MILK SECRETION 29 



The fact that "fat cannot be fed into a cow" 

 is very important. A farmer can test the milk of 

 a heifer, and if she does not produce milk of a 

 satisfactory quality he need not keep her, for he 

 may rest assured that the quality of her milk will 

 not materially change later on in her life. In 

 this way, therefore, it is possible for a farmer 

 to build up a good herd by selecting his cows. 

 This topic will be discussed more at length in a 

 later chapter. 



EXERCISES 



1. Why are large "milk veins" necessary to high 

 milk production? 



2. How do we know that the udder is not a reser- 

 voir in which milk is stored to be drawn at milking time 1 



3. On the other hand, how do we know that milk is 

 being secreted all the time but principally at milking 

 time? 



4. "Why do cows sometimes "leak" milk? Does this 

 ever happen with light milkers ? Hard milkers ? 



.5. Can fat be fed into milk ? 



6. What influence does feed have on milk, if any? 



7. Do you know which cows of your herd give the 

 richest milk ? Which the poorest ? 



LABORATORY PROBLEMS 

 III. To Determine the Albumen in Milk 



1. Heat the filtrate obtained in Problem II to a 

 boiling point for five minutes and filter ; boil for another 

 five minutes and filter again. The filtrate should then 

 be clear and will contain the sugar, ash, and some potash. 



2. Dry the residue on the filter paper. It is albumen. 



