330 SCIENTIFIC FEEDING OF ANIMALS 



were extracted from the milk, there must have 

 been at least 17-69 kg. of milk fat, and all the milk 

 sugar formed from the carbohydrates. 



The nitrogen-free extract substances, then, supply 

 the mammary gland with material for the produc- 

 tion of milk fat and milk sugar. These two com- 

 ponents of the milk can, it is true, probably be 

 formed from the protein of the food, but as the 

 amount of this is not as a rule excessive, there is 

 not likely to be much available surplus after the 

 proteins of the milk have taken what they require. 

 Should there be a lack of non-nitrogenous material 

 in the ration there must, in the course of time, be 

 a decrease in the formation of milk. In the begin- 

 ning, it is true, the body fat would be a substitute 

 for the lack of carbohydrates, and would have to 

 supply material for the formation of milk fat and 

 milk sugar. After the gradual using up of the body 

 fat a falling off in the milk yield is to be inevitably 

 expected. 



The nitrogen-free nutrients have, further, another 

 indirect influence upon the secretion of milk in 

 that they greatly diminish the consumption of 

 protein (p. 72). This fact is of great practical 

 importance, for by feeding large amounts of carbo- 

 hydrates (mangels, molasses, beet slices) the quantity 

 of concentrated food can be profitably reduced. 



The effect which is exercised by the fat of the 

 food upon the amount and properties of the 



