What is thrush?
Thrush is an unpleasant infection of the horse’s frog, which is
predisposed by moist, damp, dirty ground or stable conditions.
What causes thrush?
Thrush is an infection of the central and lateral sulcus (clefts) of the
frog of the horse’s foot, most often involving bacterial and occasionally
fungal infection. One species of bacterium (Fusobacterium necrophorum)
is particularly aggressive, invading and destroying the frog, sometimes
exposing the deeper sensitive tissues. Long heel conformation encourages
the development of deep narrow frog sulci, which are more prone to the
development of thrush, if environmental conditions are right. If
the horse has an imbalanced foot in the lateromedial (inside-outside)
plane then this also predisposes the horse to thrush.
How is thrush diagnosed?
Thrush produces a foul smelling black discharge in the affected sulcus
of the frog. There is pain on applying pressure to the area.
The hind feet are more often affected than the front feet and, occasionally,
infection may result in a general swelling of the distal (lower) limb.
How is thrush treated?
The horse should be moved to a dry clean environment. The foot should
be thoroughly cleaned out, removing debris from within the affected frog
sulcus, and then the horn is pared out down to healthy tissue, allowing
air to reach any remaining damaged tissues. The frog and its sulcus
should be scrubbed daily with dilute iodine solution or other antiseptic
Thereafter, the horse should be kept in clean, dry stable conditions and
the frog should be cleaned and treated regularly until the infection is
controlled and the tissues heel.
How can thrush be prevented?
Prevention is better than cure and thrush can be avoided by good stable
management and regular foot care and inspection. Stable your horse
in clean dry conditions and have your horses' feet regularly trimmed and
shod to avoid the development of long heel conformation and to keep the
frog healthy. Any mediolateral foot imbalance should also be addressed
by the farrier.
With early treatment and good stable and environmental management, the
prognosis for complete recovery for cases of thrush is good. Treatment
will usually be required for 7-14 days. The prognosis for complete
resolution is good unless the infection has been allowed to become chronic
and/or there is extensive involvement of deeper tissues.
Contact the Hospital if you require assistance with a horse with thrush.
The material contained in this website is presented for information purposes
only . The material is in no way intended to replace professional veterinary
care or attention from a professional veterinary surgeon.
The advice given in any of our web pages cannot be used as the basis
for a diagnosis or choice of treatment.
Clyde Vet Group advises that you should always consult a veterinary surgeon
about any queries with animals under your care.