266 



Feeds and Feeding. 



the feeds during their passage through the alimentary tract, but 

 passes off with other useless matter in the solid voidings. 



The nitrogen and ash of feeding stuffs retained and voided by 

 the animal are given in the table below, which summarizes the 

 Eothamsted experiments as reported by Warington: 1 



Per cent, of nitrogen and ash voided as excrement or secured as ani- 

 mal produce with various farm animals Rothamsted Station. 



The above data may be considered as representative of average 

 results. From them we learn that the fattening ox retains only 

 3.9 per cent, of the nitrogen supplied in its food, voiding 22.6 per 

 cent, in the solid excrement and 73.5 per cent, in the urine ; in 

 all, 96.1 per cent, of the nitrogen supplied this animal in his 

 food re-appears in the excrement and less than 4 per cent, is 

 stored in the body. This large return of nitrogen seems reason- 

 able when we remember that during the fattening process the 

 grown ox adds little to his body besides fat, which we know con- 

 tains no nitrogen. 



With the cow, 24.5 per cent, of the nitrogen in the feed is used 

 mainly for the production of the casein and albumen of the milk, 

 and 75.5 per cent, appears in the excrement. 



Of the ash from 2.3 to 10.3 per cent, is retained by the ani- 

 mal or goes into the milk. Thus it is shown that from 75 to 95 

 per cent, of all the fertilizing constituents of feeding stuffs re- 

 ' appears in the solid and liquid excrement. 



419. Composition of excrement. It is important that the farmer 

 understand the composition of the excrement of farm animals 



1 Chemistry of the Farm, pp. 124-25. 



