BULLETIN No. 637 
Office of the Secretary q eu a 
Contribution from the Office of Farm Management 
W. J. SPILLMAN, Chief 
- Washington, D.C. ¥ January 14, 1918 
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- A METHOD OF CALCULATING ECONOMICAL BAL- 
ANCED RATIONS. 
By J. C. RunpD1LEs, Scientific Assistant. 
CONTENTS. 
Page. Page. 
_New method of balancing rations............ 27) How tojuse;DablelV ce 322225 ek -aa.conet 12 
How ro use-Tables: T and Iz)... .52.s..5.. 7 | Relative value of carbohydrate feeds when the 
Maplerot equivalent prices. -2.-..55...05.22.. 7 cheapest available feed is nitrogenous ...-- 13 
owsouse Tabled... 6:2 225... 222.25. 222 8; How to. useable V 23225 3.2 eee) ates 16 
Relative value of feeds...........:........--.- S2| How-to uses Mable: Vile iene see cere eee 17 
Relative value of protein feeds...........-.. 8 
- Economy in feeding is of prime importance to the feeder. It in- 
. volves judgment in the selection of feeds as well as skill in the mixing 
of rations. The feeder may know that he needs a concentrate rich 
in carbohydrates or one rich in protein, yet be at a loss to determine 
the cheapest form of the desired concentrate to buy. Again, he 
_ may have certain feeds available and be unable to determine the 
- most economical proportion in which they should be fed to give a 
ration of a desired nutritive ratio. This bulletin suggests ways in- 
_ which these problems may be solved by fixed rule as they arise. 
It is, of course, generally understood among students of nutrition 
that protein, carbohydrate, and fat content of a feeding stuff is not 
the only factor affecting its feed value. Proteins differ in their 
nutritive qualities, while some substances not included in the classes 
above mentioned are necessary to the proper maintenance of the 
bodily functions. The palatability and succulence of a feeding stuff 
has much to do with its value as a feed. Many feeding stuffs have 
physiological effects entirely apart from their nutritive qualities. 
Again, a ration may be perfectly balanced from the standpoint of 
relative content of protein and energy producers, and yet be quite 
_ impracticable because too bulky or too concentrated. It is there- 
fore understood that any consideration of a feeding stuff or a ration 
-18026°—18—Bull. 637—1 
