30 DOMESTICATED ANIMALS AND PLANTS 
Besides this, these animals require a large amount ‘of labor in 
caring for their needs, and a still additional expense for the 
shelter of themselves and their feed.! 
The animal population of the United States in millions as 
compared with the human is substantially as follows : 
Census of 1900 Estimated for 1910 
Human population . . 2... . 7 5,000,000 90,000,000 
Horses, mules, and asses . . . . . 21,000,000 27,000,000 
Cattleofall kinds . « 2 1 a «# + 67,000,000 7 3,000,000 
Sheep eng cor Stas, ae Se ok 61,000,000 67,000,000 
SWI hs ss (ae me ena, Geormeee & 62,000,000 68,000,000 
With five people to the family, we can say that in general 
and on the average every family has one horse, four head of 
cattle, four sheep, and four swine, with several millions left over, 
—a total average of three animals for each human inhabitant, 
or fifteen to the family. The estimate for 1910 can be only 
approximate, for these proportions vary greatly. 
It is little wonder that we raise immense acreages of hay, 
corn, and oats to maintain all these animals. It is only on care- 
ful thought that we realize how much of our lands and how 
much of our labor are devoted to the care and maintenance of 
the animals we have domesticated and brought to live among 
us, and whose support we have undertaken. 
There is argument enough now for the highest attainable 
efficiency on the score of expense, but it must be evident to the 
most casual reader that with the increase of human population 
1 Read Circular 178, Experiment Station, University of Illinois, and see how 
extensive the barns must be to shelter the large number of inefficient cows 
necessary to return the same profit as would be returned by a few economical 
producers. In the case in hand, one class of cows return fourteen times the 
profit of the other. This would mean that in order to realize a certain net in- 
come, fourteen times as many cows of the one kind would have to be kept as 
of the other, which means fourteen times as much barn room, fourteen times 
as much capital tied up in feed, fourteen times as much milking, and more 
than fourteen times as much waste and risk. 
