Equine diseases and conditions

Parkside Equine Vets are experienced in treating a wide range of equine conditions and diseases.

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Cushing’s Disease

Has your horse or pony suffered from laminitis in the past? Is your horse overly hairy, looking a bit pot-bellied or just not his or her normal self?

If the answer is yes to any of these questions, particularly the recurring laminitis one, and your horse is over 15 years of age, we’d suggest you give us a call so that we can investigate whether Cushing’s Disease (also known as Pituitary Pars Intermedia Dysfunction or “PPID”) may be to blame.

While many cases of laminitis have previously been thought to have been caused by nutritional issues, there is now a growing body of evidence that suggests that up to 80% of laminitis cases seen in practices like our own could be the result of a hormonal imbalance such as Cushing’s Disease – which is why we’re starting to talk about it.

A simple blood test could be all that is needed to diagnose Cushing’s Disease or Syndrome

 

So what is Cushing’s Disease?

Equine Cushing’s Disease is the most common hormonal disorder of older horses and ponies. We understand that over 15% of horses and ponies over 15 years of age are affected. Combine this with the fact that over 80% of horses suffering from laminitis may have an underlying endocrine disorder like Cushing’s Disease, and it is clear why all of a sudden there is an increasing level of interest in the condition. While the condition is more common in older horses and ponies, many still enjoying active lifestyles can be affected.

How does it happen?

The pituitary gland controls a range of important functions including metabolism, reproduction, growth and lactation. As your horse ages, nerves in part of the brain called the hypothalamus undergo progressive degeneration, and produce insufficient quantities of a nerve transmitter called dopamine. Dopamine normally inhibits the production of some hormones from the neighbouring pituitary, so if there is inadequate dopamine production, these hormones tend to be produced in excessive quantities, resulting in the clinical signs associated with Cushing’s.

What are the clinical signs?

We’ve already mentioned laminitis and hirsutism (abnormal coat), which are two of the most common clinical signs of Cushing’s. But there are plenty of others, which are often variable and not necessarily specific to Cushing’s, and these include:

  • Excessive sweating
  • Increased appetite
  • Increased drinking and urination
  • Lethargy/tiredness
  • Poor performance
  • Reduced immune function leading to reoccurring skin and respiratory infections including sinusitis, dental disease and an increased susceptibility to worms.
  • Loss of muscle and a pot-belly
  • Abnormal deposit of fat around the eye

Diagnosis

As with most conditions, early diagnosis and treatment of horses and ponies affected by Cushing’s Disease delivers the best outcome. If you recognise any of the signs, we can carry out a blood test to confirm whether or not Cushing’s is the cause.

Treatment & Management

Treatment of horses with Cushing’s centres on dealing with any immediate medical problems (eg: laminitis cases generally require a combination of pain relief, foot care etc), and then addressing the underlying hormone imbalance.

There is no cure for equine Cushing’s Disease, but there is an effective licensed medicine which helps get the hormone secretions back in balance. This helps to reduce the clinical signs associated with the disease – such as any laminitis.

Equine Cushing’s disease (hyperadrenocorticism) is a common metabolic disease of older horses in which there is overproduction of the hormone cortisol. Too much cortisol can result in an increased susceptibility to bouts of laminitis, a lower resistance to infections, redistribution of fat to places such as above the eyes, and coat changes where the hair remains long and curly. Not all of these symptoms are always present together, but if your horse experiences any of the above and is over 15 years old, a simple blood test can indicate if your horse is at risk and if medication could help.

www.careaboutcushings.co.uk gives you more details and occasional offers on reduced lab fees.

 

Get expert advice

For more information about Cushing’s Disease and other metabolic conditions and to discuss what tests are appropriate for your horse, call one of our equine vets on:

01382 811111

Equine Dentistry

Good oral health in the horse is paramount for a healthy horse. And many painful conditions develop without obvious symptoms. Left untreated these result in chronic pain, behavioural changes such as riding problems, headshaking and changes in general demeanour as well as the more obvious symptoms of “Quidding” (dropping feed), inappetence and weight loss.

At Parkside we are passionate about providing a comprehensive dental service with up to date modern equipment to allow diagnosis and treatment of the range of dental conditions found in horses. All our vets are trained in advanced equine dentistry techniques and are up to date with new and modern developments in dentistry.

We have facilities at both Dundee surgery and Ladybank with stocks which can be used for both routine dental appointments (you save on visit fee)  and more advanced treatments.

