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 lout, 

 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- 

 ient and practicable way of stating the food requirements of 

 the animal 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 to 29 lbs. of total dry matter, 

 From 13.4 to 16 lbs. of didgestible organic matter. 

 From 2 to 2.5 lbs. of digestible protein, 

 From 11 to 13 lbs. of digestible carbohydrates. 

 From .4 to .5 lb. 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 



