A STUDY OF RATIONS FED TO MILCH COWS. 43 
found for each test the name of the dairyman, the number and 
average weight of the cows in the herd, and the actual ration 
fed. Following the principle set forth in the Report of this 
Station for 1896, pages 73 and 83, that cows should be fed 
in accordance with the milk flow rather than their live weight, 
the rations as actually fed are of more interest and value than 
when calculated over to a uniform basis of tooo pounds live 
weight, as is frequently done. 
On the right hand pages of the table are given the digestible 
nutrients and energy in the ration as calculated from the weights 
of the food materials and their percentage composition as found 
by analysis. The average daily milk flow, the average percent- 
age of fat, and the average daily yield of butter per cow for each 
herd are also shown. ‘The yields of butter were obtained in 
the case of each cow by adding one-sixth to the daily weight 
of fat in order to obtain the estimated yield of butter. More 
accurately, it is calculated that 96.3 per cent. of the butter-fat 
will be recovered in the butter, and that 82.4 per cent. of the 
weight of the butter is actual butter-fat. This is, however, 
very nearly equivalent to adding one-sixth to the weight of 
butter-fat as determined in the milk by the Babcock test. 
The values given for the percentage of butter-fat are found 
by dividing the total amount of butter-fat obtained from the 
herd in one day by the total milk yield. ‘This gives a slightly 
different but more accurate value than would be obtained by 
taking the average percentage of butter-fat as found by actual 
test of the milk yield of each cow. 
