250 Elementary Principles of Agriculture 



fat and only 0.7 per cent mineral matter, or salts. The 

 milk from different cows varies considerably. The solids 

 may be as low as 10 per cent or as high as 18 per cent. 

 The protein (the substance that thickens and forms 

 clabber) may be low if cows do not receive feeds suffi- 

 ciently rich in protein. The fat varies, sometimes as 

 low as 2.5 per cent and sometimes as high as 8 per cent. 

 The legal standard required by state and city laws is 

 3 to 3.5 per cent fat, and 9 to 9.5 per cent solids other 

 than fat. The composition of milk is but slightly changed 

 by the feed a cow consumes. The feed does affect the 

 quantity of milk, however. 



355. How the Kind of Feed Affects the Flow of Milk. 

 The feeding of dairy cows to increase the now of milk 

 has long been studied, both by the experiment stations 

 and practical dairymen. The exact methods of scien- 

 tific investigation where the feed consumed and the 

 milk and butter produced are carefully weighed, teach- 

 that for the best results dairy cows should have: 



(a) An allowance of green, succulent food, either 

 . by pasturing, soiling crops or silage. 



(6) Some dry roughness in the form of hay, corn 

 stover, or straw. 



(c) Grains or concentrates supplying sufficient pro- 

 tein and carbohydrates to bring the ration to the normal 

 dairy standard. 



Succulent feeds promote the digestion of other feeds, 

 and give flavor and color to the milk and butter. 



Dry roughage has a wholesome effect on the health 

 and general condition of the cows. The cow craves 

 some dry feed which can be hastily swallowed, and 

 while lying down at rest, be regurgitated and chewed 

 over. 



