STRANGLES

RECURRENT AIRWAY OBSTRUCTION (COPD)

EQUINE DENTISTRY

ANAESTHESIA

LAMENESS

WORMING

CASTRATION

INFORMATION FOR OWNERS OF HORSES UNDERGOING COLIC SURGERY

BANDAGING

WHAT IS CLINICAL AUDIT?

WHAT IS EVIDENCE BASED MEDICINE?

INFORMATION ABOUT BREEDING


STRANGLES

Strangles is a bacterial disease that we prefer not to have affecting our patients. The best way to minimise its spread is to spot the signs of strangles early! Signs differ between individuals and can range from very mild to dramatic in appearance. Strangles can cause great distress to the horse and its owner. It can be difficult for the vet to treat, and can become a management nightmare for yard owners.

Signs to look out for:
• A high temperature, usually at least 39-40C or 102.5 -104F (this is usually the first clinical sign to occur)
• Depression and loss of appetite
• A runny nose (usually watery to begin with but becoming thick pus within a few days)
• A cough
• Swollen and painful glands under the jaw
• Difficulty in swallowing
• Abscesses in the throat area
• It is important to realise that not all horses show all these signs. Some may simply have a high temperature and seem off colour, so the disease can remain unrecognised until another horse is infected and shows more typical signs.

FACTS
• Bacterial disease caused by Strep equi (Streptococcus equi subspecies equi)
• Close contact between horses or direct contamination of environment is required for spread
• Many horses on a yard may succumb (30-100%) as it is highly contagious
• Young (less than 5 years old) and elderly horses may be the first to be affected and may show more severe signs although any horse may catch strangles
• Complications may occur in up to 20% horses
• May be fatal in a small number of cases
• 10% horses may become ‘carriers’, a source of future infection
• The incubation period is 3 – 10 days and clinical course about 3 weeks if untreated

SPREAD & CONTAMINATION IN THE ENVIRONMENT
Strangles spreads principally by direct contact from horse to horse i.e. rubbing noses and sharing drinking troughs, etc. Even horses kept together do not always all contract the disease. In the same way that not all members of a family all catch the same cold. Just as important as horse-to-horse contact is spread of the infection by poor hygiene amongst handlers, i.e. spread on clothes, buckets, tack and other contaminated kit. The strangles bug can linger for several weeks in the environment, so may persist in dirty stables. Fortunately this infection is not airborne, so unlike foot and mouth disease, it will not spread long distances without some kind of direct contact.
Horses may shed bacteria while they are ‘incubating’ the disease a few days before they show any signs, or for a few weeks after all their symptoms have resolved. Some horses become ‘carriers’ and may shed bacteria for years without showing any overt signs.

DIAGNOSIS is not always easy to confirm
Presumptive diagnosis may be made if horses have an infectious respiratory disease with very high fevers and abscess formation in the throat area, and rapid spread between different in contact animals. However NOT ALL cases can be PROVEN to be caused by strangles even when all clinical signs are highly suspicious; strangles may be confused with viral respiratory diseases. Confirmation of the disease can be made from laboratory tests on swabs of the nose or draining abscesses. Endoscopy is sometimes used to check inside the throat especially for carriers

MANAGEMENT OF INDIVIDUAL CASE
• Isolate individual affected horses
• Keep horse as comfortable as possible by symptomatic treatment
• Put the hay and feed on the ground to aid drainage of discharges
• Give soft, wet, palatable feed that is easier to swallow with a sore throat and a little salt to encourage drinking
• Phenylbutazone (“bute) as directed by vet to lower fever and reduce throat soreness and swelling causing discomfort swallowing
• ‘Hot-pack’ firm abscesses to encourage them to soften and burst. This may provide relief to the horse when the pressure building up is released and will speed up healing.
• A vet is only really able to lance an abscess that is almost ready to burst and has softened and feels ‘fluidy’
• Clip/trim hair overlying an abscess so it is easier to keep clean when it does burst
• Flush draining abscesses daily with very dilute antiseptic solution
• Protect the healthy skin around a draining abscess with regular cleaning and apply Vaseline around (not in) the wound.
• Turn out is fine so long as pasture contamination or horses in neighbouring fields is not a concern: fresh air can help the affected horse, but can contaminate the grazing.

WHAT TO DO IF THERE IS AN OUTBREAK ON THE YARD
Isolation is important, but difficult to maintain for up to a month after the last case occurs; other precautions include:
• Disinfectant foot bath outside isolation stables and yard entrance
• People looking after affected/ isolated horses should ideally not handle other horses or at least change all outer clothing and wash hands before doing so.
• The strangles bug will be destroyed by a hot wash so changing clothes will reduce risks of spread
• Cases of suspected strangles should be taken seriously and precautions regarding isolation should be observed until proven otherwise.
• Monitor rectal temperature twice daily in horses, as a raised temperature may be the first clue that they may be about to develop signs.
• Let people such as the farrier, dentist, vet, saddle fitter, feed delivery etc. know before they come to the yard. They may prefer to make it the last visit of the day to avoid spread to other yards
• Warn horse owners using adjoining fields or who ride close to the yard to keep their distance
• Avoid taking in-contact horses to shows where they may spread the disease to other horses and yards

TREATMENT is limited.
Anti-inflammatory medication such as phenylbutazone (“bute”) or Danilon (more palatable) as directed by your vet

USE OF ANTIBIOTICS is controversial:
• Occasionally used in very early cases
• Clinical signs often recur when antibiotics are finished
• Disease may be prolonged if abscesses are already present (these may be internal and not known to be present)
• Anecdotal evidence that antibiotics may increase the risk of developing “bastard strangles” a few weeks later
• Horse will not develop any immunity and so are likely to develop the disease later
• Occasionally antibiotics must be used despite the risks because of life threatening complications or in a persistent case which shows no signs of resolving

COMPLICATIONS are unusual but can be very serious
1. Respiratory distress. Swelling at the back of the throat may cause difficulty swallowing and in more severe cases difficulty breathing.
2. Bastard strangles. Severe illness with spread of abscesses to other areas of the body.
3. Purpura Haemorrhagica. Serious illness of the immune system that can follow on about a month after 1 to 2% of strangles cases. The clinical signs of purpura haemorrhagica vary, but can include:
• Oedema (soft swelling) of the head, limbs and other parts of the body
• Fever
• Depression
• Tiny haemorrhages on the lips, gums and other mucous membranes e.g. around the eye.
• Stiffness and reluctance to move
• Blood and serum may ooze through the skin and areas of skin may die leaving ugly raw areas
It is not a disease that will sneak up on you without you being aware something is wrong with your horse. It is unpleasantly obvious that something serious is wrong. The most obvious sign is the oedema; even spindly thoroughbred legs will appear as thick as tree trunks. This oedema is caused by fluid leakage within the body and can have other serious effects; eating and breathing can be impaired. Severe cases can show signs of colic or kidney disease. In the early stages or milder cases, the muscle stiffness and reluctance to move may be confused with laminitis.