We are also able to offer advanced dental treatments for your horses including Dental Endoscopy (High definition imaging) as well as Dental Extractions and Peridontal treatments (Diastema widening).  We also provide in-house Specialist referral treatments working with “Equine Dental Clinic” to offer advanced tooth restorative treatments.

Insurance
Many people are not aware but their horse's insurance policy will now usually stipulate the requirement for ANNUAL charted dental examination by a QUALIFIED professional. This includes Equine Vets (MRCVS) or BAEDT qualified technician. There are many non-qualified lay persons performing dentistry which may invalidate your insurance policy.

Save 10% on dentistry

Members of the Equine Health Plan receive a 10% discount on Dentistry, as well as many other great benefits to keep their horse happy and healthy throughout the year.

Equine Flu

Are your horse’s vaccinations up to date?

The Keeping Britain’s Horses Healthy campaign (KBHH) is now well established, and we are continuing to support it and hope you are, too! The aims of the campaign are supported by leading equine and veterinary organisations, such as World Horse Welfare, the Animal Health Trust, The Horse Trust, and Bailey’s Horse Feeds.

As a practice, we believe this campaign is crucial in promoting preventative healthcare that protects and maintains equine health locally and nationally.  We will be demonstrating on our website how the practice is working locally to improve the health of horses, so remember to log on regularly and check out the latest news and activities.  KBHH is now live on social media so check out @keepinghorseshealthy on Facebook and Twitter as well as our practice page for news, information and to join the community. 

 

One of the focuses of KBHH is encouraging vaccination against infectious disease and explaining the role vaccination has in protecting the individual horse and also the health of the UK horse population in general (herd immunity).

There have been recent outbreaks of flu in the North and South of England and Scotland so make sure your horse doesn’t add to the flu statistics. Call the practice to talk to us about vaccination, your horse’s vaccination history, local disease risk and other ways we can work together to make sure that your horse stays on top form this season.

If you keep your horse on a yard or you manage a yard you will be interested in our latest yard initiative, which we are running in conjunction with the KBHH campaign. Every yard is different and so it is important that a tailor-made programme is developed, covering aspects such as preventing the entry of infectious respiratory disease and the key steps that yard managers and their clients should take to prevent or control an outbreak.  Keep an eye out for our article on protecting your yard against infectious diseases, coming soon.

If you would like advice and guidance on implementing an effective yard policy, call the practice and we will be pleased to assist you. We have a range of materials that are available to use and all materials can be tailor made to suit your individual yard.

Read about the national campaign HERE

Get expert advice

For more information about equine flu call one of our equine vets on:

01382 811111

Lameness

Lameness is our most common visit to horses and most lamenesses are found in the foot! Abscesses of the sole are very common, and are mostly a complication of a puncture wound or sole bruising from rocky ground, which has become septic and painful. These are pared away to allow drainage and subsequent healing, along with antibiotics.

Many lamenesses are diagnosed and cured after the first visit, but it may be necessary to apply nerve blocks or take x-rays to come to a diagnosis. We may ask you to bring your horse to our new Kings Cross Road surgery for further investigation. Navicular disease is an example of a condition which may require additional diagnostic examinations. In Navicular Disease, the navicular bone becomes less dense; which is thought to be due to changes in blood circulation. A poor quality blood supply to the bone may cause it to become poorly calcified in areas, and the bone then becomes weak and painful. This condition can be difficult to diagnose, as the navicular bone lies almost in the centre of the hoof capsule, and it can be tricky to get high quality x-rays of the that area of the foot. In addition, Navicular disease often waxes and wanes; a horse that may be very lame one day may appear to be fine again for another week before having another bad day, which can make diagnosis more difficult.

 

This condition often causes stumbling, with the horse sometimes tripping and falling to its knees - usually on hard ground, where the concussion effect is greatest. Once diagnosed, long-term treatment can produce good recovery from this chronic condition, but some horses are limited in what work they can do. The earlier a condition is seen, the better the chance of resolution. If your veterinary surgeon suspects Navicular disease, they may request you to bring them to the Kings Cross Road surgery, where they can be trotted up on a hard surface, where extensive nerve blocks can be performed if required, and where we have the most equipment to help get the best x-rays taken of your horse.

Acute lameness may involve ultrasound scanning to assess the severity of, for example, a tendon sprain or tear. Ultrasound scanning is also used for early pregnancy diagnosis and to assess ovarian function. We have access to two ultrasound scanners, one which is a dedicated large animal ultrasound scanner. Your vet surgeon may decide that any soft-tissue injury might benefit from additional diagnostics with an ultrasound scanner, which can help distinguish between different tissues that are lying quite close to each other, but also help determine the severity and extent of any particular soft tissue injury.

