A STUDY OF RATIONS FED TO MILCH COWS. 63 
accuracy, no one will know what is the range or the average of 
nutrients in the rations actually fed by American dairymen. 
When such a range and such an average are found out, they 
will be chiefly useful.in helping to show how dairymen in 
general need to change their rations in order to make their 
feeding more profitable. But taken by themselves, they will 
be far from fulfilling even this purpose. ‘Io make the best use 
of them, standard rations will be necessary for comparison. 
As was pointed out in some detail in a previous article,* such 
a standard will have to be based upon the physiological demands 
of cows in general. To apply it to the best advantage in any 
given case, it will be necessary to take into account two further 
classes of data. ‘The first will be the special characteristics of 
the cows of the given herd; the second will be the costs of the 
feeding stuffs and the values of the products. Of these three 
classes of facts which are of fundamental importance for eco- 
nomical feeding, namely, the general physical need of cows for 
milk production, the special peculiarities of individual cows, 
breeds and herds, and the costs of raw material and value of 
the products, such estimates give no exact information what- 
ever, 
In other words, even if the figures above cited are assumed 
to represent the actual feeding practice of the 128 dairymen 
from whom the reports came, there is nothing in them to show 
which individual feeders were feeding most, and which ones 
least economically. ‘They throw no light upon the questions 
as to what is a proper physiological standard for the feeding of 
milch cows in general, or how the demands of the cows in any 
herd compare with such a general standard. ‘They leave en- 
tirely out of account the prices and values which are so es- 
sential factors of the feeder’s profit, and which may make a 
wider ration more profitable in one case and a narrower one in 
another, or very liberal feeding advantageous in one region 
or season when in another the profit would be increased by 
diminishing the ration. 
Accurate observations of kinds, amounts and composition of 
feeding stuffs used in actual practice may give an average ration 
fed by a given number of American farmers, but to designate 

~* On Standards for Rations and Dietaries, by W. O. Atwater, Report of Storrs Experiment 
Station, 1894, p. 205. 
