24 
Journal of Agricultural Research 
Vol. XXI, No. I 
and rather irregular at the time when the cow did not change her posi¬ 
tion (fig. 31, 32, 35), the temperature remained fairly uniform when 
the position was changed (fig. 32 and especially fig. 34). 
DAILY VARIATIONS IN BODY TEMPERATURE) MEASURED AT 5 P. M. 
Inasmuch as at the Institute of Animal Nutrition the determinations 
of the heat produced by cows by means of the respiration calorimeter 
are made during a period of 24 or 48 hours, it appears that a knowledge 
of the daily variations in the body temperature at exactly the same time 
of the day, corresponding to the beginning and the end of the period, is 
most essential, as far as those experiments are concerned. That the 
body temperature of the same animal varies from day to day and from 
hour to hour has been shown by most of the foregoing observations, 
even by those made during the time when there was no influence of 
water or feed (fig. 25-28). To study the extent of the daily fluctuations 
in body temperature determined at exactly the same time of the day was 
the object of the next series of observations. To avoid any effect of 
water drunk or of feed, the observations were made just before feeding 
at exactly 5 p. m. 
Figures 36 to 38 represent the temperatures of cow 886 measured at 
5 p. m. for the days there indicated. 
All these curves resemble each other very much, showing considerable 
fluctuations. In figure 36 the lowest temperature is 101.6 0 F., while the 
highest is 102.4 0 . In figure 37 the lowest temperature is 101.4 0 , while the 
highest is 102°. In figure 38 the lowest temperature is 101.7 0 , while 
the highest is 102.2 0 . 
Figures 39 to 41 represent the temperatures of cow 885 measured at 
5 p. m. for the days there indicated. 
These three curves resemble each other very much, but they are differ¬ 
ent from the three preceding curves of cow 886 in that they show much 
less variation. The lowest temperature in figure 39 is 101.6 0 F., while the 
highest is 101.9 0 . In figure 40 the lowest temperature is 101.8 0 , while 
the highest is 101.9 0 . In figure 41 the lowest temperature is 101.5 0 , 
while the highest is 101.8 0 . 
GENERAL, CONCLUSIONS WITH REGARD TO THE DAILY VARIATIONS IN 
TEMPERATURE AT 5 P. M. 
The foregoing observations show that daily fluctuations in body tem¬ 
perature depend to a large extent on the individuality of the cow. It 
is, therefore, not safe to assume in every case that the body tempera¬ 
ture of a cow is the same at the same hour of the day, even under normal 
conditions. 
Variations of 0.5 0 or o.6° F. in the body temperature of the same ani¬ 
mal (886) measured at exactly the same time of the day for several 
