Calculating Values of Feeding Stuffs 269 



ditions warrant. lu the second case, the attempt would 

 be to determine the relative physiological importance 

 of digestible protein, carbohydrates, and fats, and this 

 being done, the relative agricultural values of feeding 

 stuffs would be established on the basis of their com- 

 position and digestibility, thus providing purchasers 

 with a guide for selecting the materials costing the 

 least in proportion to their value. 



COMMERCIAL VALUES 



Experiment stations have for many years published 

 relative commercial valuations of the various brands 

 of fertilizers that are in the market. Why are we not 

 able to follow the same course with cattle foods ? Sim- 

 ply because of existing conditions. The dry matter of 

 cattle foods is made up of ash, protein, carbohydrates, 

 and fats. We practically ignore the ash and base the 

 value of a given food upon the other three classes of 

 compounds, which are the same in number as the three 

 useful ingredients of mixed fertilizers. Now if we 

 could find in the market a cattle food supplying only 

 a single ingredient, as is the case with fertilizers, we 

 could from its composition and market price determine 

 the cost of this ingredient. As a rule, however, these 

 classes of nutrients must be bought in a mixed condi- 

 tion. All commercial cattle foods, except, perhaps, 

 one waste product from sugar production, are mix- 

 tures in varying proportions of protein, carbohydrates, 

 and fats. When we buy one we buy all three. Pro- 

 tein, starch, sugar or oils as found in commerce have 



