th less flexion, hence less
pain is experienced in this manner of locomotion. When made to step
aside in the stall, a spavined horse will flex the affected member
abruptly and when weight is taken on the diseased leg, symptoms are
evinced of pain, and weight is immediately shifted to the sound limb.
This is marked during the incipient stages of spavin. Lameness usually
precedes the formation of exostosis, though cases are observed wherein
an exostosis is present and no lameness is manifested and no history of
the previous existence of lameness is available.

The "spavin test" is of value as a diagnostic measure when it is
employed with other means of examination, though reaction to this test
is seen in some cases in old "crampy" horses that have experienced hard
service. The test consists in flexing the affected leg (elevating the
foot from the ground twelve to twenty-four inches) and holding the
member in this position for a minute, whereupon the animal is made to
step away immediately at a trot. During the first few steps taken
directly thereafter, the subject shows pronounced lameness and this
constitutes a reaction to the spavin test.

Where no exostosis is present it becomes necessary to exclude other
causes for lameness but the characteristic spavin lameness is to be
relied upon to a greater extent in such cases than are other means of
examination. Such cases are known as occult spavin and may be present
for months before any external changes in structure are observable. In
some instances no extoses form even during the course of years. The
spavin test is of aid in establishing a diagnosis here but the marked
"warming out" peculiar to spavin is not so pronounced in such cases.

Prognosis.--An animal having hereditary predisposition to spavin is
not likely to recover completely whether this predisposition be due to
faulty conformation or susceptibility to bone changes. In predicting the
outcome, the temperament of the subject is to be taken into account, as
well as the character of service the animal is expected to perform. And
finally, a very important feature to be noted, is the location of the
exostosis. If situated rather high and extending anterior to the hock,
there is less likelihood of recovery resulting than where an exostosis
is confined to the lower row of tarsal bones. When situated anterior to
the tarsus a large exostosis may by mechanical interference to function,
cause lameness when all other cause