40 



THE NORMAL COMPOSITION OF MILK 



duction. Malm^jac ^ reports the following comparative figures 

 obtained in Algeria from cattle feeding on poor and rich 

 forage. 



Brewery and distillery waste grains in the wet condition 

 have often been fed to cows on account of the low price of this 

 material, but this procedure ultimately proves to be false 

 economy, as both the relative and absolute amount of milk fat 

 produced is reduced. During the last decade there has been 

 a decided tendency towards scientific feeding of dairy animals 

 with a well balanced ration which is just sufficient for the main- 

 tenance of body weight and also for the production of a definite 

 quantity of milk containing a specified amount of butter fat. 

 In this ration, digestibility, palatabihty, and proportion of 

 roughage to concentrates, are considered and calculated. An 

 example of this rational feeding is seen in the herds of the 

 Minnesota Experimental Station, as compared with the other 

 herds of the state. The common cows, i. e., cows with no dairy 

 heredity, of the Experimental Station yielded 5000 lbs. of milk 

 equal to 222 lbs. of butter per head as against 4000 lbs. of milk 

 equal to 175 lbs. of butter per head for the whole State of 

 Minnesota. 



Stable or byre conditions, fatigue, and temperature, also 

 have slight effects upon the fat content of the milk produced. 



The seasonal variation in the amount of butter fat in milk, 

 according to Droop Richmond's figures, is well marked and 

 always occurs; he finds that the fat content usually decreases 

 during the spring and summer months, reaching a minimum 

 about midsummer, and then gradually rises to a maximum 



