BUILDING MATERIAL 129 



that all feeds, especially corn, contain some protein. If 

 this were not true, hogs fed on corn alone would die on 

 account of protein starvation. Other feeds contain a con- 

 siderable quantity of protein material and are classified 

 as nitrogenous feeds. Most of these contain other nu- 

 trients, such as carbohydrate, ether extract, mineral 

 matter and also water. 



Since protein is present in all feeds, there is not much 

 danger of a pig being starved to death when he is given 

 all the corn, for instance, that he can eat, but the carbo- 

 hydrate feeds do not contain sufficient protein to allow 

 the pig to develop as he should. Consequently in order 

 to supplement the protein found in the corbohydrate 

 feeds, nitrogenous feeds are resorted to. These are feeds 

 such as skim milk, soy-beans, cow-peas, clover and al- 

 falfa. The latter are roughages and on this account will 

 not furnish sufficient protein for the maximum develop- 

 ment of the hog which is not adapted to eating very large 

 quantities of feeds of this class. 



CLASSIFICATION AND COMPOSITION OF 

 FEEDS. 



There are two general classes of feeds, namely, con- 

 centrates and roughages. Concentrates are feeds that con- 

 tain a comparatively large per cent of digestible nutrients 

 and a comparatively small per cent of ^undigestible ma- 

 terial, or, in other words, are the feeds that are not bulky. 

 Roughages or bulky feeds are the opposite of concen- 

 trates; those containing relatively large proportions of 

 undigestible material. Aside from this, feeds are classi- 

 fied according to the amounts of the various digestible nu- 

 trients they contain; those that are composed largely of 

 carbohydrate material are called carbonaceous feeds, and 



