36 Milk and Its Products 



secure and digest food of the same kind and nature 

 as its parents. The function of milk secretion in all 

 such animals, then, begins when the young is born, 

 increases rapidly for a few days or weeks, as the 

 developing infant requires more food, and then grad- 

 ually diminishes as the infant with continued growth 

 begins to seek its natural and permanent food, and 

 finally entirely ceases when the young is able to get 

 its own subsistence, at the age of a few weeks in the 

 case of most small animals, and in no event longer 

 than a few months even with the largest forms. 



The cow the only commercial milk producer. His- 

 tory does not tell us how the cow came to be devel- 

 oped as the preeminent producer of milk for man's 

 use. In all probability the milk of the goat and the 

 ass was used by man before that of the cow. But 

 in her development the cow has shown herself to be 

 so much more adaptable to the commercial production 

 of milk as to have distanced all other animals in this 

 respect. There is no historical evidence that leads 

 one to believe that in her wild state the cow had any 

 greater tendency to give milk in excess of the demands 

 of her offspring or for longer periods of time than 

 many other animals. The domestication of the cow 

 has resulted in developing an animal in which the 

 capacity for secretion has been multiplied many times, 

 and the duration of secretion has been made practi- 

 'cally continuous. As a liberal estimate, a vigorous 

 calf would not need more than 20 pounds of milk per 

 day for the first four months of its life, or 2,400 

 pounds of milk, and this, or less, would be all that a 



