CHAPTER IX 
THE FEED-UNIT SYSTEM 
The feed-unit system furnishes a convenient and practical 
method of determining the comparative nutritive values of different 
feeding stuffs. It originated in Denmark, and has been used there 
and in other north European countries during the last couple of dec- 
ades for comparing the feed consumption of farm animals during 
certain periods and the relative economy of their production. While 
originally worked out for dairy cows and mostly applied to these, the 
system has also been adapted to other classes of farm animals, espe- 
cially swine, calves, and horses. 
A simple single figure is obtained by this system for the total 
feed eaten by an animal during a given period, including that eaten 
on pasture, and valuable information may thus be secured relative 
to the economy of the production by a comparison of the total feed 
consumption and production of the animals. The different feeds are 
given equivalent values according to the results of elaborate, care- 
fully-conducted feeding experiments, most of which were made at 
Copenhagen Experiment Station. All feeds are referred to a stand- 
ard, the so-called feed unit, which is a pound of mixed grain, like 
corn, barley, wheat, or rye. 
. Numerous feeding experiments, conducted with the greatest care 
and scientific accuracy, have shown that, eg., 1.1 pounds of 
wheat bran or 2.5 pounds of mixed hay of average quality can be 
substituted to a limited extent for a pound of grain in ordinary 
rations for dairy cows without causing any appreciable change in the 
yield or the composition of the milk produced by the cows, or in- 
fluencing their body weight or general condition. The quantities of 
the different feeds given, 1.1 pounds wheat bran and 2.5 pounds hay, 
are therefore equivalent to one feed unit. Table IV in the Appen- 
dix gives a list of feed units obtained largely as a result of Scandi- 
navian feeding experiments with cows, supplemented by results of 
American trials and feeding experience. In case of coarse feeds, 
certain limits are given between which the equivalent values may 
vary, according to the quality of the feed; ¢.g., a choice grade of 
alfalfa hay will have a unit value of 1.5; 7.¢., it would take 1.5 pounds 
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