10 
BULLETIN 1281, U. S. DEPARTMENT OF AGRICULTURE 
mixture; and for that reason the nitrogen determined on the fresh 
material by Konig's method is used throughout the computations. 
APPARENT DIGESTIBILITY 
The detailed data used in computing the apparent digestibility 
of the rations will be found in the appendix. In these tables the 
salt has been added to the dry matter. The digestion coefficients 
of the feed have been collected for comparison, and are recorded 
in Table 4. 
Table 3. — Corn-position of dry matter of feed and feces 
Sub- 
stance 
Cow 
Xo. 
Period 
Dry 
mat- 
ter 
Ash 
Pro- 
tein 
Non- 
pro- 
tein 
Crude 
fiber 
Nitro- 
gen- 
free 
extract 
Ether 
extract 
Total 
nitro- 
gen 
Pro- 
tein ' r 
Energy 
per 
gram 
Per 
cent 
Per 
cent 
Per 
cent 
Per 
cent 
Per 
cent 
Per 
cent 
Per 
cent 
Per 
cent 
Per i Per 
cent cent 
Calories 
631 
615 
T 
I 
I 
J8S.970 
8.159 
14. 713 
2.698 
27.609 
44.320 
2.501 
2.928 
2.354 45.748 
4,435.77 
Alfalfa 
hay 
631 
615 
579 
631 
615 
579 
11 
Hl>89.727 
mi 
in 1-90.315 
Il'J 
8.217 
8.582 
14.069 
14.625 
2.975 
3.177 
27.465 
27. 411 
44.725 
43.546 
2.549 
2.659 
2.884 
3.016 
2.251 
2.340 
45.760 
45. 769 
4,433.11 
4, 440. 52 
631 
615 
||W. 556 
4.471 
13.947 
.400 
8.187 
68.139 
4.695 
2.465 
2. 380_ 46 145 
4, 549. 46 
Grain 
mixture 
631 
J 615 
579 
631 
615 
579 
631 
II 
n 
i 
j-86. 675 
Us. 940 
18.295 
4.384 
4.370 
10. 707 
13. 918 
13. 771 
11. 781 
.479 
.653 
1.208 
8.248 
8.008 
32.886 
68.093 
68.581 
40.499 
4.830 
4.580 
2.919 
i 2. 477 
2.489 
P2.405 
I 2. 142 
2.375 
2.350 
} 1.885 
46.055 
46.092 
46. 976 
4, 548. 37 
4, 544. 67 
4, 674. 55 
631 
ii 
18.163 
11. 156 
11.275 
1.556 
32.790 
40.540 
2.683 
fiS»'-« 
46.426 
4, 612. 25 
631 
in 
17.644 
11.279 
11.963 
1.053 
32.976 
39. 959 
2.770 
{'If"} 1.9H 
46.423 
4, 601. 24 
Feces 
615 
615 
i 
ii 
17. 421 
18. 132 
10.046 
10.043 
12.006 
10.400 
.978 
2.421 
32.106 
30.943 
42.409 
43.425 
2.455 
2.763 
f*2. 520 
\ 2.129 
P2.410 
\ 2. 179 
} 1. 921 
} 1.664 
46.954 
46. 969 
4, 651. 40 
4,644.12 
i 
615 
in 
17. ? /6 
10.222 
11.994 
.926 
33.900 
40. 535 
*«teS 
} 1. 919 
46. 796 
4, 627. 26 
579 
i 
16.249 
10. 878 
11.325 
1. 711 32. 853 
40.649 
i-nsii 
46.499 
4, 617. 21 
579 
ii 
16.404 
10.389 11.200 
2. 045j 33. 102 
40. 787 
o ,— f2 2. 566 
- 4 "\ 2.227 
} 1. 792 
46.686 
4, 608. 75 
1 Average of the other two grain-mixture samples. 
2 Nitrogen in fresh feces by Konig method, computed to dry matter. In the grain mixtures the protein 
was obtained by multiplying protein-nitrogen by the factor 5.86, and the nonprotein nitrogenous matter 
by using the factor 4.7. • 
Table 4 shows a very close agreement between the apparent 
digestibility of dry matter on a percentage basis, and also in terms 
of energy. Cow 579 shows an apparent digestibility of the ration 
approximately 2 per cent higher than the other two cows. 
The organic matter appears to be about 2.5 per cent more digestible 
on a percentage basis than in terms of energy. This difference is 
probably due to the fact that the ingredients as determined in the 
feces do not have the same composition as those in the feed. This is 
especially true of the crude fiber, which has a higher carbon content 
in the feces than in the feed. The feces invariably show a higher 
energy value per gram of dry matter than the feed. 
The divergence of the coefficient of digestibility of protein with 
cow 615, period II, from the average, is unexplained; and since it is 
accompanied by an abnormally low figure for nonprotein nitrogenous 
matter it is probably due to some error of work. Both of these 
figures have been omitted from the average for this animal. 