PREVENTION & STRANGLES VACCINE
Overall there are limitations to the current control measures available to prevent the disease. As well as watching for signs of sickness and testing horses, these include:
• Avoiding contact with horses of unknown origin
• Ensuring a yard does not become overcrowded. Close contact between horses is an effective method of spreading strangles (and other infections), so should be minimised.
• If new horses are introduced, keep them in isolation initially.
In the real world many anti-strangles precautions are not very practical, but they still should be followed as far as possible. For a long time the UK horse industry has been asking for a vaccine to help control strangles. After more than a decade of research, the UK’s first strangles vaccine was launched in 2005. It remains to be seen whether the British horse owner will welcome it. Vaccination is always a sensitive issue even though vaccines are very successful in controlling some diseases, such as the eradication of smallpox in man. In this country we currently vaccinate a large proportion of the equine population against ‘flu, and yet it is known that strangles is a more common problem in many areas. In Sweden where both diseases have to be reported to the authorities there are four cases of Strangles reported for every one of equine ‘flu.

VACCINE FACTS
The new strangles vaccine is reported to provide protection against strangles. It is said to reduce clinical signs and occurrence of lymph node abscesses. The vaccine uses modified live bacteria, which cannot produce strangles nor pass on the vaccine strain as an infection to other horses. It is not the same product as the strangles vaccines used in other parts of the world. Unlike other injections for horses, this one is administered by injecting a very small (0.2ml) volume in the upper lip. The manufacturers recommend that all horses in a yard should be vaccinated to minimise the risk of strangles taking hold. The vaccination programme will involve two injections four weeks apart. After that the need for boosters should be based on the risk of disease for the horse and the consequences of an outbreak. In general the more a horse is in contact with other horses, the greater its risk of contracting strangles. Horses in high-risk situations such as premises where strangles has been diagnosed before, or those kept in a group with new unknown animals coming and going, should be revaccinated with a single dose every three months. Medium risk horses, for instance those travelling to shows frequently, should consider the option of 6 monthly boosters. With horses being revaccinated every six months, a prompt extra booster with a single dose should be given if an outbreak of strangles occurs more than 3 months after the last booster. There is generally no need to vaccinate horses in low-risk situations, for instance those kept completely at home away from other horses. Currently the vaccine is not licensed for use in pregnant mares, but this may change. There is a big debate as to which category individual horses belong and the cost/benefit balance of protecting them with this new vaccine. The best advice has to be to talk to BELL EQUINE for guidance relating to your individual situation.

How long should a new horse be separated from the others to know that it is not ‘brewing’ strangles?
Incubation period is 3-10days from exposure. If a horse has not spiked a fever or shown any signs of ill health in 2weeks it should be safe to introduce to the herd. A horse may however be a silent ‘carrier’ and bring strangles into a yard without showing signs.

How do I know if a horse is a ‘carrier’ that is new to the yard or after an outbreak?
In theory Vets can test if a horse is a carrier by taking swabs from the back of the airway or by collecting samples via an endoscope. In most, but not all cases, if three swabs are negative, the horse is clear. This involves effort, expense and cannot guarantee a horse is free from infection, so vigilance is still required.

There’s a horse on the yard that is showing signs that might be strangles, but it has not been proven by the vet. Do we have to shut down the yard?
The mere mention of the word ‘strangles’ can cause a lot of bad feeling and worry on a yard. Strangles can be unpleasant and painful for the horse, difficult for the vet to treat, and a management nightmare for yard owners. Once one horse has been diagnosed with this infectious disease, all other horses in contact are at risk. Ideally the affected horse should be isolated and the stable yard should be closed to prevent spread.
Within reason, until you are given the all clear, it is best to start taking precautions. Delay in preventing further spread of the disease results in more horses being exposed and a more serious and longer lasting problem. Isolate horses that are showing signs and those that have been in direct contact. If it turns out to be strangles this will significantly reduce spread through the yard.

It is also worth considering cancelling excursions from the yard to avoid spreading the disease to other horses that may take it back to their yards, just as you would appreciate others showing the same consideration, so that your horse does not ‘catch something’ at a show. One difficulty is that there is no legal notification requirement for strangles. If individuals elect to carry on regardless despite persisting infection, they cannot be prevented from so doing! All this does is increase the potential for further spread.

How do I know which of the healthy horses to isolate?
Horses that have been in direct contact with a horse that has developed strangles may be ‘incubating’ strangles and may be infectious to others. This includes contact in the few days before the horse may have started showing signs.
Taking rectal temperatures twice daily of all horses (if it is safe to do so!) may allow earliest detection of a horse not yet showing other symptoms. This allows early isolation and reduces spread.

Does the vet have to examine my horse if I think he has strangles?
It is advisable to speak to a vet and describe your horse’s symptoms and yard situation to decide whether you need a visit
If you are not sure whether it is strangles, it is a good idea for a vet to come and examine the horse in case there is another disease involved.
If the vet thinks that it is suspicious of strangles they can take swabs from some affected horses. It is a good idea to try to confirm or disprove the diagnosis so that a yard is not ‘shut down’ unnecessarily.
If your horse develops difficulty breathing or very noisy breathing, a vet needs to examine your horse to make sure that there is not a risk that the airway will become blocked requiring emergency treatment
If your horse refuses to eat or swallow, the vet may need to inject “bute” to start to reduce the swelling in the throat and make your horse more comfortable so that you can then administer “bute” in the feed
If you already know that your horse has been exposed to strangles and the situation is under control, telephone advice may be sufficient.

My horse has had strangles before, can he get it again?
Most horses will be fully protected from catching strangles again for up to 5years. It is unusual for horses to catch strangles more than once.

