MINERAL NUTRITION 153 



The milking cows received daily an average of 17 pounds of hay; 53^ pounds 

 dried apple pomace; 113^ pounds grain mixture; and 23 pounds green feeds. ^ 

 Salt was added to the extent of % pound to each 100 pounds of the grain mixture, 

 and lump salt was always available in boxes in the out-of-door sheds. In addi- 

 tion the so-called mineral cows received daily, mixed with the grain, an average of 

 8 ounces of the dicalcium phosphate-calcium carbonate mixture. Running 

 water was before the animals at all times. The cows were fed and milked twice 

 daily. The hay, which was grown on the station grounds, was composed of mixed 

 grasses, timothy usually predominating, and generally was of good quality. The 

 average analysis of the feeds was as follows: 



Protein Calcium Phosphorus 



Hay 7.58 0.48 0.21 



Dried apple pomace 5.29 0.15 0.11 



Grain mixture 17.00 0.06 0.54 



The apple pomace was weighed into wooden trays daily, moistened, and the 

 grain mixed with it before being fed. The hay and green forage were weighed 

 daily into 4-bushel baskets. 



Composite samples of all feeds were taken from each lot purchased. A 5-day 

 composite sample of the milk of each cow was taken monthly. All feeds and milk 

 were submitted to chemical analyses. 



Results of the Experiment 



The effect of the supplement has been judged by the same criteria as those used 

 in measuring the effect of bone meal, viz.: 



1. General appearance and live weight of the cows. 



2. Growth of young cows and heifers. 



3. Milk yield. 



4. Composition of the milk, especially its ash content. 



5. Reproduction. 



General appearance 



As in previous work on mineral supplements, the general condition of the cows 

 has been followed closely, observations being recorded from month to month. 

 In general the cows in both groups have maintained themselves well. A study 

 of the detailed record of their condition at the commencement of the experiment 

 and again at the close shows that the cows receiving the supplement had a slight 

 advantage in this respect (see Table 1). 



Live weight 



Respecting maintenance of live weight six individuals were mature when the 

 experiment was begun and consequently can be considered from this standpoint. 

 The stage of gestation at the beginning having been noted, the date during the 

 present season when they were at a similar stage has been ascertained and the 

 average of two weighings on consecutive days as near that date as possible has 

 been taken (see Table 2). 



3 Green feed substituted for a portion of the hay. 



