We’ve rounded up a selection of the best respiratory supplements for horses to help you support your horse’s breathing and airways.

They have all been specially formulated to support the respiratory system from within and come in a variety of forms, so there’s something to suit every fussy horse.

Best respiratory supplements for horses

NB: Cost per day has been calculated using the maintenance measure for a 500kg horse in light work (where there was variation) and the RRP of the smallest available tub. Some products require you to feed more in certain situations, which will increase the cost per daily measure, while buying a larger tub will likely decrease it – these costs per day are a guide only.

This supplement provides fast, natural support to calm and soothe the delicate airways. It helps to maintain healthy respiration in horses exposed to dust, pollen and mould spores. It is fortified with liquorice, glycerine and aniseed for a highly palatable formulation.

How to choose the best respiratory supplement for horses

Look out for common ingredients that are found in respiratory and breathing supplements for horses, which include…

• herbs — many of which are known for soothing properties
• anti-oxidants, such as vitamin E, which protects against free radicals

Consider the form the supplement takes – breathing supplements for horses can come in liquid or powder forms. Your horse may have a preference to one over another, which could make all the difference as if he won’t eat it, your horse won’t receive the benefit.

Cost is another consideration – we’ve calculated the daily cost of all the supplements featured in this guide to help you compare them easily. To make it as comparable as possible, we’ve used the smallest tubs available, but you’re better off buying a larger volume of supplement if you can as the daily cost can become significantly lower.

Do I need a breathing supplement for my horse?

There is always a challenge to your horse’s respiratory system — in the summer it’s pollen particles, while increased time in the stable in the winter exposes horses to more dust from forage and bedding.

There are a number of management practices you can put in place to reduce their exposure, but the best respiratory supplements for horses can also help to maintain healthy and clear airways, support the lungs’ natural defences, while also providing a soothing effect.

Coughing can be a sign of respiratory disease so if your horse develops a cough it’s wise to consult your vet.

Can I compete if I am giving my horse a respiratory supplement?

If you compete with your horse then it is important you make sure any supplements – respiratory supplements or otherwise – you use do not contain any prohibited substances. You can also look for the BETA NOPS logo, which shows that the manufacturers are part of a scheme that prevents use of naturally occurring prohibited substances.

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While a cough can occur at any time of year, it is not unusual for some horses to develop a cough during winter. While it can be triggered by a virus or, more rarely, a bacterial infection, if a horse only develops an irritating cough when he is spending more time in his stable, and otherwise appears happy and healthy, the cause is more likely to be an allergy to contaminants in the air, such as dust and spores.

Why is my horse coughing?

The horse’s airway is made up of the upper respiratory tract (the nasal passages, larynx and trachea) and the lower respiratory tract (the lungs and the small airways – bronchi and bronchioles).

The horse’s respiratory tract overcomes contaminants in the air in two ways:

• The mucociliary escalator – specialised cells that line the airway and filter the air before it reaches the lungs
• Cellular immunity – specialised lung cells that kill bacteria and inactivate viruses

Excessive cold or dusty air, ammonia and stress can all reduce the effectiveness of these defence mechanisms, increasing the horse’s susceptibility to respiratory problems, which can result in the horse coughing.

When should I worry about my horse’s cough?

If a horse develops a cough, it is wise to isolate them until you know they are not carrying an infection. Take the horse’s temperature, monitor their general health, and speak to your vet. A vet may decide to carry out some of the following investigations to diagnose if the cough is infectious:

• A full clinical examination, including listening to the lungs with a stethoscope
• An endoscopic examination of the upper respiratory tract
• Blood tests
• Swabs from the back of the throat to test for viruses
• Taking samples of discharge to establish the presence of bacteria or inflammatory cells

Can I ride my horse while it has a cough?

It is recommended that you rest a horse that has a cough, although it should have access to plenty of fresh air. Turnout is generally recommended.

There is a traditional horseman’s saying that a horse should be rested for two days for every day they are coughing. Once this period has passed, exercise can be gradually reintroduced – light exercise can help the horse to clear any remaining mucus from its airways.

How will a vet treat a horse’s cough?

In many cases, rest and good horse husbandry (see advice below) are all that is necessary. If the vet feels medication is appropriate, this may include mucolytics to help loosen the discharge, allowing for easier drainage, and broncodilators to increase the airway diameter and reduce muscle spasm.

Anti-inflammatories can be used to help to reduce soreness and enhance the effects of other drugs; inhaled preparations are also successful in some cases. Where bacteria are involved, antibiotics may be prescribed.

How to avoid a winter cough in horses

Roger Lee MRCVS offers some helpful advice on management techniques that can help avoid a winter cough in horses.

1. 24/7 turnout

One easy way to cure the problem of winter coughing is to leave your horse outside 24/7. With a waterproof rug, field shelter and plenty of feed, even horses in full work can winter outside very well, if the ground is suitable. However, if leaving your horse out is impractical, the next best way to tackle equine asthma is to improve air quality.

2. Use dust-free bedding

Bed your horse on dust-free shavings, paper or another low-dust type of bedding – avoiding straw. Consider where your horse’s stabled – there is no point having one horse on shavings and soaked hay if every other horse around it is on straw, or if the yard’s hay/straw barn is right outside its stable.

3. Feeding regimes to reduce dust

Feed dampened hay or haylage; forage is the single biggest source of dust and spores in the stable. Feed forage from the floor as this creates four times less inhaled dust than a haynet. Hay steamers are very good at eliminating dust and spores if you wish to feed hay.

4. Maintain a clean bed

Ammonia from urine-soaked bedding is irritant to the lungs. Keep the bed clean and dig out wet patches daily. If you are using rubber mats, make sure that there is plenty of bedding on top of them, and that urine is not building up underneath.

Also do not muck out your horse’s stable or sweep while they are inside – taking your horse outside while doing these tasks will keep a stabled horse happy and healthy.

5. Improve air circulation

Simply having the top stable door open is not sufficient — there needs to be a through movement of air, so open wide any windows at the back. If there isn’t a window, see if you can safely remove some boards to create one. If you are worried about draughts, put an extra rug on your horse.

If your horse is in a barn, give him a stable near the entrance where the air quality is best. A simple test of air quality is to stand at the back of the stable and take several deep breaths. If the air smells stale and dusty, it is not going to be good for your horse’s lungs.

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When the Moreton BE90 section H winner, Boby, suddenly started struggling to make the time across country last summer, alarm bells rang for his owner-rider, Sheila Williams.

“He never showed any external signs of breathing difficulties – no coughing or wheezing – but he wasn’t comfortable going at a fast pace, so I had him scoped to find out what was going on,” revealed Sheila of the 11-year-old part-Welsh cob gelding known as Harley, who was bought as a lockdown project two years ago but has since become a permanent fixture in her Bridgwater yard.

Harley was diagnosed with equine asthma, a condition that has to be carefully managed through the daily use of a nebuliser mask which dispenses liquid steroids.

“He has to wear the mask for 20 minutes every day, and then in the medicine withdrawal period in the lead-up to an event I substitute the steroids for a product called Audevard Balsamic Air [which is competition legal] and was recommended to me by Lissa Green, who uses it on one of her horses,” explained Sheila. “He’s incredibly tolerant of it all, which is testament to his amazing temperament.”

The pair headed BE90 section H, conquering the optimum time to finish on their dressage score of 28.

Sheila Williams, who works part-time as a cleaner to fund her hobby, has her sights set on qualifying for next year’s Badminton grassroots championship.

“I competed there five years ago with another horse and it would be a dream to go back again with Harley,” she added.

Read more from Moreton in this week’s Horse & Hound magazine, dated 31 March. 

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• This article has been edited and approved by Karen Coumbe MRCVS, H&H’s veterinary advisor since 1991.

Horses with equine asthma suffer from inflammation and/or obstruction of the lower airway so are unable to breathe as well as a healthy horse. An accumulation of excessive mucus in their airways can cause the horse to cough from time to time and affects their ability to exercise, while severe cases show a clear increased effort to breath while at rest, traditionally referred to as heaves or being broken-winded.

This condition, which has previously been described as chronic obstructive pulmonary disease (COPD), is now widely referred to within the veterinary community as ‘equine asthma’. Research has shown¹ it is more closely aligned to asthma in humans than it is to COPD, which is typically caused by chronic smoking or exposure of the human lungs to other damaging substances.

Equine asthma can be mild to moderate, when it is termed inflammatory airway disease (IAD), or severe, when it is described as recurrent airway obstruction (RAO). IAD is typically seen in young to middle aged horses, although it can be found in horses of any age. RAO is most often seen in horses over seven years of age.

Equine asthma: Signs | Causes | Diagnosis | Treatment | Prognosis 

Signs of equine asthma

In mild to moderate cases (IAD) a horse will cough occasionally both at rest and during exercise for four weeks or more and a loss of performance will be seen.

This loss in performance may be subtle, and may go unnoticed, especially in mild cases where the horse is not in hard work. Some cases will improve following changes to management while others will require treatment, but the risk of recurrence is low as long as the necessary management changes are maintained.

In severe cases of equine asthma (otherwise refered to as RAO) the coughing will be more frequent, the ability to perform will be more significantly impacted and a clear effort to breathe at rest will be seen. The severity may vary over time and may last for weeks to months before being diagnosed. Signs of RAO usually improve with strict environmental control and/or treatment, but the condition cannot be cured.

Not all cases of IAD will become ROA, although an untreated case of IAD could develop into ROA over time. These conditions have the potential to be debilitating and performance-limiting and are reported to affect 14% of horses in the northern hemisphere.

New research is being done to look at the different allergens that are involved in severe equine asthma² and also biomarkers³, which are measurable substances in the body, particularly the blood. The hope is that over time these can be used to correctly identify affected horses.

What causes equine asthma?

Stable dust, as well as fungi, mold spores, bacterial products and other irritant particles found in forage and bedding, is a primary cause of equine asthma. When horses at pasture are affected, the stimuli are most commonly pollen and dust particles. Some horses show more obvious signs when the weather is hot/humid or when pollen levels are high.

How is it diagnosed?

Your vet will diagnose equine asthma based on the horse’s history, management and clinical signs.

The obvious clinical clues are a cough at rest or at exercise (especially on gait changes), a white nasal discharge, a raised breathing rate and poor performance, particularly rapid fatigue and a prolonged high breathing rate after exercise.

Airway endoscopy– most commonly standing at rest or while exercising either on a treadmill or more likely via exercise endoscopy – can be used to ascertain the severity of the condition.

Fluid sampling of the discharges within the airways enables the severity of the airway inflammation to be assessed. This can be done by:

• Either a tracheal wash, where fluid is sampled from the trachea
• Or bronchoalveolar lavage, when a sample is collected from the lower airways.

Healthy horses have either no or very little mucus in their airway. Poor performance can occur with a tracheal mucus score of 2/5 in racehorses and 3/5 in sports horses. The fluid can then by analysed under the microscope and the different cells checked, particularly neutrophils, eosinophils and mast cells.

In mild to moderate equine asthma, bronchoalveolar lavage is recommended, If there is a neutrophil percentage of more than 6% in racehorses or 10% in sport horses , it can be sufficient to affect performance.

