1070 
Journal of Agricultural Research 
Vol. XXXI, No. 11 
If there is a gain of protein by the body, then nitrogen is stored 
which would have appeared in the urine had actual nitrogen equi¬ 
librium been attained. In this case the correction for nitrogen is 
added to the energy of the urine. In case there is a loss of body protein 
there appears in the urine nitrogen derived from the body tissue and 
not from the feed. Therefore the correction is subtracted. 
Having thus brought the body to nitrogen equilibrium by correct¬ 
ing the energy of the urine, and therefore the metabolizable energy, 
it becomes necessary to apply a corresponding correction to the 
computed energy equivalent of the protein stored or lost. This has 
been done in the last three columns of Table XV. It will be noted 
that the energy correction for the protein is always subtracted, because 
in computing the energy equivalent of the protein the full heat value 
(heat of combustion) of the protein is used, while in reality a portion 
of the protein energy is not utilizable, but appears in the urine in 
the form of incompletely oxidized nitrogenous compounds. In the 
case of a loss of protein, the energy equivalent is abstracted from the 
body and does not enter into consideration of the feed. 
THE BALANCE OF ENERGY 
From the data recorded on the preceding pages the balance of 
energy has been computed and the results set forth in Table XVI. 
Table XVI. — The balance of energy per head and day 
* 
221D 
221D 
885-1 
885-11 
885-III 
886-1 
886-11 
886-III 
Income___ 
Outgo®.... 
Metabolizable___-- 
Heat... .. 
Gain by body: 
Protein®_ 
Fat___ 
Error___ 
Cals. 
16,843.9 
7,855.9 
8,988.0 
8,380.3 
-200.6 
+987.1 
-178.8 
Cals. 
25,057.3' 
11,583.2 
13,474.1 
9,607.4 
+125.7 
+4,249.4 
-508.4 
Cals. 
17,808.9 
8.172.6 
9,636.3 
8.816.7 
+72.2 
+274.6 
+472.8 
Cals. 
17,503.5 
8,242.5 
9,261.0 
8,058.6 
+160.5 
+692.6 
+349.3 
Cals. 
27.867.4 
12,735.0 
15.132.4 
10.474.5 
+112.3 
+4,245.6 
+300.0 
Cals. 
17,492.7 
8,127.9 
9,364.8 
7,914.1 
+149.8 
+704.0 
+596.9 
221.E 
221F 
221F 
885-1 
885-11 
874-1 
874-11 
887-1 
887-H 
Income. ___ 
Outgo®___ 
Metabolizable-- 
Heat--- 
Gain by body: 
Protein®..__ 
Fat___ 
Error. ___ 
Cals. 
21,514.9 
9.860.7 
11,654.2 
9.721.7 
+462.8 
+2,034.0 
-564.3 
Cals. 
15,727.3 
7,462.2 
8,265.1 
8,735.5 
+88.3 
-267.9 
-290.8 
Cals. 
27.577.9 
12,819.0 
14.758.9 
10,964. 2 
+74.9 
+3,404.8 
+315.0 
Cals. 
18,460.5 
8,863.2 
9,597. 3 
9,076. 8 
+26.7 
+125.4 
+368.4 
Cals. 
24.953.3 
11,317.0 
13.636.3 
10,327.2 
+115.1 
+2,871.9 
+322.1 
Cals. 
16,705.5 
7,695.5 
9,010.0 
8,395.0 
-131.1 
+407.6 
+338.5 
« Corrected for nitrogen gained or lost by the body. 
Considering now cow 885, of whose erratic behavior more will be 
said in subsequent pages, there was a net gain of energy by the body 
in each of the periods of experiment 22ID. Since Periods I and II 
were designed to approximate maintenance the gain was slight, and 
