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15
EQUINE MATTERS
The use of probiotics
in horses
Many horse owners feed their horses
probiotics in the belief that they help maintain
digestive health; but what exactly are
probiotics, how do they work and when
should they be used
?
The digestive system of the horse is populated
by a diverse range of bacteria and yeasts,
known as the microflora, that play a key role
in the health of the animal. Disturbances in the
gut microflora have been associated with
colic, laminitis, grass sickness and colitis
(figure 1)
.
Probiotics are live bacteria and
yeasts that are thought to play a role in
preventing or treating disease by maintaining
or restoring the microflora. They are different to
prebiotics, which are a source of food that
helps probiotics to grow in the gut. Probiotics
are generally considered safe, are easy to
administer and fairly low cost which, together
with extensive marketing, has led to their
increasing use.
So what is the evidence that
probiotics really work in horses?
Dietary yeasts have been shown to increase
the digestible energy of feed and improve fibre
digestion in horses, although not all studies
have reported beneficial effects. Of the most
commonly studied yeasts,
Saccharomyces
cerevisiae
has been shown to increase
digestibility of fibre and protein, especially
in horses fed low quality forage, and
Saccharomyces boulardii
has been shown
to reduce duration and severity of acute
diarrhoea. However, other studies have shown
no effect and further research is required to
evaluate the potential for live yeasts to help in
cases of colic, laminitis and other diseases.
Yeasts are often included in commercial
feeds, so additional supplementation may
not be required and is perhaps best reserved
for horses on poor quality forage or for
treatment of specific conditions based on
veterinary advice.
Scientific evidence to support the use of
bacterial probiotics is even more limited.
Studies on foals with diarrhoea have found
that some bacterial strains do have a
beneficial effect, whereas others actually
increase the severity of diarrhoea. Individual
strains can have very different effects and must
be carefully tested and proven. More research
is needed before recommendations can be
made regarding the use of bacterial probiotics
in horses.
As with many supplements it is likely that
probiotics do have a role to play in equine
medicine but they are not a cure-all and
individual products need to be carefully
evaluated. It is important to be aware that the
type and quantity of organisms in commercial
probiotics is highly variable and in the main
do not contain nearly enough to exert a
clinical effect. If you are in any doubt about
whether a product is suitable for your horse
please consult your veterinary surgeon
for advice.
Veterinary surgeon
Lorna Buckley
XLEquine practice
North West Equine
Vets Ltd
Figure 1.
Probiotics may help stabilise
the gut microflora in patients with diseases
affecting gastrointestinal motility, such as
grass sickness
Lorna Buckley BVMS MRCVS,
North West Equine Vets Ltd
.
PROB IOT I CS