34 AGRICULTURAL EXPERIMENT STATION. [Jan. 



phoric acid and potasli of the ration fed that will l)e found 

 in the manure. In case of milch cows this amounts on an 

 average to 80 per cent, of the fertilizing ingredients con- 

 tained in the feed. The other 20 per cent, goes into the 

 milk or flesh of the animal. The value of the nitrogen, phos- 

 phoric acid and potash thus excreted is based upon the retail 

 cost of these articles in the open markets. When the experi- 

 ment was in operation this amounted to 15 cents i)er pound 

 for nitrogen, 5^ cents per pound for phos})horic acid and 4J 

 cents per pound for potash. The net cost of a ration is that 

 cost remaining after the value of the manure has been de- 

 ducted from the total cost. 



Quantity and Cost of Milk lyroduced Daily. 



If we notice the averages in the above table, it will be 

 seen that the cows declined slightly and regularly in the 

 yield of milk during the three months of trial. There was a 

 decrease of 7.8 per cent, in the milk production between the 

 tirst and second periods and a further decrease of 6.8 per 

 cent, between the second and third periods, making a total 

 decrease of 14.6 per cent, during the three months of trial. 

 This is by no means excessive. Five of the six cows gave 

 an average increase of 19 pounds each in live weight during 

 the vetch and oats period. When it is also remembered in 

 cases of the hay and the vetch and oats periods that the 

 former lasted but 12 days and the latter 84 days, the differ- 

 ence in yield in favor of the hay would be still further 

 reduced. The cost of feed per quart of milk is about the 

 same in all three periods, a very slight difference in favor 



