MILK 



TABLE 1. CONSUMPTION OF MILK IN 15 REPRESENTATIVE SECTIONS OF ROCHESTER, 



N. Y. (WILLIAMS) 



Milk a Valuable Food. The milk industry has attained this im- 

 portance because milk, skim-milk, butter and cheese are among the best 

 and cheapest of foods. Most people are fond of them and digest them 

 easily. Good fresh milk is all but essential to the welfare of young chil- 

 dren, and to the nursling that for any reason is deprived of its mother's 

 milk, cow's milk is practically indispensable. The reason that milk is 

 such good food must be sought in its composition. 



Definition of Milk. Milk is the nutritive secretion of the mammary 

 glands. In a general way all milks are similar for they are watery fluids 

 containing fats, proteins, sugars, salts and gases. The fat is in suspension, 

 the proteins are mostly in colloidal suspension but in part in true solution 

 and the salts likewise are in solution and suspension, whereas the sugars 

 and gases are in true solution. Each species of animal has its own 

 peculiar milk; that of animals of the same species differs a little and the 

 milk of a single animal is of slightly inconstant quality. Since in the 

 United States the milk of the cow is the only one that is of commercial im- 

 portance, it is the one with which this book deals. 



Breeding of the Cow. Under the best management a heifer is bred 

 at 15 to 18 months of age, the period of sexual maturity, being reached 

 earlier by some breeds than others. After a period of gestation of 9 

 months she calves and comes into milk. At an estrum occurring about 

 3 months later, she is bred again, but continues to furnish milk for about 

 10 months when the nutrients that have been devoted to milk produc- 