Get expert advice

For more information about Lameness, call one of our equine vets on:

01382 811111

Laminitis

Laminitis (or founder) is caused by inflammation of the sensitive tissues or lamina, within the hoof. This swells, but cannot expand due to the hoof surrounding it and so causes pain and unwillingness to walk. The horse has an appearance of leaning back when standing - the horse's way of taking pressure off the toe. It can affect all 4 feet, but one may be worse than others, or the front feet may be worse than the back feet. If the laminitis progresses, the pressure can cause the last bone in the leg (pedal bone) to rotate so that the tip of the pedal bone presses on the sole causing even more pain and eventual penetration of the sole in the most extreme cases. These extreme cases result in euthanasia. Obviously it is better to prevent this in the first instance!

 

You can help prevent laminitis by avoiding high risk situations.

The following is a list of "causes" or circumstances which we know commonly precede the onset of laminitis.

  1. Obesity from general over-eating (=over-feeding!)
  2. Overeating on foods rich in carbohydrate or rapidly fermentable fibre i.e. cereals, coarse mixes, rapidly growing or fertilised grass - especially in the Spring and Autumn but in a wet year there is potential for laminitis during all the growing season. This is the most common cause.
  3. Any illness which involves a toxaemia. This may be a bacterial infection or following the ingestion of plant or chemical toxins.
  4. Cushing's Disease. This is a condition which follows an abnormality affecting the pituitary gland in the horse's head. It results in the horse failing to shed its winter coat. The coat becomes long and matted and eventually curly. The horse drinks and eats increased amounts of food while sweating excessively and losing weight. All Cushing's cases suffer from chronic laminitis and can have acute episodes.
  5. Weight-bearing laminitis. When the horse is severely lame on one leg and has to put all his weight on the contra-lateral limb they often suffer from founder in the weight-bearing limb. This is particularly common in hind feet.
  6. Concussive laminitis (road founder). When horses are subjected to fast or prolonged work on hard surfaces they may develop laminitis as a result of trauma to the laminae, particularly if their horn quality is poor.
  7. Hormonal problems. Animals which are "good doers" may be hypothyroid or have an abnormal peripheral cortisol enzyme system. The latter condition, recently described has been called obesity related laminitis or peripheral Cushing's disease. Others develop laminitis when they are in season.
  1. Cold weather. A few horses show laminitis during cold weather, fitting warm leg wraps during cold snaps prevents the problem in most cases.
  2. Stress. Worming, vaccination, travelling or separation from a "friend" can trigger an attack of laminitis in a few horses.
  3. Drug induced laminitis. Although some wormers can precipitate laminitis, the most common group of drugs which cause laminitis are the corticosteroids. Even injecting short acting corticosteroids into joints can cause severe laminitis. This is why we never routinely use these in horses at Parkside.
  4. Overeating / Obesity are the most common high risk situations which lead to laminitis. The secret to avoiding laminitis in this situation is not to turn the horse out whilst he is fatter than condition score 3. This means he should not have a fat deposit along his crest or at the tail head, around the sheath or udder or over the loins. You should be able to feel his ribs easily by running your hand along his side yet you should not be able to see his ribs easily. If you are unsure about how to check your horse’s body condition, ask your vet surgeon to show you while they are out giving vaccines, as we all check body condition when we do our vaccination exams.
  5. Limiting the grass intake can also be accomplished by using a grazing mask or muzzle or (perhaps more easily) by restricting the area available for grazing, and paying careful attention to grass growth in the spring and fall, and avoiding turnout during the period of the highest sugars (dawn and dusk, particularly in spring and autumn). There are also now low-sugar feed supplements that make it easier to administer medication (such as Danilon) in feed without adding sugars and unnecessary calories to your horse’s diet. If you are concerned about essential vitamins and nutrients, Parkside offer a low-sugar, highly palatable supplement (sometimes called a balancer) that can be used instead of feeding high sugar, high calorie feeds.

Get expert advice

For more information about Laminitis call one of our equine vets on:

01382 811111

Ringworm

The name Ringworm comes from the red ring-like lesion which shows in the human infection, although there are no worms involved at all. Ringworm is caused by a fungal skin infection and is commonly seen first on sites where horses rub, or where tack rubs. It is VERY infectious and usually means having to treat ALL horses in a specific area to effect a cure. Spores will live on wood and soft stone walls as well as tack, buckets, and grooming equipment, which spread the spores if shared, and people can carry the spores too. Lesions are usually dry, bald, grey, thickened and scaly, and can become complicated if the horse rubs the lesions or they become infected with bacteria.

