentrate are commonly used 

 to-day by persons referring to feeding stuffs. AVhen a farmer 

 speaks of roughage, he means hay, corn fodder, or some 

 coarse feed of that kind. By a concentrate, he means seeds 

 that may be fed, or products made from them, such as bran, 

 corn meal, oil meal, etc. Any form of feed for farm animals 

 that does not contain a large amount of fiber, and is rich in 

 protein or some form of nitrogen-free extract, such as starch 

 as it occurs in the grain of rice, is usuallj^ regarded as a 

 concentrate. Roots differ from roughages or concentrates 

 in their general appearance, and, being succulent, contain a 

 large amount of water, which often exceeds 90 per cent. 

 Thus it may be seen they contain but little nutriment. On 

 account of their composition in dry matter, and small 

 amount of crude fiber, they are regarded by chemists as con- 

 centrates rather than roughages. 