Management and treatment

Dealing with equine asthma effectively is likely to require both day-to-day management changes and medical treatment.

It is important to try to prevent exposure to causal factors, such as dusty hay and bedding. Choosing a dust-free bedding option and soaking hay for at least 30 minutes or feeding haylage will be beneficial. Steaming hay with a Haygain steamer or other effective steaming system is useful, but rinsing hay is not sufficient and homemade steamers are unlikely to work effectively. Horses that are stabled part or all of the time should be kept in well-ventilated areas with dust-free bedding, such as good quality shavings or paper. A well-ventilated stable should have at least one square metre of open space, achieved by using door chain or bars, opening or removing windows. This ventilation space should start below the horse’s muzzle level.

If a horse is badly affected when the weather is hot/humid or when pollen levels are high, exposure to these conditions should be avoided as far as possible. It is hard to make recommendations other than to keep the horse in the windiest field or bring them in. Environmental management is essential in all cases. The two key aspects are to reduce exposure to allergens in the air and improve ventilation.

Medication is also used. Oral bronchodilators (inhaled medication to open up the airways) in conjunction with steroids are the basis for initial treatment. Inhaled medication, very much like in human medicine, can be administered via an inhaler or nebuliser. If the horse is due to compete or race, check with your vet whether the medication is allowed under FEI or BHA rules.

There is a wide range of nutritional respiratory supplements on sale that have been formulated purporting to help support healthy airways in order to maximize equine health and performance. However, under Veterinary Medicines Directorate rules, nutritional supplements cannot claim to treat an established medical condition.

Prognosis

Once diagnosed, most horses with equine asthma will regain their ability to exercise at their former level once they have undergone treatment and their management has been adjusted to suit their needs. However, the condition will not disappear and will need to continue to be monitored and management changes made as required.

References:

• Inflammatory Airway Disease of Horses—Revised Consensus Statement – March/April 2016
• Antigen array for serological diagnosis and novel allergen identification in severe equine asthma – October 2019
• Investigation of blood biomarkers for the diagnosis of mild to moderate asthma in horses – July 2019

Unlike the heart, or other muscles, equine lung function does not improve with training. This means that a horse’s breathing — his respiratory system — is always a limiting factor in his performance.

Equine asthma (EA), in a mild to moderate form, can compromise lung function and, in turn, affect athletic capacity.

The condition causes airway inflammation and mucus accumulation, which increases the resistance to airflow in the horse’s lungs. As a result, less air is inhaled with each breath and more energy is used to move the muscles of the chest. This impairs the exchange of oxygen and carbon dioxide — meaning that less oxygen-rich blood is delivered to the muscles to power the body during hard or fast exercise.

The more severe the airway inflammation, the greater the reduction in performance. Its significance will also depend on activity, because muscles demand less oxygen for lower intensity exercise.

Up to 80% of thoroughbred racehorses have airway cytology (the study of cells) evidence of mild-moderate EA, with increasing inflammatory cell numbers associated with reduced racing speed. The number of stabled sport horses affected may be even higher, although the association with athletic function is less clear and more individual.

As many as three-quarters of horses presented for high-speed treadmill investigation of poor performance have EA in its mild-moderate form.

Subtle signs

Aside from performance issues, there may be little obvious evidence of mild-moderate EA.

Most of the increased mucus transported up the trachea (windpipe) is swallowed, so only a small amount may be coughed up or appear as nasal discharge. Fewer than half of horses affected display a chronic intermittent cough, which is more common at the beginning of exercise.

Any signs of increased respiratory effort at rest would suggest the presence of severe EA. An exaggerated breathing effort during exercise may be apparent, however, or a prolonged increased breathing rate afterwards.

One prominent feature of mild-moderate EA is airway hyper-responsiveness — the development of bronchoconstriction (narrowed airways) and a cough during exposure to an allergenic environment, which in a normal horse would have no effect. The condition most commonly occurs in a stable setting, although a summer version also exists.

Typically, clinical signs will have been present for at least four weeks. A more variable history can also occur, however, with spontaneous improvement and worsening that reflects variation in environmental stimuli. Physical examination and bloodwork should be carried out to exclude any evidence of systemic infection.

The main diagnostic test for human asthma is forced exhalation — known as peak flow. After taking a deep breath in, you blow as fast as you can into a peak flow meter. This is repeated frequently and the results are interpreted based upon your age, gender and height.

With horses, it is impossible to confirm a diagnosis of mild-moderate EA using peak flow measurement outside of a research environment. Instead, a two-stage approach is used: airway endoscopy, to visualise and grade tracheal mucus, followed by fluid sampling from the trachea (a tracheal wash) or the lower airways (bronchoalveolar lavage).

Healthy horses have either no visible mucus and are graded 0/5, or only a few isolated specks and are graded 1/5. Poor performance can occur with a tracheal mucus score of 2/5 in racehorses and 3/5 in sport horses.

The fluid from the tracheal wash or bronchoalveolar lavage is then analysed for specific inflammatory cells, namely neutrophils, eosinophils and mast cells. In mild-moderate EA, bronchoalveolar lavage is the recommended sample: a neutrophil percentage of more than 6% in racehorses or 10% in sport horses is sufficient to affect performance.

Positive prognosis

Medical treatment revolves around control of airway inflammation using corticosteroid anti-inflammatory drugs. Alongside this, environmental modification is essential. Giving the horse corticosteroid therapy while keeping him in a dusty atmosphere will lead to improved clinical signs and lung function, but airway inflammation will persist and clinical disease will recur at the end of treatment.

In mild-moderate EA there is little bronchoconstriction at rest, so the routine use of bronchodilators (medicines to make breathing easier) is typically not necessary — although they may contribute to improved exercise tolerance during the early stages of corticosteroid treatment.

The most suitable treatment will be based upon clinical signs, exercise tolerance and the results of airway endoscopy and airway fluid sampling. The efficacy of this plan should be monitored by repeat airway fluid sampling, at a suitable interval.

The prognosis is excellent with appropriate treatment and a low-dust environment, since airway remodelling (structural change) does not seem to be a component of the condition. Mild moderate asthma is a reversible condition, but can recur if exposure to allergens recurs. However, progression to severe EA has not been shown.

Ref Horse & Hound; 26 September 2019

An owner who hopes to raise awareness about the amount of dust in hay has urged others to consider wearing a face mask when filling haynets.

Emily Boyce, 20, who is in her final year of equine studies at the Royal Agricultural University in Gloucestershire, was filling haynets for samples for her research project when she discovered the mask she was wearing had become very dirty.

Emily told H&H: “I wouldn’t usually wear a mask but you need to wear one for healthy and safety at university. I had 45 haynets to fill in total and the mask was so dirty after 20.

“I’ve always thought about dust when I make up haynets at work or on the yard but the mask really put it into perspective just how much there actually is.”

Emily, who works on a hunting yard every Sunday, owns a New Forest pony, Rufus, who suffers from “severe” equine asthma.

“Rufus has fuelled my interest in the subject of hay and trying to reduce the clinical symptoms of horses who suffer from respiratory disorders,” said Emily.

“The bale was just a normal bale and didn’t seem dusty, it was in a large space and the doors were open. One of the lab technicians at the university who is also a horse owner thought it was really interesting how dirty the mask was.”

Emily put a picture of the mask on Facebook and has received hundreds of comments.

“When I saw how much dust was on the mask I thought other owners should know and be aware of these things. I was surprised how many people have commented – there’s been a lot of people having problems with dust and saying they are going to buy masks – the picture has had a big impact which I wasn’t expecting,” said Emily.

“Some of the comments spoke about farmer’s lung and someone said they knew someone that developed it. I’d heard of the condition but never read about it before.”

Continued below…

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Emily said: “It just made me think if there was that much dust coming out of 20 nets, there are people who work on yards that fill more than 20 in a day. I’m going to buy a mask to wear in the future.”

The Health and Safety Executive (HSE) website states farmers lung is the most common occupational form of extrinsic allergic alveolitis – which refers to a group of lung diseases that can develop after exposure to certain substances. The condition is the outcome of an allergic response to a group of microbes which form mould on vegetable matter in storage. During handling of mouldy straw, hay or grain, particularly a confined space such as a poorly ventilated building, inhalation of spores and other antigenic material is very likely.

The HSE advises respiratory protection should be worn when handling stored crops.

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Rick Farr of Farr & Pursey Equine Vets shares his expert advice on Chronic Obstructive Pulmonary Disease, or equine asthma, how to manage it and what you can expect

Q: My gelding has been diagnosed with COPD (Chronic Obstructive Pulmonary Disease) at 15 years old. We showjump up to 1m/1.05m and obviously I am concerned at the affect the COPD will have on our competing. Does anyone have a horse with COPD, how do you manage it, how debilitating is it, do horses go back to full work and do they eventually find they have to have a slower pace of life?

A: It is strange how things move on within the veterinary industry and how we describe various conditions. COPD, or Chronic Obstructive Pulmonary Disease, was the term historically used to describe a condition in horses which was characterised by an increased respiratory effort as a result of allergic airway disease. However, COPD is actually a condition described within human medicine as a result of chronic smoking.

Over time, we as vets we started to use the term RAO, or Recurrent Airway Obstruction, but again, this terminology was not ideal. Now we describe the old COPD/RAO cases as Equine Asthma which, when put in context, is much easier to understand as most people are aware of asthma in people. Therefore, from this point on, I will refer to the condition as such.

Continued below…

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In both people and horses, asthma is a managed condition and should not prevent an individual from having a ‘normal’ life. The differences arise as a result of the severity of the condition within the individual and how responsive they are to medication, in conjunction with environmental management.

In the UK the prevalence of Equine Asthma is reported to be approximately 14%. Furthermore, there are suggestions that there is an increased risk of the condition in animals over four years old, Thoroughbred breeds, horse residing in urbanised areas and those that have been exposed to hay/straw in early life.

So, how is it diagnosed?

The best way to confirm the lower airway inflammation causing the condition is to perform two tests: a tracheal wash (fluid/sample taken from the trachea) and a broncheoalveolar lavage (a sample from the lung). The samples are then sent to the lab for analysis.

How do you treat the condition?

It is important to try to prevent exposure to certain causal factors, such as dusty hay/bedding. Horses should be kept in well ventilated stables. Very much like human asthma, some individuals are also worse when the weather is hot/humid or when pollen levels are high, therefore avoiding putting horses into these conditions can help. Environmental management is essential in all cases. Medication is also used to help — oral bronchodilators (drugs to open up the airways) in conjunction with steroids should be the basis for initial treatment. Often we progress onto treatment with inhaled medication, very much like in human medicine. This can either be administered via an inhaler or nebuliser.

You asked if the condition is debilitating. Initial management and control can always be a challenge, however medication with environmental changes can make sure your horse does not have to slow down. You do have to be aware though that, when competing under certain governing bodies, you may be required to check if any of the medications are on the prohibited substances list; this may affect your horse’s ability to compete in the future.