There are good treatments available, which are mainly topical preparations to kill the fungus and more importantly the spores which spread the infection. Tack can be soaked and walls sprayed with these washes as well, to reduce the chances of re-infection.

Hair samples sent to the lab will confirm ringworm, although results can take three weeks, so if we suspect an infection, we will usually start treatment immediately. Generally, the fungus itself is cleared relatively readily, although it may take time for the hair to grow back in affected areas.

It will infect people, so take hygienic precautions. Those people who may have weakened immune systems like the very young or the elderly should stay away from affected yards and horses.

Get expert advice

For more information about ringworm call one of our equine vets on

01382 811111

Sarcoids

 

What Are Sarcoids?

Sarcoids are persistent fibrous growths that affect horses and come in multiple types. They are commonly seen as round nodules or warty clumps that grow, usually just under the skin, though they can ulcerate and become messy, especially in the summer. Some sarcoids grow slowly and cause few problems for the horse and their owner, but others can grow quite quickly and can require extensive treatment. They can be difficult to treat and unsightly, but are most problematic when they occur around the ears or girth area.

Cause

Sarcoids appear to be caused by a virus, one of two types of a particular bovine papilloma virus (BPV), which is named that because they were initially thought to just cause warts (or papillomas) in cattle.

In cattle, these very closely related viruses cause warts to grow on young cattle and then fade away as the cattle age and their immune system grows stronger.  Very rarely, in cattle, the warts progress to become growths similar to sarcoids. However, there appear to be horse-specific variants of the virus, that are found in cattle and horses, that are responsible for sarcoids in horses.

Usually, we would expect that a horse with a strong immune system would be able to fight off the virus and cause the growths to spontaneously recede, but horses with sarcoids are only very rarely able to do this. Research has shown that differences in the cells that make up the horse’s immune system may interact with the virus, and this may explain some of why some horses are severely affected with sarcoids and some are not, especially as many healthy horses have the virus but no sarcoids. It is suspected that the virus is transmitted by flies and possibly by contaminated equipment (for instance, a head-collar or brush which came into contact with an ulcerated sarcoid), particularly around wound sites or sites of other trauma, but direct transmission from horse to horse is less likely. As always, keeping equipment clean and separate for each horse is important!

Treatment

We can treat sarcoids with specially formulated pastes that are applied by us, under licence. These formulations are much stronger than what can be found online, and can therefore only be applied by a veterinary surgeon. The pastes are made at Liverpool University and are ordered specially for every case after we have supplied photographic evidence of the sarcoid to be treated, and are supplied along with a customised treatment plan for each sarcoid. At the moment, there is no 100% successful treatment for sarcoids of any type, but we do know that the first cycle of treatment has the highest rate of success, and these cytotoxic pastes have the best rate of success over a variety of sarcoid types, sometimes in combination with other therapies.

Other treatments vary depending on the site of the sarcoid, the size, and how severe the sarcoid is, and also how difficult it will be to treat with the cytotoxic cream. The treatment with the highest rate of recurrence is to ‘band’ the sarcoid or to remove it surgically. ‘Banding’ involves placing a tight elastic band at the root of the sarcoid to cut off the blood supply, so the sarcoid gradually dies, shrinks and falls off. Surgical removal is faster, but can lead to scarring, and can lead to wounds that are difficult to heal as well as more sarcoids developing along the scar.

Other treatments can include immune-stimulating injections into the sarcoid, placing cisplatin beads into the sarcoid (these are a form of chemotherapy) with or without UV light as well, or removing the sarcoid with controlled freezing by liquid nitrogen. This is a very complex and complicated area, however, so we advise talking over any plans of treatment with your vet surgeon for the best possible outcome.

For further information on sarcoids please visit: www.equinesarcoid.co.uk

Get expert advice

For more information about Sarcoids call one of our equine vets on

01382 811111

Strangles

 

The Disease

Strangles is a highly contagious, infectious disease of the upper respiratory tract and can be severe or rarely even fatal as a result of late diagnosis or complications. Know what to look for, and you will have a much better chance of avoiding the unnecessary suffering of your horse and others. Rarely, complications can occur such as bastard (metastatic) strangles, where abscesses can form elsewhere in the body, and purpura haemorrhagica, where the body’s immune system starts attacking the body tissues instead of the infection.

The disease is spread either directly from horse to horse or indirectly via fomites (inanimate objects). Direct infection occurs by bacteria being shed in the discharge from the nose or abscess of an infected horse coming into contact with a non-infected horse. Importantly, the disease can also come from horses showing no signs of illness (shedders or carriers).

