CALCIUM AND PHOSPHORUS IN THE FEED OF DAIRY COWS. 17 



compared with those of other approximately similar animals used 

 as controls. 



The data in the case of the animals which had been on test are 

 rather complicated. In our experiments all these animals were dried 

 off 60 days or more before they were due to calve and were fed during 

 this period on a basal ration of 3 pounds grain mixture D, 5 pounds 

 alfalfa hay, and 30 to 35 pounds corn silage. The controls received 

 this ration fed in the usual way and without any supplement. The 

 others received grain and hay on alternate days and with phosphate 

 added to the grain. It would be possible to compare the experiment 

 animals directly with the controls in this series, but as they are not 

 exactly comparable and as the cases are few we have thought it better 

 to take into account the past records of both controls and experiment 

 animals. We have, therefore, compared the performance of each 

 animal, after either control or phosphate feeding, with her perform- 

 ance in the preceding year and determined whether the phosphate or 

 control performances compare the more favorably with the preceding 

 performance of the same animal. 



For several years before the experiments began the cows from the 

 general herd, of which the histories are tabulated in Tables 1 and 2, 

 were fed approximately according to the Savage standard. They 

 received on the average about 0.25 pound protein and 1 pound total 

 nutriment more daily than this standard calls for. The building of 

 the calf annually is not taken account of in this calculation, but the 

 yearly 91 pounds protein and 365 pounds total nutriment received 

 over and above what the standard calls for should have provided 

 sufficiently for this process, according to Eckles's results (3). 



The manner in which the test cows were fed contrasts strongly 

 with the above method. During the year in which they were on test 

 and actually milking these animals received a daily average surplus 

 of 1 to 1.5 pounds protein and about 4 pounds total nutriment. For 

 a number of weeks before they calved they received the enormous 

 daily surplus of about 4 pounds protein and 16 pounds total nutri- 

 ment. In other words, the ration fed before calving in preparation 

 for the test contained about six times as much protein and about 

 three times as much total nutriment as is required for maintenance. 

 In the course of a year, taking into account the dry period before 

 going on test, these animals received about 100 per cent more protein 

 and about 50 per cent more total nutriment than is called for by the 

 Savage standard. 



It will be noted that the character of the experiments has made it 

 necessary to keep the animals under observation for periods of more 

 than a year, and to use the milk yield as a measure of the results >to 

 be'studied. In the course of a year innumerable small things, which 