Once you have your diagnosis, getting the horse stable and managing the condition can take some time. However, once done, it is essential to monitor the response to any changes made. Some months the condition may be worse and require “tweaks” to the management — the condition will not disappear over night. With all this said, however, you should not be putting your horse in retirement just yet!

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Dr David Marlin explains why riders shouldn't think a horse that coughs during its warm-up is in the best of health

In the unfit or untrained horse, it is the heart that is the main limitation to exercise performance followed by the muscles. As a result of training both the heart (which is made of a special type of muscle) and the muscles change and become more able to cope with exercise. However, the respiratory system cannot and does not change as the horse gets fitter with training and so in trained horses, the respiratory system is the main limitation to exercise performance.

Many survey type studies have found that after lameness, the most common reason for a vet to be called out or for horses to not be able to be exercised or competed is respiratory disease. In a study of 3000 horses in Germany, it was observed that respiratory disease occurred in 420 horses over one year (Knubben et al. 2008) and in another study of horses referred for a veterinary examination because of poor performance, four out of five were found to have respiratory disease (Nolen-Walston et al, 2013).

Recurrent airway obstruction (RAO or “heaves” or equine COPD or “broken wind”) is the most common chronic (essentially there for life) respiratory disease affecting horses in the UK. It is a disease affecting older horses, predominantly those over eight-years-old.

Respiratory disease in horses can be caused by infections (bacteria, virus, fungi), allergy (grass pollen, tree pollen, crop pollen, shrub pollen, moulds, fungi, dust, forage mites, bacterial toxins) or irritant (ammonia produced by bacterial breakdown of protein in the horses urine, dust (e.g. fine sand), cold air) and sometimes a combination.

In younger horses, respiratory disease due to bacterial infection is more common than due to viruses or allergy. In older horses, allergic disease is more common.

The most common external (i.e. ones that can be seen without the need for a veterinary examination with an endoscope, stethoscope, blood test, x-ray or ultrasound) clinical signs of respiratory disease in horses can include any combination of one or more of the following:

• Cough
• Nasal discharge (clear, white, yellow, green, think and runny or thick or foamy)
• Increased respiratory rate at rest
• Increased respiratory effort at rest
• Increased temperature
• Abnormal breathing during exercise (e.g. abnormal noise or irregular breathing)
• Slow recovery after exercise
• Poor exercise performance
• Frequent swallowing during exercise
• Blood at the nostrils after exercise

A horse with respiratory disease may have one or more of the above symptoms.

It is a myth that a horse must be healthy if it doesn’t cough. Compared to people horses are much less likely to cough even when they have quite severe respiratory disease. It is often said that it is “ok for a horse to cough a few times” during warm-up as this is simply the horse clearing its throat. This is NOT true and the horse that coughs a few times during warm-up is likely to have some respiratory disease that should be investigated by a vet.

Common treatments prescribed by vets for the treatment of respiratory disease include:

Antibiotics: when there is evidence of bacterial infection these may be given orally or by injection.

Bronchodilators: drugs which open up the airways (e.g. Ventipulmin) to allow the horse to breathe easier and to clear mucus. These may be given in feed, intravenously or by inhalation.

Anti-inflammatories: drugs that reduce inflammation (e.g. dexamethasone). These may be intravenously, into the muscle, in feed or by inhalation.

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In addition to veterinary prescribed pharmaceutical treatments for respiratory disease, high dose antioxidant supplements have been shown in several controlled studies to be beneficial in reducing respiratory symptoms (Deaton, Marlin, Smith et al. 2004).

Deaton, C.M., Marlin, D.J., Smith, N.C., et al. (2004) Antioxidant supplementation in horses affected by recurrent airway obstruction. J Nutr 134, 2065S-2067S.

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Veterinary scientists are calling for the term “equine asthma” to be used to describe breathing ailments in horses, which are now among the most common veterinary problems.

In the May issue of Equine Veterinary Education, Canadian professor Jean-Pierre Lavoie wrote an article titled: “Is the time primed for equine asthma?”

He argues that the complex and evolving terminology that has been used to describe inflammatory syndromes affecting the lower airways of horses “has led to confusion for veterinarians and clients alike”.

Prof Lavoie said evidence has emerged recently to show that inflammatory airway disease (IAD) and heaves in horses “share striking similarities with human asthma”.

The professor puts forward the case that “equine asthma” should be used to describe chronic, non-infectious lower airway conditions currently known as IAD and heaves or RAO (recurrent airway obstruction).

The terminology would both improve “communication with clients” and would also provide “a wide umbrella, which remains appropriate as the diversity of the disease manifestations (phenotypes) and underlying immunological processes emerge in the future,” he added.

In the article he charts the many terminologies used to describe breathing problems in horses, from “heaves” or “broken wind” — which has been used for more than 30 years — to new terms introduced following recent research, such as “tracheal IAD”and “summer pasture associated pulmonary disease”.

The term equine asthma “allows for both flexibility and consistency over time, as some terms fall out of favour” said Prof Lavoie.

Cases of horses prone to breathing problems in the summer are likely to rise this week as temperatures soar to the high eighties in parts of the south, and forecasters are warning of “very high” pollen counts.

H&H vet Karen Coumbe added: “We have seen several cases of horses with non-infectious respiratory disease recently. A large number can be controlled with changes in management to minimise exposure to the common allergens such as dust, moulds, fungal spores or pollen.”

How to manage respiratory problems

* Horses with respiratory disease benefit from minimal dust environments

* Turn out as much as possible and avoid hay and straw, unless horses are allergic to pollen, in which case turn-out will not help

* If stabled, make sure stables are well ventilated with good air flow

* Soak or steam hay thoroughly or consider using haylage

* Choose dust free bedding, ideally for all horses using the same airspace

* Feed from the floor

* Keep the muck heap as far away as possible from stable and keep the affected horse out when you muck out

Ref: Horse & Hound; 9 July 2015

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What’s the first thing you do when you’re feeling poorly? Maybe lie down, take pain relief or seek medical advice. As prey animals, a horse’s natural instinct is to suffer in silence rather than highlight that they are ill and attract unwanted attention.

So whether you’ve owned horses for years or will soon be buying your first, remembering to make the following checks on a daily basis will ensure you know what is normal for your horse. This, says H&H vet consultant Karen Coumbe MRCVS, will enable you to spot the subtle signs that something is wrong.

1. Respiratory

What is normal?

8-16 breaths per minute.

How do you monitor it?

– Watch your horse’s chest move in and out. An inhale and exhale counts as one breath.

– Alternatively, look for air coming out of the nostrils — but this will only work on a cold day.

– “A healthy horse at rest has quiet, steady breathing. Knowing what is normal for your horse makes it easier to spot when it is laboured,” says Karen.

2. Temperature

What is normal?

Less than 38.5°C.

Consistently higher than normal temperature readings are likely to be associated with infection and inflammation, and you should isolate the horse and call your vet. A transiently higher than normal temperature reading can be associated with exercise and overheating, but if it remains high it needs to be taken seriously.

How do you monitor it?

– A rectal temperature reading is the most accurate. A rapid digital thermometer is quick and easy to use, only taking 10 seconds to register a reading and bleeping to alert that it has been recorded.

– “The more regularly this is done the better your horse will cope with the procedure. It helps if they are used to temperature checking regularly, starting when they are young foals,” states Karen.

3. Pulse

What is normal?

Between 30 and 36 beats per minute (bpm).

A horse’s pulse is affected by pain, fear, shock, fever and exercise. “In some horses their resting pulse can be between 24 and 40 beats, so it’s variable,” explains Karen, “but if it’s consistently high [over 60bpm] or pounding, something is seriously wrong.”

How do you monitor it?

-Press two fingers (not your thumb) on the horse’s jaw, where the submandibular artery runs.

-The pulse can also be felt on either side of the fetlock — the digital artery — and is useful when checking for lameness, especially in the foot.

-A basic stethoscope is handy to have at home. Place it in the girth area on the left side of the chest, just behind the elbow. Each ‘lub-dub’ of the heart is one beat. -Count the number of beats for 15 seconds and then multiple by four for the total per minute.

-“It is normal for a foal’s pulse and respiratory rate to be higher than stated here because they are smaller. The younger they are the faster/higher their rates are,” adds Karen.

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The dry, wheezy cough of a recurrent airway obstruction (RAO) sufferer is all too familiar in winter, when cold, wet conditions mean that all but the hardiest of horses are spending most of their time indoors.

It’s this indoor lifestyle — rather than the season alone — that can cause the common respiratory condition to flare up at this time of year.

A horse with RAO will have inflammation and increased accumulation of mucus in the airways, triggered by exposure to the dust, ammonia, moulds, dust mites and fungal spores commonly found in stables.

Stabling causes airway inflammation even in healthy horses, but the response is exaggerated in those with RAO. The mucus becomes stickier and less easy to clear, similar to human asthmatics. Airways also become constricted, reducing airflow and increasing the breathing effort.

The perils of pollution

Research from 2007, which involved a questionnaire survey of UK horse owners, identified exposure to this “urbanised environment” as a significant risk factor for RAO. This is most likely due to a combination of increased stabling and air pollution — pollution is certainly implicated in asthma in humans.

Other risk factors included increasing age (with an average age at diagnosis of 11 years), exposure to hay and history of a respiratory infection in early life.

The resulting clinical signs include exercise intolerance, cough, nostril flare, wheezing, respiratory distress and increased abdominal effort, characterised by marked muscle appearance known as a “heave line”.

Bouts of coughing are common and affected horses may have episodes of acute crisis followed by periods of disease remission.

Diagnosis is based on an assessment of the horse’s health history and a clinical examination, often backed up with endoscopy and collection of fluid from the trachea and lungs. Routine blood tests are usually normal and therefore rarely helpful.

Easing the airways

Once diagnosed with RAO, a horse is susceptible for life. Control of his environment is vital and may be all that is required for a significant improvement, although note that it can take up to four weeks for remission of clinical signs.

A severely affected horse may need to be kept entirely at pasture with provision of a shelter. Some very sensitive horses only need brief exposure to hay to cause clinical signs — even bringing such a horse inside for grooming may trigger an allergic response.

Because the inflammation induced after even a short exposure to dust can last for weeks, many affected horses need additional medical treatment to control signs and provide relief.

The aims of therapy for RAO are to reduce both the spasm in the airway and the inflammatory response. Bronchodilators alleviate the spasm to provide immediate relief and can be given intravenously, orally or via inhalation.

Corticosteroids reduce the inflammation and are the mainstay of long-term therapy. They too can be administered by intravenous injection, oral medication or inhalation devices. Inhaled corticosteroids have the advantage of being administered directly into the respiratory tract, requiring a lower dose and reducing the risk of side effects.

Aerosol sprays, such as those used by human asthmatics, are commonly prescribed (pictured top). They require careful administration for full effect, however, and are not well tolerated by all horses.

An equine nebuliser is often more effective. This inhalation mask, similar to those used in human medicine, delivers a mist of medication, without the hissing noise produced by inhalers to which some horses are particularly adverse. As such, it is a well-tolerated treatment option.

Steam or soak?

If there’s no alternative to winter stabling, how can you control the condition? The main aim should be to keep his immediate environment dust-free and well ventilated. Stable him away from forage stores and always remove him from the area when you muck him out.

