CHAPTER II 

 THE RELATIONS OF PLANT AND ANIMAL LIFE 



Animal nutrition has an intimate relation to plant 

 growth. The farmer producing meat and milk should 

 understand the relation which animal life sustains to 

 plant life in order that he may so direct plant production 

 as to best serve his purposes in feeding whatever class of 

 animals he utilizes. The efficiency of the various plant 

 products in sustaining animal life is to him a matter of 

 great importance. 



1. Origin of animal foods. — ^The compounds which 

 together constitute animal foods have their origin in plant 

 hfe. For this reason, a study of the fundamental facts 

 of animal nutrition begins with the plant. It is in the 

 plant that the simple compoimds derived from the soil 

 and air are utilized for the production of the more highly 

 complex compounds which are used for the growth of 

 the animal body and for the maintenance of its 

 activities. 



As soon as the young rootlets from a germinating seed 

 come in contact with the soil and the first leaves reach the 

 air, assimilative growth begins and continues, as for 

 instance, in the wheat plant until the stalk of grain has 

 reached its full height and has attained the ultimate 

 object of its existence in the production of seed. Certain 

 agricultural plants have the capacity of producing not 

 less than 10,000 pounds an acre in a single year of plant 

 substance which may serve as food for animals. 



(9) 



