460 
Journal of Agricultural Research 
Vol. XI, No. 10 
The results are of quite the same order of magnitude as those obtained 
in previous experiments on similar mixed rations of hay and grain (2, 
p . 477; 4, p. 385). In the fattened animal there appears to have been 
an increase of about 5 per cent in the energy expended in the various 
processes intermediate between the prehension of the feed and the storage 
of protein and fat in the tissues. To this extent the experiment sustains 
the view outlined in the introductory paragraphs. The difference, how¬ 
ever, is small and it is perhaps questionable whether it exceeds the 
experimental error. At any rate, it is far from accounting for the very 
marked difference in the economic utilization of the feed which is indi¬ 
cated by the approximate calculation of Table XI, and is of little sig¬ 
nificance in comparison with another factor to be considered immediately. 
The relations shown in Table XIII may also be expressed in another 
way by comparing the percentages of the metabolizable energy which 
were recovered in the gain made in the unfattened and fattened states, 
respectively, as shown by the energy balances (Table XIV). 
Table XIV .—Percentage of metabolizable energy recovered in gain 
Condition and period No. 
Metaboliz¬ 
able energy. 
Body gain. 
Percentage 
recovered. 
Unfattened: 
Period 2. 
Calories. 
25.398 
12,269 
Calories. 
8, 887 
1,364 
Period 1. 
Difference... 
13 ,129 
7 » 523 
57*3 
Fattened: 
Period 3. 
27,865 
14, 33 s 
7.873 
243 
Period 4.. 
Difference. 
137527 
7.630 
56-4 
The foregoing results accord with those recently reported by Moulton (£), 
who computes from the results of comparative slaughter tests that in a 
fat and a very fat steer 53.39 per cent and 52.49 per cent, respectively, 
of the metabolizable energy supplied in excess of maintenance was recov¬ 
ered in the gain. 
MAINTENANCE REQUIREMENT 
The comparisons of Table XIII also afford data for computing the 
fasting katabolism of the steer in the manner described in an earlier 
publication (3, p. 53). 
Each kilogram of dry matter consumed increased the katabolism by 
1,197 Calories in the unfattened and by 1,256 Calories in the fattened 
state. It may be computed, therefore, by how much the katabolism 
would have been reduced had the feed been entirely withdrawn, while 