Hay and bedding are the main sources of the trigger substances, such as dust. The horse’s movements around the stable will increase the amount of airborne particles — particularly in the “breathing zone” immediately around his nostrils.

Even good-quality hay contains large amounts of dust and moulds. When hay is obviously dusty and has visible mould, the amount inhaled by the horse will be enormous. Haylage generally has much less dust and may be better tolerated.

Soaking hay can reduce the amount of dust, but this may not be sufficient to reduce RAO signs and will not remove the mould and spores.

Studies have shown that steaming significantly reduces the amount of bacteria, fungi and yeasts in hay, whereas prolonged soaking can actually increase bacterial colonies. Steamed hay is also far less likely to induce clinical signs in RAO-susceptible horses than dry hay. Even so, dampened pelleted forage may need to be fed to some very sensitive horses.

With regards to bedding, some shavings can contain even higher levels of dust than good-quality straw. A better alternative is dust-extracted shavings, paper or cardboard, or rubber matting. Deep litter is not suitable as it allows a large build-up of moulds and fungi.

There is no cure for RAO, but early diagnosis and appropriate management can allow horses to remain competitive for many years and may even result in lifelong remission.

Is ROA inherited?

Recent research from the past three years in Switzerland has shown a strong genetic predisposition for the development of RAO. Offspring from affected parents therefore have a significant risk of developing the disease as adults.

Unfortunately, the genetics are quite complicated and involve several genes, so a single genetic test is not available. The affected genes are not identical in each RAO-susceptible horse; individuals may be allergic to different environmental factors, but the overall clinical signs are the same.

Additionally, there is a strong association between the risk of developing RAO and increased risk of the same horse developing allergic skin disease such as insect bite hypersensitivity (sweet itch). It is also suggested that exposure of horses to hay at a young age may increase their likelihood of developing RAO in the future.

This new and really exciting area of research may help future breeding programmes reduce the number of horses affected by this potentially debilitating disease.

What’s in a name?

RAO is the new name for COPD (chronic obstructive pulmonary disease). The name change occurred because COPD in humans is an irreversible disease, commonly related to smoking — clearly not an issue for horses.

RAO more closely resembles human asthma and is an exaggerated inflammatory response to hay and stable dust, predominantly affecting horses over seven. It can cause significant distress to the affected horse, as well as considerable expense in terms of treatment and long-term management. It is an important cause of poor athletic performance.

Signs of RAO may not only occur when stabled. There is a summer form of the disease associated with inhaled pollens and dusts at pasture. This can be more problematic to control than simple RAO and often needs long-term treatment and removal from pasture. The two forms of the condition can occur together, making management very difficult as both stabling and turnout cause clinical signs.

Managing winter coughs: a case studies

For Ben, a 13-year-old riding school cob with limited available turnout, minimal exposure to dusts is key.

Ben was diagnosed with RAO after developing a summer cough that was exacerbated by exposure to smoke from a neighbouring farmer’s field. Despite initial treatment, he continued to show periods of increased respiratory rate and effort when stabled. Endoscopy showed increased mucus in his trachea; a lung wash sample revealed significant inflammation and confirmed RAO.

Ben was treated with bronchodilators to allow easier breathing, along with corticosteroids. He is now back in work and his environment is carefully managed to reduce his exposure to dusts, moulds and pollens.

With two competition horses prone to winter dust allergy problems, Alison Payne is keen to keep her yard as dust-free as possible.

“They’re fine while they’re out in summer, but in winter the coughing and runny noses can start,” said Alison, who uses rubber stable mats and low-dust bedding for Langarth Delia and Rarumba. She also turns them out as much as possible in winter and steams their hay in a Haygain steamer.

Research at the Royal Agricultural University in 2010 showed that steaming hay at the high temperatures achieved in Haygain steamers kills all bacteria and mould and reduces the respirable particle content by more than 95%.

This Veterinary Clinic feature was first published in Horse & Hound magazine (12 December, 2013 edition)

Horse feed company Blue Chip has added a new garlic supplement to its range.

“Blue Chip Garliq” is in a liquid form meaning it is absorbed into the bloodstream faster and more efficiently.

“[The liquid form] also means less mess and less waste when feeding,” said a company spokesman. “Blue Chip is always at the forefront of innovation and this latest product is no different.”

Garlic is known for being a natural fly repellent, powerful anti-oxidant and respiratory supplement.

“Blue Chip Garliq” costs at £15.99 and the company says a one litre bottle should last over two months.

For more information visit: www.bluechipfeed.com

Read more about respiratory problems

Find an equine vet

“ROARING”, “whistling”, “gurgling”, “thick winded”, “snoring” and “choking up” are all descriptions of respiratory noises made by horses in motion.

The first two are associated with RLN, but can be caused by the collapse of other structures, while gurgling and choking are often the result of dorsal displacement of the soft palate (DDSP).

There are three ways to tell if a noise is abnormal:

• The timing: some horses make a “fluttering” sound on breathing out, which is due to the nostrils vibrating slightly – this is called “high blowing” and is considered to be a variation of normal. In contrast, if a horse makes a noise while breathing in, this could signify a problem. Because breathing is synchronised with locomotion at the canter and gallop, it is easy tell whether a noise is inspiratory or expiratory, because expiration occurs when the horse’s leading leg hits the ground, forcing air out of the chest, while inspiration occurs as the leading leg comes up and leaves the ground.
• The volume: the louder the noise your horse is making, the more likely it is to be abnormal.
• Reduced performance: a sudden loss of energy or speed, particularly during fast work, could indicate that something is amiss.To read the full veterinary article on breathing problems see the current issue of H&H (5 January 2012)Do you want to know more about respiratory problems?Do you need an find an equine vet?

Learn more about respiratory problems in horses

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At the British Equine Veterinary Association (BEVA) annual congress last month, mention was made of a newly recognised lung condition first reported in the USA in 2007.

Equine multinodular pulmonary fibrosis (EMPF) is a disease where horses develop hard, fibrous lumps on the surface of their lungs.

It leads to weight loss, loss of appetite, coughing, rapid breathing and fever.

A particular variety of equine herpes virus, EHV 5, appears to be associated with the disease, although little is known about how it is transmitted or the prevalence of the virus throughout the general horse population.

Horse vets in the UK have been following this unfolding story with interest, but more for academic interest than clinical concern.

But in the week before the congress, Liverpool Vet School reported that it had diagnosed two cases of this disease in the UK – and both horses also carried the EHV 5 virus.

Vets from Austria, the Czech Republic and Hungary reported six more cases, only one of which appeared to recover after expensive treatment with an anti-viral therapy.

We do not know whether the disease has been present at a very low level in this country for some time and has not been recognised, or whether it is new.

For the time being, it is not something we should be unduly worried about, but further clinical research is on the cards.

For the full verterinary article on the latest research and development, see the current issue of Horse & Hound (13 October, 2011)

Read more about respiratory problems in horses

Bleeding from the lungs is common in racehorses, where high blood flow rates are essential to deliver oxygen to rapidly contracting muscles.

The pressures generated by this blood flow in the small, thin-walled pulmonary arteries result in rupture and haemorrhage.

“Horses that bleed on the track often do not bleed again when they finish racing. The exertion their lungs are placed under in any discipline outside of racing will be nothing compared to what they were used to before,” says Caroline George MRCVS from Lambourne Equine Vets, who has an ex-racehorse of her own that she hopes to event next season.

The 1995 Cheltenham Gold Cup winner Master Oats suffered from EIPH, but that didn’t stop him going on to hunt with the Heythrop well into his 20s.

For the full veterinary article on health management for ex-racehorses, see the current issue of Horse & Hound (29 September, 2011)

To reduce levels of airborne virulent R.equi in the environment and maximise foal immunity, you should:

• Ensure good stable hygiene and ventilation, and minimise dust levels
• Reduce the number of mares and foals in each paddock
• Pick up droppings regularly from nursery paddocks and all fields used for young foals
• Reduce dust levels in paddocks, gateways and all-weather surfaces
• Keep a mare in the environment she will foal in for at least a month prior to foaling to maximise the appropriate antibodies in the mare’s colostrum
• Ensure good immunity levels in the foal. Make sure it suckles within four hours of birth and that the mare’s colostrum has a good level of antibodies
• Use a prophylactic transfusion (of plasma with high levels of antibodies to R.equi) when the risk of exposure to R.equi is high. This is usually given at two days old and may need to be repeated at 23-28 days of age. This must be done by a vet and is expensiveFor the full veterinary feature on rattles, see the current issue of Horse & Hound (28 July, 2011)

Research scientists have found two new non-invasive ways of testing for respiratory problems.

The simple assessment methods include a cough monitor and a device that tests the pH of exhaled breath.

Previously, endoscopy — a tube that goes up the horse’s nose, down the throat and looks into its airways — was the main method available and this can be difficult to administer and uncomfortable for the horse.

But with the new techniques, vets will be able to diagnose respiratory disorders quickly and monitor the progress of treatments.

Respiratory airway inflammation affects from 10 to 50% of horses and can impede performance for competition horses.

The benefit of the new techniques over methods such as endoscopy is that they can be used repeatedly — both for diagnosis and monitoring — to assess whether treatments are effective, without causing discomfort to the horse.

H&H vet Karen Coumbe said: “A clinical examination [observing a horse] doesn’t tell you everything you need to know for respiratory conditions so an endoscopy can be very informative.”

“However it is invasive and not something you would want to do every day, so any research that fills the gap between a non-invasive examination and endoscopy would be great.”

The cough monitor involves attaching a digital recorder to the horse’s headcollar, which will record the number of times the horse coughs over a set period of time.

This data can then be analysed as cough frequency is believed to be a reliable indicator of respiratory inflammation.

The second technique involves attaching a device to the horse’s head that will collect samples of its exhaled breath.

Vets measured the pH of the breath condensation and noticed that horses affected by respiratory inflammation have a higher pH.

The research, which was funded by the charity The Horse Trust, was led by Sandy Love, Professor of Equine Clinical Studies at the University of Glasgow.

“Both of these techniques could be easily commercialised to enable vets to quickly and ethically monitor respiratory inflammation in horses,’ he said.

“They could also improve treatment of respiratory conditions as vets will be able to objectively assess which treatments work for a particular horse.”

The Horse Trust chief executive and veterinary director, Paul Jepson said: “We are delighted that the research we have funded has led to new, non-invasive ways of monitoring respiratory inflammation.”

“These techniques could have a major impact on improving the diagnosis and treatment of this common condition.”

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More articles on lameness and respiratory problems

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Lameness

Bone, joint and muscle injuries are the commonest causes of poor performance in dressage horses and show jumpers.

It is not unusual to have to nerve-block horses affected with subtle bilateral lameness in order to prove to their connections that lameness is indeed the problem.

By repeating standard exercise tests before and after, or following treatment with anti-inflammatory drugs like phenylbutazone (bute), it is often possible to prove that removing joint pain not only increases the maximum speed a horse can attain, but also greatly improves its willingness to exercise.

Respiratory problems

Inflammation of the lung and airways — the lower respiratory tract — is common in performance horses.

