1 June 2017

horse grazing in paddock

Laminitis

Conditions & Illnesses, Horse Health /

Laminitis

Laminitis is a painful inflammatory condition of the tissues (laminae) that bond the hoof wall to the pedal bone in the horses hoof. It can affect any horse, of any age or sex, at any time of the year. Laminitis is caused by weakening of the supporting lamina within the hoof, leading to painful tearing of the support structure suspending the pedal bone within the hoof.

Acknowledgments: Illustrations and format- JamesOrsini, Dvm ACVS. Equine Laminitis in McGraw-Hill yearbook of science and technology. 2008, 114-118.

The level of pain a horse demonstrates does not necessarily indicate either laminitis or founder. Some horses show tremendous pain while they are laminitic, and others show very little.There are many, many different causes of laminitis and it is a common misconception that laminitis is caused by over-eating grass only. We occasionally see laminitis in horses on box rest, or on very limited turnout. There are often a number of factors surrounding the onset and exacerbation of an episode of laminitis.

The type of grazing can be important. Nowadays, many ponies are liveried on land once used for cattle. This type of grazing may have been heavily fertilised and re-sown with particular species of grass which are not ideally suited to horses and ponies. Poor grass which is stressed by such things as an overnight frost or overgrazing will result in the formation of a type of sugar known as fructan in the grass, it is this type of sugar that can directly cause laminitis.
Occasionally, laminitis can develop in one limb where the opposite limb is painful for another reason. This is particularly a problem in heavy horses if they are affected by a foot abscess; the foot abscess causes the opposing limb to take more weight that it is accustomed to, resulting in laminitis.

Equine Cushing’s Disease, also known as PPID, is a very common disease in equine animals from their mid-teens onwards, although it can be seen in animals as young as eight years old. The laminitis which develops secondary to PPID is very difficult to control unless the underlying disease is also treated. Owners with older horses and ponies should be extra careful about their animal’s weight and liaise with us, to discuss blood testing for PPID, and develop a suitable nutritional strategy.

Equine metabolic syndrome (EMS), is another disease of overweight ponies and horses that leads to insulin resistance, and therefore an increased risk of laminitis. In cases of laminitis, we will often blood test for signs of EMS as well as Cushings disease.

Delays between foot trimming or shoeing are an important cause of stress and damage to the laminae. Regular visits by the farrier will also pick up the early warning signs of laminitis.

Laminitis usually affects both front feet but can occasionally affect one foot and occasionally hind feet. In most instances the affected animal will shift its weight from one limb to another, will be reluctant to move, may lie down and there is sometimes heat in the hooves with an increased ‘digital pulse’. A digital pulse can be difficult to find, but please ask one of our vets to show you how to find them next time we are with your horse. In milder cases, there may be only a slight change in the animal’s gait, moving in a ‘pottering’ fashion. These animals will go on to deteriorate further, unless they are rested and treated correctly.

It is absolutely essential that you contact your vet should your horse or pony show signs of laminitis. The treatment of this disease is time consuming and can be difficult, with a poor outcome in some cases.

There are a variety of medicines which can be used to help settle the pain, and reduce the ongoing damage. Box rest is extremely essential. The box should be well bedded down, over the entire surface area of the stable. At Shotter and Byers we aim to make as rapid a diagnosis as possible, and get your pony or horse in frog support pads as soon as possible, to reduce the pain and the damage being caused by the laminitis. Over time, It is absolutely crucial that the affected animal loses weight in a controlled fashion and we strive to work closely with our clients, to make this as easy as possible.

Horses or ponies with laminitis should not be forced to walk or be exercised. Affected animals must not have their feet placed in cold baths, streams or ice unless under veterinary direction. Do not starve overweight horses in an attempt at inducing rapid weight loss.

Clearly prevention is preferable to treating the disease, and the key to the prevention of laminitis is weight control. Being overweight is the most important known risk factor for the development of laminitis. Just being fat will not in itself cause the disease, but it puts the animal at such a high risk of succumbing to laminitis that any additional stress (such as transport or inclement weather) could cause the full blown disease. If you are concerned about your animal’s weight, then please speak to us.

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horse head

Equine PPID – Cushing’s Disease

Conditions & Illnesses /

Equine Cushing’s disease most commonly occurs in horses aged 19years or older but can occur in horses of a much younger age.