How should I clean abscess discharges?
Wipe and flush daily with very dilute iodine or Hibiscrub. The horse may resent this and warm water may help. It is not worth a battle if the horse will not allow it

There is a massive hole where the abscess burst, is that ok?
The wound may appear distressingly large but this is very common and will fill in and heal remarkably quickly

What disinfectant should I use in footbaths or to clean stable, headcollars etc?
Virkon or Trigene are effective

How long until the paddock is safe for other horses?
A paddock (especially fences, gates, water troughs, etc) can remain contaminated for one or two months


RECURRENT AIRWAY OBSTRUCTION (RAO)


Recurrent airway obstruction (RAO) is one of the names given to a common respiratory disease syndrome that affects horses and ponies. It is also known as chronic obstructive pulmonary disease (COPD), and ‘heaves’. The disease is similar in many respects to asthma in recurrent airway disease (RAD), “broken wind” humans.

CAUSES
It is caused by inhalation of dust and toxins from the environment, usually when a horse is stabled. Hay and straw contain fungal spores and organic material which trigger an allergic response causing inflammation and narrowing of the lower airways. The inhaled particles that cause the allergic reactions in susceptible horses are known as allergens.

When hay is baled with high moisture content (above 20%), the bales heat up and the growth of moulds such as Aspergillus fumigatus, Faenia rectivirgula and Thermoactinomyces vulgaris occurs. All hay made in this country has mould growth, even good quality hay. Inhalation of such spores triggers the airways to become hypersensitive. It has now been shown that inhaled endotoxin from bacteria present in the environment triggers airway inflammation in normal horses. This is also likely to be a contributory factor in causing the disease. The source of these bacteria has not yet been identified but they are likely to be from faeces, the horse’s coat and the forage (hay and straw).

It is thought that some horses have a genetic susceptibility to RAO and are more easily sensitized than others.

Free radicals and oxidative stress
The horse’s respiratory system is constantly exposed to external irritants. This can cause the release of abnormal amounts of ‘free radicals’ which can attack cell membranes.
A free radical is a molecule or atom that has one or more unpaired electrons. It is unstable and tries to attract electrons from other molecules to pair up with these. This can start a chain reaction with increasing amounts of free radicals being released. If the production and removal of these is not controlled, tissue damage may occur leading to inflammation. This is known as ‘oxidative stress’ and may be an important factor in the development of RAO. In a normal horse, the production of free radicals is controlled and those produced are ‘neutralized’ by well-developed antioxidant defence mechanisms. Experimental work has shown that the major antioxidant in the fluid lining of the lungs is ascorbic acid (vitamin C) and horses suffering from RAO or airway inflammation often have reduced levels

Predisposing factors
• Repeated exposure to hay and straw dust containing moulds, forage mites, endotoxins and inorganic material
• Dusty feeds
• Long hours in the stable
• Poor stable hygiene
• Inadequate ventilation
• A respiratory virus eg equine influenza which damages the epithelial surface of the respiratory tract. This adversely affects the clearance of inhaled allergens and may alter the immune response of the horse

CLINICAL SIGNS
The disease usually develops over a period of time. Affected horses do not have a temperature and they appear well in themselves. In performance horses (especially racehorses and eventers) mild RAO may produce no overt clinical signs, and the only indication of airway disease may be a loss of exercise tolerance.

In other horses, the first clinical signs include:
• reduced exercise tolerance
• increased respiratory rate
• increased expiratory effort; the abdominal muscles are used to force the air from the lungs. This results in a characteristic biphasic expiratory movement
• an occasional cough, usually at the start of exercise
• milky white nasal discharge from both nostrils, especially first thing in the morning and after exercise

As the condition progresses
breathing out (expiration) requires even more effort and there is considerable movement of the abdominal muscles; this is known as ‘heaving’
• the abdominal muscles become overdeveloped and ‘heave line’ is seen
• the respiratory rate increases further
• expiratory airflow at the nostrils is biphasic
• the horse’s anus moves in and out in time with the respirations
• the nasal discharge may become thick and yellow
• the horse coughs at rest in the stable
• lumps of mucus are coughed up

Once a horse has become sensitized, it may suffer acute attacks of the disease and develop severe respiratory difficulties in a short period of time. The animal breathes with flared nostrils and heaving flanks, and has spells of continuous paroxysmal coughing. Wheezing and crackling sounds may be heard at the nostrils.

The incidence of the disease increases with age.

Why do these signs develop?
The expiratory difficulty is caused by obstruction of airflow in both the large and, especially, small airways. This is due to spasm of the smooth muscle (bronchospasm) in the larger airways, and bronchospasm, inflammation and the accumulation of mucus in the small airways (bronchioles). Both lead to a reduction in airway diameter so breathing requires more effort. These changes occur within a few hours of a susceptible horse being placed in a stable or dusty environment

If the disease is not controlled, structural changes occur in the lungs over a period of time. The chronic inflammation leads to thickening of the mucosal lining of the proliferation of the smooth muscle. In severe, long term disease, the alveoli (air sacs) become over-inflated and emphysema (ie structural destruction of the alveoli) can develop.

When to call the vet?
Call the vet at the first sign of the disease. Early diagnosis, treatment and management changes often prevent it from developing into a serious problem.

DIAGNOSIS
The diagnosis is made based on the history and the clinical signs. In mild cases the vet may not hear any abnormal sounds with the stethoscope. In severe cases, a wide range of lung sounds including crackles and wheezes may be heard.
If the upper respiratory tract is examined with an endoscope, a stream of mucopus may be seen in the trachea. Examination of airway secretions taken by tracheal aspiration or bronchoalveolar lavage reveals large numbers of neutrophils (pus cells) when compared with secretions obtained from an unaffected horse


TREATMENT AND CONTROL
Once a horse has developed a hypersensitivity to stable dust, there is no cure. If treated promptly, the changes are reversible but the horse remains more sensitive to respiratory allergens than normal.

Treatment involves:
• environmental control
• administration of bronchodilators to relieve the bronchospasm
• corticosteroids to reduce the inflammation
• antioxidant supplementation

Management
The key to both treatment and prevention of the disease is environmental control by good stable management and stable design.

