30 Milk and Its Products 



The variation in the percentage of fat in the 

 milk first and last drawn is very great. The first 

 milk drawn is much the poorer in fat. Differ- 

 ences so wide as 1 and 10 per cent of fat in 

 the first and last few pints have not infrequently 

 been noticed. This is due in large measure to the 

 fact that the larger globules of fat, being of 

 nearly the same size as the smaller milk ducts, 

 pass along these vessels less readily than the more 

 fluid portions of the milk, and are only drawn 

 out with the last milk drawn. The milk first 

 drawn has been in the milk cisterns and larger 

 vessels for a considerable period of time, and so 

 has been subject to the reabsorptive action of the 

 lymphatics for a longer time, which also would 

 tend to make it poorer in fat. 



The food also has a considerable influence upon 

 the quality of the milk, although the quantity of 

 the milk is more easily affected by changes in the 

 amount and character of the food than is quality. 

 In fact, with cows kept under favorable conditions, 

 with an abundant supply of food, it is hardly 

 possible to increase the proportion of fat to other 

 solids by a change in the food. On the other hand, 

 while the amount of the various constituents of 

 the milk is not easily affected by the food, the 

 quality of the constituents themselves may be 

 considerably influenced, notably in the case of the 

 fat. Certain foods have a marked influence upon 

 the character of the milk fat. Thus linseed meal, 

 gluten meal and certain other foods make a soft, 



