260 BEGINNINGS IN ANIMAL HUSBANDRY 



walls of plant cells. The chemist may dissolve out the 

 starch and the sugar from the plant cells; what is left is the 

 fiber. The starch, sugar, and fiber are all carbohydrates, 

 but the first two are much better for food, as they are very 

 much more easily digested than the fiber. In general we see 

 carbohydrates all about us in plants and plant products. 

 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; therefore this is the cheapest as well as the most 

 common constituent of animal feeds. Animals cannot sub- 

 sist on carbohydrates alone, although they are very valuable 

 as a source of heat and energy. However, the farmer must 

 depend largely on materials rich in these substances to supply 

 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 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 

 today by persons referring to feeding stuffs. When 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 contains much protein is usually considered a con- 

 centrate. 



