INTRODUCTION 7 



mercial feeding-stuffs. These purchased materials are 

 not wholly the cereal grains whose value through long 

 experience has come to be measured by certain prac- 

 tical standards, but they consist in part of compara- 

 tively new by-products from the manufacture of oils, 

 starch, and human food preparations feeding-stuffs 

 which differ greatly in their nutritive properties. Besides 

 all these changes, animal husbandry is now called upon 

 as never before to feed the prosperous part of humanity 

 with high-class products having special qualities of 

 texture and flavor that depend to some extent upon 

 feeding. Certainly the conditions and problems to be 

 met in this branch of human industry have grown more 

 and more complex. 



We must add to this the fact that, as is true with 

 every department of man's activity, science has laid 

 her hands upon the business of the farmer and has forced 

 him into a new range of thought and practice. This 

 influx of knowledge has greatly influenced the require- 

 ments for meeting a sharpened competition and has 

 rendered it imperative for the practitioner to bring to 

 bear upon a great variety of agricultural problems a 

 clear understanding of fundamental facts and principles. 



The feeding of animals involves many difficult ques- 

 tions. These begin with the production of forage and 

 grain crops where it is necessary to discover what ones 

 will yield the largest food-values to a unit of expendi- 

 ture. Economy demands that the several feeding-stuffs 

 which are at command shall be so combined that there 

 shall be no waste of material or energy. With several 

 considerations in view, a decision must be reached as to 

 the most profitable commercial foods to purchase when 

 the number is large and the range of prices is wide. The 



