Poor Performance

Joint Disease as a Cause of Poor Performance

 Once a joint has been identified as a problem, the next step is to investigate that joint further to see if there is a major bone problem or whether it is a simple synovitis from a joint sprain. Radiographs of the joint can be very helpful. Often now, a set of radiographs is obtained when a horse starts out on its sporting career as these act as useful reference images if there are problems in the future.

The images may show problems in a joint that would direct us to investigate the joint further. This can be done by performing a bone scan to look at bone turnover associated with margins of the joint, which may help in identifying cracks or stress fractures in the bones adjacent to and thus involving the joint. Bone scans can also be helpful in older horses to investigate problems such as with the hock joint.

MRI is an important way of investigating joints, particularly in the distal limb and hoof regions. A horse that goes sound by blocking the coffin joint may actually have a problem with one or more of the complex ligamentous or tendinous structures, such as the collateral ligaments or the insertion of the deep digital flexor tendon. By correctly identifying the problem, correct therapy and management can be instituted.

Some joints will be investigated surgically using a procedure called arthroscopy. A camera is placed through a keyhole incision into the joint so the articular cartilage within the joint as well as the synovial lining of the joint and any visible ligaments can be assessed. The advantage of this investigative procedure is that any cartilage problems identified can be surgically curetted at the time. Few sport horse joints would need surgery; however in an older horse that is having continued problems with a specific joint, it would be better to operate sooner rather than later. Ultrasound can be used to assess the articular cartilage within some joints, and also the ligaments around the joints. Most of the time when there is a problem with a joint, a simple block to confirm which joint and a few x-rays will suffice.

Wet Winter Problems

Thrush is an infection of the horses frog resulting from poor foot hygiene and prolonged exposure to wet conditions These infections most often involve the bacteria Fusobacterium necrophorum and occur in the central and lateral sulcus (clefts or grooves) of the frog.. Thrush appears as a black, foul smelling discharge from the central or lateral sulci of the frog. Affecting either hind or front feet, deep narrow clefts predispose to thrush more than normal. Discharge from the affected area is variable and may not be noticed unless the sulcus is closely examined and cleaned out. In more advanced cases the frog and sole tissue can become under-mined or under-run. Infection of the deeper more sensitive tissues and exposure of sensitive corium can cause lameness and may lead to a secondary cellulitis and swelling of the lower limb.

THRUSH

Often horses with contracted heels and atrophied or weak and narrow frogs are more susceptible due to the depth of the sulci and similarly, horses with overgrown hooves are more prone to the problem.

Prevention is better than cure and thrush can be prevented with good stable management, cleaning and inspection of your horse’s frog. Additionally, providing clean, dry bedding for horses is vital, as horses that live in a wet, muddy or dirty environment are more susceptible to infection. Exercise helps to maintain healthy blood flow to all regions of the foot and helps to maintain a healthy frog with normal hoof architecture. One of the most important and basic steps to take to prevent this is to pick your horse’s feet out at least twice a day.

Treatment of early, mild cases involves debridement of affected tissue and sometimes topical treatment with iodine or hydrogen peroxide. Affected horses should be kept on a clean dry bed. More serious cases may require a more extensive debridement, antibiotic therapy and therapeutic shoeing that protects the affected area whilst it heals.

MUD FEVER

Mud fever, also known as pastern dermatitis, is another aliment arising from wet weather conditions. It is caused by a combination of different factors including skin irritation, bacteria, and moisture. The equine skin has a normal balance of bacteria on the surface however if the skin is wet for prolong periods of time the skin softens and the bacterial population change and become unbalanced, these then multiply in the damp warm environment and can lead to infection and mud fever.

Factors predisposing to mud fever include: long periods of damp and standing in wet environments, washing and scrubbing legs that causes abrasions and if not dried properly leads to a damp environment, feathers and cob types as these are harder to dry properly and also may have chorioptic mites that will break the skin allowing bacteria to enter.

