SYSTEMS OF FARMING ON DAIRY FARMS 231 



was used, so that if the cows were kept in the barn all the 

 time and if no manure were lost, there would have been 

 nearly 15 tons of manure per 1000-pound cow. 



INluch of the year the cows are either at pasture or in the 

 ban yard so that part of the manure is lost. About a ton 

 of n anure per cow per month is ordinarily available when 

 cow^ are kept in the barn and turned out in the barnyard for 

 a pn rt of the day. In the Northern States 8 to 10 tons of 

 man are a year, including bedding, are usually available for 

 eacl cow or animal unit kept. 



208. Fertility of Feed Returned by Cows. The propor- 

 tions of the constituents of the feed that are returned in the 

 excroment are somewhat variable. A fat animal that is 

 not working or giving milk returns a very large proportion 

 of the food materials. A good dairy cow from the very 

 fact that she is an efficient machine returns a small propor- 

 tion. 



TABI E 27. PROPORTION OF CONSTITUENTS OF FOOD THAT ARE 

 RETURNED IN THE EXCREMENT OF DAIRY Cows 



R. E. Deuel determined the average results for a herd of 

 46 dairy cows. These results as well as the results by Wolff 

 are given in Table 27. Dairy cows return somewhat over 

 40 per cent of the organic matter and nitrogen of the food 

 eaten, and more than half of the mineral matter. Dry 



1 C. M. Aikman, Manures and Manuring, pp. 227, 281. 



