THE COW AS A FOOD PRODUCER. 339 



when the question is to get from pasture the greatest 

 amount of product useful to man." 



This gives us a clear explanation of the reason for the 

 large consumption of food by the best milch cows. As 

 the milk is made from ttie extra food consumed by the cow 

 over what is necessary to supply the waste of her own sys- 

 tem, we see it is quite necessary that she should be a good 

 eater and digester. 



COMPOSITION OF THE 6,000 LBS. OF MILK. 



Dry Substance. Lbs. 



Casein and albumen 234 



Fat, or butter 228 



Milk-sugar (whey) 1278.4 



Salts, or ash 39.6 



Total dry substance 780.0 



Water 5, 220 



This statement of the elements of the dry substance in 

 the 6,000 Ibs. of milk yielded by a cow in her milking 

 period, shows that the food should be rich in albuminoids 

 and fat, or the elements out of which fat is elaborated, in 

 the animal system. 



How FAT is PRODUCED. 



Animal chemists and physiologists are not agreed upon 

 this question of the formation of fat in the animal body. 

 Some quite elaborate experiments made by Voit, Petten- 

 kofer, Henneberg, Wolff, and some other German experi- 

 menters, led them to believe that the albuminoid matter 

 eaten as food was a large source of the fat laid up in the 

 animal system, and that this and the oil in the food eaten 

 constituted the sources from which all the fat in animals 

 is produced. Almost all kinds of fodder contains fat, but 

 not in quantity sufficient to account for all the fat laid up 

 by the fattening animal or the fat in the milk of the cow. 

 The urea constantly extracted from the blood by the kid- 

 neys comes from the albuminoid matter. The extraction 



