Productivity of Farm Animals 403 



based the productive- power of food when utilized by 

 the various classes of animals. Data of this kind are 

 practically our only means of studying the economics 

 of producing those human foods which are most costly 

 in proportion to their nutritive value, a study which is 

 very important wherever it becomes necessary to econo- 

 mize energy. It shows the coefficients of efficiency of 

 various species of animals in maintaining the human 

 species. The sources of all these figures are not given, 

 for they are so numerous as to make this difficult : 



PRODUCTION BY FARM ANIMALS 

 Proportions of carcass and edible substance 



Carcass Per cent* Per cent of 

 Number in per cent of edible edible dry 



of of live dry matter matter in live 



animals weight in carcass animal 



Steers, general average 97 61.4 33.2 20.4 



Steers, Iowa 5 64. 33.2 21.2 



Steers, Kansas 5 61.4 33.2 20.4 



Steers, Maine! 8 57.7 32.3 18.6 



Sheep 4 50.7 37.4 19. 



Lambs 44 50.7 33.7 17.1 



Lambs, Iowa 133 54. 33.7 18.2 



Swine, general average 97 81.2 62.7 50.9 



Pigs, Iowa 56 77.9 62.7 48.8 



Calves 23 57.2 22.2 12.7 



Fowl, large 12 80.8 27. 21.8 



Fowl, small 7 78. 27. 21.1 



Chickens, broilers 107 82.lt 14.7 12.1 



Eggs 34? 88.8|| 26.3 23.3** 



* From Bull. 28, Office of Experiment Stations. Revised edition, 

 t Grown from calfhood, entire bodies analyzed. 

 tNot drawn. 

 Number of samples. 

 II Per cent after removing shells. 

 ** In eggs with shells. 



