PRINCIPLES THAT GOVERN FEEDING 169 



their free use in feeding stuffs tends to cheapen the ration. 

 Moreover, they are readily eaten and digested by all the ani- 

 mals of the farm. And yet a sufficiency of protein must be 

 fed since the nitrogenous substances constitute so large a 

 proportion of the animal body, since many of the vital proc- 

 esses are dependent on them, and since they are so neces- 

 sary to performance as in the production of flesh, milk and 

 muscular exertion. 



Crude fibre is that tough woody portion of the plant 

 which constitutes its framework. It is the portion that re- 

 mains after the softer parts have been dissolved and washed 

 out. Young plants contain considerably less of crude fibre 

 than those which have produced seeds, and the seeds of 

 plants also contain much less than the stems and leaves. 

 It is not easily digested, especially by animals which do not 

 ruminate. The portion digested is thought to have prac- 

 tically the same function as the other digestible carbohy- 

 drates, and is supposed to equal them in value. The indi- 

 gestible portion, oftentimes a tax upon the digestion, may 

 sometimes serve a useful purpose in the bulk which it fur- 

 nishes. 



Ash, the inorganic portion of plants and of animal bod- 

 ies, is that part which remains after either has been con- 

 sumed by flame. In plants it is most abundant in the leaves. 

 These mineral matters are usually amply present in all foods 

 to meet the needs of animals, with the exception of salt, 

 which must be supplied. In the form of lime and phosphate 

 they go to make bone, as soda and chlorine they aid the di- 

 gestive juices, and as iron they probably help in the forma- 

 tion of the red corpuscles in the blood. For reasons that 

 will be manifest young and growing animals need them in 

 largest supply. 



Importance of nitrogenous substances. From what 

 has been said, it will be apparent that the nitrogenous sub- 

 stances of the body are by far the most important since they 

 include nearly all the solid parts except the fat and the min- 

 eral constituents of the bones. Therefore, for the sake of 