Vets are yet to quantify the effect of this inflammation on performance during low-intensity exercise, but we know that when infectious outbreaks occur in racing stables, there can be immediate and sometimes long-term effects on performance.

Exercise-induced pulmonary haemorrhage has detrimental effects on race performance, although its role in limiting the performance of other equine athletes, in whom it also occurs, is less certain.

Allergic lung disease causes more problems in older horses.

Although not quantified, it seems logical that low-grade disease could reduce performance either directly or indirectly by adversely affecting the horse’s well-being and its willingness to work.

The upper respiratory tract can also cause problems during exercise.

Displacement of the soft palate (gurgling), laryngeal paralysis (roaring) or collapse of the tissues around the larynx can all obstruct air flow to the lungs and limit the ability to carry oxygen. This forces the horse to slow down or fade quickly.

As affected animals do not always gurgle or roar, viewing the larynx with an endoscope during exercise is the only method for accurate diagnosis.

The heart

In a small percentage of horses the heart and cardiovascular system is the primary cause of poor performance.

Most commonly an abnormality of the heart rhythm, known as atrial fibrillation, is responsible.

Very rarely a severe heart valve leak can also reduce athletic performance but, surprisingly, valve leaks and heart murmurs are not associated with poor performance in most cases.

For the full article on poor performance, see the current issue of Horse & Hound (26 November, ’09)

Looking for more articles on lameness and respiratory problems?

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More veterinary advice

Other articles on respiratory problems

Mild respiratory problems have often been overlooked in show jumping, but recent research has shown that breathlessness could limit equine performance more than originally thought

For every stride a horse takes in canter and gallop it takes one breath. Unlike in walk and trot, where inhalation and exhalation occur independently of the steps, in the two fastest gaits breathing and stride are locked together in perfect synchrony.

It stands to reason, therefore, that if a horse has trouble moving air in and out of its lungs it will have an effect on stride pattern.

So if your horse is struggling to catch his breath, what can we do about it?

Ways to optimise respiratory efficacy

• Make sure that you give your horse adequate time to warm up. During exercise the horse relies on the contraction of its spleen to push more red blood cells into circulation to carry more oxygen.

Not warming up your horse can mean the spleen won’t release as many red blood cells, thus limiting the amount of oxygen and causing earlier fatigue.

If the warm-up is too intense, this can result in the horse using up large amounts of glycogen and production of a high level of lactic acid may result in fatigue during the round.

• Consider getting your horse scoped by your vet once or twice every season, particularly

in advance of any major competition or long journey.

• Ensure that if your horse starts making any abnormal respiratory noise you get it investigated for upper airway obstructions such as roaring (laryngeal paralysis), which may be compromising equine performance.

• If your horse has a breathing problem, consider using equine nasal strips if your vet agrees.

These are scientifically proven to reduce the resistance to air movement through the nasal passages, which will mean the horse has to put less effort into breathing and can concentrate on jumping.

Nasal strips have also been proven to reduce bleeding during exercise.

For the full article on respiratory problems and equine performance, see the current issue of Horse & Hound (19 March, ’09)

Looking for more veterinary advice?

Want to see other articles on respiratory problems?

Recurrent airway obstruction (RAO), is an equine disease with similarities to, but also significant differences from, asthma in people.

It is caused by allergies mostly to moulds, fungal spores and bacterial fragments, and causes breathlessness, nasal discharge and impaired tolerance to exercise.

This form of respiratory disease is a significant health problem affecting horses, with a prevalence of around 14% in the UK.

In many cases it is controllable, especially with good stable management, but there are instances, particularly in competition horses, where medical intervention may be necessary.

Diagnosing wheezers

A definitive diagnosis requires investigations and tests. RAO is an inflammatory disease that causes the airways to narrow and become inflamed, so in the first instance a horse will usually be scoped.

By examining samples of mucus from the trachea and lower down from the smallest branches of the airways, under a microscope, inflammatory cells can be identified and the appropriate treatment initiated.

“Drugs are not a long-term fix,” says vet Tim Mair MRCVS. “But they can be beneficial in some cases.”

Inhalation therapy is recognised as a valuable treatment for RAO. Like humans who need a quick puff of an inhaler when they get short of breath, horses can benefit from a high concentration of medicine being delivered directly into the lungs.

There are several instances where this treatment can be particularly beneficial in the case of an acute flair-up of the disease and when every other avenue of stable management has been explored.

When masking can help the problem

According to vet Andy Durham MRCVS, who has undertaken extensive studies into the benefits of inhalation therapy for horses, one of the most effective and practical devices for administering treatment is the metered dose inhaler (MDI) of which a wide selection are available on the human market.

The MDI has to be used in association with a “spacer” or “holding chamber” device.

Horses, like humans, will need to wear a face or nose mask.

For more on managing respiratory disease, see the current issue of Horse & Hound (5 February, ’09)

For many years it has been recognised that abnormal respiratory sounds are linked to upper airway obstruction in horses.

Recently a variety of obstructions have been identified, largely thanks to the use of treadmill endoscopy whereby the horse is examined during strenuous exercise on a high-speed treadmill.

Now, recent research has simplified this, so it is possible to perform endoscopy during ridden exercise.

What’s that noise?

All normal horses make quiet breathing sounds. These are more evident when the horse breathes out (expiration) and may range from a soft blowing noise to a louder more vibrant sound associated with vibration of the nostrils (high-blowing).

In contrast, very little is usually heard when the horse breathes in (inspiration), even during strenuous exercise.

Abnormal respiratory sounds are created by air turbulence in the upper airways as a result of some obstruction to normal airflow. Various conditions can cause abnormal sounds and in many horses more than one condition may be present.

When to investigate?

If abnormal respiratory noise can be heard, it is likely that the horse has some form of obstruction to its airflow. This can also cause poor athletic performance by reducing the amount of oxygen available for the muscles to work effectively.

Detecting what’s wrong

It is now understood that performing an endoscopic examination of the upper airways when the horse is standing at rest is not always a reliable way to diagnose obstructions.

Using a treadmill

Exercise endoscopy can be really useful to provide an accurate diagnosis. Until now, this has meant the horse has to be exercised on a high-speed treadmill.

Unfortunately, the lack of centres with such facilities as well as misconceptions regarding the cost and safety of this procedure, mean that many horses are not referred for treadmill endoscopy, but undergo surgical treatment without an accurate diagnosis first being established.

New ideas

Over the past four years, a portable remote-controlled endoscope for use during ridden exercise has been developed at Bristol University with the images being viewed on a separate screen as the horse works. This project has been aided by funding from the Horserace Betting Levy Board. The result is an exciting new system which is small enough to be mounted on the horse’s head.

The way forward

This new method of exercise endoscopy should allow more horses to be fully assessed and this will have a considerable impact in improving equine welfare. Certainly, it may help to identify which are the most effective treatments for upper airway disorders.

Dr Sam Franklin and Kate Allen are from the University of Bristol Equine Sports Medicine Centre

To read the article in full, see this week’s issue of Horse & Hound (13 November, ’08)

VETS at the University of Glasgow Equine Hospital have become the first in the UK to use equipment to look inside a horse’s airway as it gallops on a track.

The Dynamic Respiratory Endoscope (DRE) has a small camera that is passed up through the nose and into the horse’s respiratory tract.

It then beams back live pictures of the horse’s airway in action to vets who can assess the patient.

The revolutionary equipment was acquired by the university as a joint venture with one of the UK’s top racehorse trainers, qualified vet Mark Johnston.

Professor Sandy Love, director of the Glasgow Equine Hospital, said: “It will be used by specialists at the university’s Scottish Performance Horse Clinic to offer a range of diagnostic testing for all causes of poor performance including respiratory, cardiovascular and musculoskeletal systems.”

Previous technology could only be used on a horse running on a treadmill, but the new system allows for causes of poor performance and minute changes to be detected in horses in normal training.

Mr Johnston added: “The DRE will revolutionise what we know about horses when they are being exercised.

“Understanding the airway of a horse is the key to understanding so much more about them and how they function.”

Glasgow Equine Hospital website

www.markjohnstonracing.com

Stay in touch with all the news in the run-up to and throughout the major shows and events during 2026 and beyond with a Horse & Hound subscription. Subscribe today for all you need to know ahead of these major events, plus online reports on the action as it happens from our expert team of reporters and in-depth analysis in our special commemorative magazines. Have a subscription already? Set up your unlimited website access now

A new study has found that as many as one in six horses suffers from Respiratory Airway Obstruction (also known as COPD or heaves).

The research, funded by the Home of Rest for Horses, also established that many equines were kept in poorly ventilated stables surrounded by fodder and bedding — a challenge to the respiratory tract of any horse.

A horse’s respiratory system is adapted for its natural environment: open pasture and limitless fresh air, the report notes. It also suggests that many owners adopt better management practice only when their horse develops a respiratory problem, rather than taking action to prevent it from occuring.

Now The Home of Rest for Horses, working with the British Horse Society, has published a free educational booklet to help horse owners understand, prevent and manage this distressing and debilitating condition.

“Good ventilation is essential for horse health,” said Paul Jepson, Veterinary Director of The Home of Rest for Horses. “This is undermined when the breathing zone is surrounded by bedding and forage containing dust and fungal spores. Horse owners must understand that they should make every endeavour to improve the air quality of their horse’s stable.”

A copy of the booklet, Horse Respiratory Health is available free on receipt of a stamped addressed envelope from The Home of Rest for Horses, Lacey Green, Bucks, HP27 0PP.

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Recurrent airway disease (RAD) is a common chronic progressive inflammatory condition of the lower respiratory airways. It has various other names, including chronic obstructive pulmonary disease (COPD), allergic airway disease, equine asthma, stable cough, heaves and broken wind.

RAD is essentially an airway allergy and/or hypersensitivity to inhaled dust particles, particularly from hay and straw, which contain environmental elements (“allergens”) such as fungal spores. These trigger an inflammatory reaction and an accumulation of mucus in lower airways, together with thickening and constriction of the airway walls. The result is a disruption to airflow in the lungs plus varying degrees of difficulty in breathing, resulting in “poor performance” or exercise intolerance.

Although it is primarily a winter disease, more cases tend to be noticed in spring. This is because many RAD-affected horses are at rest over the winter and show few or no signs, and it is not until they are brought up in preparation for the competition season that the problem comes to light.

Predisposing factors of RAD can be put into three categories:

Environmental factors

• Cool, wet climates: horses are more likely to be stabled and bedding and food is more at risk of getting wet and mouldy
• Prolonged stabling with poor ventilation
• Moulds, dust and spores from food
• General cleanliness of yard/air pollution
• Inadequate clearance of staled bedding/deep littering, causing build-up of ammonia fumes

Prior infection

RAD can follow a previous respiratory infection, especially if the stable management is poor or the animal not rested for long enough.

Inheritance

There appears to be a definite genetic susceptibility, possibly due to individual variations in the airway clearance mechanisms. RAD tends to become more common with age, and to reoccur. With each “attack”, or if the allergen source is not removed, further damage can occur to the airways. In addition, affected horses appear to become increasingly sensitive to other stimuli, until one is left with a chronically broken-winded animal, which is extremely difficult to manage.

