42 



DOMESTICATED ANIMALS AND PLANTS 



i 



milk per year up to over 12,000, and from less than 50 pounds 

 of butter fat ^ to over 500 pounds. Manifestly a whole herd like 

 the poorer cows would swamp their owner unless prices were 

 enormous or unless their food consumption were correspond- 

 ingly lower. 



To test this point, the department conducted investigations 

 into the relative efficiency of commercial cows on the basis of 

 food consumed. Accordingly two or more cows were purchased 

 from each of several of the largest commercial herds of the 

 state, the aim being in every case to secure the very best and 

 the very poorest individuals in the herd, according to the best 

 basis of judgment at hand. The yearly record of these cows 

 is shown in the following table : 



Variability of Cows on the Basis of Food Consumption 



1 By butter fat is meant not butter, but the fat of butter. Commercial butter 

 contains about 85 per cent fat, the rest being water, salt, curd, etc. 



2 Numbers by which the cows were designated in the records. 



3 Each group from the same herd. 



* After multiplying number of pounds of fat by 2.4. This represents the 

 amount of food digested by each cow. 



^ n -^ m = nutrients divided by milk produced. 

 ® n -f- f = nutrients divided by fat produced. 