Prevention (which is better) and treatment is based on keeping the skin dry and clean. If a horse does have or is prone to mud fever, it may require stabling until the horse can recover and maintain a healthy skin surface. Gentle cleaning with chlorhexidine, iodine or medicated shampoos can help re-establish a healthy population of normal skin bacteria, but you must rinse and dry them properly afterwards. Over washing or vigorous scrubbing will traumatise the skin surface and can lead to mud fever, so be conservative. If your horse has a scab, do not pick them unless they are soft and ready to fall off, picking scabs breaks the skin barrier and allows the bacteria to enter the skin again. There are many topical treatments that soften scabs whilst bathing the skin in anti inflammatories. If keeping your horse in a dry stable is not feasible then you can apply a barrier cream to the leg, these creams are designed to repel the water away, keeping the leg dry. Bandaging is also an effective way of keeping the leg dry but you must ensure the bandages do not get wet on the inside and do not rub. Sand schools or sandy soils are particularly abrasive to the skin so washing legs after exercise or turn out is important but be gentle! Proper pasture management to avoid mud pits will also help prevent mud fever.

Sometimes a mud fever infection can lead to cellulitis, when the leg swells and the swelling travels up the leg or a hot painful pitting oedema develops, it is likely your horse has cellulitis. Cellulitis will require veterinary care as horses should be assed and possibly prescribed anti-inflammatories and antibiotics to help your horse fight the infection.

Dr. C. Baldwin, BVetMed, MRCVS

Welcome New Directors

Congratulations to Three New Directors - Paula Broadhurst, Andy Crawford and Simon Staempfli have joined Ed Lyall, Matt Waterhouse and Rob Van Pelt in becoming directors of the Arundel Equine Hospital this month. This exciting news means that we have guaranteed that the future of the practice will be in safe hands for many years to come. The three new directors will now assist in the day to day running of the ever growing practice, as well as dealing with their clinical case load. Paula has in fact made history in that she is the very first lady director (partner) that the practice has ever had!

“Tying Up”

‘Tying up’, also known as Azoturia, Monday Mornings Disease or Recurrent Exertional Rhabdomyolysis (RER) is the most common muscle disorder in horses, frequently limiting performance in sport horses of varying breeds. Tying-up is basically muscle cramps, the largest muscles in the horse (back and hindquarters) are most often affected by a combination of different (it is not fully understood) mechanisms, leading to a buildup of lack of muscle oxygenation, lactic acid and muscle cell death.

‘Tying-up’ usually affects horses in a high level of work that are rested for 1 or more days and still fed a high carbohydrate:low fat diet. It most often occurs after 20-30 mins of work during the first exercise following a period of rest. However, it may also occur as a result of increasing intensity of work or unfit horses undergoing prolonged periods of exercise. Any breed of horse can be affected. It most often occurs amongst younger horses and affects mares more than males. Some horses experience only one or two isolated cases, whilst others suffer repeat episodes which subsequently limits their athletic potential.

Stress, excessive sweating, lack of drinking before and after work or not travelling well will cause electrolyte imbalances or disturbances which predispose a horse to ‘tying-up’. As can a diet high in cereals (as these contain a high potassium:sodium ratio) or deficient in certain minerals and vitamins. Some blood lines are also prone to producing horses that regularly ‘tie-up’ so there is a suspected genetic component too.

Depending on the severity of the episode, horses will demonstrate varying clinical signs from a mild discomfort and stiff gait to a very stiff gait and refusal to move or even in severe cases recumbency due to the pain. Most horses will have firm painful muscles in the gluteal, hamstring and back area, some horses will develop muscle swelling. Tying up is very painful and horses may become distressed and anxious, they may increase their respiratory rate, sweat or even show colic like behaviour.

If you are out riding away from your horse’s stable and your horse ‘ties-up’, phone for help. The horse should be transported by lorry or trailer to limit any further muscle damage. Once the horse is in a stable, keep them warm with plenty of rugs and offer water.

Diagnosis is made based on clinical signs and a blood test measuring muscle enzymes and kidney parameters. The enzymes are released from inside muscle cells when they are damaged. Myoglobin is a product also released by damaged muscle cells. This can discolour the urine brown or orange, potentially causing kidney damage if severe enough.

