94 ILLINOIS DAIRYMEN'S ASSOCIATION. 



best. No man had any wish or expectation of permanently 

 altering the form of the breed. Nevertheless, we may infer 

 that this process continued during centuries would improve and 

 modify the conformation of the animal in the same way as Bates, 

 Collins, etc., by this very same process, only carried on more 

 methodically, did greatly modify even during their life times, 

 the forms and qualities of their cattle. The selection for cen- 

 turies of the best milking animals, and the constant demand of 

 man for more milk has now unquestionably established a definite 

 type known to the milking strain of cattle. Whether the selec- 

 tions or the standards used are the best is not necessary to dis- 

 cuss. It is sufficient to say that through years of constant milking 

 the domesticated animal produces considerably more milk than 

 her wild parents, and she has a very much modified form. 



During all this time the animal has been called upon to do 

 much harder work than her ancestors, consequently through use 

 she has developed certain organs that might be called abnormally 

 large, and even artificial, while on the other hand, through disuse 

 certain portions of her body have become atrophied. The wast- 

 ing away of certain portions has caused the parts which are used 

 by her in the manufacture of milk, to stand clearly marked and 

 well defined from her sister whose whole function is to make 

 beef. The dairy cow's special function has developed four main 

 centers which are actively engaged when the animal is produc- 

 ing milk. The centers are namely: The digestive organs, the 

 circulatory system, the nervous system, and the milk secreting 

 system. 



Digestive Organs. 



The digestive organs, on account of her special work, have 

 become exceptionally large and they are capable of handling large 

 quantities of food. So efficient is the digestive tract in some 

 animals that a single cow has been able to consume, digest and 

 assimilate enough material to produce in one year nearly twenty 

 times her own weight in milk. As a rule the best cows show 



