THE FATTENING OF MATURE ANIMALS 359 



and intramuscular fat, and, second, an increase in the muscular 

 tissues themselves, due in part at least to an increase in the 

 soluble protein and in the nitrogenous extractives. The dep- 

 osition of fat adds directly to the nutritive value of the meat, 

 materially increasing its fuel value. Moreover, its mechanical 

 effect in separating the fibers may be presumed to render the 

 meat more tender, while the products of its decomposition in 

 some forms of cooking (roasting and broiling) probably add to 

 the flavor of the meat. The increase of the soluble protein is 

 also doubtless one cause of the tenderness of the meat of fat- 

 tened animals, while the other nitrogenous matters, though 

 of little or no direct nutritive value, are an improvement through 

 the added flavor and palatability which they bring about. 



2. FEED REQUIREMENTS FOR FATTENING 



447. Comparison with maintenance. In the two preceding 

 chapters it appeared that the maintenance requirements are 

 determined substantially by the amounts of protein and of 

 energy which are katabolized in fasting and which, therefore, 

 must be made good from the feed in order to maintain the body. 

 By analogy, the amounts of protein and energy stored up in the 

 process of fattening may be taken as the measure of the require- 

 ments for fattening i.e., of the amounts which the feed must 

 be capable of supplying in an available form. In other words, 

 the requirements for fattening are equivalent to the tissue 

 produced just as the requirements for maintenance are equiva- 

 lent to the tissue whose loss is to be prevented. The 

 total feed requirement of a fattening animal, then, is to be 

 regarded as made up of the maintenance requirement plus the 

 fattening requirement. 



In one important respect, however, the fattening require- 

 ment differs from the maintenance requirement. The latter, 

 while not invariable, is still more or less constant for the same 

 animal. In fattening, on the other hand, there may be a 

 varying rate of production up to the limit set by the in- 

 dividuality of the animal and its capacity to eat and digest 

 food. Accordingly, as slow or rapid fattening is anticipated 

 or desired, the daily requirement of the animal may be higher 

 or lower. 



