CHAPTER X 

 THE FATTENING OF MATURE ANIMALS 



439. Disposal of surplus feed. When an animal consumes 

 feed in excess of that required simply for maintenance, a pro- 

 duction of some sort results. The surplus feed may be trans- 

 formed into material products as flesh, fat, milk, etc., which 

 are stored up in the body or secreted, or it may be katabolized 

 and its energy expended in the performance of work. 



One of the simplest and most familiar examples of such pro- 

 duction is afforded by the fattening of mature animals. Such 

 fattening, it is true, is not of great economic importance, since 

 the larger share of the world's meat supply is derived from 

 animals which have not yet reached full maturity. Fattening, 

 however, as well as growth, forms an essential part of the pro- 

 duction of at least the better grades of meat, and while it is 

 practiced largely on immature animals its feed requirements 

 can be studied to better advantage in the mature animal. The 

 purpose of the present Chapter is to consider the general nature 

 of the fattening process and the demands which it makes upon 

 the feed supply, leaving its economic aspects for discussion in 

 connection with meat production. 



440. Fattening requirements. Just as the quantities of 

 matter and energy required for maintenance depend, in the 

 first instance, upon the amounts lost from the body during 

 fasting, so the quantities which must be supplied in excess of 

 maintenance to support the fattening process will depend 

 primarily on the amount and composition of the gain made. 

 The obvious first step in considering the feed requirements of 

 the fattening animal, therefore, is a study of the composition of 

 the increase. 



i. COMPOSITION OF THE INCREASE IN FATTENING 



441. Increase chiefly fat. The discussions in previous 

 chapters have rendered it evident that the chief function of 



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