Turning out
All horses should have plenty of fresh air with minimal exposure to dust and fungal spores.. Whenever possible, the first step in treatment of horses with RAO is to turn them out completely for a period of at least two to three weeks (preferably longer). The field should be well away from the muck heap and the hay store. Bringing the horse into a stable for even a short period, eg for grooming or for the farrier, will cause further inflammatory changes to take place in the lungs and prolong the period of recovery. The best management for a horse with RAO is to keep it permanently out at grass with no access to hay or straw.

Stable design
Where it is not possible for horses to live out, changes in stable management and design may be all that is required to control the symptoms. Good ventilation is essential for the horse’s health. Many modern boxes have low roofs and insufficient air vents to achieve the recommended ventilation rate of 8-10 complete air changes per hour. The ventilation of most boxes can be improved with relatively little expense.

These improvements could include:
• additional air inlets and outlets. To avoid draughts, air inlets should be positioned at the same height as the eaves. Ideally, each stable should have an outlet at the highest point in the roof.
• an extra window at the back of the box can improve the air quality and considerably reduce the incidence of the disease
• top doors should routinely be left open
• wherever possible, each horse should have its own air space and the side walls should reach the roof of the stable.

Bedding
Straw is not ideal as it has higher levels of fungal contamination than a well managed peat, dust-extracted wood shavings, cardboard or paper bed. All beds need to be kept clean and dry; the urine and droppings must be removed each day to prevent mould growth. Deep litter is not recommended as high levels of noxious gases such as ammonia and hydrogen sulphide may be produced; mould will also grow in the bedding when it becomes damp and soiled. These gases are irritant to the respiratory tract (as are some disinfectants, pesticides and preservatives). Rubber matting may be helpful if used with a small amount of bedding material. However, good drainage and management are required with rubber mats to prevent pooling of urine and an unhealthy atmosphere.

Mucking out
It is essential that all the bed is removed and replaced at regular intervals. Wood shavings and paper beds that look clean can develop high levels of fungal growth after several months in the stable especially if the environment is damp.
During normal mucking out, the number of fungal spores and the dust levels in the stable is increase three to six fold, and remain airborne for many hours. It therefore makes sense to muck out as soon as the horse is turned out so the spores and dust have a chance to settle before the horse is brought back in again. Mucking out while the horse is in the box should be avoided in all cases.
Ledges and window sills should regularly be cleared of dust and cobwebs to remove dust, fungal spores, bacteria, endotoxins etc.

The muck heap
The muck heap should be sited as far from the stables as practical and preferably downwind.

Transport
When travelling, horses are often exposed to high dust levels. Straw and shavings in lorries and trailers quickly become musty and mixed up with old hay. The best solution is to use rubber matting and be careful if feeding hay inside the vehicle. Also lorries should be well-ventilated.

Respiratory infections
Horses with RAO should avoid contact with others suffering from respiratory viruses. The symptoms may be exacerbated following a respiratory infection. Remember that all horses that catch a respiratory virus infection are at increased risk of developing RAO at this time, so they should be kept in a “clean air” and “minimum dust” environment.

Hay
Wherever possible, hay should be excluded from the diet altogether as even well made, good quality hay has very high levels of dust and fungal spores. Grass, silage or vacuum-packed forage such as Horsehage are suitable alternatives.

Buying and storing hay
It is always worth buying the best quality hay that is available. When a bale is opened it should have a fresh, sweet smell with no visible mould or dust. Hay should be stored in a separate building from the horse because millions of fungal spores are released into the atmosphere when hay nets are filled. In order to minimize fungal growth, the bales should be raised from the floor on wooden pallets.

Soaking hay
The area within 30 centimetres around the horse’s nose is called the ‘breathing zone’. When a horse pulls dry hay from a net, large numbers of fungal spores and dust particles (up to 63,000 per litre of air) become airborne and are inhaled. Soaking the hay prior to feeding (total immersion in clean water for a couple of hours) significantly reduces the amount of dust inhaled provided it is all eaten before it dries out. Soaking hay for longer than a few hours should be avoided since it decreases the nutritional value of the hay.
Ideally the hay net should be positioned by the door or a window. If the stable is large enough, it should be tied so there is minimal mixing with the bedding and any that is not eaten can be swept up and removed.

Vacuum-packed forage
Vacuum-packed forage has been developed as an alternative to hay. Grass is cut and allowed to wilt before being baled and compressed. The bales are sealed in bags to exclude air and a mild fermentation process begins. Under these conditions mould growth is inhibited and the feed will keep for up to 18 months.
Vacuum-packed forage has a higher nutritional content than most hay. It should be introduced to the diet over a period of 2 – 3 weeks and concentrates may need to be reduced. Opened packs should be used within 5 days. If the bag is accidentally punctured it should be fed immediately. A feeding guide can be obtained from the manufacturers. Hay nets with small holes slow down the intake of this forage.

Concentrates and Grains
A complete cubed diet or molassed mix has considerably less dust and fungal spores than rolled grains such as oats or barley.

Antioxidant supplementation
Antioxidants are sometimes known as ‘free radical scavengers’. They are able to donate an electron and neutralize free radicals without becoming a fee radical themselves. Some antioxidants occur naturally in the body but their capacity may be overwhelmed in the face of challenge. Horses and ponies suffering from RAO often have low natural antioxidant defences. Dietary supplementation with a balanced antioxidant mix has been shown to improve lung function and reduce inflammation in horses with RAO. Vitamins C is the most important antioxidant in the fluid lining of the lungs

Exercise
Horses with moderate to severe breathing difficulties should not be worked. Mildly affected horses should have their exercise restricted to a level they can manage comfortably. During a bout of coughing, the horse should be allowed to extend its head and return to walk.
With good management, a definite improvement should be seen in mildly affected horses within 3 – 4 weeks. However, moderate and severely affected horses require medication to alleviate the respiratory distress and aid recovery.

MEDICATION
The most useful medications are bronchodilators and corticosteroids.

Bronchodilators
Bronchodilators are used to relieve the respiratory distress from bronchospasm experienced by horses during acute episodes. They relax the smooth muscle in the airways.

