The addition of 4.63 pounds of hay to the basal ration of Period 

 III diminished the draft on the body tissues by 2.124 Therms, this 

 being equivalent to 0.459 Therm for each pound of, hay. Obviously, 

 the latter number expresses the value of one pound of this hay for 

 maintenance and to maintain a steer with an average requirement 

 of 6.1 Therms would plainly require 6.1 -f- 0.459 = : 3- 2 9 pounds of 

 this particular timothy hay. 



Kellner at the Moeckern Experiment Station has made a large 

 number of similar experiments on heavier rations which produced 

 more or less gain by the animals. For example, an experiment in 

 which oat straw was added to a basal ration gave the following re- 

 sults : 



Oat straw Energy stored in 

 eaten gain of body tissue 

 Ibs. Therms 



Period i 8.8 3.535 



Period 3 (basal ration) o 1.777 



Difference 8.8 1.758 



Each pound of straw produced a gain of tissue equivalent to 

 0.2 Therm of energy. This is its "production value" as part of a 

 fattening ration. 



It is not yet certain that the production values obtained in this 

 way correspond exactly with the values below the point of main- 

 tenance obtained in the manner described in the previous paragraph. 

 The indications are, however, that the two agree substantially for 

 concentrated feeds, while for the coarse fodders the production 

 value may be somewhat less than the maintenance value. For the 

 present, however, and until more extensive determinations of main- 

 tenance values are available, it appears advisable to disregard this 

 possibility and to consider the maintenance and production values as 

 for practical purposes identical. Upon this assumption, and largely 

 upon the basis of Kellner's results, the following table 1 has been 

 .computed, showing approximately the* energy values either foi 

 maintenance or for production of a number of the more important 

 feeding stuffs. 



1 Originally published in Bulletin No. 71 of this Station and reproduced 

 in Farmers' Bulletin No. 346 of the U. S. Department of Agriculture. 



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