1889.] PUBLIC DOCUMENT — No. 4. 419 



first cost in the market, and on the value of the fertilizing 

 constituents left in the manurial matter after it has served 

 for food. The market value and actual feeding efiect of one 

 and the same article do not necessarily correspond with each 

 other ; in fact, they rarely coincide. The market value may 

 be stated for each locality by one definite number. The 

 feeding effect of one and the same substance, simple or com- 

 pound, varies under different circumstances, and depends in 

 a controlling degree on its judicial use in compounding diets. 



1. Physiological or Feeding Value. 



As no single plant or part of plant has been found to sup- 

 ply economically and efficiently, to any considerable extent, 

 the wants of our various kinds of farm stock, it becomes a 

 matter of first importance to learn how to supplement our 

 leading farm crops to meet the divers wants of each kind. 

 To secure the highest feeding value of each article of fodder 

 is most desirable in the interest of good economy. The 

 judicious selection of ingredients for a suitable and remu- 

 nerative diet for our dairy stock obliges us, therefore, to 

 study the value of fodder articles at our disposal from both 

 standpoints. 



To ascertain the chemical composition of a fodder ration, 

 in connection with an otherwise carefully managed feeding 

 experiment, enables us to recognize with more certainty the 

 causes of the varying feeding effects of one and the same 

 fodder article, when fed in different combinations. It fur- 

 nishes also a most valuable guide in the selection of suitable 

 commercial feed stuffs ^from known sources to supplement 

 economically our home-raised fodder crops. Practical ex- 

 perience in feeding stock has so far advanced that it seems 

 to need no further argument to accept it as a matter of fact 

 that the efficiency of a fodder ration in the dairy does not 

 depend, aside from its general or special adaptation, on the 

 mere presence of more or less of certain prominent fodder 

 articles, but on the presence of a proper quantity and a cer- 

 tain relative proportion of certain prominent constituents of 

 plants which are known to be essential for a successful sup- 

 port of life and of the special functions of the dairy cow. 



Investigations into the relations which the various promi- 