The commonly used ones include:
• Clenbuterol (Ventipulmin) relieves bronchospasm and increases the speed of clearance of mucus from the airways. The drug can be given intravenously or orally. Some horses require up to four times the normal dose of this drug to be effective. Advice should be sought from your veterinary surgeon regarding the dose of Ventipulmin if your horse fails to show a satisfactory response to the standard dose – any increase in dose rate must be undertaken gradually. At higher doses, side effects of sweating, trembling and raised heart rate may occur. With long term use, horses can become resistant to the effects of Clenbuterol, so it is generally best used in acute episodes or “flare ups”.
• inhaled bronchodilators such as salbutamol are occasionally administered using an Equine Aeromask or other inhalation devices but their duration of action is relatively short.
• atropine which may be given once by intravenous injection at the start of treatment to relieve acute respiratory distress. If bronchospasm is a contributory factor, the drug will be effective and provide relief within 15-20 minutes, but this can cause colic as a side effect so is not safe for regular usage.
Bronchodilators are useful in the short term to relieve bronchospasm, but they do not address the underlying problem of inflammation of the small airways.

Corticosteroids
Corticosteroids are the most effective drugs for reducing inflammation in the lungs of horses with RAO. They can be administered systemically (ie by injection or orally) or by inhalation. A horse with severe disease may need corticosteroids to be given by injection or by mouth because to start with they are unable to breathe in enough of the drug in by inhalation. Alternatively, bronchodilators may be given first, to allow better distribution of the inhaled drug. Dexamethasone and prednisolone are commonly used injectable and oral forms. Once the symptoms are controlled, inhaled medication is preferable as there is less risk of side effects which include laminitis, Cushings-type signs and suppression of the immune system. Immunosuppression increases the risk of the horse succumbing to bacterial infection. The inhaled corticosteroids include beclomethasone dipropionate and fluticasone propionate. The horse is treated twice a day using a metered dose canister. A number of systems for delivering the drug are now available. Examples are the Aeromask (which is a facemask with an attached spacer and metered dose canister) and the “Equine Haler” inhalation spacer.

Other drugs
Disodium cromoglycate is sometimes used as a prophylactic treatment to prevent the disease occurring when a horse that is known to be susceptible to RAO is unavoidably exposed to allergens. It is administered by nebulization. The response to this treatment is not consistent. It appears to work for a few horses but not for most others.
Mucolytics are drugs that help to break up the mucus so it is more easily cleared from the airways. The efficacy of these drugs in horses has not been proved, but they can be useful in cases where there is a lot of thick, tenacious mucus present in the airways.
Antimicrobials are usually unnecessary as secondary bacterial infection is rare.

PROGNOSIS
If managed correctly, the changes in the lungs of most affected horses are reversible. However, once a horse or pony has been sensitized, the symptoms will recur if it is exposed to the offending environmental allergens. The airways also become hyper-responsive to other irritants in the atmosphere such as noxious gases. The condition tends to become worse with age and causes reduced exercise tolerance in performance horses. The prognosis is therefore guarded.


EQUINE DENTISTRY

At what age should I start getting my horses’ teeth checked?

The first dental examination should be performed at birth, alongside the post-foaling check-up. This will pick up, at an early stage, abnormalities such as parrot mouth, wry nose and cleft palate. Any attempted treatments will need to be started early, so prompt recognition of these abnormalities is required. Young horses have softer teeth and, as a result, form sharp edges more quickly. Some horses will need to have routine dental examinations (and rasping of the teeth if necessary) from 1year of age.

How often should I get my horses’ teeth checked?

Equine dental care is best performed on a little and often basis. Assuming that routine removal of sharp hooks is all that is required, horses up to the age of 10 years should be checked every 6 to 12 months. This interval may be lengthened to 12 months for individuals with good dentition. Your dental practitioner should be able to advise you appropriately.

I think my horse may have a dental problem. Who should I contact about this?

In the first instance you need to be sure that your horse does indeed have a dental problem. For example, a horse which is losing weight may have other conditions such as intestine or liver damage. If you are in any doubt whether your horse’s signs are the result of a dental problem you should contact your usual veterinary surgeon for an appointment. He/she will then be able to examine your horse and advise you accordingly.

My horse is due for a routine dental checkup. Who should I contact about this?

There are an ever increasing number of people offering equine dental services. Whilst some are very experienced and skilled, others have limited knowledge or training. In the first instance you should contact your usual veterinary surgeon, who should be able to advise you on local services that are available. If you wish to use the services of an equine dental technician, check out his/her credentials. Many technicians have gained training and certification abroad. The level and standard of this is incredibly varied. Most technicians who are working to the highest standards, have been examined by the British Equine Veterinary Association and British Veterinary Dental Association. Having passed this examination, they are eligible to join the British Association of Equine Dental Technicians (BAEDT). BAEDT members work to the highest possible standards, maintain a commitment to continuing professional development, are bound by a code of conduct and carry the appropriate medical malpractice insurance. Details of members can be found at the BAEDT website

My veterinary surgeon offers equine dental services but I have been told that having a vet for equine dental care is like going to your GP for a filling.

Contrary to popular belief, a large amount of a veterinary surgeon’s training is relevant to the field of equine dentistry. Most veterinary schools have recognised equine dental care as an important area and have put in place the appropriate tuition and research. Many equine veterinary surgeons have sought extra tuition and training in this discipline and are well equipped and experienced to offer a complete equine dental care service.
An important point to note is that should a sedative be required for your horse to receive dental care, this can only be provided by a registered veterinary surgeon. Equine dental technicians are breaking the law if they administer sedatives or other drugs, and due to lack of appropriate training (and insurance cover) this may have serious untoward consequences for your horse. If you are concerned that a technician is sedating horses, then please contact the British Equine Veterinary Association.

My veterinary surgeon/equine dental technician wants to use motorised equipment to perform dentistry on my horse. I am worried about this.

Motorised dental instruments can be very useful in dental care of the horse. It allows very precise removal of overgrowths compared with manual equipment and when used appropriately is preferable.
However, the potential for incorrect removal of tooth material and damage to soft tissues means that the patient (your horse) needs to be restrained adequately with a sedative. The use of motorised instruments in unsedated patients is risky, and can result in serious damage that cannot be corrected. Motorised instruments can also cause thermal trauma to teeth, and therefore it is recommended that the equipment used is water cooled.
Use of motorised instruments requires a great deal of skill and experience. You should seek a veterinary surgeon or BAEDT member if this type of work is required



ANAESTHESIA

Whate are the risks of equine general anaesthesia?

