Ulcers in Racehorses
By ABC TV program " Catalyst"
Stomach ulcers prevalent - claims TV program
In a recent edition of the ABC TV science program
"Catalyst", it was claimed the prevalence
of stomach ulceration in racehorses in training
is higher than previously recognised.
Dr Leanne Begg (Specialist in Equine Medicine
Randwick Equine Centre) and Dr Craig Suann (Senior
Official Veterinarian NSW Thoroughbred Racing
Board) have collaborated to compile the following
essay titled "Management strategies for
gastric ulceration in racehorses":
Overseas studies have shown that a significant
proportion of performance horses examined by
gastro-endoscopy has evidence of gastric ulceration,
although not all of these horses show actual
A recent study conducted by the Randwick Equine
Centre in Sydney where 304 thoroughbred racehorses
in training were gastroscoped demonstrated an
occurrence of gastric ulceration similar to
that reported in the overseas studies.
The common clinical signs observed in horses
with gastric ulceration can include a reduction
in appetite, loss of body weight and condition
and suboptimal performance.
However, many horses are asymptomatic. Ulcers
tend to be more severe in older horses and horses
that have been in training for a greater length
The only way to definitively diagnose gastric
ulceration is by a veterinarian performing an
endoscopic examination of the stomach.
A three metre long endoscope is required to
adequately examine the entire stomach of an
Causes of Gastric Ulceration
High concentrations of hydrochloric acid in
the stomach are thought to be a major factor
in the production of gastric ulcers.
Horses secrete gastric acid continuously since
they have evolved as forage feeders, grazing
continuously over a 24-hour period in the natural
state. In some horse stables, there can be periods
of time when acid levels in the stomach of horses
This is because there has been the tendency
to feed grain meals two to three times per day
while limiting the amount of hay between some
of these meals.
Eating causes release of bicarbonate-rich saliva
which buffers the acid production, and the feed
itself also neutralises the effects of the acid.
During periods of feed deprivation, however,
the acid level in the stomach soon rises.
The lower part of the stomach has a protective
lining of mucous and bicarbonate, but the upper
part of the stomach is prone to damage from
this high level of acid and is the usual site
of ulcer formation.
Management strategies such as continual access
to hay will aid in lowering acid levels in the
stomach and reduce the incidence and severity
of clinical signs.
Some leading racing stables allow their horses
unlimited access to hay, whether it be lucerne
hay, long stick oat hay, or meadow hay, depending
on season and availability and the preference
of the horses.
It has been shown that continual access to
hay will usually not affect the intake of grain
and/or hard feed, in fact good hay eaters are
invariably good grain eaters.
Continual access to hay may also lower the
incidence of certain behavioural disorders in
Minimising the use of non-steroidal anti-inflammatory
drugs such as phenylbutazone, as well as corticosteroid
preparations, is also important.
These drugs inhibit the formation of certain
prostaglandins (PGE2) in the stomach. PGE2 is
known to enhance the secretion of bicarbonate-rich
mucous and promote mucosal blood flow in the
lower part of the stomach, as well as to suppress
hydrochloric acid production.
Inhibition of PGE2 by the administration of
these drugs will reduce its protectant effects
on the stomach mucosa and may exacerbate ulcer
Medical treatment of gastric ulcers is aimed
at reducing the hydrochloric acid level in the
Several classes of drugs can do this, however
only ranitidine has been registered in Australia
for use in horses.
Ulcerguard® is a registered paste formulation
of ranitidine that is given orally three times
Trainers are reminded that ranitidine is a
Schedule 4 prescription animal medicine, and
should only be used under veterinary supervision.
Detection studies examining Ulcerguard®
paste have been recently conducted and demonstrate
that it can be used in horses in work, albeit
with some restrictions pre-race.
For information on the results of these studies,
you should consult your veterinarian or the
TRB Veterinary Department on (02) 8344 5050.