CHAPTEE 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-rconducted 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, e.g., 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; e.g., a choice grade of 

 alfalfa hay will have a unit value of 1.5 ; i.e., it would take 1.5 pounds 



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