CHAPTER XVIII. 



CONSIDERATIONS THAT RELATE TO MILK 

 PRODUCTION. 



Prominent among the considerations that relate to 

 milk production are the following: 



1. Formation of milk. 



2. Composition of milk. 



3. Foods and milk production. 



4. Milk production and cost. 



5. Quantity in milk production. 



6. Quality in milk production. 



7. Breeds and milk production. 



8. Lactation and milk production. 



9. Age and milk production 



10. Large and small cows. 



11. Relative milk giving capacity. 



12. Protection for cows in summer 



13. Shelter for cows in winter. 



14. Feeding grain to cows on pasture. 

 These are discussed in the order given. 

 Formation of milk. As has been pointed out by 



Armsby, milk is not simply a secretion from the blood, 

 as urine is in the kidneys, or as the digestive juices are in 

 the stomach and intestines. That it is not a transudate, that 

 is a variant, a filtrate of the blood, the result of the pas- 

 sage of its fluid constituents through membrane, is shown 

 in its composition. Milk differs from blood: (i) In that 

 it contains factors not found in blood; (2) in the marked 

 contrast in the ash in blood and milk respectively and (3) 

 in the sustaining power of each. Cow's milk contains 

 from 2 to 5 per cent protein, and from 3 to 5 per cent 

 milk sugar. But the protein of the blood exists as al- 

 bumin or fibrin, while the greater portion of that in milk 

 exists as casein, which is found in considerable quantity 