Immediate treatment depends on the severity of the episode but the aim is to provide pain relief, reduce further muscle damage and protect the kidneys. If mild; encourage the horse to drink (restoring electrolyte balance) and if the horse is comfortable you can walk them around to stop them stiffening up further, but do this with caution! If the horse is very painful, reluctant to move or recumbent, do not try to move the horse! This may lead to further muscle damage. Call your vet and allow them to provide pain relief and anti-inflammatories. The vet may also give acepromazine (ACP), a drug that calms the horse down and causes the blood vessels to dilate, increasing blood supply to the muscles. If the horse is dehydrated there is a risk of kidney damage so the horse may require rehydration by oral fluids or intravenous (IV) fluids. Other drugs are available to help stabilise the muscles and protect from further damage.

Prevention is better than cure and so if you have a horse prone to tying up it is important to provide a high-fat (bran and oils), low-carbohydrate (grains) diet, ensure your horse is properly warmed up and cooled down before and after work and exercise the horse every day, as one or more days of inactivity seems to preclude ERE episodes.

Vitamin E and selenium supplements can also be of benefit, as can antioxidants and other drugs and herbal supplements which your vet can inform you about.

Some horses suffer from chronic ER, these horses require further investigations to define why they continue to ‘tie-up’, this can involve repeat blood tests, exercise tolerance tests, and muscle biopsies.

Chris Baldwin, BVetMed, MRCVS

Sacroiliac Joint

Sacroiliac pain in horses is a performance limiting condition that can be challenging to diagnose and manage. To understand why horses develop this problem we first need to understand the anatomy involved.

The pelvis is a ring of bones formed of three fused bones; Ilium, ischium and pubis. The lower part of the horses back, the sacrum, is formed of 5 fused vertebrae. The sacroiliac joint (SI) is the joint where the sacrum passes underneath the top of the pelvis (tubera sacrale). The SI joint is strengthened by the ligaments; dorsal, ventral and interosseous sacroiliac ligaments. SI pain is either in-flammation of the joint or ligaments surrounding the joint. The SI joint functions to transfer propulsion from the hindlimbs to the spine, supporting the horses back and driving the horse forward from its hindquarters when in motion.

SI pain typically affects heavier, taller horses usually between the ages of 5 and 15 years old. There is no documented association between a horse’s confirmation and developing SI problems. Warmbloods, Thoroughbreds and Thoroughbred crosses are over represented, as are horses used for show jumping and dressage, which may be due to athletic demands placed on these horses during their work.

The signs that a horse maybe suffering from SI pain are subtle and insidious in onset and progression. Typically the signs are exacerbated when the horse is ridden under-saddle and can be easier to appreciate by the rider than to be seen by an observer. There may be no overt lameness to be seen. Table 1 lists the common signs of SI pain.

 

Common complaints related to SI pain

 

* Poor performance / unwillingness to work / holding back

 

* Lack of impulsion or animation 

 

* Intermittent lameness

 

* Reluctance to be shod or have the leg held in a flexed position for a prolonged period of time

 

* Poor or stilted canter, becoming disunited, taking the wrong lead leg

 

* Stiff through the back, refusing jumps

 

* Poor lateral work

 

* Change in behaviour or performance when worked on the bit

 

Diagnosis is challenging due to the mass of muscles surrounding the SI joint. A thorough physical exam by a veterinarian is required to rule out other conditions. SI pain is a consequence of a change in the mechanics of the horse’s back and hindlimbs. Therefore conditions such as suspensory ligament desmitis or kissing spines (impinging spinous processes) can be a precursor or sequel to SI pain.

Xray and ultrasound of the SI region is limited due to the anatomy. The most sensitive form of diagnosis is a bone scan (nuclear scintigraphy). The SI joint can also be anaesthetised (blocked) and if there is pain at this site an improvement maybe seen or felt.

