VARIATION OF FAT IN MILK 



73 



According to experimental evidence, milk drawn with a 

 machine contains more bacteria than milk drawn by hand-. 

 This is claimed to be due to the suction on the exterior of the 

 teat, and to the tubes through which the milk must pass after 

 it is drawn. 



Fore-milk and After-milk. — The fore-milk, or the milk 

 drawn from the cow's udder first, contains much less fat than 

 does the milk drawn subsequently. The very first milk drawn 



Fig. 22. — Milking goats in Norway. 



appears watery and contains as little as 0.1% of fat, while 

 the very last milk in the udder may contain as high as 12%. 



The reasons assigned for this variation are (1) the milk in 

 the canal of the teat, and lower portion of the milk-reservoir 

 is present under such conditions as to allow creaming to proceed. 

 (2) The larger fat-globules are about as large as the smaller 

 milk-dusts in the cow's udder; consequently the downward 

 passage of these fat-globules meets with some obstruction 



