Sept. 1,1925 
Net-Energy Values of Feeding Stuffs 
477 
Table VIII. Computation of net-energy value of grain mixture No. 1 
Period No. 
Dry matter 
eaten 
Total 
metab- 
Metab¬ 
oliz¬ 
able 
energy 
equiv¬ 
alent 
of the 
hay 
Metab¬ 
oliz¬ 
able 
energy 
of the 
grain 
Total 
net 
energy 
of 
ration 
Net 
energy 
equiv¬ 
alent 
of the 
hay 
Net 
energy, 
of the 
grain 
Net 
energy 
per 
kilo¬ 
gram 
dry 
matter 
of 
grain 
Utili¬ 
zation 
of the 
metab¬ 
oliz¬ 
able 
energy 
of the 
grain 
Hay 
Grain 
oliz- 
able 
energy 
of 
ration 
1.. 
2_ 
Average_ 
Kgms. 
2 .9349 
2.9487 
Kgms. 
1.9962 
4.7590 
Cals. 
12,061 
20,553 
Cals. 
6,125 
6,154 
Cals. 
5,936 
14,399 
Cals. 
6,956 
11,584 
Cals. 
3,454 
3,471 
Cals. 
3,502 
8,113 
Cals. 
1,754 
1,705 
Per cent 
59.00 
56.34 
1,730 
57.67 
1 
The net energy values computed by the new method for the 
timothy hay (Table VII) are 1,184 Calories and 1,170 Calories per 
kilogram of dry matter, in periods 3 and 4, respectively, the average 
being 1,177 Calories as compared with 1,190 Calories by the current 
method. For the grain mixture the net-energy values computed by 
the new method are 1,754 Calories and 1,705 Calories per kilogram 
of dry matter in periods 1 and 2, respectively, the average being 
1,730 Calories as compared with 1,682 Calories by the current method! 
There is, likewise, a difference in the average percentage utilization 
of the metabolizable energy of the hay and grain as computed by 
the two methods. These differences are due to the differences in 
procedure. According to the new method, the average of the 
several determinations of the heat-increment values of the feed is 
made the basis for the computation of the maintenance requirement 
of the animal. This departure from the current method is made in 
consideration of the variations in the heat-increment values obtained 
by comparison of different periods and of the possible causes for 
these variations. From the nature of the computation and assump¬ 
tions involved, any experimental error in the total heat production, 
or any possible influence of the plane of nutrition, or of (ufference in 
activity of the animal, on the net energy used for maintenance, 
would be reflected solely in the heat-increment value. The influence 
of such factors on the heat-increment value may be greatly exag¬ 
gerated, if the difference in heat production and the difference in 
feed between the two periods compared are small. On this account, 
the consideration by Armsby ana Fries of the value obtained by 
comparison of the greatest and least amounts of feed consumed as 
representing an average value in their computations of net-energy 
values is not without justification. However, since the maintenance 
requirement of the animal is a factor in the determination of the 
heat-increment values, the average of several determinations would 
afford a more accurate basis for the computation of the maintenance 
requirement during the several periods of an experiment than would 
a value computed only from the two rations of greatest and least 
amounts. In the particular example cited above tne heat-increment 
value used for the hay was the same in both methods, there being 
only one value, while the difference between the average heat-incre¬ 
ment value of the grain used in the new method and that used in 
the current method is only 10 Calories (1,319 and 1,309). This 
difference alone can not entirely account for the difference in the 
