1072 
Journal of Agricultural Research 
Vol. XXXI, No. 11 
cow was slaughtered after the close of experiment 22 IE, and, although 
the quantity of fat on the internal organs was unusually great, she 
appeared to be sound. The data obtained with this cow have been 
carried throughout the computations, but on account of the question 
as to their significance have not been included in averages. 
The data presented for the two cows in experiment 22IF require 
no special discussion. They are apparently normal in every respect. 
It will be noted that the gains of energy by the body in all the 
maintenance periods are small, and it is assumed that they will not 
adversely affect the computations of net-energy values for main¬ 
tenance. 
In two maintenance periods, 221D-885-I and 221F-887-II, there 
was a slight loss of body protein. In the case of cow 885 there was a 
slight gain of protein in reriod III, which was designed to duplicate 
Period I. 
THE OBSERVED AND COMPUTED HEAT PRODUCTION 
In Table XVII data are collected for comparison of the observed 
and computed heat production as obtained in these experiments. 
Excluding the data for cow 885, which are questionable, the agreement 
is reasonably good. The effect of the refused feed in the case of cow 
885 is clearly apparent in the data presented in this table, and, as 
will be shown in the computation of the net-energy values, the heat 
increment per kilogram of the feed is much too low. As is shown 
in an analysis of the subject by Max Kriss { 6 ) the possible sources 
of error in the observed as compared with the computed heat produc¬ 
tion are as indicated in the discussion following Table XVII. 
Table XVII. — Observed and computed daily heat production 
Experiment, animal, and period Nos. 
Observed 
Computed 
Error 
Computed 
Observed A1UU 
Cals. 
Cals. 
Cals 
Per cent 
221D-885-I___ 
8,380.3 
8,201.5 
-178.8 
97.87 
II___ 
9,607.4 
9,099.0 
-508.4 
94.71 
III____ 
8,816.7 
9,289.5 
+472.8 
105.36 
221D-886-I__ 
8,058.6 
8,407.9 
+349.3 
104.33 
II___ 
10,474. 5 
10,774. 5 
+300.0 
102.86 
III_ 
7,914.1 
8,511.0 
+596.9 
107.54 
221E-885-I_ 
9,721. 7 
9,157.4 
-564.3 
94.20 
II___ 
8,735.5 
8,444.7 
-290.8 
96.67 
221F-874-I__ 
10,964. 2 
11,279.2 
+315.0 
102.87 
II___ 
9,076.8 
9,445.2 
+368.4 
104.06 
221F-887-I____ 
10,327.2 
10,649.3 
+322.1 
103.12 
II___ 
8,395.0 
8,733. 5 
+338. 5 
104.03 
The factors entering into the observed heat production, and there¬ 
fore effecting the net-energy values, are (1) the heat emission by 
radiation and conduction; (2) the heat emission as latent heat of 
water vapor; (3) the relative time spent in the standing position as 
compared with that spent lying; (4) the refusal of feed; (5) the gain 
or loss of matter by the body; and (6) the thermal environment. 
In connection with the computed heat production there enter into 
the writers’ computations the neat of combustion of the feed, of the 
excreta, of the methane, and of the shed hair and scurf, together 
