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.

8. Cold weather. A few horses show laminitis during cold weather, fitting warm leg wraps during cold snaps prevents the problem in most cases.
9. Stress. Worming, vaccination, travelling or separation from a "friend" can trigger an attack of laminitis in a few horses.
10. 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.
11. 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.
12. 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.

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

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.

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.

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