Stinky Feet..... the Dangers of Thrush
Bryan S. Farcus, B.S., C.F.
If you smell a foul odor while picking your horse's feet, chances
are he has contracted thrush, a frog-eating, anaerobic bacterium.
Thrush is a primary concern, whether your horse lives mainly at
pasture or in a stable, especially in wet weather. Since this
bacterial disease is anaerobic, it survives without the presence
of oxygen. In fact, oxygen will actually kill it. In many minor
cases, just a hoof picking a day will be enough to keep thrush
Conditions that accelerate thrush are conceptually (but not
literally) relative to those that accelerate tooth decay within
our teeth. It sounds absurd to hear that someone died of tooth
decay. Unfortunately, I have heard of horses being put down due
to advanced cases of thrush and I think how absurd, because
thrush (frog decay) and cavities (tooth decay) are both
hygiene-related and both easily prevented.
Generally speaking, thrush is not deadly. Most studies suggest
that minor cases have a three-day window to arrive and a
three-day window to disappear, provided that appropriate measures
Thrush problems for horses are essentially fostered by poor
hygiene. It's difficult to comprehend the seriousness of
something that appears so subtle, but due to the horse's hoof
construction, it can be deadly if not dealt with properly.
The frog has two distinct layers--the external skin is called
horn tissue and the corresponding vascular layer of tissue is
called the sensitive corium. Beneath the inner sensitive layer
lies a pad-like shock absorber that reduces concussion for the
horse's hoof and his entire limb, called the deep digital
The signs of thrush will be noticeable at the deep crevices of
the frog (sulci) when a black, puss-like discharge accompanied by
a foul odor is present.
Thrush is likely to take over a hoof that is left in unsanitary
conditions. A wet environment that primarily consists of urine
and acidity from manure is a breeding ground for the anaerobic
bacterium that are attracted to any necrotic (decayed) tissue
that exists on the horse's frog. Not stopping at that, the
bacteria will form deep-seated pockets and literally drill into
the frog, eating away at the remaining healthy tissue.
One way to prevent thrush is by a thorough, daily hoof picking.
It's not necessarily true that horses at pasture won't get
thrush. They can, in certain seasonal situations. Horses left in
muddy areas, particularly in the northeastern part of the U.S.,
may have to cope with wetter climates most months of the year,
increasing the odds of contracting thrush. Horses that spend time
in unsanitary conditions are also more susceptible to the
In serious cases, the thrush bacteria invades the sensitive
layers of the frog. It is common in these cases to see bleeding
of the frog as well. If this happens, you should move your horse
into a clean, dry area and use an antiseptic foot wash with
Betadine solution or a foot soak with warm Epsom salt water. If
bleeding still persists, apply a temporary bandage.
Remember, it's always a good idea to confer with your vet, who
will probably suggest your horse receive a lockjaw shot. Once the
healing of the frog begins, it would be wise to maintain a
"cleanliness-first" policy for your horse's feet.
Thrush needs tough treatment to eliminate it. Farrier Bryan
Farcus has found several commercial products that successfully
combat the frog-eating disease: Thrush Buster by Mustad, Kopertox
by Fort Dodge and Thrush Remedy by Absorbine. Remember that
regardless of the type of thrush medication you choose, it will
be most effective when administered directly after a thorough
Prevention is the best cure.
"It's always a good idea to do a routine hoof picking so that you
can keep a watchful eye on your horse's hoof health," concludes
Bryan Farcus is a certified Farrier & instructor in West Virginia