1074 
Journal of Agricultural Research 
Vol. XXXI, No. 11 
in the course of the computations as to materially affect the energy 
equivalent to the fat gained, and through this the net-energy values 
determined by the indirect method. 
Careful consideration of the items enumerated and comparison of 
the available data leads to the conclusion that the observed heat pro¬ 
duction as determined here is the more accurate, but that the coin- 
puted heat production may be used in the determination of net-energy 
values without significant compromise. 
In Table XVIII the data relative to the metabolizable energy 
have been collected for ready reference in connection with the sub¬ 
sequent computation of the net energy value of the ration and the 
maintenance requirements of the cows. 
Table XVIII .—Metabolizable energy -per kilogram, of dry matter of rations 
Experiment, animal, and period Nos. 
Dry matter 
eaten 
Total me¬ 
tabolizable 
energy 
Metaboliz¬ 
able energy 
per kilo¬ 
gram dry 
matter 
221D-885-I....... 
Kg. 
3.6674 
6.4676 
3.8505 
Cals. 
8,988.0 
13,474.1 
9,636.3 
Cals. 
2,450.8 
2,464.4 
2,502.6 
II....... 
Ill...... 
Total and average__ 
12.9855 
32,098.4 
2,471.9 
221D-886-I.. __ .... 
3.8131 
6.0809 
3.7821 
9,261.0 
15,132. 5 
9,364.8 
2,428.7 
2,488.5 
2,476.1 
II_ _ .. .... 
Ill. __ _ .... 
Total and average ___ 
13.6761 
33,758.2 
2,468.4 
221E-885-I______ 
4.7012 
3.4475 
11,654.2 
8,265.1 
2,479.0 
2,397.4 
II_ __ ___ 
Total and average.____ 
8.1487 
19,919.3 
2,444.5 
221F-874-I_______ 
5.9803 
4.0032 
14,758.9 
9,597.3 
2,467.9 
2,397.4 
II_____ 
Total and average __ __ _ 
9.9835 
24,356.2 
2,439.6 
221F-887-I______ 
5.4183 
3.6274 
13,636.3 
9,010.0 
2,516.7 
2,483.9 
II.. ..... 
Total and average____ 
9.0457 
22,646.3 
2,503.5 
THE NET-ENERGY VALUE OF THE RATION 
^Only a part of the metabolizable energy of a ration is utilizable by 
the body. That part which is utilized can be determined, however, 
and it is a true measure of the actual value of the feed to the animal, 
from the energy standpoint. To this available portion of the metabo¬ 
lizable energy the term net energy is applied. 
In the fmlowing computations, which are based upon the heat 
production of the subject of the experiment, the heat production as 
measured has been computed to the standard day of 12 hours 
standing and 12 hours lying, using the method outlined by Fries and 
Kriss (5) in their recent discussion of the influence of standing and 
lying on the metabolism of cattle. The results of this computation 
are presented in Table XIX. 
