456 
Journal of Agricultural Research 
Vol. XI, No. io 
METABOLIZABLE energy 
Tables 2 £0 5 of the Appendix afford data for computing the percentage 
losses of energy in the several excreta and the percentage metabolizable. 
On the assumption that the corresponding values for the alfalfa hay were 
the same as those found for the same hay in an experiment upon the same 
animal during the previous year, the corresponding figures for the con¬ 
centrate mixture may also be computed. The results are recorded in 
Table VIII. 
TabIvB VIII .—Percentage distribution of energy 
Percentage losses. 
Percentage 
metaboliz¬ 
able. 
Item. 
In 
feces. 
In 
urine. 
In 
methane. 
Total ration: 
Period 1 ... 
24. 44 
5. 16 
9 - i 5 
61.25 
Period 2 . 
26. 61 
4 * 55 
6. 72 
62. 12 
Period 3. 
25. 88 
4.91 
6. 4 3 
62. 73 
Period 4. 
24. 42 
5.38 
8. 80 
6l. 40 
Assumed for hay. 
42. 60 
5 - 92 
6. 77 
44 - 71 
Computed for concentrates: 
Period 1 ... 
15.62 
4 - 79 
10. 30 
69. 29 
Period 2. 
18.81 
3.88 
6. 70 
70. 61 
Period 3.. 
17.80 
4. 42 
6. 34 
71.44 
Period 4. 
15.64 
5 - 11 
9. 78 
69. 47 
As in earlier experiments, the heavier rations suffered relatively greater 
losses of energy in the feces but smaller ones in the urine and methane, 
so that the percentage of the gross energy which was metabolizable was 
slightly greater in the heavier rations. It must be remembered also that 
the metabolizable energy as here computed includes that evolved as heat 
in the methane fermentation. Estimating this at 6.07 Calories per 
gram of methane (2, p . 468) the proportion of the gross energy of the 
rations which was available to sustain the tissue metabolism averaged 
57.24 per cent for the lighter rations and 59.43 per cent for the heavier. 
No distinct difference in this respect is manifest between the unfattened 
and fattened condition. 
The results recorded in Table IX show a close agreement with those of 
earlier experiments on similar rations. 