Treatment of SI pain requires a combination of medication, physiotherapy and a rehabilitation programme. The SI region can be injected with steroids to reduced inflammation of the joint and ligaments. This will be performed by your veterinarian when required and usually requires more than one treatment. Physiotherapy and rehabilitation are important in making sure the horse works to build up strong muscles around its hind quarters so the SI region is protected and used correctly. Each horse with a diagnosed SI condition will have a tailored rehabilitation program outlining the details of exercises and time period. In feed, anti-inflammatories or joint supplements may be beneficial in reducing in-flammation and promoting healthy joints. Other treatments such as acupuncture or magnetic rugs/boots, may be of benefit however there is little published evidence supporting this.

In summary, the SI is the connection point between the horse and its hindlimbs. The condition mainly affects larger horses undertaking dressage and Show jumping. the signs of SI pain are very subtle. Diagnosis is challenging and treatment involves a combination of medication and rehabilitation.

Chris Baldwin, BVetMed, MRCVS

Atypical Myopathy

Atypical Myopathy was first recognised back in 1984 but has largely come to prominence over the last few years with outbreaks in the UK and Europe. It occurs in individuals or groups of horses at pasture and is likely caused by ingestion of seeds known as ‘helicopters’ (and possibly to a lesser extent leaves) of the sycamore tree (Acer Pseudoplatanus) that contain a specific toxin. This toxin has been identified as hypoglycin A. The amount of toxin within seeds is variable and it is not understood why some seeds have more toxin than others nor is it understood how many seeds have to be eaten for a horse to become sick. It is likely that some horses will be more susceptible than others with younger horses appearing particularly susceptible, particularly those in poor bodily condition, on relatively poor quality pasture. As older horses are less likely to become affected it may be that they develop some tolerance to the toxin.

Incidences tend to occur in the autumn and in the spring following large autumnal outbreaks and are often following a sudden adverse change in weather conditions, such as a frost or heavy rain. 

It can cause a variety of clinical signs which can present as dullness or lethargy or as a sudden onset of muscle stiffness or weakness that can progress rapidly to recumbency. Other reported signs also include reluctance to work, choke, whinnying, head tossing or an abnormally low head carriage. It can affect the diaphragm resulting in difficult or laboured breathing and some cases may show some colic like symptoms such as paddling or stretching the limbs. Due to the breakdown of the muscle urine often appears dark red and brown. If it affects the heart muscle it can result in a fast or irregular heart beat and in the worst case some horses may present as a sudden death. The mortality rates vary from 40-100% and vary from year to year.

DIAGNOSIS

Diagnosis is based on clinical signs alongside an increase in serum muscle enzymes (AST/CK) and the presence of red/brown urine.

TREATMENT

Prompt diagnosis and treatment is essential if horses are to have any chance of survival. There is no specific treatment only supportive care which involves hospitalisation, intensive intravenous fluid therapy and nursing. Fluids are required to provide cardiovascular support as horses can become very dehydrated and to support the kidneys as the product of muscle breakdown (myoglobin) can affect their function and can cause renal failure. If there is concern over the kidney function then they may also be given a diuretic to help the kidneys maintain a good urine output. This condition can be extremely painful and so a variety of powerful painkillers and anti-inflammatories may be required. When horses become recumbent then they require frequent turning to encourage them to stand and to prevent sores. If they are inappetant then they are provided with an alternative source of nutrition usually by stomach tube in order to provide their energy requirements. Supplementary vitamins and minerals have also been shown to be useful in some cases.

Prognostic factors for survival are normal mucosae, no respiratory distress signs, a standing position most of the time, no temperature, and normal abdominal transit.
Factors unfavourable to a recovery include recumbency, abundant sedation, anorexia, tachycardia (a high heart rate), tachypnoea (high respiratory rate), respiratory difficulties and severe acid-base disturbances. Euthanasia may have to be considered when horses appear to have reached the stage where they are no longer likely to respond to supportive treatment.

In horses that do recover, recovery is initially slow, but most go on to make a complete recovery and return to work with no long-term effects of the disease.

