14 BULLETIN 1144, U. S. DEPARTMENT OE AGRICULTURE. 
tuberculosis the cows are not a total loss. Cows culled from the best 
herds may be attractive purchases for herds of lower standards of 
production, and the shrinkage in value may thus be distributed over 
a number of farms, but ultimately the cow will find her way to the 
butcher or will die on some farmer's hands. Breeders probably suf- 
fer less from depreciation than farmers who buy their stock, because 
they have young stock increasing in value. 
Normal depreciation has not been of sufficient importance to attract 
strict analytical study. As an indication of the scope of the problem, 
it may be remarked that besides the 18 per cent here estimated under 
conditions acknowledged to be unusual, a rate of depreciation of 26 
per cent in one year has been observed in one herd of over 300 cows, 
where the rearing of young stock was not a part of the farm business 
and so did not obsfure the figures, and of about 11 per cent in another 
herd of 40 cows where all the factors involved were kept strictly 
separated. In each of these latter cases, the cows were forced and 
used up much faster than dairy farmers usually find economical. 
In times of rising prices there may be an increase in the value of 
cows more than enough to offset physical depreciation. 
On the whole, from the year-after-year viewpoint, it would seem 
fair to allow a minimum of 6 per cent for depreciation instead of the 
18 per cent claimed for 1920. and 6 per cent interest, both based on 
the valuation at the first inventory. At this rate there would be a 
charge of $19.80 per head, or 27 cents per 100 pounds of milk for 
these cows. If the full depreciation claimed by these farmers were 
allowed, the cow cost would be 62 cents per 100 pounds, of which 14 
cents is for interest. 
BULL SERVICE. 
Bulls vary widely as to their value and the size of the herd they 
head. So far as milk production alone is concerned, bull service as 
a cost is just short of negligible. Except for his influence on the 
young stock, one bull will do as well as another, and the prevalence 
of grade and scrub bulls throughout the State indicates that many 
farmers fail to appreciate the bull's influence on the value of the 
stock. Frequently bulls are kept on farms for convenience only, 
and, except for convenience (occasionally contagious abortion in a 
neighborhood may be the deciding factor), keeping a bull is not 
warranted on a large number of farms. By cooperative ownership 
some farmers have been able to secure all the advantages of the us& 
of a high-class pure-bred bull in improving their young stock. Occa- 
sionally a farmer with a small herd is obliged to maintain a bull 
because of inability to secure service locally at a reasonable fee. 
Bull service does not count as an offset to cost of keep on the 
farms under discussion. Under ordinary circumstances in Wiscon- 
sin the difference between the cash received for veal calves and the 
current market value of the milk fed to them is sufficient to meet the 
cost of keeping an ordinary grade bull, especially in view of a gen- 
eral tendency to include the bull's feed and care with the feed and 
care of cows in farm calculations. Any costs incident to higher 
valuations are properly assigned to the cost of the offspring and do 
not therefore affect the cost of milk. 
