6 
BULLETIN 1101, U. S. DEPARTMENT OF AGRICULTURE. 
A cow digesting her feed utilizes on the average approximately 25 
per cent of the nitrogen, 30 per cent of the phosphorus, and 15 per 
cent of the potash contained in the feed. It is evident, then, that 75 
per cent of the nitrogen, 70 per cent of the phosphorus, and 85 per 
cent of the potash are voided in the urine or in the solid portion of 
the manure. 
Dairymen who wish to reduce their net cost of production should 
remember two important facts in regard to manure : First, that a 
large proportion of the fertility value represented by the purchase 
price of the feeds may be recovered by saving all the liquid and 
solid portions of the manure; and, second, that the urine is more 
valuable than the solid manure as a source of that high-priced plant 
food, nitrogen. One of the big losses in liquid manure on many 
farms is due to leaky floors in the stable. 
Table 4. — Credits for manure and -fertilizing constituents during the tiro winters 
and the two summers. 
Winter. 
Summer. 
Item. 
1919-20 
1920-21 
Aver- 
age. 1 
1919- 
202 
1920- 
212 
Aver- 
age. 1 
Total manure saved tons. . 
Manure per cow pounds. . 
Manure credited per 100 pounds of milk do 
606.O 
5,269 
180 
8 515.7 
3,806 
150 
585.9 
4,506 
165 
153.8 
1,238 
47 
81.4 
558 
20 
117.6 
870 
32 
Winter average. 
Summer average. 
Nitro- 
gen. 
Phos- 
phoric 
acid. 
Pot- 
ash. 
Nitro- 
gen, 
Phos- 
phoric 
acid. 
Pot- 
ash. 
Fertilizing constituents in manure pounds. . 
Credit per cow do 
6,035 
23.2 
2,226 
8.6 
4,922 
18.9 
1,211 
4.5 
447 
1.7 
9S8 
3.7 
1 The averages are weighted. 
2 See notes to Table 1. 
3 Not as large a proportion of the manure voided the second year was saved. 
According to Table 4, an average of 4,506 pounds, or slightly over 
2.2 tons, of manure was saved per cow during the winter six months. 
A 1,000-pound cow voids about 6^ tons of manure in six months. 
The difference between these two amounts shows the quantity which 
was voided in the yards or was lost in storing or handling. This was 
due to the fact that much of the manure, especially the liquid portion, 
was lost through the floors in the barns or allowed to leach away when 
stored in piles exposed to the weather. Only the manure which was 
or could have been saved by using reasonable care with the equipment 
available was credited to the cows. The quantity of manure dropped 
was approximated by keeping a record of the time the cows were 
actually in the barn. 
