CHAPTER III 

 FACTORS THAT AFFECT THE COMPOSITION OF MILK 



IN the preceding chapter it has been seen that cow's milk is 

 subject to wide variations in composition. There are many 

 things which cause these variations, certain conditions affecting 

 the composition of the milk permanently, others causing only 

 transient modifications. Probably all the constituents of milk 

 are subject to more or less fluctuation in percentage and amount, 

 but those which show the greatest changes are the water, the 

 fat, and the total solids. 



FACTORS WHICH AFFECT THE WATER-CONTENT OF COW's 



MILK (Van Slyke) l 

 Amount of variation. 



The amount of water normally contained in milk varies, 

 depending on such conditions as individuality, breed, stage of 

 lactation, age, character of food, amount of water drunk, state 

 of health. In the case of single milkings of individual cows, 

 the water may vary from 82 to 90 per cent or more ; in the case 

 of milk from herds of cows the water varies less, usually ranging 

 from 86 to 88 per cent. 

 The influence of breed. 



The following figures from the records of the New York Agri- 

 cultural Experiment Station illustrate the influence of breed 

 on the water-content of milk : 



1 Modern Methods of Testing Milk and Milk Products, Orange 

 Judd Co. 



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