ANIMALS. 131 



Differences in the quality of the food will also cause 

 variation, as in reckoning the feeding value. 



The figures given are obtained by reckoning the nitro- 

 gen at sixteen cents per pound, the phosphoric acid 

 at eight cents, and the potash at five cents. 



The values of these substances are reckoned the same, 

 in whatever food they are found. There is, however, 

 some difference in point of fact, since in some articles 

 of food they are in a more available condition than in 

 others, and can be made more immediately serviceable 

 as fertilizers. 



The Value of Manure from Food. To determine the 

 real value of the manure from different kinds of food, a 

 deduction must be made from the total manurial value 

 for certain losses that occur. 



1. We must deduct the amount which the animal re- 

 moves from the food in digestion. This may be reckoned 

 upon the average at fifteen per cent. 



2. The three substances are not g nerally so valuable 

 in stable manure as in commercial fertilizers, because 

 they are not so largely available at first, and are subject 

 to greater losses before they can be used for plant food. 

 Probably twenty per cent, should be deducted on this 

 account. 



It must also be remembered that, in addition to these 

 deductions, there is always more or less loss from fer- 

 mentation and drainage ; but this is so variable that it 

 cannot be definitely stated. It can only be estimated in 

 individual cases, after a knowledge of the facts involved. 



All articles of food fed to stock upon the farm have 

 thus a double value : a feeding value, determined by the 

 digestible albuminoids and carbo-hydrates ; and a manu- 

 rial value, determined by the amount of nitrogen, phos- 

 phoric acid, and potash in the manure. 