Clinical signs of the disease include:

• Polyuria (increased urination)
• Polydipsia (increased drinking• Polyphagia (increased appetite)
• Weight loss
• Muscle wastage
• Hirutism (thick, curly coat with delayed shedding)
• Laminitis
• Supraorbital (above the eyes) fat pads
• Lethargy and depression
• Hyperhidrosis (increased sweating)

There is no significant breed or gender predilection, but studies have shown that ponies are more commonly affected than horses.

Diagnosis

Diagnosis is usually made by the presence of one or more of the above clinical signs, signalment (age, type etc) and diagnostic tests. The tests that are most commonly used are:
• Basal ACTH level testing – this is best carried out during the months of August – October as there is a seasonal rise in the levels of ACTH at this time which gives us an increased diagnostic rate. It involves a simple blood test.

• The overnight dexamethasone suppression test (ODST) – this is not very popular anymore due to the more involved nature of the test and also because of the risks associated with dexamethasone administration in horses with a suspected elevated level of steroid already in their system.
• Thyrotropin-releasing hormone (TRH) stimulation test – this involves injecting TRH into the horse and then collecting a blood sample 2-10 minutes after administration. However, TRH is not licensed in horses and some adverse reactions have been seen. These are usually short lived and not severe.

Treatment

Treatment is aimed at reducing the clinical signs of Cushings rather than curing the disease. It is also about improving the quality of life of your horse, with this in mind treatment consists of:
• Clipping excess hair to reduce sweating
• Treating secondary infections
• Increasing weight with diet management
• Treating any laminitis that may occur.

Medical management consists of using a dopamine agonist (pergolide) which comes in the commercially available form of Prascend. This is started at an initial dose of 2g/kg/day. Bloods tests measuring ACTH levels should then be assessed with a repeat blood sample 30days after the initial blood test confirming Cushings. This way doses can be adjusted as required. After this 6monthly repeat blood tests are recommended, these are best carried out in autumn and spring as this is when naturally occurring peaks in ACTH will occur

Prognosis
Generally the prognosis with Cushings is good; however, this is a lifelong condition that requires lifelong treatment and management.

Equine PPID – Cushing’s Disease Read More »

horse in stable

Recurrent Airway Obstruction (RAO)

Accident & Emergency Care, Horse Health /

Recurrent airway obstruction (RAO) is a common condition in many different types of horses. It is a performance limiting problem commonly caused by an allergic respiratory response. Signs include:
– chronic cough
– nasal discharge
– increased respiratory rate (tachypnoea) and effort (dyspnoea)

Episodes of RAO are usually caused by exposure of susceptible animals to common allergens. The most common culprits are organic dusts mwhen horses are stabled, bedded on straw, and fed hay (in particular round bales). Removal of these causal agents will usually result in remission of any signs. It most commonly starts at around 9 years of age, although 12% of mature horses have some degree of allergen induced lower airway inflammation. There is no breed or gender predilection, but there does seem to be a heritable component to susceptibility.

Clinical Signs

Signs of RAO include flared nostrils, increased respiratory rate (tachypnoea), cough and if the problem has been going on for long enough then the horse can have a heave line. Breathing usually includes a prolonged, laboured expiratory phase. Usually a cough is heard when the horse is exercised or being fed. Mildly affected horses may present with minimal signs at rest but coughing and exercise intolerance are noted during increased performance.

Some horses can demonstrate signs during summer, which, usually indicates sensitivity to pollens and certain moulds and this is called summer pasture-associated obstructive pulmonary disease. Management of this is similar to RAO except with the addition of pasture avoidance.

Diagnosis

Most commonly diagnosis is made on clinical exam and history alone, routine blood samples are commonly unhelpful in this scenario, x-rays of the chest are also not commonly not beneficial. Bronchoalveolar lavage (BAL) is usually not required in horses with obvious clinical signs and can be contra-indicated in horses with breathing difficulties at rest.

Treatment

The most important aspect of treating RAO is to limit exposure to the causal agents. Medical treatment will stop the signs and symptoms but these will return as soon as it is stopped if management chenges haven’t been put in place. Medical treatment consists of a combination of drugs to open up the airways (bronchodilators) and steroids to reduce inflammation.

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Brown horse

Top Ten Equine ‘Strangles’ Guidelines

Advice & Tips, Conditions & Illnesses /

1. If you think your horse may have Strangles and need advice?

Call the practice on 01306 627 706. We will be able to offer some guidance and arrange for one of our vets to make a visit.

