14 BULLETIN 1446, U. S. DEPARTMENT OF AGRICULTURE 
as compared with an average of 41 acres on nontractor farms. The 
hours of annual work on tractor farms averaged 131 less per head 
than on nontractor farms. 
The net cost of keeping work stock averaged $97 per head on 
tractor farms as against $85 on nontractor farms, although on tractor 
farms the hours worked per head per year were materially less than 
on nontractor farms. The greater cost of keeping work stock on 
tractor farms, together with the lesser hours worked, resulted in a 
cost per hour of horse work which was 4 cents higher than on non- 
tractor farms. The cost per hour of horse work for each farm was 
computed by dividing the total cost of keeping the work stock by the 
total annual hours of horse work for each farm. 
Studies of the cost and utilization of work stock on tractor and on 
nontractor farms in other regions have, in many cases, shown a smaller 
number of hours of horse work per head on tractor farms, together 
with a lower cost of maintenance per head. There appear, however, 
to be several reasons why the cost of maintenance of work stock on 
these tractor farms, as well as on those in a number of other regions, 
should be greater than on nontractor farms, even where the number 
of hours of horse work per head was smaller on the tractor farms. 
In the case of Sherman County farms on which tractors were owned 
the quantities of grain fed, the hours of human labor spent in the care 
of work stock, and the charges for depreciation were somewhat greater 
than on nontractor farms. Likewise, the average value per head of 
work stock on tractor farms was higher than on nontractor farms, 
which in turn entailed an interest charge greater than on nontractor 
farms. On nontractor farms surplus work stock kept for harvest 
work with the combine was not of as good a grade as the smaller 
numbers kept on tractor farms. These horses on nontractor farms 
were fed larger quantities of wheat hay, especially during the harvest 
season, and lesser quantities of threshed grain and mixed feed than 
those on tractor farms. On tractor farms larger quantities of grain 
and chaff and straw were fed to take the place of the reduced hay 
ration. From these comparisons it would appear that a better grade 
of work stock was kept on tractor farms which received relatively 
better care than that kept on nontractor farms. The grain ration 
fed as grain on both tractor and nontractor farms was relatively low, 
because much of the grain consumed was fed as grain hay. 
A comparison of the number of head of work stock kept on tractor 
and on nontractor farms of specified sizes and the hours worked per 
head per year is given in Table 10. Care was taken not to include 
any farms in these comparisons which influenced unduly the num- 
ber of head of work stock kept on the farm or the hours worked 
per head per year. No farms were included on which more than 
one tractor was owned, on which there was an appreciable amount 
of contract work, or where outside work was done. On 640-acre 
tractor farms the number of head of work stock averaged 5.6 less 
and the hours worked per head per year averaged 18 hours less than 
on nontractor farms of the same size; on 1,280-acre tractor farms 
5.2 less head of work stock were kept and the hours worked per 
head per year averaged 112 less than on nontractor farms of the 
same size. 
