YH 454 combined pdf

vet notes l fighting flies
notes
vet
What you’ll learn:
l The different types of fly
l How they affect your horse
l Management tips
Flying
nuisance
The warmth of summer brings with it pesky flies
and biting insects. Leona Bramell MRCVS
discusses the common problems they can cause
After a cold or wet winter,
most horse riders welcome
the onset of summer, but one
downside to the longer days
and warmer weather is the
arrival of flies. Some horses are more
adversely affected by these insects than
others, so knowing how to reduce and
manage fly irritation will help your horse
stay happy and fly-free this summer.
As well as being
annoying, flies can cause
a range of health issues
Photo: Oscity/Shutterstock
meet the expert
Leona Bramall CertAVP(EM)
MVB MRCVS is an equine vet at
Gillivervet Ltd in Lancashire. She
holds an advanced veterinary
practitioner certificate in equine
medicine and her primary areas of
interest lie in dermatology and gastrointestinal
disease. Visit www.gillivervet.co.uk/vets.aspx
Sweet itch
Sweet itch is caused by an allergic
reaction to the saliva of the Culicoides
biting midge. Affected horses
develop itching of the mane and tail
and, in some cases, the face and poll.
Itching begins in summer, but for
some horses sweet itch can be a
year-round problem. The level of
severity varies; while some horses
itch themselves bald, others may
develop ulceration or secondary
bacterial infections.
Precautionary measures
Prevention is based on reducing
exposure to the offending midges.
If at all possible, avoid fields with
stagnant water or those adjacent to
woodland areas that inherently have
high midge populations. Horses
affected with sweet itch should be
stabled at dawn and dusk when the
midges are most active. Fans may
deter midges from entering stables.
Sweet itch fly masks and rugs also
play an integral role in prevention, as
do fly and insect repellents, although
the effectiveness of these varies.
Veterinary intervention
Contact your veterinary surgeon if
itching continues despite using the
above preventative measures, if skin
is hot and inflamed, or if you’re
concerned about possible infection.
Your vet will examine your horse and
may prescribe injectable, oral and/or
topical (cream) medications.
Insect hypersensitivity
In addition to sweet itch, some horses can
develop skin lumps (urticaria), with or
without associated itching secondary to
other flies and insects. Severity varies, from
a small lump at the site of contact to an
extensive hypersensitive response.
Stick ‘em up
If your horse is stabled during the day,
ensure his stable is kept as clean as possible
to reduce the number of flies in the stable
environment. You can also spray the stable
with fly repellents, but don’t spray directly
near water or feed buckets.
If the lumps are extensive, don’t appear
to be resolving, or make your horse itch,
seek advice from your veterinary surgeon.
Contact your vet
if lumps become
itchy or don’t
resolve on their own
Sweet itch fly
masks and rugs
help reduce
exposure to
midges
Lumps on your horse’s
skin can indicate a
hypersensitive response
Photo: Bauer library
Photos: Leona Bramall
Horse flies are
persistent and
extremely annoying
Photo: Bauer library
The main enemies
1 Horse flies
No doubt we’re all more than familiar with
horse flies (Tabanus spp.). Normally, there is
one generation of adult flies per year, which
emerge in early summer. Peak feeding
activity occurs on warm, humid days in July
and August. Horse flies are generally
persistent in their attempts to feed and are
therefore a source of great annoyance.
2 Bot flies
Bot flies (Gasterophilus spp.) are bee-like in
appearance and generally active for a
number of weeks in late summer. They can
cause immense irritation and distress when
laying their eggs — generally on the skin and
coat of your horse’s limbs and, occasionally,
around the lips and under his chin.
Check his coat
Bot eggs are normally easy to spot and are
visible as white or cream-coloured eggs,
about 1-2mm in length. They are firmly
attached to the hair, but can be removed
using a commercial bot egg knife. If bot eggs
are noted during the preceding year, your
horse should be wormed with an ivermectinbased
wormer after the first winter frost.
Prevention
At times of peak fly activity, especially
when bot flies are out, consider
stabling your horse during the day and
turning him out at night. Fly masks,
rugs and insect repellents may help too.
Sarcoids
These are arguably the most prevalent form
of skin tumour in non-grey horses. They are
believed to be caused by a strain of bovine
papilloma virus and transmitted by flies, so
summer is a key time for spread. Fly control
plays an integral role in preventing and
reducing sarcoids.
It is likely that individual horses have a
genetic predisposition for the disease.
Sarcoids can occur at any location on the
skin, but the most commonly affected areas
are those prone to sweating — which, in turn,
attract flies — such as the armpits, inside of
the hindlimbs and, in geldings, the sheath.
Spotting the signs
There are six different types of sarcoid, so if
you notice any skin masses or lesions on
your horse that you’re concerned about, seek
advice from your veterinary surgeon.
Sarcoids can occur
anywhere on the
horse’s body
Sarcoids are skin tumours, so early
detection and treatment as advised by your
veterinary surgeon is very important. Early
intervention enables the sarcoid to be
treated before it increases further in size and
reduces the chance of spread and further
lesions developing. The treatment
recommended by your vet will depend on
the type of sarcoid and its location.
Photo: Leona Bramall
Fly strike
Although not a pleasant thought,
open wounds can sometimes be
subject to fly strike, whereby green
and bluebottle flies feed and lay their
eggs, with the fly larvae/maggots
hatching three or four days later.
To prevent this, open wounds
should be managed appropriately
by keeping them clean and covered
(see Managing wounds, p74) and fly
control measures should be used.
If you notice a larval-infested
wound, contact your veterinary
surgeon. They will likely advise
hosing the wound and subsequently
cleaning it with a disinfectant. The
vet will generally visit and administer
an injection against the larvae.
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