The signs of RAD range from subtle and sub-clinical through to severe and even life-threatening. They can come on gradually or be very acute. In the mildest cases, horses simply don’t perform to expectation. In the worst, their body becomes starved of oxygen, they lose weight, become cyanotic (turn blue) and even die. These are common signs:

• Afebrile (normal temperature)
• Cough at rest that worsens with exercise; may be soft and persistent or paroxysmal and explosive
• Occasional mucky nasal discharge
• Increased respiratory rate (up to 25 breaths per min, with normal being 8-12bpm)
• Increased, often biphasic (double) expiratory effort, with a visible abdominal effort
• A “heave line”; a visible ridge along the flank due to the muscular effort needed to breathe out
• Audible crackling and wheezing in the lungs
• Flaring of the nostrils

Many cases can be accurately diagnosed simply from the history and the fact that “common things occur commonly”. However, your vet may also want to endoscopically examine the trachea. He or she may even take a sample from the lower airways to check for the presence of inflammatory cells. Sometimes the fact that there is an improvement with treatment is sufficient to confirm a tentative diagnosis.

Recently blood tests aimed at measuring antibody levels to various environmental allergens have become available. But their correlation value, and therefore interpretation, remains questionable at present.

Treatment

The most important aspect of dealing with RAD is how it is managed. Medical treatment can help in the short term, and certainly with acute cases, but, ultimately, maintaining a healthy, dust-free environment is essential.

• Turn out as much as possible
• Feed haylage or another dust-free hay alternative
• Feed pelleted hard food, dampened down just beforehand
• Feed from the floor to encourage mucus drainage from the airways
• Bed on rubber, paper or some other dust-extracted bedding
• Muck out daily
• Move horse away when mucking out or sweeping yard
• Always groom outside
• Improve stable ventilation
• Keep muckheap and hay and straw store well away and preferably downwind

There is a variety of medication available to alleviate the signs of RAD. The two most often used are bronchodilators (for example, Ventipulmin), which relax the muscle walls, decrease mucus viscosity and accelerate its clearance from the airways, thus opening them up, and anti-inflammatories (for example, corticosteroids), which reduce lung inflammation. Other types of medication that can be of use include mucolytics, which break down airway mucus (for example, Sputolosin) and diuretics, which relieve lung congestion (for example, Frusemide).

There are also several “alternative” forms of treatment, including immunotherapy (allergen neutralisation with hyposensitising vaccines) and homeopathy, both of which have anecdotal support but no scientific evidence of efficacy. In-feed supplements containing anti-oxidants, garlic or bio-available sulphur (such as MSM) continue to be popular.

Remember that once a horse has been affected it will remain sensitised and will be likely to react again. Studies have shown that sensitive horses only need to be exposed to dust for 1-2hr for a reaction to be triggered.

Long-term management remains key to the problem and it makes sense to create as healthy an environment as possible, whether your horse coughs or not. Dusty or mouldy hay is probably still the major culprit, and buying the best hay possible is money well spent. I advise soaking hay routinely by submerging it fully for 30-60min because this causes any spores to swell and stick to the hay — then being ingested rather than inhaled. This will only work if the hay is fed wet, rather than allowed to dry out again. Ultimately, dust-free hay alternatives are safer and less labour intensive, albeit more expensive.

This veterinary feature was first published in Horse & Hound (17 March, ’05) 

Recurrent airway obstruction (RAO) is a disease that affects the horse’s respiratory system. It used to be called chronic obstructive pulmonary disease (COPD) but most vets now prefer the term RAO to avoid confusion with a similar condition in humans. The colloquial term is ‘heaves’, as difficulty in breathing causes the horse’s flanks to heave.

There is also a disease called ‘summer pasture-associated obstructive pulmonary disease (SPAOD)’, which produces the same symptoms, but which is linked to different causes. Up to now, SPAOD has been seen mainly in the USA, but cases are now being seen more frequently in the UK. One explanation may be changes in global weather patterns.

Both RAO and SPAOD affect the smaller airways of the lungs. They result in the production of excess mucus and the thickening of the airway walls, which affect the animal’s breathing.

RAO is caused by repeated exposure to dusts and moulds, notably in bedding and forage. SPAOD is linked to dust and pollens to which the horse is exposed in summer, particularly at times of heat and high humidity.

Both diseases can affect any type of horse or pony, but the keys are the environment in which they are kept, and repeated exposure to the causes, rather than any other predisposition. All breeds and types are at risk, but because they are caused by repeated threats to the respiratory system rather than a single episode, sufferers are typically aged seven and over.

RAO is categorised as a disease in horses that are regularly stabled for long periods – even stabling overnight can be a problem once the respiratory system has been sufficiently challenged. It can occur at any time of year, whereas SPAOD improves as weather conditions change.

Either disease is something no horse or pony owner can afford to ignore. Research has shown that in the UK, up to 80% of horses who are stabled all or part of the time have some degree of airway inflammation – and mild cases often worsen into full-scale RAO as their defences are weakened.

The first signs that a horse is suffering from a respiratory problem is a regular cough, usually when the horse is exposed to dust or mould spores or when exercised. Coughing is the horse’s natural attempt to shift mucus.

Unless the causes are removed, the horse will then usually show signs of nasal discharge and a reduced tolerance to work — for instance, he will not be able to carry out faster work without becoming more breathless than would be expected. In the very worst cases, a horse or pony will have difficulty breathing whenever he is exposed to dust or other causes.

In many ways, these diseases are similar to human asthma – it isn’t so much a case of effecting a cure as removing the threats that cause the problem.

The Animal Health Trust (www.aht.org.uk) advises:

• Keep horses suffering from RAO turned out as much as possible – ideally, all the time. When looking after horses with SPAOD, it is best to discuss a management regime with your vet
• If stabling is essential, follow a minimal-dust regime and make sure your horse’s stable airspace is not shared with one where this regime is not used. Ensure that all bedding, feed and forage is dust-free – good ventilation is also vital for respiratory health
• Feed your horse at floor level, as lowering his head will help to clear secretions from the lungs
• Don’t groom or muck out your horse while he is still in his stable. This rule applies to all animals, not just those with respiratory problems
• Follow the minimal dust rule when travelling. Ensure good ventilation and tie the horse up so that he is still able to lower his head
• If you need to stable your horse away from home, such as at a competition, follow the same regime. If necessary, ask your vet about medication
• Don’t work your horse in dusty schools

This first aid special feature was first published in HORSE magazine (November ’04)

During high-speed exercise, one of the common problems affecting breathing, and therefore performance, is a malfunction of the soft palate called DDSP (dorsal displacement of the soft palate). This is commonly referred to as “choking up”, “gurgling”, or “swallowing the tongue”.

It is caused by the soft palate temporarily becoming dislodged from its normal position and dramatically reducing the airflow in and out of the lungs. This is commonly accompanied by a sudden onset of a gurgling-type noise and poor performance. Despite extensive research the cause of DDSP remains a mystery.

Endoscopic examination of the horse at rest cannot provide a diagnosis of DDSP because it is a functional problem occurring only when under the pressure of hard exercise. Nevertheless, a resting examination will provide useful information about whether there is a primary physical problem that might make the palate unstable.

Examples of primary problems might be a cyst within the palate itself or in the tissues beneath the epiglottis, an ulcer on the edge of the palate or excessive inflammation within the throat. In these cases, treatment for the DDSP will not be successful until the primary problem is sorted out.

In the past 10 years, the development of high-speed treadmill endoscopy has proved a very useful tool in investigation of DDSP. Horses are trained to exercise on a treadmill and an endoscope is placed via the nostril and attached to the noseband so that images are viewed of exactly what is happening in the airway when the problem occurs. Treatment can be given that is specific to those findings.

The palate actually displacing can be the result of a complex series of events and each horse may displace its palate as a result of a slightly different set of circumstances.

There are several theories on the possible causes of DDSP and the variety of treatment options used by different surgeons reflects this. Possible

hypothesized causes include:

• Open-mouth breathing, leading to the soft palate billowing up and making the seal with the epiglottis liable to break
• The tongue being pulled backwards, leading to lifting of the soft palate and breaking the seal
• Increased negative pressure in the airway, possibly secondary to lung disease
• A small or flaccid epiglottis, weakening its ability to keep the soft palate tucked underneath it
• An inherently incomplete seal between the palate or epiglottis
• The strong ventral neck muscles pulling the larynx back excessively, thus reducing the area of epiglottis in contact with the palate
• Excessive head flexion
• Lack of pharyngeal/throat tone associated with unfitness

Because of the difficulty in determining the cause of DDSP, it is not surprising that a variety of treatment options have evolved, many with only a moderate success rate.

The use of tongue ties and figure-of-eight nosebands to keep the tongue under the bit and prevent oral breathing are often tried and are sometimes helpful

In cases where there is a lot of inflammation in the throat region, medical treatment may be a solution. This can be carried out daily, by both oral and topical anti-inflammatory agents (with a flexible catheter passed via the nostril and up into the throat region).

In all cases, the horse’s level of fitness should be assessed and, if necessary, increased, before deciding on a surgical option. It is only once any medical issues have been addressed and there are no underlying primary reasons for the palate becoming displaced that the horse becomes a surgical candidate.

No one surgical option for DDSP has been entirely satisfactory and surgeons are still seeking an ideal solution to the problem. One of the earlier surgeries performed was cutting a strip off the back edge of the soft palate (staphylectomy). This is still a popular option with a relatively high success rate, but exactly how it improves stability of the palate is not clear.

It is thought that the scarring at the edge of the palate may stiffen it and produce a tighter seal, thus reducing the likelihood of DDSP. Also, if displacement were to occur, a shorter palate would obstruct the airway less and would be more easily returned to its normal position underneath the epiglottis.

In the early 1990s, a surgical procedure was developed to take a “tuck” in the palate from side to side, making the palate tighter and less likely to billow up and displace.

Some surgeons try to make the palate firmer and more stable by firing it in lines along its length. Another popular treatment is removing a section of the muscles (myectomy) on the underside of the neck that are responsible for pulling the larynx backwards, thus reducing the area of epiglottis in contact with the palate. This is often performed in combination with a staphylectomy.

In horses with a small or flaccid epiglottis, some surgeons felt that it was advantageous to increase its stiffness, thus enabling it to maintain its position above the palate more easily and preventing DDSP. This view led to an operation being developed where a Teflon paste was injected on the underside of the epiglottis. In some cases encouraging results were seen, but this procedure has been less commonly performed recently.

In America, a surgery has recently been developed that moves the larynx forward

(a laryngeal “tie-forward” operation). Large sutures, attached to a bone in front of the larynx, are tensioned to each side of the larynx, thus pulling it forwards. This means that the epiglottis is well hooked over the palate and at exercise the neck muscles are not able to pull the larynx backwards.

This surgery has been performed in more than 100 cases so far and early results look encouraging. Nonetheless, it is probable that some cases of DDSP will still be a perplexing problem for vets in the future.

This veterinary feature was first published in Horse & Hound (14 October 04).