Indirect infection occurs when the bacteria being shed from the horse’s nose or discharge from an abscess is carried to other horses by any object, such as people’s hands/clothing, tack, grooming and yard equipment (fomites). The incubation period is up to 14 days, so there can be up to 21 days between cases showing signs of infection as the abscesses can take up to a week to appear.

All horses are susceptible, and even horses that have had strangles previously may not have sufficient immunity to prevent having it again. Recovering hoses can shed bacteria for six weeks. About 10% of horses recovering from the disease will carry the bacteria within their head (in the guttural pouches) and will be healthy horses, but intermittently be a source of bacteria for months to years that can infect other horses. Identifying these carrier horses is key to stopping the outbreak re-occurring on your yard and preventing spread from yard to yard.

How do I know if my horse has strangles?

  • Fever (above 38.5℃) accompanied with depression and loss of appetite.
  • Profuse yellow or green nasal discharge from both nostrils (thick mucus).
  • Swellings on the side of the head and throat which may burst and discharge pus. These abscesses are usually hot and painful and occur some days after the initial fever.
  • Sore throat – difficulty eating, extending the head.

Atypical strangles

(becoming more common, especially in healthy adult horses)

  • Mild short term fever – may lose appetite for a brief period of time.
  • Mild clear nasal discharge.
  • No abscess formation.

These horses are a risk to other horses and should be treated as infectious. However; these clinical signs can be seen with a wide variety of diseases and not just strangles. Ask your veterinary surgeon for advice if you have any concerns.

Isolating affected horses and seeking immediate veterinary attention is essential to stop the spread of the disease.

Tests and Prevention

Culture and PCR of three throat swabs (nasopharyngeal) 5-7 days apart – any horses returning positive results need guttural pouch lavage via endoscopy.

Culture and PCR of one guttural pouch lavage via endoscopy.

Serology blood test – any horses with positive results need guttural pouch lavage via endoscopy.

Preventing strangles 

Entering a yard involves isolating all new horses for at least three weeks, including horses that have been off the yard and in contact with other horses for any reason, including competitions. Consider performing serology blood tests on all new horses moving on to a yard or keeping a dedicated quarantine section.

MSD Animal Health do produce Equilis StrepE which is a licensed vaccine for strangles. However, this vaccine requires two doses placed in the horse’s lip 4 weeks apart for initial immunity, and then a booster every 3 months to maintain immunity. If the booster schedule is not maintained, then the initial two doses must be repeated.

Two caveats for this vaccine:

  1. The first is that it will not eliminate strangles from a carrier animal or one which has already been exposed to strangles and has not yet become ill.
  2. The second is that it is a modified live vaccine, which means that it can very rarely infect other horses with the vaccine strain of strangles. This risk is very low, but it means that vaccinated horses should not come into contact with unvaccinated horses until after the lump that the vaccine produces subsides.

Finally, it is currently impossible to tell by a blood test whether a horse has been exposed to strangles or just been vaccinated for strangles, the only way to determine whether the horse is potentially a carrier is to perform a guttural pouch wash and test for the strangles bacteria DNA.

We currently recommend a combination approach: keep all new horses in isolation and away from other horses on the yard, and perform paired serology blood tests (one at coming onto the yard, one on leaving isolation) or a guttural pouch wash to confirm that the new horse will not be bringing infection onto the yard. Of course, for this to be of maximum benefit, it is helpful to first be sure there is no strangles carrier on the yard! This is also best done with paired serology tests, but the plan will differ for different yards in different situations, so please phone your Parkside team for the best individualised advice.

Case histories

Recently Parkside Equine dealt with an outbreak of strangles on a yard in this area after a horse was introduced into the yard. This horse was a carrier and spread the disease to lots of other horses. Some showed clinical signs and others did not. One horse developed purpura haemorrhagic and was referred to the Edinburgh Dick Vet Large Animal Hospital for intensive nursing and treatment and fortunately survived. A testing process was put in place to identify affected horses until all horses were clear except for the carrier horse. We investigated this horse with our endoscope and found it to have chondroids (lumps of pus) in its guttural pouch which were removed surgically at the Dick Vet.

The yard is now happily free of the disease after all their hard work and perseverance.

