988 
Journal of Agricultural Research 
Vol. XXX, No. 10 
Table VII.— Daily milk production , and pounds of potash , phosphorus , and nitro¬ 
gen recovered 
FIRST DIGESTION TRIAL 
Animal 
Milk 
pro¬ 
duced 
K 2 0 
P2O5 
N 
Con¬ 
sumed 
Voided 
Re¬ 
covered 
Con¬ 
sumed 
Voided 
Re¬ 
covered 
Con¬ 
sumed 
Voided 
Re¬ 
covered 
Pounds 
Pound 
Pound 
Per cent 
Pound 
Pound 
Per cent 
Pound 
Pound 
Per cent 
Cow No. 1_. 
24.16 
0.4624 
0. 2848 
61.59 
0. 2186 
0.0954 
43.64 
0. 5194 
0.3182 
61.26 
Cow No. 2.. 
22. 66 
.3540 
.3390 
95. 76 
.1914 
.0966 
50.46 
.4454 
.3206 
71. 98 
Cow No. 3_ 
18.44 
.3474 
.2680 
77.14 
.1826 
.0910 
49. 83 
.4236 
.2922 
68.98 
Cow No. 4__. 
25.42 
.4234 
.2458 
58. 05 
.2114 
.0936 
44. 27 
.5036 
.3118 
61.91 
SECOND DIGESTION TRIAL 
Cow No. 1_ 
20.74 
0. 4612 
0. 3816 
82.74 
0.2848 
0. 0926 
32. 51 
0. 7058 
0. 5096 
72. 20 
Cow No. 2_. 
23. 36 
.3558 
.3350 
94.15 
.2390 
.0854 
35. 73 
.5800 
.4298 
74.10 
Cow No. 3_ 
18. 92 
.3516 
.2950 
83. 91 
.2306 
.0756 
32. 78 
.5640 
.3906 
69.25 
Cow No. 4_ 
23. 58 
.4160 
.3258 
78.31 
.2656 
.0772 
29.06 
.6526 
.4454 
68.25 
CONCLUSION 
During the first of the two trials the 
amount of potash recovered in the 
manure was between 58 and 96 per cent 
of the total fed; the recovery of phos¬ 
phates ranged between 44 and 50 per 
cent of the total fed; and the recovery 
of nitrogen ranged from 61 to 72 per 
cent. In the second trial the ranges 
were, for potash, 78 to 94 per cent; for 
phosphates, 29 to 36 per cent; for nitro¬ 
gen, 68 to 74 per cent. From these 
results it seems fair to presume that the 
dairyman may expect to recover to his 
land approximately four-fifths of the 
potash, two-fifths of the phosphates, 
and two-thirds of the nitrogen fed to 
lactating cows. This is a saving of feed 
values that is by no means insignificant. 
Contrary to such information as the 
writers have been able to gain from the 
literature, they have found that, after 
taking all precautions for accuracy of 
analysis, blanks having been run on the 
reagents used, there is an appreciable 
and measurable quantity of phosphorus 
voided in the urine. 
SUMMARY 
Recognizing that the drawing of 
general conclusions on the basis of these 
limited data may not be warranted, the 
writers submit certain inferences which 
are apparently warranted; but these 
inferences are, of course, subject to 
amendment by further investigation 
and study. 
The quantity of the different con¬ 
stants—nitrogen, phosphorus, and po¬ 
tassium—here examined varies quite 
markedly. There is consistently more 
of the potash and nitrogen recoverable 
in feces and urine than of phosphorus. 
This fact, however, by no means new 
to the literature, is but merely con¬ 
firmatory. 
The quantities of the nitrogen, phos¬ 
phorus, and potassium vary strikingly 
with the type of animal. In this ex¬ 
periment the highest values returned to 
the soil through the voided material 
were returned by the Ayrshire, which 
also maintained a high milk production 
at the same time. 
The quantities varied with the daily 
milk production. In a very general 
way, the recovery of potash and nitro¬ 
gen was in inverse relation to milk pro¬ 
duction, while the phosphorus recovery 
paralleled the production of milk. But 
the last-named constant is seen to be 
less influenced by the amount of milk 
produced than the other two. 
The above-suggested relation be¬ 
tween milk production and the potash 
and nitrogen voided is more apparent 
in the instances wherein the daily milk 
production varies widely. 