A horse may require a general anaesthetic for a routine planned procedure such as castration or for an emergency such as urgent colic surgery. When you are told that your horse needs surgery, there is a tendency to focus on the operation itself and forget the anaesthetic. It is easy to take anaesthesia for granted as an integral part of the procedure. However, for every horse, it is essential to consider the anaesthetic risks, when making the decision whether or not to proceed with surgery. A recent detailed survey on equine anaesthesia reviewed more than forty thousand anaesthetics. This investigated the perioperative deaths, i.e. those during and within seven days of general anaesthesia. This study revealed an overall death rate of 1.6%. If the sick colic cases were excluded, the death rate was still approximately 1%. One death in a hundred horses is frightening in comparison with the perioperative mortality rate in man, which is one in ten thousand. In companion animals (cats and dogs) it is about one in seven hundred. This means that there is a significant risk of any horse dying under any anaesthetic.
Although 1% might almost be an acceptable anaesthetic death rate for horses that are ill, it is alarming when it applies to normal healthy horses undergoing surgery for routine procedures. For this reason it is important that any anaesthesia and surgery is only ever performed when it genuinely justifiable rather than removing blemishes for cosmetic reasons. If it is not going to truly benefit the horse, you need to ask whether it is worth doing. Your vet should be able to advise you.

Why are horses difficult to anaesthetise?

There are several reasons why horses are difficult to anaesthetise. For a start to have a general anaesthetic, the horse has to be made to lie down. Unlike people, horses are not already lying down quietly counting to ten, when the anaesthetic drug is administered. Care has to be taken to ensure that they do not harm themselves as they fall or when they struggle to stand after surgery. Modern anaesthetic techniques help, as do the well padded “knock down and recovery” boxes available at many equine hospitals, which are designed to reduce injury. At Bell Equine we constantly monitor every horse throughout anaesthesia and during recovery, and assist them to their feet, when required.
Unfortunately the horse’s large size complicates anaesthesia. They are extremely heavy, especially when they are lying still under anaesthesia for any length of time. The muscles on their underside can be squashed and the blood supply reduced by their bodyweight. When horses are positioned on their backs during an operation the large stomach and hindgut squash the lungs and make it more difficult for the horse to inhale enough oxygen with each breath. Their large hearts beat slowly anyway, and under anaesthesia the heart can all too easily stop altogether. Cardiac arrest was the commonest cause of anaesthetic death in the survey of perioperative equine fatalities.

What you should do if your horse needs a general anaesthetic:

In an emergency there will be no opportunity to plan ahead, but for a routine operation you should:
• Notify your insurers first. Always discuss the details of any operation with your insurers since you need their agreement to proceed. Some companies request an extra premium to cover the extra risk. In an emergency, the insurers should be notified as soon as it is possible to do so.
• Arrange for the shoes to be removed before any surgery, so that the horse does not damage itself when lying down or standing after the anaesthetic.
• Check with Bell Equine about starving the horse before surgery. Many vets routinely starve a horse overnight and sometimes longer for certain operations.
• Arrange for the operation to be performed in the safest possible place. In order to carry out major surgery, the horse should be admitted to the hospital where full theatre facilities and vets with specialist skills in both anaesthesia and surgery are available. This reduces the risks involved with an anaesthetic, and if problems do occur more equipment and expertise is readily available. Some surgery is done in the field, particularly relatively minor procedures such as castration, in which case ensure there is a clean empty paddock available. Check with us in advance exactly what will be required. Nowadays there are such good equine hospital facilities available that it is foolhardy to carry out major surgery in the field.

What doe a general anaesthetic involve?

1. The vital planning phase, which may include giving painkillers and any other treatments in advance of surgery. A thorough check-up is carried out to detect any potential dangers. The anaesthetic regime can then be modified to suit that horse or, if necessary, the operation postponed until the horse is fit enough to be anaesthetised. In addition the horse’s temperament can be assessed. Frequently the neck is clipped and a catheter inserted into the jugular vein to provide a pain free route for giving the anaesthetic injections and for intravenous fluid therapy. The area for surgery may also be clipped to save time later.
2. Pre-anaesthetic: this often includes giving the horse a “pre-med” injection of a tranquilliser, which reduces anxiety and provides protection for the horse's heart once anaesthetised. The horse is then groomed, the feet washed and the tail bandaged.
3. Induction or start: Ideally the anaesthetic is induced or started in a padded box, so that the horse lies down onto a soft surface. Initially the horse is heavily sedated and then several minutes later an anaesthetic injection is given to render the horse unconscious.
4. Maintenance of anaesthesia: Once the horse is lying down an "endotracheal tube" - a long hollow tube - is passed through the mouth, via the larynx (i.e. throat) and down into the windpipe. A cuff is blown up around the tube so that the horse only breathes the gases supplied via the anaesthetic machine. This is a mixture of oxygen and the anaesthetic gas that keeps the horse "asleep". Sometimes cocktails of intravenous anaesthetic drips are used instead of breathing in anaesthetic gases.
An overhead hoist may be used to move the horse from the padded box into the theatre - some patients may weigh 1000kg or more. The horse is then carefully positioned on the operating table, either on its side or back depending on the surgery to be performed. Positioning is very important, especially for operations lasting several hours, particularly to avoid a complication known as post-anaesthetic myopathy, where horses muscles to become swollen and painful as a result of poor blood supply whilst being "squashed" by the horse’s weight during the operation. For some horses, this can be a serious and distressing (and even life-threatening) problem.
5. Recovery: Once the operation is finished, the horse is hoisted back into a padded recovery room. Usually the horses are left alone to slowly "come round" in a darkened, quiet environment whilst being constantly and carefully watched from a safe distance and via CCTV Sometimes it is necessary to give further sedative drugs to make the recovery smoother. Excitable horses that try to stand up before they are co-coordinated enough to do so, may require this. The recovery phase of the anaesthetic is a risky time when complications can occur. Occasionally a horse may fracture a leg whilst trying to stand. As the horse comes round from the anaesthetic its movements are unpredictable and it is dangerous for people to be in with them. It is not until the horse is safely standing up that the operation is considered to have been successfully completed.
The ideal anaesthetic prevents pain and stress for the horse before, during and after surgery. Some procedures can be performed with the horses standing under heavy sedation and by using local anaesthesia, but in many cases a general anaesthetic is essential for successful surgery to be performed. Pain relief is crucial throughout any procedure, as an unstressed and pain free patient will heal faster.
During any operation the horse is constantly monitored so that the depth of the anaesthetic is known. The eye reflexes are noted and the rate and character of breathing are recorded. Sometimes it is necessary to control the horses breathing via a ventilator. Sophisticated monitoring equipment records the horse’s heart rate and rhythm and other vital signs. A catheter may be placed in an artery to monitor blood pressure and if it drops, specific extra treatment is given. Low blood pressure during surgery can result in major complications.