Another yard put in place a testing and quarantine regime to ensure they were free of strangles, as they had no symptoms of strangles and no recent arrivals, before bringing some new horses onto the yard. Out of 91 horses and ponies, four tested positive for antibodies to strangles (in spite of not having been off the yard in a couple of years, they had been exposed to new arrivals occasionally, though not recently) and three of those were found to be negative on the guttural pouch wash and DNA test. The fourth was found to have chondroids in one guttural pouch with active strangles bacteria, which were removed via the endoscope at Parkside Vet Group before antibiotic treatment, and that horse has subsequently tested negative on guttural pouch washes for strangles DNA. The one horse carrying chondroids was not actively shedding infection at the time, but if they had become stressed or their immune system compromised, they might have shed strangles bacteria to the entire yard and caused major issues.

Get expert advice

For more information about Strangles speak to one of our equine vets by calling:

01382 811111

Sweet Itch

Sweet Itch is an allergic reaction and therefore an immune system problem. Unfortunately, these are notoriously complicated and difficult to deal with.

The disease is a delayed hypersensitivity to insect bites and results from an over-vigorous response by the animal's immune system. In the process of repelling invading insect saliva (which actually contains harmless protein), the horse attacks some of its own skin cells 'by mistake' and the resulting cell damage causes the symptoms described as Sweet Itch.

In the UK several species (of the 1,000 or so that exist) of the Culicoides midge and, to a lesser extent, the larger, hump-backed Simulium Equinum, a member of the blackfly family, are responsible. Each has a preferred feeding site; Culicoides tend to be body feeders and the Simulium ear feeders.

Symptoms of Sweet Itch

Sweet Itch, or Summer Seasonal Recurrent Dermatitis (SSRD), is a problem that affects thousands of horses, ponies and donkeys in many countries of the world to a greater or lesser degree. Virtually all breeds and types of ponies and breeds can be affected, from tiny Shetland ponies to heavyweight draught horses, although the condition is rare in English Thoroughbreds.

Symptoms include severe pruritus [itching], hair loss, skin thickening and flaky dandruff. Exudative dermatitis [weeping sores, sometimes with a yellow crust of dried serum] may occur. Without attention sores can suffer secondary infection.

The top of the tail and the mane are most commonly affected. The neck, withers, hips, ears and forehead, and in more severe cases, the mid-line of the belly, the saddle area, the sides of the head, the sheath or udder and the legs may also suffer.

The animal may swish its tail vigorously, roll frequently and attempt to scratch on anything within reach. It may pace endlessly and seek excessive mutual grooming from field companions. When kept behind electric fencing with nothing on which to rub, sufferers may scratch out their mane with their hind feet and bite vigorously at their own tail, flanks and heels. They may drag themselves along the ground to scratch their belly or sit like a dog and propel themselves round to scratch the top of their tail on the ground.

There can be a marked change in temperament - lethargy with frequent yawning and general lack of 'sparkle' may occur, or the horse may become agitated, impatient and, when ridden, lack concentration. When flying insects are around he may become agitated, with repeated head shaking.

Diagnosis

Diagnosis is not usually difficult - the symptoms and its seasonal nature (spring, summer and autumn) are strong indicators. However symptoms can persist well into the winter months, with severely affected cases barely having cleared up before the onslaught starts again the following spring.

Horses that go on to develop Sweet Itch usually show signs of the disease between the ages of one and five and it is common for the symptoms to appear first in the autumn.

There is anecdotal evidence that stress (e.g moving to a new home, sickness, or severe injury) can be a factor when mature animals develop Sweet Itch.

Hereditary predisposition may be a factor in Sweet Itch and work to identify the gene(s) responsible is at an early stage. However environmental factors play a major part - where the horse is born and where it lives as an adult are at least as significant as the bloodlines of its sire and dam.

Sweet Itch is not contagious, although if conditions are particularly favourable to a high Culicoides midge population, more than one horse in the field may show symptoms.

In the UK Sweet Itch is classed by Vets as a reportable condition, which must be disclosed by an owner to a prospective purchaser before the sale. For the purpose of a vetting the allergy may be regarded as seriously as an unsoundness.

CONTROL

At present there is no cure for Sweet Itch. Once an animal develops the allergy it generally faces a 'life-sentence' and every spring, summer and autumn are a distressing period for horse and owner alike. The animal's comfort and well being are down to its owner's management.

Some methods to reduce the syptoms -

MINIMISE MIDGE ATTACK 

Avoid marshy, boggy fields. If possible move the horse to a more exposed, windy site, e.g. a bare hillside or a coastal site with strong onshore breezes. Chalk-based grassland will have fewer midges than heavy clay pasture. 

Ensure pasture is well drained and away from rotting vegetation (e.g. muck heaps, old hay-feeding areas, rotting leaves). 

