Dec. 1 , 1925 
Revised Net-Energy Values of Feeding Stuffs 
1095 
of the maintenance requirement of net energy, the writers would 
suggest that, with the exception of experiment 217, the experimental 
periods were short (three or four weexs only), while the changes in 
the amount and kind of feed consumed were considerable. It 
seems probable, therefore, that the larger part of the variation in 
weight must be ascribed to differences in the content of the alimentary 
tract, and that the actual effect on the basal metabolism was but 
slight. In view of all these considerations, the writers are inclined 
to ascribe the apparent variations in the maintenance requirement of 
net energy, in the different experimental periods of a series, in Table 
IV, to the cumulative effect of experimental errors, and to consider 
the average of the several determinations as applying to each of the 
individual experimental periods. 
In experiment 217 the animal was actually fattened during the 
transition period of more than three months, between Periods II 
and III, and made considerable gain in weight (see Table I). In 
this experiment the maintenance requirements of the animal in the 
unfattened condition and the fattened condition have been computed 
separately, the values being as shown for Periods II-III and III-IV, 
respectively. 
NET-ENERGY VALUES OF FEEDS 
The total net energy of the rations is obtained, by addition, of 
the average of the determinations of net-energy requirement for 
maintenance, as reported in Table IV, and the gains of energy, 
as given in Table II. These total net-energy values, divided by the 
dry matter of the rations, give the net-energy values per kilogram 
of dry matter of the rations. The net-energy values of the grains 
are computed by subtracting from the total net energy of the mixed 
ration the net-energy equivalent of the hay, by the use of a value 
previously determined in the hay rations. The remainder represents 
the net energy of the grain, and by dividing this by the kilograms of 
dry matter of grain the net-energy value per kilogram of grain is 
obtained. 
We have also computed, in each case, the perqentage utilization 
of the metabolizable energy. This is another way of expressing the 
net-energy value of a feed, and is obtained by dividing the net energy 
of the feed by its metabolizable energy (instead of the dry matter), 
and multiplying the result by 100.' The net-energy values, on both 
bases, are presented in Table V. 
