Dec. 1 , 1925 
The Maintenance Requirement of Dry Cows 
1069 
DAILY EMISSION AND PRODUCTION OF HEAT 
It is obvious that the heat emission equals the heat production 
only in case there is neither gain nor-loss of matter by the body during 
the time of measurement. In the experiments herein considered 
the animals gained or lost varying amounts of fat and protein. 
Hence, it is neoessary to compute the thermal equivalent of these 
gains or losses in order to arrive at the heat production of the animal. 
This computation has the effect to bring the body mathematically 
to its state as at the beginning of the experiment. 
In order that this computation may not be confused with the 
determination of the energy value of the tissue exchange, the data 
for experiment 221E-885-I are given in detail. 
COMPUTATION OF THE CORRECTION FOR THE TEMPERATURE 
OF THE GAIN BY THE BODY, EXPERIMENT 221E-885-I 
Average body temperature, 38.61° C.; calorimeter temperature, 17.86° C. 
Protein_ +0.1038 kg.XO. 3 X20.75 = + 0.65 Cal. 
Fat_ +0.2141 kg.XO. 66X20.75= + 2.93 Cal. 
Water_ -3.6163 kg.XI. 0 X20.75= -75.04 Cal. 
Irregular excretion of dry matter_ 0.2334 X0. 4 X20.75= + 1.93 Cal. 
Correction for gain by body_ —69.53 Cal. 
It will be noted that the average body temperature of the animal 
has been used, ignoring the small daily fluctuations. For the 
specific heats of protein and fat, RosenthaFs values ( 9 ) have been 
applied. In the experiments with steers variations in the dry matter 
excreted per day were relatively small, and this item was neglected 
in computing the thermal effect correction. However, in these 
experiments the variations were so great as to require correction as 
shown above. 
Since the nitrogen contained in the urine represents incompletely 
oxidized protein it is necessary to bring the energy balance to a com¬ 
puted state of nitrogen equilibrium in order to arrive at a true value 
for the metabolizable energy. This has been done in Table XV. 
The method of computation followed is the same as in previous publi¬ 
cations from this institute. 
Table XV. — Energy of urine , and of protein gained or lost, corrected to nitrogen 
equilibrium * 
Experiment, animal, and 
period Nos. 
Energy of 
urine un¬ 
corrected 
for gain or 
loss of 
nitrogen ® 
Gain of 
N by 
body 
Correc¬ 
tion 
NX 7.45 
Corrected 
energy 
Energy of 
protein 
uncor¬ 
rected 
Correc¬ 
tion, pro¬ 
tein 
X5.7 
Corrected 
energy of 
protein 
Cals. 
Grams 
Cals. 
Cals. 
Cals. 
Cals. 
Cals. 
221D-885-I_ 
6, 595. 0 
-7.5 
-55.9 
6, 539.1 
256.5 
-55.9 
200.6 
II_ 
9, 660.1 
+4.7 
+35.0 
9,695.1 
160.7 
-35.0 
125.7 
III_ 
6, 508. 7 
+2.7 
+20.1 
6,528.8 
92.3 
-20.1 
72.2 
221D-886-I_ 
6, 681.8 
+6.0 
+44.7 
6, 696. 5 
205.2 
-44.7 
160.5 
II_ 
10, 569.7 
+4.2 
+31.3 
10, 601.0 
143.6 
-31.3 
112.3 
III_ 
6, 517.1 
+5.6 
+41.7 
6, 558. 8 
191.5 
-41.7 
149.8 
221E-885-I_ 
8,045. 0 
+17.3 
+128. 9 
8,173. 9 
591.7 
-128.9 
462.8 
II_ 
5, 991.8 
+3.3 
+24.6 
6,016.4 
112.9 
-24.6 
88.3 
221F-874-I_ 
10,636. 7 
+2.8 
+20.9 
10, 657.6 
95.8 
-20.9 
74.9 
II.. 
7, 265.3 
+1.0 
+7.5 
7,272.8 
34.2 
-7.5 
26.7 
221F-887-I_ 
9,180. 7 
+4.3 
+32.0 
9,212. 7 
147.1 
-32.0 
115.1 
II_ 
6,236. 7 
-4.9 
-36.5 
6,200. 2 
167.6 
-36.5 
131.1 
« Corrected for loss on drying. 
