4 DAIRY CATTLE AND MILK PRODUCTION 



worth $8.60. A ton of milk at $ 1.50 per hundred is worth 

 $ 30 per ton and is worth $ 2.56 on the basis of the fertility 

 contained. 



The comparison is still more striking when cream or butter 

 is sold. 'Since butter fat contains only carbon, hydrogen, and 

 oxygen, it has no value as a fertilizer. The only element of 

 fertility in butter is the small amount of nitrogen contained in 

 the curd, amounting in value to only 64 cents per ton while 

 the market value of this amount of butter at 30 cents per 

 pound is $ 600. 



A dairy cow weighing 1000 pounds voids about 12 tons of 

 solid and liquid manure in a year, worth on the basis of the 

 elements of fertility contained $ 30 in round figures. The 

 Minnesota and Ohio experiment stations found from field 

 experiments that barnyard manure has an actual value of 

 from $2.50 to $3.50 per ton when applied to the land, depend- 

 ing upon the fertility of the soil. Under fairly good con- 

 ditions at least 80 per cent of the fertilizing constituents of 

 the manure may be returned to the soil. 



But this does not tell all the story. The dairy farmer usu- 

 ally is a purchaser rather than a seller of grain, and by this 

 means adds constantly to the fertility of his farm. The pur- 

 chase of concentrated feeds rich in protein, as will be seen from 

 the table, add a large amount of fertility to the farm. Fur- 

 thermore, the keeping of dairy cattle usually means that a 

 large proportion of the land is kept in grass, which makes it 

 possible to prevent washing of the soil, which is responsible for 

 the rapid deterioration of many farms. 



It is a well-known fact that the yield of grain per acre of 

 the agricultural lands of Denmark, Germany, and parts of 

 England whene dairy farming has been followed for a period 