Stable at dusk and dawn, when midge feeding is at its peak, and close stable doors and windows (midges can enter stables). The installation of a large ceiling-mounted fan can help to create less favourable conditions for the midge. 

For slight to moderate cases of Sweet Itch this can help. However a seriously itchy, stabled horse has hours of boredom during which to think up new ways of relieving his itch - manes and tails can be demolished in a few hours of scratching against a stable wall. If stabling can be avoided it is best to do so.
Use an insect repellent.

DEET (the acronym for N,N-Diethyl-m-toluamide), has a track record stretching back over 40 years and has proven to be highly effective. It is the active ingredient in many midge and mosquito repellents for use by people.

Use an insecticide

Some owners achieve good results with insecticides whilst others find they have shown little benefit in controlling Sweet Itch. 

Benzyl benzoate was originally used to treat itch-mites (scabies) in humans and has been used for many years to combat Sweet Itch. In its neat form it is a transparent liquid with an aromatic smell, but it is more commonly obtained from Vets or pharmacies as a diluted milky-white suspension. It is listed as an ingredient in several proprietary formulations, including Carr, Day & Martins' 'Kill Itch' and Pettifer's 'Sweet Itch Plus'.

Benzyl benzoate should be thoroughly worked into the skin in the susceptible areas every day. However it is a skin irritant and should not be used on the horse if hair loss and broken skin have occurred - application should therefore start before symptoms develop in the spring. If used later its irritant properties can cause areas of skin to slough-off, in the form of large flakes of dandruff. 

Other insecticides, including permethrin and related compounds, tend to be longer lasting but should also be used with care. Permethrin is available by veterinary prescription (e.g. Day, Son & Hewitt 'Switch' pour-on liquid). Application instructions should be followed. 

Note: Gloves should be worn when applying insecticides, including benzyl benzoate. Particular care should be taken if they are used on ponies handled by children - they can cause eye irritation, for example if fingers transfer the chemical from the pony's mane to the eyes.

Coat the susceptible areas of the horse with an oil 

Midges dislike contact with a film of oil and they will tend to avoid it. Commonly used preparations include Medicinal Liquid Paraffin, and 'Avon Skin-so-Soft' bath oil (diluted with water). There are several oil-based proprietary formulations, for example Day Son & Hewitt's 'Sweet Itch Lotion'. 

Oils and other repellents that are effective usually work for a limited time: In summer a horse's short coat-hair does not retain the active ingredient for long and it can be easily lost through sweating or rain. Re-application two or three times every day may be necessary.

Greases (usually based on mineral oils) stay on the coat longer, but they are messy and therefore not ideal if the horse is to be ridden. They can be effective if only a small area of the horse is to be covered. However it is impractical and often expensive to cover larger areas. 

Some preparations contain substances (e.g. eucalyptus oil, citronella oil, tea tree oil, mineral oil or chemical repellents) that can cause an allergic skin reaction. Always patch test first on the neck or flank of the horse - apply to an area about 3 cm across and look for any sign of swelling or heat over a 24 hour period before using more extensively. 

Use a Boett® veterinary blanket. This is by far the most effective Sweet Itch protection to date and avoids the need need to use insecticides, oils or greases.

ALLOW MIDGE ATTACK, BUT TRY TO MINIMIZE THE RESULTANT ALLERGIC REACTION BY:

Depressing the immune system with corticosteroids (e.g. by injection of 'Depo-Medrone' or 'Kenalog', or in tablet form as 'Prednisolone') may bring temporary relief but there can be side effects, including laminitis, in some animals. With time, corticosteroids may become less effective, requiring ever larger and more frequent doses.

The use of anti-histamines may bring some relief but high dose rates are required and they can make the horse drowsy. 

Applying soothing lotions to the irritated areas. Soothing creams such as Calamine Cream or 'Sudocrem' can bring relief and reduce inflammation, but they will not deter further midge attack. Steroid creams can reduce inflammation. 

It is often difficult to assess the effectiveness of a particular treatment. The incidence and severity of Sweet Itch is so highly dependent on midge numbers, apparent success may simply reflect a temporary fall in numbers due to a change in the weather, for symptoms only to return again later when weather conditions are more midge-favourable.

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Worming -

Use less wormers

Everyone will admit that horses MUST be wormed regularly over the warmer months, but there is an increasing problem of resistance to horse wormers - a study in the UK and Europe found worm resistance on 82% of yards to the wormer active ingredient ‘Fenbendazole’, which is in many brands of wormer.