LAMENESS

How long will I have to be at the clinic if I bring my horse in for a lameness examination?

In some cases, the cause of lameness will be relatively easy to determine based on a physical examination. In other cases, a more prolonged and detailed examination will be required. An in-depth lameness evaluation (including nerve and joint blocks) can be very time consuming and is often necessary to identify the origin of a horse’s lameness (especially chronic lameness). Your horse is likely to have to stay at the clinic for the entire day. The presence of the owner however might not be required for the entire day. Most horses will be able to go home in the evening, although in some cases the examination may need to be continued on another day.

A few helpful hints for owners who are bringing in their horses for a lameness evaluation:

• Pain killing medications such as bute (equipalazone and others) should not be given in the last 4 days prior to the work up.
• Where possible, no farriery should be performed on your horse’s feet in the week prior to the visit and shoes should not be pulled. Any of the above mentioned could impair our ability to accurately diagnose the origin of a lameness.
• Try to ensure that your horse is noticeably lame on the day of the visit. Mildly lame horses might have to be worked daily for several days prior to the lameness examination in order to have a horse which is lame enough to be able to perform a meaningful evaluation. It might also be helpful to bring your tack in order to see the horse move under saddle (especially in cases of mild hindleg lameness or gait problems).
• Owners are welcome to stay during the entire work up, or may be able to leave their horse at the clinic and pick it up on the same evening or the following day.




WORMING

Worming programmes

There are many considerations that affect one’s choice of worming programmes such as:
• grazing history of the pasture,
• stocking density - ideally 1 – 2 horses per acre,
• the ages and worming history of the horses grazing together – young and very old horses often carry higher worm burdens,
• the level of co-operation between owners – grazing groups of horses should be treated identically.

Pasture Management

One of the easiest ways to prevent a build up of the number of eggs and infective larvae on the paddock is to regularly remove droppings. This has the added benefit of increasing the grazing area available as the droppings don’t ‘sour’ the grass. The best policy is daily removal although once or twice a week is also effective. In warm, sunny weather the pasture can be harrowed to spread and dry the droppings to kill the larvae,but this can have the detrimental affect of spreading parasitic infection to all the grass in warm and damp conditions and is really not recommended in the UK unless a prolonged hot dry spell of weather can be garanteed. =If possible other types of animals (such as sheep or cattle) should be allowed to graze on the pasture, as they will not be infected by horse worms and will be happy to eat the rough or ‘soured’ areas. Although strongyle (redworm) larvae can survive over winter and ascarid eggs can remain viable for years, resting fields can also reduce contamination. If clean pasture becomes available, horses should be dosed effectively and then stabled for 2 – 3 days to allow any eggs in their system to be passed before moving fields.

Wormer Choice

There is a wide choice of wormers (anthelmintics) on the market. No wormer is effective against all worm types; a combination of treatments based on test results should be used. Choice therefore depends on whether it is being used to treat a specific problem or as part of a routine control programme. Worm egg counts should be done several times during the first season of a worming programme on all the horses in a grazing group to ascertain the level of risk. If the egg count is low or negative it would be wise to discuss the treatment intervals with your vet as this will depend on several factors. The need for tapeworm treatment can be identified with an annual blood test which means that susceptible horses can be identified and unnecessary treatments avoided.
Your vet is the best person to ask for advice as he/she will be familiar with your situation and also be aware of any local problems of resistance to a particular medication.
WORM CONTROL TABLE Click Here

Worming interval

There are three different ways of using worming preparations:
• Interval dosing - treatments are given at the manufacturers recommended intervals through the year.
• Strategic seasonal dosing - wormers are dosed through the grazing season three times but this can be a hit or miss system.
• Targeted strategic dosing - horses with worm egg counts (wec) of more than 200 eggs per gram are wormed at specific times of the year. At one point in the year a larvicidal treatment should be given, usually in November.

General Rules for Worming

• Every horse in the field should be wormed with the same product at the same time unless worm egg counts/tapeworm blood tests show that individuals do not require treatment.
• It is essential that each horse receives the correct dose based on bodyweight.
• A record should be kept of the product used and the date given.
• New horses should be tested and then given a larvicidal drug and kept in for 3 days before being allowed onto pasture.
• Foals should be wormed with some preparation from 4 weeks of age.
• Mares should be wormed when they return from stud and one month before foaling.

Testing

Regular Diagnostic Testing should be used to monitor the efficacy of the programme. This is a cost-effective way of determining whether horses actually require treating for worms. It can also be used once or twice a year to check that worm control programmes are working. There are two tests currently used:
• Faecal worm egg counts. This simply requires you to submit a small (a teaspoon sized amount will be sufficient) labelled sample of fresh droppings to your vet or lab for analysis. This will assess the number of worm eggs present, which is useful for checking the parasite status of a particular horse and deciding whether or not it needs treatment. A result of less than 200 eggs per gram is acceptable and usually indicates that treatment is not required. It is sensible to tolerate low levels of worm infection, which are not harmful to your horse and may stimulate their natural immunity.
• A blood sample can be taken by your vet and sent for a specific antibody test for tapeworms. Routine worm egg counts do not detect tapeworms, so blood samples are a useful to screen healthy horses as well as those with recurrent colic; see www: diagnosteq.co.uk .It is best to take samples just before the horse is due to be wormed.

Paste or granules?

Both types are equally effective. Granules are often cheaper and can be added to the feed although fussy feeders may not consume the whole treatment. Paste is usually quick and easy to administer.

WARNING! Moxidectin and ivermectin can have severe adverse affects on dogs and cats. Keep syringes safely and make sure these animals have no access to feeds containing the paste or the droppings of the horse for 3 days after worming. Wherever possible, administer the paste directly into the horse’s mouth.
Moxidectin can also be toxic to horses if overdosed – this is most likely to happen in foals and Shetland ponies / miniature horses

IT IS ADVISEABLE THAT A VET CHECKS THE WORMING PROGRAMME AT LEAST ONCE A YEAR SINCE TREATMENTS, PROCEDURES AND PARASITES CONTINUALLY CHANGE.



