292 ELEMENTS OF AGRICULTURE 



feeds on the basis of digestible material. This would 

 make the timothy worth 58 per cent as much as the corn 

 meal, whereas it is worth only 48 per cent as much for 

 maintenance, and 37 per cent as much for production. 



Clover hay contains about two-thirds as much diges- 

 tible material as oats, but the clover is much harder to 

 digest. Zuntz calculated that the net nutrients, after 

 allowing for the amount used in chewing and digestion, 

 were about one-third as much for clover hay as for oats. 1 

 Similar results have been obtained by other investigators. 

 (See Appendix, Table 9.) 



We thus see that it is not safe to compare hay feeds 

 with grain feeds on the basis of digestible nutrients. It 

 is approximately correct to compare feeds of the same 

 class on this basis. Hay may be compared with hay and 

 one grain with another without very great errors. 



BALANCED RATIONS 



271. Food Requirements of Different Animals. Animals 

 must be fed very differently for different kinds of work. 

 The kind of feed that is adapted to producing wool, eggs, 

 milk or muscular work is not the kind that is best adapted 

 to fattening an animal or to maintaining it when not 

 producing. If we expect a product that contains a high 

 percentage of protein, as milk or eggs, we must feed a 

 protein diet; otherwise, it will be absolutely impossible 

 to keep up the production. 



Very many experiments have been conducted in order 

 to determine what is the best proportion of the different 



> Farmers' Bulletin No. 170, p. 41. 



