New YorK AGRICULTURAL EXPERIMENT STATION, 67 
information the limitations of the average physiological stand- 
ard can be made more definite. All records of production under 
rations constructed in conformity with standard requirements 
should furnish information of more or less value. The results of 
departure, on one side or the other of the path marked out, 
should be worth recording. 
The data published in this bulletin show changes in milk pro- 
duction which have immediately followed changes in the com- 
position of the ration. Some changes in the ration appear to 
have no immediate effect on milk production. Others apparently 
have-in a moderate degree either stimulating or depressing 
effects. 
For many years rations conforming to certain limitations have 
been recommended by different investigators. The most conven- 
lent and practicable way of stating the food requirements of 
the anima! in a concise and general manner has been in terms of 
digestible nutrients. As ordinarily grouped, these are protein, 
carbohydrates and fat. The total digestible organic matter is 
stated as well as the total dry matter. Water is taken for 
granted, and the mineral nutrients, although important, are not 
considered because the foods naturally available for supplying 
other nutrients would contain abundant ash. 
In formulating a feeding standard for cows considerable differ- 
ence of opinion exists as to the limits of variation, both in bulk 
and composition, that can be made without appreciable influence 
on production. The standard rations usually recommended for 
milch cows of average capacity require, for 1000 lbs. live weight: 
From 27 to29 Ibs. of total dry matter, 
From 13.4to16 Ibs. of didgestible organic matter, 
From 2 to 2.51bs. of digestible protein, 
Fromi11 to13_ Ibs. of digestible carbohydrates, 
From .4to .51b. of digestible fats; 
with a nutritive ratio of from 1:6 to 1:5.7.. For cows not approxi- 
“mating 1000 lbs. in weight, for cows of inferior capacity or for 
very heavy milkers, the standard is modified. The standard 