CASTRATION

Why castrate a colt

Colts are generally castrated for ease of management. If a colt is left entire it is usually impractical/impossible to run them in company, with either mares, geldings or other stallions, especially as they mature. They can become difficult to handle, and in some cases can be so dangerous as to pose a serious risk to the people and other horses around them. The added concern with an entire male is the risk of mares having an unwanted covering, resulting in pregnancy, either by an undesirable sire or when breeding was not even being considered.

When to castrate a colt

A colt can be castrated at any age. It is traditionally done in the spring of the yearling year, but in reality it can be performed earlier, as a foal, or later in life. There is a body of opinion that castration should be left as late as possible, in order to allow the horse to ‘mature’. However there is no evidence that foals left entire develop any differently from those castrated early. Indeed, on the continent it is common place for colt foals unsuitable to be kept for breeding purposes to be castrated when still suckling from the mare. There is evidence to suggest that those foals castrated at such a young age recover from the operation faster and with fewer complications than their older counterparts.

Colts can be castrated at any time of year; however they should ideally be castrated either in the spring or autumn, in order to avoid the flies of summer and the deep mud of winter, both of which can increase the risk of post-operative complications.

Both testicles must have descended into the scrotum for a colt to be castrated. If only one is present (a ‘rig’), the owner is faced with two options: either give the colt more time in the hope that the missing testicle will eventually descend, although this does not always occur (if the testicle has not descended by one year of age, then it becomes increasingly unlikely that it will ever “drop”); or taking the rig to a hospital for castration. This may incur significantly more surgical intervention and cost, as the retained testicle can be anywhere from the inguinal ring (groin) to within the abdomen, which would necessitate either laparotomy or laparoscopy (ie surgical procedure to enter the abdomen) to remove it. It is also important to check that there is nothing else apart from two testicles within the scrotum, as rarely a horse may have a hernia, in which case they should be castrated in a hospital.

Where to castrate

Colts can either be castrated at Bell Equine, or at the owner’s premises providing they are suitable. The obvious advantage to castrating a colt at home is that it removes the requirement for transportation. Someone experienced in handling horses will be needed, and preferably one who does not mind the sight of blood. The vet will also require a source of warm, clean water.

If the colt is having a general anaesthetic they should ideally be starved overnight, although still having free access to water. However this is simply not practical if the colt is still suckling form the dam. A flat grass field would be preferable to a stable when castrating a colt, as a general anaesthetic will require the colt to lie on the ground during the operation. Stables are often too small to anaesthetise a horse safely, and there is the increased risk of a horse hurting himself on any protuberances on the stable wall, during either induction of, or recovery from, anaesthesia.

The majority of castrations are performed under general anaesthetic, but it is also possible to castrate a colt standing under heavy sedation, and using a local anaesthetic, providing that they are of a suitable size and temperament. In this instance the ideal location to castrate the colt would be in a large well lit stable or barn.

It is best to discuss the facilities you have available with your vet to see if they are suitable, before booking the appointment for the castration itself.

The surgical procedure

Regardless of whether a colt is castrated standing or under general anaesthesia; at home or in an operating theatre; the basic surgical procedure is identical. Both testicles are removed via a surgical incision into the scrotum – either one incision through which both testicles are removed, or two incisions, one for each testicle. The blood vessels and other network of tubes running from the testicle into the abdomen must be crushed and cut at the time of removal of the testicle.

There are two different techniques to castrate a colt under general anaesthesia. Either the ‘open’ technique, where the scrotum and vaginal tunic containing the testicle are incised and then left open for drainage; or the ‘closed’ technique where the tissue layers are sutured once the testicles are removed, in order to reduce the risk of herniation. The closed technique takes longer and requires the cleaner environment of an operating theatre, therefore incurring a higher cost; however it has a lower risk of associated complications in older or very large stallions. When horses are castrated standing, under sedation, the open technique is used.

Post-operative care

The exact details of post-operative care will vary on a case by case basis; however they will focus on cleanliness, close observation and exercise.

Young animals can be turned out in a small paddock soon after surgery. Exercise will encourage drainage and minimise swelling at the surgical site. If a colt will not exercise sufficiently solo, enforced exercise may be required, wither with in-hand walking or lungeing. The colt may be prescribed a short course of antibiotics and painkillers following surgery, and the vet will ensure that the colt is protected against tetanus. If your colt has not already received the primary course of vaccinations, anti-toxin should be given at the time of surgery, thereby providing immediate cover.

The surgical site will need to be inspected on a daily basis for rapid detection of any possible complications. If there are no post-operative complications the incisions should be completely healed within two weeks. However, the colt should not be turned out with mares for at least two months following castration, in order to ensure that they are no longer fertile and they have lost the hormonal influence leading to ‘stallion-like’ behaviour.

Complications and risks

Castration is generally regarded as being a routine procedure, and in the vast majority of cases it is both straightforward and uncomplicated. However, it should not be forgotten that it is an invasive surgery and occasionally complications will occur.

A general anaesthetic in any healthy horse carries with it an element of risk, although every attempt is made to minimise this risk. An anaesthetised horse can sustain fatal injuries when either ‘going down’ or getting back up during recovery. Some horses can suffer an adverse reaction to the anaesthetic drugs used, in which case they may not be able to recover from anaesthesia.

Large blood vessels are crushed and cut when the testicles are removed, and occasionally post-operative bleeding may occur. A small amount of blood dripping from the wound in the first twenty-four hours after castration is normal, but if it exceeds a fast drip ring Bell Equine immediately. Another common complication, as horses do not live in a clean environment, is post-operative infection. The sheath and scrotum can swell dramatically, and the colt may become lame behind due to the extent of the swelling. You may also notice that he becomes depressed and goes off his food if he develops a temperature. This will require veterinary attention: it may be that he only requires a course of antibiotics, but sometimes the incisions will need to be re-opened to allow drainage. This can usually be done under sedation.

A potentially more serious complication can arise, if anything if seen to be hanging down from the surgical incision. This may just be a small piece of the vaginal tunic – the fibrous sac within which the testicle sits, in which case it can either be left alone to dry or trimmed off, depending on how much is protruding. In more serious cases may be a piece of intestine, if a hernia has developed; this is an emergency a