MAINTENANCE THE ENERGY REQUIREMENTS 287 



From the foregoing results it appears that the average daily 

 energy expenditure of fasting swine at rest and above the critical 

 temperature is about 1.25 Therms per 100 pounds live weight, 

 and consequently that a maintenance ration must supply this 

 amount of net energy. Assuming a value of 9.02 for the con- 

 stant k of Meeh's formula (346), this average is equivalent to 

 1.089 Therms per square meter of body surface. Using an 

 entirely different experimental method, Fingerling, Kohler and 

 Reinhardt l have computed the average energy requirement 

 for maintenance of two growing pigs at almost the same 

 amount, viz., 1.045 Therms per square meter. 



378. Metabolizable energy in maintenance rations. Un- 

 fortunately, few determinations of the net energy values of 

 feeding stuffs for swine have been reported (761) and most of 

 the data regarding the maintenance requirement of this species 

 are expressed in terms of digestible matter or of computed 

 metabolizable energy. The metabolizable energy contained 

 in actual maintenance rations of swine has been determined in 

 a single respiration experiment by Von der Heide and Klein 2 

 and may be estimated more or less accurately in a number of 

 live weight experiments. Such experiments have been re- 

 ported by Taylor, 3 Carlyle, 4 Ostertag and Zuntz 5 and Dietrich. 6 

 The results show a very wide range, from a minimum of 0.897 

 Therm per 100 pounds live weight for 5o-pound pigs on a 

 ration of one part meal and 4 parts skim milk to a maximum 

 of 2.558 Therms for loo-pound pigs on a ration of shorts, 

 corn meal and oil meal. For this there may be a variety of 

 reasons. Live weight results are notoriously uncertain (281- 

 283), and in growing animals especially the possibility of a main- 

 tenance of live weight by a substitution of water for fat (372) 

 has to be borne in mind. The feeds used, too, were varied, 

 and there seem to be indications that, in some cases at least, 

 a smaller " work of digestion," especially in the case of rations 

 containing much milk, may have contributed to reduce the 

 amount of metabolizable energy necessary for maintenance. 



The averages computed from all the experiments and those ob- 

 tained by the omission of a few extreme results are as follows : 



1 Landw. Vers. Stat., 84 (1914), 149. 2 Biochem. Ztschr., 55 (1913), 195. 



3 Wis. Expt. Sta., Rpt. 1901, p. 67. * Ibid., Bui. 104 (1903), P- 3i- 



5 Landw. Jahrb., 37 (1908), 226. 6 Ills. Expt. Sta., Bui. 163 (1913). 



