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DEHYDRAT ION
Veterinary surgeon
Heather Urquhart
XLEquine practice
Scarsdale Veterinary
Group
Prevention
Ensure your horse always has a plentiful
supply of clean, fresh water, which can
be easier said than done especially in the
winter months when water troughs and
buckets can freeze readily. If you notice
your horse is drinking less during winter,
try offering warm water to drink, ensure
that any bucket feeds are wet, and
consider soaking hay.
Many horses at competitions refuse water
– try taking water from home, and add
chopped apples or other tasty treats to
encourage him to drink.
Electrolytes are essential salts including
potassium, sodium and chloride that bind
to water and aid absorption from the
gastrointestinal tract. They are also lost
from the body alongside water with
diarrhoea or when sweating. Powdered
electrolytes can be added to the feed or
drinking water, or ready made syringes
can be purchased to allow easy
administration. Some horses find
electrolytes in water unpalatable, so
always offer plain water too.
Heather Urquhart BVMS CertAVP(EP) MRCVS,
Scarsdale Veterinary Group
Horses can become dehydrated due to decreased water intake or increased
water losses. Reduced intake occurs if water is unavailable, unpalatable or the
horse chooses not to drink, such as during periods of cold weather or at
competitions. Increased losses can occur via sweating during periods of hot
weather or intense exercise, or the gastrointestinal tract during episodes of
diarrhoea or colic. Dehydration can be very serious, and in severe cases damage
to internal organs can occur; early recognition and treatment is therefore
necessary for a successful outcome.
Figure 1 – Horse receiving intravenous
fluids for rehydration.
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EQUINE MATTERS
Fluids can be administered orally or
intravenously, depending on the clinical
signs and the underlying cause – a mildly
dehydrated horse, for example after
intense exercise, may be able to correct
his own fluid balance simply by being
offered water +/- electrolytes from
a bucket.
Nasogastric intubation permits several
litres of fluid to be delivered directly into
the stomach, allowing quick correction of
mild to moderate dehydration. Electrolytes
should be added to aid water absorption.
However, the gastrointestinal tract must
be able to absorb fluids for this to be
effective, so would therefore not be
suitable for use in horses with diarrhoea
or some types of colic.
In these cases, or where the dehydration
is severe, the horse is likely to require
admitting to a veterinary hospital, and
intravenous fluids given directly into the
bloodstream
(Figure 1)
.
Treatment can be stopped when all
calculated fluid losses have been
replaced, when the horse is clinically
normal, or when blood and urine samples
indicate a normal hydration status.
Dehydration in
horses
Treatment
Treatment of dehydration involves
replacing the fluids and electrolytes that
have been lost. The amount of fluid
required can be calculated by taking into
account how much your horse requires
on a daily basis for maintenance,
combined with how much has been lost,
for example in sweat or diarrhoea. The
clinical condition of the horse is also
taken into consideration; signs such as a
prolonged 'skin tent', dry or tacky mucous
membranes, sunken eyes and an
increased heart rate can indicate
dehydration. Blood and/or urine samples
can give additional information.