68 REPORT OF DEPARTMENT OF ANIMAL HUSBANDRY OF THBP 
which has been longest used as a general guide gives for the 
average cow in milk, per 1000 lbs. live wejght 
24 ‘Ibs. total organic matter, 
15.4 1bs. total digestible organic matter, 
2.5 Ibs. total digestible protein, 
12.5 Ibs. total digestible carbohydrates; 
with a nutritive ratio of about 1:5.4 and a fuel value of about 
30,000 Calories. 
These standards have been in large part drawn from averages. 
Slight individual modifications have therefore been occasionally 
desirable or without disadvantage. In practice, of course a close 
conformity may often be unprofitable because of relative market 
prices. The efficiency, however, of the modified standard ration 
is the point for first consideration. 
While the results of only a few weeks under a ration will not 
show its permanent sustaining power, they may perhaps suggest 
the stimulating effects. To these are often attributed results 
not fully explained by the known utilization of nutrients in the 
product and the work of its construction. It is thought that the 
presence of a supply of protein considerably in excess of the 
indispensable amount which can be directly accounted for, tends 
to stimulate milk production. 
In feeding a dairy herd at this Station during several years the 
common standards were followed in a general way. From the 
daily records of this herd are drawn the data before referred to. 
They represent both winter and summer feeding at different 
times during seven years. Individual records were kept of the 
food consumed, the changes in live weight and the milk yield. 
Analyses were made of the foods and of the milk at regular inter 
vals so that the amounts of the different constituents in the food 
and in the milk have been calculated for each cow and averages 
made from these data. The records for short periods selected for 
use in these averages were taken at that stage of lactation when 
only very moderate changes in the milk flow might be expected. 
Of these limited-period, individual records, 981 have been used in 
making the averages considered here. When grouped according 