PREVENTION

Given the high mortality rate prevention is better than cure. If sycamore seeds are present in your fields then the following is advised

- Avoid letting horses graze pasture that are contaminated with the sycamore seeds. 
- Move horses out of the field to as distant a point as is practical, or stable the horses during the risk period. 
- If you are unable to remove horses from pastures then fence off areas where the seeds and leaves have fallen and offer supplementary hay but do not leave it on the ground to get wet and feed extra concentrate.
- Rake up or hoover and remove the seeds, dead leaves and saplings where possible.
- Reducing the stocking density can help to ensure there is good grazing for every horse.
- If you are suspicious that your horse may have ingested some of these seeds then call your vet out to check the muscle enzyme levels (AST/CK) to identify subclinical and pre-clinical cases.

If you suspect that your horse is showing any signs of atypical myopathy then contact your vet IMMEDIATELY. If you have any other concerns then please do not hesitate to contact your vet practice for further advice.

Images of Sycamore trees and seeds.

VWH – 15th July

Tuesday 15th July

After we finished lecturing in Helsinki it was back to the port and onto another overnight ferry to Stockholm. We were crammed into windowless cabins (four of us per cabin) in the bottom of the boat next to the engine rooms and it was a relief to reach Stockholm. The approach to Stockholm by water is beautiful with hundreds of small islands each with the Swedes' summer houses and yachts moored outside. The Swedish police were on fearsome top form and breathalysed every driver coming off the ferry with a 'welcome to Sweden' message for each of us! A long ride to the lecture venue in the middle of Sweden with 35 Swedish equine vets in attendance to hear the full 5 hour programme of talks. There was a lot of discussion about back problems and how best to treat these, in addition to practical questions abut how to manage outbreaks of infectious diseases like flu and strangles. The local organiser did an amazing job and there was a supper for the speakers and delegates at the end of the evening's lectures. Tomorrow we are back on the bikes and off to Norway for an evening of lectures at Sandefjord.

VWH 2014 Tour

Andy Crawford, one of the surgeons from The Arundel Equine Hospital is currently making his way around North Europe with Vets With Horsepower.

Vets with Horsepower is a charity, orginally set up by Professor Derek Knottenbelt from Liverpool University, in which a group of equine specialists partake in long distance tours on motorbikes giving talks to other vets and members of the public on veterinary topics. The fees raised by these talks are all donated to two charities:-

'Gambia Horse and Donkey Trust' www.gambiahorseanddonkey.org.uk

'The Smile Train' www.smiletrain.org.uk

Andy's first blog....

Monday
I left Arundel on Friday afternoon on the bike and before I had got to Horsham I had to stop to put on wet weather gear! Great, only 2700 miles to go! I met up with Professors Roger Smith and Josh Slater at Folkestone and we rode the three bikes in the rain to Antwerp on Friday night. The next day took us 400 miles through industrial Holland beyond Eindhoven where we finally got into green countryside with small farms and yards with lots of very smart Warmbloods and a big selection of other breeds including ponies and a few heavy horses. It was a relief to see a gentle landscape with trees, grass paddocks and horses after so many miles of industry. The rest of the day was a high speed blast up the German autobahns past the industrial centers of Essen and Dortmund, across the Rhine and the Ruhr and then a turn northwards through more horse country to Munster and then onto Bremen and finally Hamburg.

We had a 30 hour ferry journey to Helsinki which gave us time to work on our talks for the lecture tour this week and, of course, experience our first Scandinavian sauna. We discovered two things: first the Finns are passionate about saunas, and everyone goes for at least one sauna a day, second, the Finns do everything naked - not for the fainthearted! (and certainly not for us).

We arrived in Helsinki the next morning and met up with the main bike group to give our first lectures of the Scandinavian leg. The lectures covered flu vaccination, tendon injuries, back problems, sedation and I spoke on advanced diagnostic imaging in the horse including scintigraphy, MRI, and CT. We had 55 delegates which was great and an unexpectedly large turnout because this is normally a holiday in Finland. We are back on the ferry this evening for a night crossing to Stockholm and tomorrow morning's lectures. Not sure whether we will be brave enough to try the sauna again......

COPD

Chronic obstructive pulmonary disease (COPD) also known as recurrent airway obstruction (RAO) or “broken wind” is a chronic condition of horses involving an allergic bronchitis characterised by wheezing, laboured breathing, coughing (usually associated with exercise or eating) and nasal discharge (especially when the head is lowered or after exercise).

