sufficiency of a ration for maintenance has been judged by its effect 

 upon the live weight. As is well known, the live weight of an 

 animal is a very uncertain indication of the results of short feeding 

 periods. When, however, the weight of a mature animal is main- 

 tained with but little variation through a long period, it is safe to 

 consider that the average ration consumed approximates very close- 

 ly to an exact maintenance ration. This is not true, however, of 

 young animals, as has been shown by Waters. Such animals may 

 grow at the expense of their fat tissue on an insufficient ration, 

 maintaining their live weight by an increase in the water content of 

 the body. 



Such experiments are those of the writer 1 , of Haecker 2 and of 

 Evvard 3 . For the present purpose a detailed description of the ex- 

 periments appears unnecessary. The results are summarized in 

 the following table ; all of them refer to thin animals. 



Energy requirement of cattle for maintenance. 

 (per 1000 Ib. live weight.) 



The average of the live weight results is greater than the aver- 

 age of the respiration results on account of a single exceptionally 

 high result. The average of the other experiments is 6.31 Therms 

 as compared with 6.16 Therms for the respiration experiments. 



1 Penna. Expt. Station, Bulletin No. 42. 



2 Minnesota Expt. Station, Bulletin No. 79. 



3 Thesis for degree of M.S., University of Missouri, 1909. 



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