Recent research on young racehorses by the Animal Health Trust (AHT) in Newmarket, supported by the Levy Board, has shown that nearly 80% of animals suffer from inflammatory airway disease in their first year of training.

Inflammatory airway disease can have serious repercussions on performance, and may also be associated with poor performance in National Hunt horses, which is currently credited to “a virus”.

While the incidence of IAD in hurdlers and steeplechasers is currently unknown, the AHT and the Levy Board intend to remedy this through a three-year study, which began recently.

Signs of respiratory disease vary considerably but may include:

• Low exercise tolerance
• Coughing
• Difficulty in breathing
• Excess mucus production

Good stable management is essential to reduce the risk of respiratory disorders, while recent research has indicated that dietary antioxidants may help reduce the incidences and severity of inflammatory airway disease.

Factors that may exacerbate respiratory disorders include exercise, pollution, dust and pollen. These result in reactive oxygen species (free radicals) damage to the lungs. Recent research has indicated that feeding a combination of antioxidants can significantly reduce this damage.

Free radicals are produced as a result of the body’s normal processes and environmental conditions. Normally the body uses antioxidants to prevent free radicals from damaging the body’s cells, however, in times of stress, such as when in training or racing regularly, excessive levels of free radicals may be produced. This will increase a horse’s risk of illness, including respiratory disease.

Antioxidants include vitamins, such as vitamin E and C, and minerals, such as selenium. In order for antioxidants to work effectively, a mixture of nutrients are required, which will help to reduce the risk of respiratory disease and airway inflammation caused by free radical damage.

In their natural environment horses would receive adequate levels of antioxidants from fresh grass. However, the current way in which most horses are managed reduces the levels of antioxidants available to them, while training methods increase the need for these vital nutrients.

Recent research published in the equine scientific press has shown that the levels of the important antioxidant, vitamin C, are significantly reduced in the lungs of horses suffering from airway disease. Most horses take several months to recover while some animals may never recover without dietary supplementation.

Without a healthy respiratory system, no horse can perform to its maximum ability so antioxidants could help make the difference between winning and coming second.

After lameness, horses with chronic respiratory problems are probably the biggest bane of their owner’s lives. According to Bruce McGorum of Edinburgh Vet School’s Easter Bush Veterinary Centre owner attitudes and commitment are vital to managing recurrent airway obstruction (RAO).

“We’re trying to move away from the term COPD to avoid confusion with an identically named but unrelated lung condition in humans,” says Bruce. “The preferred labels now are recurrent airway obstruction (RAO) or, quite simply, heaves.”

RAO closely resembles a type of occupational asthma that is well-recognised in humans working in dusty environments. In all cases, horses included, the disease results from inhaling dust, which is contaminated with endotoxin from certain bacterial cell walls, and/or a variety of moulds or fungal spores. For horses, the most common source of all these components is mouldy hay and straw.

“There is no quick fix to the problem of RAO,” Bruce explains. “Treatment with drugs such as bronchodilators to open the airways in the lungs is only partially and temporarily effective, and only really worthwhile as an adjunct to the critically important task of maintaining horses in as dust-free an environment as possible.

“This is where owners can make so much difference to the success and well being of their horses,” says Bruce.

“The best possible solution is to turn your horse out. Many horses, if rugged up properly, can happily live out all the year round, grazing and drainage permitting. But with racehorses and other high-performance horses, this option isn’t possible, so maintaining the stable environment dust free becomes the goal.

“Straw bedding is definitely out. Shavings, paper or rubber matting are the preferred options, with shavings the most common and easiest to use. The essential thing is that the shavings are kept spotlessly clean.

“Deep litter is not permitted as the endotoxin-producing bacteria multiply rapidly in urine and dung-stained shavings, making them just a bad as straw. Use the shavings sparingly and clean them out on a daily basis.

“Diet is also an important consideration. Although it’s easy to spot severely mouldy hay, visual inspection can’t pick up a more mildly affected but equally damaging product. Soaking hay doesn’t adequately reduce exposure to dusts and moulds and also leaches out much of the nutritional value. Hay is therefore ruled out of the diet in favour of low-dust alternatives such as silage, a complete cubed diet or, best of all, haylage.

“In addition to the above, good stable ventilation is essential. Keep the half-door

open at all times and install a vent with baffle in the opposite wall so that there is a constant flow of fresh air. And remember the adjacent environment, too. There’s little point trying to keep one stable in a yard dust-free if all the other horses close by are kept on hay and straw.

“The major limiting factors to success are the practicalities of the regime and the expense involved. But it is a rewarding condition to treat because if you alter the environment sufficiently, animals become both clinically and endoscopically normal within a fairly short space of time. If, however, the condition is neglected, structural lung changes can take place, resulting in permanent loss of optimum function.

“It is well worth stressing the point that ALL horses, not just those suffering from RAO, will reap substantial benefits from living in a dust-free environment. In addition, keeping dust levels low is important for human health, as it will reduce the chances of you and other staff developing dust-induced cough and asthma.”

This article was originally published in full in the 25 December issue of Horse & Hound. To purchase a back issue (tel: 020 8532 3628).

The respiratory tract is a common point of entry for many infections that can quietly take a hold despite showing no visible signs until the infection is well established. This is a good enough reason to consider quarantining all new arrivals at a yard.

A horrified horse owner may suddenly find that their horse has developed a respiratory infection with a combination of one or more of the following signs:

• A dirty nose
• A nasal discharge — this could be watery or thicker and yellow
• Swollen glands in the throat
• Fever
• Lack of appetite
• Depression
• Abscesses in the throat region

Depending upon which signs are presented, in an unvaccinated horse a dry cough, lack of appetite and high fever, for example, may be equine influenza, whereas a thick yellow nasal discharge and swollen glands may suggest strangles.

But all these signs can have many different causes. Flu is generally avoidable by vaccination, and although strangles is a common equine bacterial infection, a vet is unlikely to be able to determine exactly what infection is involved without laboratory testing.

Vet Karen Coumbe of Bell Equine recommends that “regular vaccination is advisable to reduce the severity of respiratory disease, and horse owners should contact their own vet for advice”.

Respiratory infections are common when large numbers of young, susceptible horses are brought together at sales and shows or for weaning and training.

Such infections can be spread by a number of factors:

• Direct contact — for example, horses touching noses and sharing water troughs
• Via human contact on clothes, buckets, hands and tack, etc
• Infected bedding, dried pus or nasal discharge — the strangles bug can live in these for weeks

If a respiratory infection is suspected, the following steps should be taken:

• Take the horse’s temperature regularly — it may be worth checking healthy horses too. An increased temperature may be an early indication of infection (use separate thermometers or disinfect)
• Isolate infected horses
• Avoid all contact between healthy and sick horses
• Provide adequate ventilation
• Be vigilant about hygiene and handling. Do not allow those caring for infected horses to handle others on the yard without a change of clothes and a shower
• Ensure all horses are vaccinated
• Maintain separate feeding, cleaning and grooming kit and, ideally, personnel for sick horses
• Treat any suspicion of a respiratory infection with care and contact your vet

This article was originally published in Horse & Hound as part of its popular Accident & Emergency series.

The most common cause of chronic coughing and equine breathing problems is an allergic reaction or hypersensitivity to the spores within the dust from hay and straw.

Horses which develop recurrent airway obstruction (RAO), or as it was formerly known chronic obstructive pulmonary disease (COPD), will, at worst, be constantly breathless, may cough repeatedly and suffer laboured breathing, or in milder cases they cough occasionally, lack stamina or have an increased rate of respiration.

Most horse owners are aware if their horse has a breathing problem and try to modify their stable management to minimise dust by incorporating some of the following suggestions into their daily routine.

• Use a dust-free bedding such as rubber matting and ensure good stable ventilation (not draughts)
• Feed haylage or soaked hay of good quality
• Groom outside
• Keep affected horses away from the muck heap, hay store and other horses on dusty bedding
• Remove the horse from the stable while mucking out
• Travel the horse in a dust-free environment
• Always feed from the floor

Signs that the condition may need veterinary intervention include wheezing, constant coughing, rapid shallow breathing or heaving — where a line appears along the bottom of the rib cage at the intake of each breath — and thick nasal discharge.

A horse suffering from acute symptoms should be turned out into a dust-free, airy space such as a paddock, kept quiet and closely observed.

Call the vet immediately if:

• The horse is really gasping and does not improve within the hour
• He has a temperature — this could indicate an infection
• If there is severe coughing that will not stop — this may indicate a blockage in the gullet or airway
• If there is a new loud roaring/snoring sound
• If the horse has had a recent chest injury

Veterinary surgeon Karen Coumbe from Bell Equine says: “If a vet is called to a horse with acute breathing difficulties, there are treatments which will help. However, they may only temporarily control the signs, not cure the condition.

“A closer examination, possibly involving passing an endoscope to examine the inside of the airways, may be suggested, to help find a longer-term solution. Many cases are reversible with aggressive treatment, particularly through good dust-free management.”

This article was originally published in the 30 October issue of Horse & Hound as part of the Accident & Emergency series. Don’t miss the current Accident & Emergency feature, which focuses on respiratory infections.

A range of different terms including heaves, COPD and RAO, have been used around the world in recent years to describe the signs of a cough and mucus in the horse.

However, the increased use of comparative medicine, between equines and humans for example, has made it important that both vets and medics use the same definitions when comparing research results.

According to Professor Edward Robinson from Michigan State University, who has undertaken extensive research into equine airway disease and presented his finding at the BEVA conference, COPD is no longer being used to describe airway disease in equines.

COPD is a human disease, predominantly suffered by old people who have smoked throughout their lives, who have a reduced response to bronchodilators and corticosteroids. Horses that suffer from a respiratory syndrome, are all ages, and have a good response to both bronchodilators and corticosteroids, therefore we should think of their syndrome as being environmentally induced asthma.

All horses suffering from an airway inflammation show similar signs:

• Airway obstruction from mucus or broncospasm due to a thickening of the airway wall
• cough
• hyper responsiveness of the airways

Recurrent airway obstruction (RAO) is the correct name for the most severe form of airway inflammation. Horses showing less severe signs are described as having inflammatory airway disease or IAD.

The degree to which your horse might suffer from RAO or IAD will depend on a number of factors but the one that you should be able to control the most is his environment.

The longer that he is exposed to dust or spores from hay the greater his response is likely to be.

Professor Bruce McGorum from Edinburgh Vet School is adamant that 95% of hay made in Britain is not of a sufficient hygienic quality to be fed to horses, therefore all hay for all horses should be fed soaked.

Horse owners should also consider the environment around their stables and in the school or arena in which you exercise their horses. A horse suffering from RAO or IAD will be hyper-responsive to all dusts in the air.

