188
Methods of Yoking Bullocks
animal. By the time that the spirit of enquiry
had spread sufficiently and the numbers of research
workers had increased to the point where such pro-
blems might have had more serious attention, the
development of the internal combustion engine,
applied particularly to the tractor, had progressed to
the stage where it seemed likely to displace animal
power in agriculture. If animal power was to be
displaced, there seemed little value in studying it
or in trying to improve it or its application. This
probably largely accounts for the scarcity of litera-
ture on the subject.
A few efforts have been traced to improve yokes
in India. Krishnamurty of the Madras Veterinary
College designed an improved yoke but it was not
included in the types of yokes reported in common
use in Madras by the Director of Agriculture. Simi-
larly, Mushtaq Ahmad of the Punjab Veterinary
College designed an improved yoke which was not
included in the types reported by the Director of
Agriculture, Punjab, in response to our enquiries for
designs to be tested. A 'yoke' or wooden collar
was designed for a single bullock at Poona Agricultural
College and was included in the types submitted by
the Director of Agriculture, Bombay, and a similar
yoke with no reference to origin was included in those
reported used in Gwalior. Charley at Coimbatore
designed a leather strap harness for a single bullock,
described in leaflet No. 85 of the Department of
Agriculture, Madras. No publication which has
come to attention gives any information on com-
parative usefulness of any of these, the published
material being confined to descriptions and to the
uses to which they may be put. In some cases,
authors make claims of superiority but do not cite
tests to prove the claims. No foreign publication
has come to our attention from anywhere in the
world dealing with tests of harness or yokes. The
field therefore seems to be a completely virgin one,
unexplored and apparently practically undiscovered.
The literature on the testing of animals is scant but
not quite non-existent. Bulletin 240, October
1926, of the Agricultural Experiment Station, Iowa
State College of Agriculture and Mechanic Arts,
by Collins and Caine, devotes 28 pages to 'Testing
Draft Horses'. This is the only publication in
English devoted primarily to discussing tests of draft
horses which has come to our attention.
'Investigation of the Working Performance of
Swiss Cattle' by Hans Wenger, Bern, 1939, is the
only study of the draft ability of bovine animals
which has been available during this study. It is
in German and no English translation has been found.
Wenger lists a bibliography of 58 items, only three
being in English, one a work on statistical methods,
on the bulletin by Collins and Caine referred to
above and the third a study by Brody of Missouri
University. From a translation of the index and
summary, it does not appear to contain anything on
the question of harness or yoking nor does the biblio-
graphy refer to any publication on the subject.
With such a scarcity of work done on draft power,
it is not surprising that there is little material available
on methods and equipment for testing draft power.
Wenger gives a detailed description of the loading car
which he used, which is of the general type described
by several other workers, particularly Collins and
Caine.
Collins and Caine in Iowa State Bulletin 210 des-
cribe three variations of a traction dynamometer car
for testing animals as follows :
'In the first dynamometer, built for this work
provision was made for hitching each of two horses
to weights in a manner similar to that shown in fig, 2,
In this case the tractive pull resulting from lifting the
weights is more than enough to propel the dynamo-
meter and it is necessary to apply some resistance
to hold the machine back. This was done by gearing
the rear wheels to a rotary pump and then regulating
the discharge from the pump to produce the desired
resistance. This regulation was made automatic
by connecting the valve so that it is operated by a
change in the height of the weights relative to the
frame.'
'When the weights are at the bottom the valve is
closed and the rear wheels are locked. As the
weights are lifted the valve gradually opens until at
the top it is wide open and the pump furnishes a
minimum of resistance. In action this automatic
control allows the dynamometer to move just fast
enough to keep the weights suspended whenever the
team is moving. The condition of the road surface
or the grade does not affect the amount of work
done by the team but merely requires that more or
less resistance must be furnished by the pump.
The tractive pull exerted by the team is constant and
equal to the sum of the weights which are held sus-
pended.'
'In action, then, the tractive force required to
move the dynamometer (variable) plus the resistance
furnished by the pump (governed by position of
weights) is equal to the tractive pull exerted by the
team (constant). The dynamometer, of course, has
practical limits. On slippery roads it is difficult
to get enough traction for the wheels, in which case
the weights would not be lifted and the team would
be exerting a tractive force something less than the
weights. On the other hand where the roads are
extremely soft or a very steep hill is encountered, it is
quite possible that the tractive pull required to
move the machine itself will be greater than the
amount of the weights. This may readily occur i f
only a light load were applied. In such a case the
weights would strike the top of their guides and the
team would be exerting a greater tractive pull than
the amount of the weights.'