The condition was known as ‘heaves’ because horses with COPD have very inflamed narrow airways and as such breathing both in and out is difficult and requires recruitment of other chest and abdominal muscles to aid with respiration, these muscles become enlarged and hence the horse develops “heave” lines.

COPD is an allergic reaction to certain otherwise innocuous substances - allergens. These allergens are typically dust, mould and fungal spores (e.g. Aspergillus). It is therefore most common in horses fed hay and bedded on straw. It is similar to asthma and farmer’s lung in humans.

Allergens enter the horse’s lungs and the horse’s hypersensitive immune system over-reacts to the “normal” pollens. The lungs become inflamed and swollen, causing the airways to become narrowed and mucus production to increase, which then leads to the signs we see in our horses.

Diagnosis is usually based on the results of a clinical exam and auscultation of the horse’s lungs. However sometimes further diagnostics are required, in which instance an endoscopic exam of your horses trachea and bronchioles can be performed and samples can be taken.

Acute flare ups can present dramatically, your horse maybe distressed with markedly elevated respiratory rate and effort, flared nostrils and sweating. If a horse is severely dyspnoeic (really struggling to breathe), the most important measure to take is to REMOVE IT FROM THE STABLE OR BARN into FRESH AIR. Keep the horse (and yourself) CALM and CALL YOUR VET IMMEDIATELY.

Treatment is all about management and minimising exposure to the allergens. When removed from the allergens the symptoms will usually subside, although they will recur if the horse is exposed to the allergens again, even short periods of re-exposure can induce acute episodes.

If it is not practical to stop stabling all together then the following changes will be of benefit:

• Minimise dust and maximise air quality in the stable.
• Soak hay or feed a low dust alternative such as haylage or bagged grass. If you are going to feed hay it should be soaked hay, you only need to soak the hay for an hour to remove the majority of pollens and allergens 60 minutes. Soaking hay for longer will reduce the carbohydrate load of the forage, good for horses and ponies that suffer from laminitis or are looking to lose weight but not necessary in managing COPD.
• Feeding from the ground allows any mucous to drain out of the lungs. Horses are designed to graze for approximately 20 hours a day, during which time the horse has its head down to the ground where mucus within the horses trachea and bronchioles can be expelled, because of this design the horse is very poor at clearing mucus from its lungs without the aid of gravity, by feeding on the floor you encourage the horse natural mucus clearing function.
• Bed on a dust free bedding. Those horses that must be stabled should be bedded on rubber matting and paper, or low-dust wood shavings. Straw contains dust, moulds and fungal spores and so is least advisable. In severe cases horse may be intolerant of any bedding in which case the mats can be washed daily. The matting has a fairly high initial cost but there is a considerable saving in bedding (and veterinary costs if your horse has RAO).
• Make sure the stable is well ventilated.
• Don't muck out or brush up while your horse is in the stable to minimise the dust in the air.

All the stables in the vicinity need to be similarly maintained or the environment will remain high risk for the horse and aim to stable your horse away from the muck heap.

Despite management changes, medication is often required, these break down into 3 broad categories:

• Bronchodilators, theses dilate (open) the bronchioles and smaller airways allowing the horse to breath more freely.
• Corticosteroids: these reduce the inflammation in the airways and damped down the immune hypersensitivity reaction.
• Anti Histamines: these damped down the immune hypersensitivity reaction that leads to the inflammation in the lungs.
• Mucolytics: these make the horse’s mucus less viscose and so easier to clear form the airways.

Care should be taken with all these drugs in competition horses, as many of them are forbidden substances under racing and FEI rules.

If the condition occurs in the summer when the horse is at pasture then it is known as summer pasture associated obstructive pulmonary disease (SPAOPD) In this case, the allergens are derived from the pasture. This is more common is summer, and management is reversed: horses should be stabled in well ventilated areas. Some horses can suffer from RAO and SPARAO which can be very difficult to manage.

RAO often limits the horses' ability to work, and it may find strenuous activity difficult. However, with prompt diagnosis and treatment the condition can be managed successfully.