OBSERVATION BY HAECKER 135 



great a difference in the composition of milks as 

 there is in feed stuffs, there has been no adjustment 

 of the nutrients in the ration to the quantity and 

 character of the solids contained in the milk yielded, 

 though, as has been shown, such an adjustment ap- 

 pears to be quite simple and practicable. If in for- 

 mulating a ration it is deemed necessary in economic 

 milk production, to take note of the fact that one 

 feed stuff contains 12 per cent, of protein and an- 

 other 20 per cent., is it not equally important in our 

 attempt to adjust the ration to the needs of the cow 

 in milk production to also take into account the fact 

 that one cow may give milk containing 3 per cent. 

 fat while that of another may contain twice as 

 much? It would seem quite as consistent to feed an 

 animal food regardless of its composition as to 

 feed an assumed balanced ration regardless of the 

 composition of the product which is to be elaborated 

 from the nutrients in the food. 



Great stress has been placed upon the fact that the 

 nutrients in milk have a nutritive ratio of approxi- 

 mately one to five, and that therefore the ration for 

 a milch cow should have a similar nutritive ratio; 

 apparently overlooking the fact that only about 50 

 per cent, of the ration is used in milk production 

 and the balance for maintenance of body. If note is 

 taken of the fact that about half the ration is used 

 for maintenance and that the maintenance ration 

 has a nutritive ratio of I to 10, it becomes apparent 

 that for the production of milk of average quality by 

 an animal of average milk producing powers the 

 nutritive ratio of the ration should be approxi- 