Therefore to preserve the current wormers, we advise a more targeted approach to worming horses. Targeting aims only to worm your horse when they require worming. We do this by taking worm egg counts from a sample of your horse’s dung. There is a cost for this, currently £47.5 in 2019, but in the long term for horses that only require 1-2 worming treatments a year the overall cost is less. Be careful to check how the sample is being examined, some techniques are better suited to horse samples than others, and we find the more proper and complete examinations cost more but are well worth it for peace of mind and confidence in the result.

Taking dung samples is as simple as picking up 1-2 balls of fresh dung from your horse, place in a small plastic bag, e.g. a freezer bag; labelling them with your name, address, your horses' name; the date you last wormed your horse and the wormer product you used at that worming. Then drop the sample them off at the surgery for analysis. If the sample is sent off to an external laboratory, results usually are back within three working days. Unfortunately, worm egg counts are not reliable for assessing if your horse has tapeworms. To check for tapeworms your vet needs to take a blood sample and send it off, the laboratory looks for antibodies to the tapeworm and indicates the level of infection intensity in your horse. Blood sampling can be done at any time of year, and so we often do it when we are giving your horse its annual health check and vaccination.

As well as a targeted worming program other methods are equally as important in reducing the worm population:-

  • Poo picking paddocks at least twice weekly in summer and once weekly in winter
  • Grazing sheep with horses or following the removal of horses
  • Avoiding grazing foals and young stock on previously grazed pasture every year 

Our current best practice advice is to start taking dung samples from your horse in the Spring (usually April but if the spring is cold and wet you can wait until May when it warms up.) If the egg count is less then 100 eggs per gram, you should take another dung sample 12 weeks later. If the egg count is between 100 and 200 eggs per gram, you should take another dung sample in 6 weeks. If the egg count is greater than 200, you should worm your horse (your vet will advise which worming product based on what you have been using previously and the time of year), and then take another sample 2 weeks later. The reason for this is so we can check your horses’ worms are not resistant to the wormer you have used. If there is no resistance, then the count will be zero or very low.

In a lot of cases we do not need to use any routine wormers in our patients based on the results of samples, but you must always discuss the results and the appropriate management with one of our vets, even if the result is low or zero. They will want to ensure that tapeworms and cyathastomes in particular, are controlled as these two parasites can cause severe colic.

Whatever method of worm control you are using it is always advisable to check how effective your control is by taking a dung sample during the summer.

It is worth bearing in mind that some products are not suitable for use in young foals and so your Parkside vet’s advice should be heeded as to the best product to use in young foals. Horses do develop natural immunity to worms as they get older. This immunity protects adult horses from developing a substantial worm burden if they can graze a clean pasture. Young stock up to 3 years old will not have developed their immunity fully, so will need more frequent attention. Dung samples and worming treatments may be required and as horses get older. Their natural immunity can start to reduce so they also need to be monitored more carefully and frequently.

Any new arrivals to your yard should be wormed with a broad spectrum wormer and then a dung sample was taken two weeks later (while they are still in isolation) to check they have not brought a resistant worm onto your yard. We advise a minimum three week isolation period; this allows you to get a dung sample tested and have the results back before the end of the isolation period. This length of isolation period also protects against the new horses bringing other infectious diseases such as strangles and ringworm onto your yard.

In summary with no new worming products likely to become available for the foreseeable future, we need to use wormers only as required to try to slow the build-up of resistance, targeting the use of a wormer with the horses that need them by using dung and blood samples. This will save you money, reduce your reliance on wormers and slow wormer resistance development.

TARGETED WORMING

Parasite control is about far more than just worming. Targeted worm control provides a tailor made approach designed by our vets, taking into account your individual horses needs. With resistance to wormers (where previously effective wormers no longer kill the worms) increasing far faster than new wormers are discovered it is essential that we reduce our reliance on these drugs. How does it work? Faecal Worm Egg Counts (FWEC) are taken three times a year (April, June and Sept/Oct). Our annual tailored worming programme costs just £43 per horse, this includes 3 worm egg counts, an autumn wormer (that covers tape and round worms) and free advice and reporting from our dedicated equine vets. (please note, additional wormers will be at an extra cost). We discuss the results with you and, if required, provide advice on, and supply the most appropriate wormer; last year 90% of the horses we tested didn’t need worming! Simply call the Dundee surgery to order enough kits for each of your horses, send off the samples in our postage paid bags three times a year and we will take you through the rest.
Email reminders are provided and results are delivered in the same way to ensure that the whole process is quick, easy and provides your horse with the best possible programme.

Read about Parasite Control from Keeping Britains Horses Healthy HERE

Get expert advice

For more information about worming call one of our equine vets on

01382 811111