90 FEEDS AND FEEDING 



The disposition of an animal to fatten depends upon breed and 

 temperament. While a wild animal, nervous and active, can be fattened 

 only with extreme difficulty, domesticated animals are more quiet and 

 usually fatten readily. The restless animal is rarely a good feeder, while 

 the quiet one, which is inclined to ' ' eat and lie down, ' ' will show superior 

 gains. This is not due to difference in digestive or assimilative powers, 

 but rather to the fact that the quiet animal has, from a given amount of 

 food, a greater surplus of nutrients available for fat building. Fatten- 

 ing animals must not be allowed to exercise too much as this wastes 

 nutrients which they might store in their bodies. 



III. STUDIES ON GROWTH AND FATTENING 



131. Comparative economy of animal production. The economy with 

 which the various classes of farm animals produce human food is 

 discussed in detail in the respective chapters of Part III, but it will be 

 interesting to compare directly in the following paragraphs the economy 

 of each class of animals with the others. 



Cooper and Spillman of the United States Department of Agriculture 34 

 have computed the following instructive estimates of the amounts of 

 human food produced from an acre of crops fed to live stock and also 

 from an acre of various crops consumed directly for human food. In 

 each instance the pounds of digestible protein and the therms of 

 energy furnished by an acre are shown. The production of live stock 

 per acre was arrived at by assuming that the land was devoted to crops 

 suitable for feeding the kind of animal under consideration and in the 

 proper proportion to make a well balanced ration. For instance, in the 

 case of hogs, four-fifths of the acre was in corn and one-fourth in clover, 

 and it was estimated that an acre used in this manner would produce 

 350 pounds of live weight increase in hogs. In some instances in order 

 to make an efficient ration, it was assumed that a part of the product of 

 the acre was exchanged for a high-protein feed not produced on the farm, 

 such as cottonseed meal. 



The estimates given for the various farm animals are for merely the 

 edible human food after all waste in the carcass and in slaughtering has 

 been deducted. The figures for corn, wheat, and soybeans are for the 

 entire seeds and not for the milled product, such as corn meal and wheat 

 flour. The estimates for rice are for polished rice and those for oats for 

 the hulled kernels. 



The table shows that the dairy cow leads all other classes of live 

 stock in the economy with which she produces human food from a given 

 area of land. When milk is used as human food, 711.8 therms (711,800 

 Calories) of energy are secured from 1 acre, and 72.3 Ibs. digestible 

 protein. This fact, together with the high nutritive value of milk as a 

 food because of its many superlative qualities (104, 115), explains the 



M U. S. D. A. Farmers' Bui. 877. 



