26 BULLETIN" 858, U. S. DEPARTMENT OE AGRICULTURE. 
The average ton of manure, without bedding, produced by the 
cows in the winter months contained: 
Pounds. 
Nitrogen 9. 7 
Commercial phosphoric acid 3. 1 
Potash 9. 
Since these amounts are based directly on the contents of the feed 
consumed and bedding used, they are fairly representative of the 
manure and bedding, and manure alone, from average dairy cows 
handled for market-milk production. 
Table 14 summarizes the total costs represented by the feed, labor, 
and overhead and other charges, and the credits represented by the 
calves and manure: 
Table 14. — Proportion of total costs represented by feed, labor, and overhead and other 
costs. 
Cost factors. 
Average 
of 2 
winters. 
Average 
of 2 
summers. 
Average 
of 2 
years. 
Per cent. 
59.6 
Per cent. 
36.0 
19.0 
Per cent. 
49 4 
8.2 
59.6 
19.1 
20.1 
55.0 
20.1 
23.4 
57.6 
19 5 
21 6 
98.8 
1.2 
98.5 
1.5 
98 7 
1 3 
Total cost including depreciation on cows 
100.0 
100.0 
100 
Credits allowed for calves and manure: 
6.0 
23.7 
8.0 
4.8 
6 8 
15 5 
29.7 
12.8 
22 3 
The depreciation on the cows is reported separately from the over- 
head and other costs because there was such a wide variation in the 
figures representing this item for the two years. There was a depre- 
ciation on cows during the first year, which increased the cost of 
production approximately 6 per cent, but during the second year 
the total cost was reduced by about 3 per cent on account of an 
appreciation in their value, due in part to an increase in market 
prices for cows. It will be noticed also that the labor cost amounted 
to 19.1 and 20.1 per cent, respectively, for the winter and summer 
periods, while the overhead and other costs, including depreciation 
on cows, increased from 21.3 per cent in the winters to 24.9 per cent 
in the summers. This difference, however, was not caused by a 
variation in the overhead and other costs, but was a result of a 
lower charge in the summer periods than in the winters for labor 
and feed, including pasture, which were required to produce a certain 
amount of milk. These percentages are necessarily changeable, since 
