VARIATION 203 



in milk can easily be determined. The cow, Pedro's 

 Ramaposa, during a period of one year produced 8522.9 

 pounds of milk which contained 1317 pounds of dry 

 matter. In the production of this quantity of milk she 

 consumed in feed 9362 pounds of dry matter. In other 

 words, the consumption of 100 pounds of dry matter 

 in the feed resulted in the production of 91.12 pounds of 

 milk containing 14.06 pounds of dry matter. Stated 

 in other terms, the cow here described produced one pound 

 of dry matter in the milk for each 7.1 pounds of dry 

 matter consumed in the feed. i 



194. Variations among different cows. The milking 

 function is hereditary and is a comparatively well-fixed 

 character among the dairy breeds of cattle. It is true, 

 however, that there still exist wide variations in the 

 productive capacity of cows, even of the same breeding 

 as well as those of different ancestry. The Illinois 

 Experiment Station 1 in several tests has clearly demon- 

 strated the wide differences which may exist between 

 individuals. 2 Two native cows, Rose, nine years old, 

 and Nora, six years old, were fed the same kind of 

 a ration for twelve months. The amount fed was de- 

 termined by the appetites of the animals. The table 

 on the following page gives the essential facts of interest 

 in this connection. 



" Reduced to a like feed basis, for every 100 Ib. of milk 

 given by Nora, Rose gave 139.5 Ib., and for every 

 100 Ib. of butter-fat produced by Nora, Rose produced 

 180.7 Ib." 



Commenting on this test, Fraser says, 3 " As milk is 



1 Fraser, Illinois Experiment Station, Bulletins 51 and 66. 



2 Davenport, "Principles of Breeding," p. 78. 



3 Loc. cit. 