2. What causes ‘Strangles’?

Strangles is a highly contagious infectious disease of the upper respiratory tract. Strangles is caused by a bacterium called Streptococcus equi (S.equi) and affects horses, ponies and donkeys.

3. What are the main clinical signs?

• Depression and dullness
• Loss of appetite
• Nasal discharge
• Development of a cough
• High temperature
• Swelling of the lymph nodes (glands) under the jaw or on the head or neck which can lead to abscess formation at a later stage

The abscesses which cause the lymph nodes to swell may burst discharging highly infectious, creamy-yellow pus. In some cases the glands swell so much they restrict the airway, hence the name strangles.

4. What is the incubation period / when will I first see symptoms?

The incubation period of strangles is on average 7 to 14 days. However, because infected horses can shed the bacterium for long periods after symptoms have stopped showing, the interval of time between new cases in an outbreak can be up to 3 weeks or more.

5. How is it transmitted / passed between horses?

Strangles can be spread easily by direct contact between horses or indirectly by handlers, equipment or contamination of the environment. This can lead to large outbreaks with many horses becoming infected if strict biosecurity measures are not put in place and adhered to. For example, the infection can be spread:

• by direct contact such as nose to nose contact between horses
• via equipment shared with infected horses, such as:
• water troughs where the bacterium can survive for long periods
• feed buckets
• grooming equipment
• tack / clothing

6. How long can items such as grooming kits and buckets harbor the disease for?

On water buckets in particular, the bacteria can live for long periods, and up to approximately one month. However, using proper anti-bacterial cleaners such as Virkon will kill the bacteria quickly.

7. What can you use to clean your items to kill the Strangles?

Most anti-bacterial cleaners will be effective at killing Strangles. We have had success with Virkon which can be found here:

http://www.hyperdrug.co.uk/Stable-Disinfectants-Odour-Control/products/49/#/?_=1&filter.brand=Virkon&page=1

8. How is it diagnosed?

There are three main methods of diagnosis:

a) Swabbing is where three consecutive swabs are taken at weekly intervals and sent for testing in a lab.

b) Testing via endoscopy has been said to be the most reliable method. A sample is taken directly from the guttural pouch in the throat and sent for testing. This can also determine whether a horse is a carrier or not.

c) Blood tests identify if a horse has antibodies to the Strangles bacteria in their bloodstream. Antibodies are produced approximately two weeks following exposure to the bacteria and last up to six months.

Horses that have been exposed to the bacteria in the last six months will test positive.

9. What is the treatment and is there anything else I should be concerned about?

Treatment is a largely debated subject. Some say the bacteria should be left to run its course on its own without treatment, some say it should be treated aggressively with penicillin. This will be a joint decision with you as an owner and your vet.

There is a second form of Strangles called ‘purpura haemorrhagica’ which is associated with a previous bout of strangles. The head, legs and underbelly of the horse are most often affected and it also causes bleeding into the skin, gums (seen as areas of red spotting) and organs such as the lungs. It can prove fatal within a very short period of time and therefore an exceptionally quick diagnosis is very important.

A third form of Strangles also exists known as Bastard Strangles which can be a complication from the initial infection. It can be seen in the abdominal or lung lymph nodes which may develop abscesses and rupture, sometimes weeks or longer after the first infection seems to have resolved. In severe cases abscesses may rupture in the brain causing sudden death or abscess may burst in the throat and the pus will be inhaled into the lung.

10. How long will it take to recover?

On average the standard form of Strangles can take ten to fourteen days to run its course without drug intervention, this depends on the severity of the case and the general health of the horse at the time of infection. It should however be kept in mind that the bacteria may continue to shed after symptoms have left and therefore testing on more than one occasion after symptoms have gone is recommended.

Other queries?

Please call the practice and we would be happy to help.

Please also review the HBLB Strangles guidelines in the Codes of Practice (http://codes.hblb.org.uk) and Strategy To Eradicate and Prevent Strangles (STEPS at http://www.strangles.org/).

This guide is for information purposes only, if you suspect your horse may have strangles please call the practice and arrange a visit from a vet. The opinions presented in the Guidelines are subject to change and should not be considered to be a treatment recommendation for any individual patient. We cannot attest to the accuracy, completeness or currency of the opinions contained herein and does not accept any responsibility or liability for any loss or damage caused to any patient or any third party as a result of any reliance being placed on these Guidelines or as a result of any inaccurate or misleading opinion contained in the Guidelines.

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