AGE AND KIND OF STOCK 141 



The manure from older animals is somewhat more 

 valuable than that from young animals, even when 

 fed the same kind of food. This is because more of 

 the phosphoric acid and nitrogenous matters are re- 

 tained in the body of a young animal. It is not so 

 much a difference in digestive power as a difference 

 in retentive power. In older animals the proportion 

 of new nitrogenous tissue produced is much less than 

 in young animals, and more of the nitrogen of the food 

 is used for repair purposes and subsequently voided in 

 the manure, while with younger animals more of the 

 nitrogen of the food is retained for the construction 

 of new muscular tissue. 



When an animal is neither gaining nor losing in 

 flesh, and is not producing milk, an equilibrium is es- 

 tablished between the nitrogen in the food supply and 

 the nitrogen in the manure. Under such conditions 

 practically all of the nitrogen of the food is returned 

 in the manure. 57 



175. Cow Manure. A milch cow when fed a bal- 

 anced ration, will make from 60 to 70 pounds of solid 

 and liquid manure a day, of which 20 to 30 pounds 

 are liquid excrements. The solid excrements contain 

 about 6 pounds of dry matter. When a cow is fed 

 clover hay, corn fodder, and grain, about half of the 

 nitrogen of the food is in the urine, about one-fourth 

 in the milk, and the remainder in the solid excre- 

 ments. Hence, if the solid excrements only are col- 

 lected but a quarter of the nitrogen of the food is ob- 

 tained, while if both solids and liquids are utilized 



