454 Journal of Agricultural Research voi. in. No. 6 



accompanied by a substantially corresponding increase in the gaseous 

 excretion. 



Since conclusions regarding the influence of feed consumption on the 

 heat production must be drawn from comparisons of two or more periods 

 on different amounts of feed, it is obvious that the periods must be made 

 as nearly identical in other respects as practicable. It being impossible 

 to control the standing and lying of the subject, it became necessary, 

 therefore, to attempt a quantitative determination of the influence of 

 standing upon the metabolism of the animal as measured by its heat 

 production and on this basis to correct the results of each period to some 

 uniform ratio of standing to lying. It was natural to suppose that the 

 increment of the metabolism during standing was due to the work of 

 supporting the body in an upright position, but it soon became evident 

 that it was also to a very considerable extent a function of the feed con- 

 sumption. 



The apparatus used in these experiments is a flow calorimeter, the 

 temperature difference between the ingoing and the outcoming water 

 being read every four minutes. Since the hydrothermal equivalent of 

 the absorber system and the contained water is only 6 kg., it is possible 

 to follow very closely the rate of elimination of heat by radiation and con- 

 duction. The results found by the authors (ii) show that the heat car- 

 ried off as latent heat of water vapor is substantially proportional to that 

 eliminated by radiation and conduction. On this basis the average heat 

 elimination per minute and for 24 hours during standing and lying has 

 been computed for each 48-hour period (or, in experiments 174, 190, 200, 

 and 207, from selected uniform intervals). The addition of the necessary 

 correcdon for the gain or loss of matter by the body gives the average 

 heat production when standing or Ipng, respectively, while the difference 

 between the two represents the increment due to standing for 24 hours. 

 The following example, taken from experiment 179, period i, in which 

 76.65 per cent of the total heat emitted was given off by radiation and 

 conduction and 23.35 P^r ^^^^ ^^ latent heat of water vapor, and in which 

 the correction for loss of matter by the body was - 1 27 Calories, may serve 

 to illustrate the method. 



Method of computing heat production of cattle when standing or lying 



Standing. Lying. 



Time standing or lying minutes. . i, 767 i, 113 



Heat emitted by radiation and conduction: 



Total Calories. . 12,652 5, 128 



Per minute Calories. . 7. 160 4- 607 



Total heat production computed per 24 hours: 



• Standing 7. 160X1, 440^0- 7665-127 = 13,324 Calories. 



Lying 4.607X1,440-^0.7665 — 127= 8,528 Calories. 



Difference 4. 796 Calories. 



