Maintenance ration in terms of available energy : If the foregoing 

 results are correct, then a ration which, according to the table, fur- 

 nishes 6.1 Therms of energy value should be an average mainten- 

 ance ration for a thousand pound steer, provided, of course, it con- 

 tains sufficient protein. There are a number of experiments on 

 record by means of which the truth of this can be tested. The most 

 extensive trials of this sort are the Moeckern experiments of Kiihn 

 and Kellner already mentioned, made with the aid of a respiration ap- 

 paratus. The results of the respiration experiments at this insti- 

 tute of course show an agreement because they are the basis upon 

 which the maintenance requirement is computed. 



It should be understood that it is only rarely and by accident 

 that the exact maintenance ration can be hit upon in such an ex- 

 periment. Practically these refined methods always show some 

 gain or loss by the animal, the energy equivalent of which can be 

 estimated from the results of the respiration experiments. The 

 energy value of the feed consumed is, therefore, corrected by adding 

 to it the energy of the loss or subtracting from it the energy of 

 the gain in order to obtain the exact maintenance requirement. 



The energy values required for the maintenance of eight mature 

 cattle, computed substantially in the manner just indicated 1 , were 

 as shown in the following tabulation. The very high requirement 

 indicated for Ox B was doubtless due to the fact that he never laid 

 down during the respiration experiments; accordingly he has been 

 omitted in computing the average. It will be seen that the average 

 result and the range of variation agree well with those obtained 

 in the experiments at this Institute tabulated on page 9. 



Energy requirements for maintenance per 1000 pounds live weight. 



Ox V 5.50 Therms 



Ox B 8.39 Therms 



Ox A 5.91 Therms 



Ox IV 7-32 Therms 



Ox III 6.06 Therms 



Ox II 6.60 Therms 



Ox VI 5.31 Therms 



Ox XX 6.67 Therms 



Average, omitting Ox B 6.20 Therms 



There are also on record a number of experiments in which the 



1 A more exact discussion of the method of comparison will appear in a 

 bulletin of the Bureau of Animal Industry of the U. S. Dept. of Agriculture, 

 entitled "The Maintenance Requirements of Farm Animals". 



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