458 PRINCIPLES OF ANIMAL NUTRITION, 
ing experiments, and which show a range of 13.5 per cent. of the 
average. Second, the computed maintenance ration is based upon 
experiments with coarse fodder only. We have seen reason to be- 
lieve, however (pp. 388-391) that the net availability of the metabo- 
lizable energy in coarse fodders is decidedly less than in case of con- 
centrated feeds, and that consequently more metabolizable energy 
would be required for maintenance on a ration composed of coarse 
fodder than on one containing concentrated feeds, as did Kellner’s 
basal rations. In other words, Kellner’s assumed maintenance 
ration is probably somewhat too large and his computed utiliza- 
tion of the basal ration, therefore, also somewhat too high. Third, 
it is by no means demonstrated that the maintenance ration of 
fattened as compared with unfattened animals is, as Kellner as- 
sumes, in proportion to the two-third power of the live weight. 
In the absence of any direct determinations of the utilization 
of the basal rations, however, there seems to be no course open but 
to follow substantially Kellner’s method of computation and assume 
a maintenance ration for each of the animals in proportion to the 
two-thirds power of its live weight during the period under con- 
sideration. 
Computation of Results—The method of computing the correc- 
tions for the differences in live weight and in the amount of the 
basal ration consumed may be illustrated by the same two periods 
which were used on pages 288-9 to exemplify the computation of 
metabolizable energy, viz., Periods 4 and 7 with Ox H, on meadow 
hay. In Period 4, on the basal ration, the live weight was 668.9 
kgs., the computed maintenance requirement 13,989.1 Cals., and 
the gain by the animal 2003.2 Cals. The percentage utilization 
therefore was as follows: 
Metabolizable energy of ration........ 17,388.8 Cals. 
Computed maintenance requirement .. 13,989.1  “ 
Excess £00. 6. oa eaeeb enka scees 3399.7 Cals. 
Gal ssa esc es sea d amie eee eae 2003.2 “ 
Percentage utilization............... 58.9 % 
In Period 7 the total metabolizable energy of the ration was 
26,013.0 Cals. and the gain 5643.2 Cals. Of the excess of 8624.2 
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