Top tips to reduce dust

• Thoroughly shake the hay before soaking for half an hour and feed while it is still wet
• If using straw bedding, then shake thoroughly before putting down, preferably in the straw store rather in the stable
• Dampen all surfaces before sweeping
• Remove the horse from the stable while mucking out
• Turn out every day
• Remember that soaking hay does remove nutrients especially the electrolyte minerals, so make sure that you feed a well-balanced ration
• Try and feed hay on the floor, so that the horse is not having to put its nose into a haynet, which is a concentrated dust carrier
• Consider dust-free alternatives to hay such as haylage or straw/alfalfa chops
• Alfalfa Chaff and Fibergy will keep a horse occupied longer than hay fed on the floor

Many feed companies provide hay analysis for horse owners who are concerned about the quality of their hay. Dodson & Horrell’s standard analysis focuses on protein, energy, sugars and fibre levels and costs £5, while a more in-depth analysis that looks at moulds and respirable particles is available for £40.

• For advice on feeding to balance your horse’s hay or haylage this winter call the Dodson & Horrell Helpline (tel: 0870 442 3322) normal national rates apply

In the worst cases of breathing difficulties, the affected horse will be perpetually breathless and/or coughing. His breathing will be laboured with heaving chest and flared nostrils.

In mild cases, they may just cough occasionally and have less stamina.

These symptoms develop as a result of an allergic response to organic dusts, particularly hay and straw dust and the fungal spores therein. If a sensitised horse is exposed to large amounts of an allergen, he will start to wheeze, cough and have difficulty in breathing.

In Britain, breathing problems are usually associated with a dust allergy. Conditions such as pneumonia are rare. Horses with Recurrent Airway Obstruction (RAO) suffer in the same way that people with asthma have allergies that make them breathless and wheezy.

General breathing difficulties can be due to either problems with the lungs (not taking on board enough oxygen), or an obstruction in the airways (preventing air getting in or out of the lungs).

If the lungs are involved, the horse may be wheezing, coughing or breathing rapidly and may sometimes have a sticky white or yellow discharge from the nose. If a blockage is suspected somewhere in the airway, the horse may make a loud respiratory noise that sounds as though he is roaring or snoring.

What to do

• Place the horse in a dust-free space, such as a paddock. Keep him quiet and under close observation. Exercise can make breathlessness worse, so do not make him move unnecessarily.
• Check the horse’s temperature for fever. This is unlikely but, if he has one, it suggests an infection. Contact your vet immediately.
• If the horse is breathless and gasping, and this does not improve within an hour, call your vet, particularly if the condition has come on rapidly.
• If there is severe coughing, the horse may have something stuck in his airways or gullet.
• If the horse has recently suffered a chest injury, call your vet at once.
• If there is a loud snoring or roaring sound all the time, call your vet. If this noise is only noticeable during exercise, it is not urgent, but do talk to your vet within a week.

This depends on the suspected cause. Medicines can be prescribed to help many breathing problems improve rapidly, but they may only control the symptoms temporarily rather than provide a cure. If there is an obstruction, the vet may perform a tracheostomy. In some cases, your vet may recommend an endoscopy, to examine the airways and lungs.

For practical help on what to do in an emergency, read First Aid for Horses by Karen Coumbe (JA Allen, £19.99).

Q: My 11-year-old 14.2hh cob gelding suffered from a virus last winter. He was very flat and exhausted. The vet came out and prescribed antibiotics and Ventipulmin for his breathing and he stabilised. I then gave him six weeks off and he’s been living out ever since. However, last month he collapsed.

The vet gave him chromoglycate and steroid nebuliser, which helped him recover. Now, he is off steroids, but he is still not 100 per cent and my vet has diagnosed “small airway disease”. He had a booster vaccine, which gave him a cough for a while afterwards, and is also is prone to mud fever. Can you help?

Homeopathic vet Nick Thompson MRCVS replies: This is a common problem – people get it too. Glandular fever and M.E. are thought to be manifestations of this chronic post viral fatigue-type syndrome.

One way to look at it is to imagine the virus comes along, hits the body and puts it out of balance. The virus is then more or less eliminated from the body, but the body cannot right itself.

Conventional medicine is very good at alleviating the symptoms – indeed, it may have saved your horse’s life – but if he does not get better, one gets into a chronic fatigue situation.

The homeopathic remedy Thuja is a good one to start with. It is often usedfor problems arising from a vaccine. In your horse’s case, there is not a direct link, but it is likely he had a reaction to his vaccine, as he had a cough afterwards.

This remedy can also help mud fever. I use a 1M potency twice daily for five days for treating skin, then stop and assess the response after a week.

Silica can also help vaccine-related problems, and is good for treating chronic weakness and allergies. Signs you’d look for are a yielding, delicate horse with a lack of confidence, that may be anxious about noise.

They hate cold weather, but dislike stuffy stables, especially when acutely ill. Lymph nodes are often enlarged and hoof quality may be poor. This type of horse will be a poor doer.

The horse’s larynx or “voicebox” is situated at the back of the throat and hasseveral important functions. It is at the crossroads between the respiratory system and the digestive passages and also has a role to play in vocalisation.

Just in front of the larynx is the soft palate, which is an extension of the roof of the mouth. Boluses (balls) of food are formed below the soft palate and above it is the horse’s airway.

For the majority of the time, the larynx is locked into this part of the airway with an airtight seal. During each breath, air moves from thenose, through the nasal chambers, over the soft palate and through the larynx into the windpipe.

This means that, at exercise, the horse must breathe through its nose and the positioning of the healthy larynx provides excellent streamlining of the airway, so that there is minimal disruption to the smooth flow of air and breathing is efficient.

In contrast, when the horse is eating and swallows food, the airtight seal is broken momentarily. The soft palate flips upwards to block offthe back of the nose and prevent the return of food through the nostrils.

The larynx closes to prevent food entering the windpipe which then allows food to pass down the gullet. If food enters the windpipe accidentally, it causes irritation andmakes the horse cough.

Diseases affecting the airway

The most common disease of the larynx is laryngeal paralysis due to a recurrent laryngeal neuropathy or paralysed nerve. Affected horses are often referred to as whistlers or roarers. A respiratory noise is caused by a disruption to the smooth flow of air along the respiratory route into the windpipe.

Recurrent laryngeal neuropathy is a disease which affects the recurrent laryngeal nerve and causes it to function poorly or not at all.

The healthy nerve energises a muscle on the larynx, making that side of the larynx open. If the nerve is diseased, it causes one side of the larynx (almost always the left side) to become weak or, in severe cases, completely paralysed.

This means that part of the larynx is not pulled open, tissue hangs down, obstructing the airway, and the sacule (a small opening on the side of the larynx) sags open.

Noise is generated at exercise when the horse breathes faster and air passes through the partly closed larynx and across the entrance of the open sacule. The air becomes turbulent, producing a whistling sound.

In addition to the respiratory noise, this disease also affects the amount of oxygen the horsegets into its lungs and, therefore, his bloodstream. The reduced oxygen intake diminishes the horse’s athletic performance.

Recurrent laryngeal neuropathy is thought by some to be an inherited disease and horses of more than 16hh are most susceptible. It is increasingly rare in horses under 15.2hh. This is because, in bigger horses the affected nerve is longer, making it more likely to function badly. The condition is often noticed once faster exercise starts, quite soon after the horseis broken in.

Solving breathing problems

The Hobday is a straightforward operation, which involves entering the larynx from underneath the throat and removing the sacule which is causing the turbulent air at exercise.

The vocal cord adjacent to the sacule is also often removed. This operation reduces the amount of respiratory noise produced at exercise but does not dramatically increase the amount of oxygen the horse obtains with each breath and so may have little effect on performance.

Another commonly performed operation is the tie-back. This involves placing a large suture on the affected side of the larynx to hold it in a permanently “open” position. The end result is improved oxygen uptake at exercise and,therefore, improved performance, but complications can arise.

The larynx is held permanently open and food can enter the windpipe causing coughing. Another problem is when the suture breaks, or pulls through, and the larynx loses its open position.

Affected horses

Horses performing only relatively light work such as quiet hacking don’t require high levels of oxygen so appear unaffected by laryngeal paralysis.

Show jumpers and dressage horses perform with maximum effort for relatively short periods of time and are not often required to perform fast work, so a degree of laryngeal paralysis can be quite easily tolerated.

Event horses manage much less well with any laryngeal paralysis once they have to attainfaster times on the cross-country phase. Any horse with poor laryngeal function will perform better if it is fitter than a normal horse would need to be to perform the required activity.

Q: My horse suffers from ROA. She is fine during the summer as she lives out, but she suffers quite badly when in at night during the winter, even though I feed haylage. Do you have any suggestions on how I can help relieve her symptoms?

Christine Smy replies: Recurrent Airway Obstruction (RAO), formerly known as Chronic Obstructive Pulmonary Disease (COPD), is a common respiratory problem. It is associated with dust and mould spores commonly found in sun-dried forages, such as hay and straw.

Even the best quality hay, which appears to have no dust when shaken, will contain thousands of microscopic spores, potentially causing a challenge to the respiratory system, resulting in coughing and wheezing.

There are several ways to feed forages to COPD sufferers:

• Soaking hay: Pull the hay apart, shake it and submerge totally for 10 minutes only. This either washes out the spores or swells them so they are ingested rather than inhaled. Soaking for more than 10 minutes will destroy nutrients.
• Feeding haylage: This has a higher moisture content than hay, around 35-50% compared to 15% in hay. The higher moisture sticks the spores to the stem, preventing them from being inhaled.However, in your mare’s case, it isn’t working, so your haylage may be too dry and releasing some spores. If possible, check the moisture content of your haylage by either looking at the bag (if it is a proprietary brand), asking who you bought it from or by feelingit. If it has a dry texture similar to hay, it may well be too dry.Once a bag of haylage is opened, keep it away from both heat, to prevent it drying out, or damp, which would encourage mould. Use it up within three days.
• Feed a hay replacer: The best are a blend of dried grass or alfalfa mixed with oat straw or hay and lightly coated with molasses. Don’t substitute hay with a molassed chaff as it will not provide adequate fibre or nutrition.
• Replace straw bedding with dust-free shavings or paper bedding. Make sure you muck out thoroughly, every day and do not muck out while your horse is in the stable.
• Make sure your mare isn’t stabled near horses bedded on straw or fed hay, or near to hay or straw storage as spores can travel long distances in the wind.

Respiratory disorders are common in horses, especially at this time of year when increasing numbers of horses are spending a larger proportion of their time indoors.

The most common respiratory condition suffered by adult horses in the UK is recurrent airway obstruction (RAO) which is also refered to as chronic obstructive pulmonary disease (COPD), ‘broken wind’, emphysema or heaves.

RAO facts

• Recurrent airway obstruction (RAO) is an allergic condition.
• RAO sufferers are usually allergic to mould spores in their environment.
• Affected horses should be kept in minimum-dust conditions.
• Drugs may help RAO, but are no substitute for good management.
• Your vet can advise you on minimum-dust management and whether drug therapy is necessary for your horse.

Creating a healthier environment

Hay is a major source of mould allergen and even the best hay contains sufficient spores to induce clinical signs of RAO in affected animals. Ideally, RAO sufferers should be fed mould-free haylage-type products.

If hay has to be fed, it should be thoroughly soaked prior to feeding so as to remove as many mould spores as possible. While it has been shown that soaking hay reduces its nutritive value, in most cases this is not a vital issue – RAO-affected horses are far more likely to be overweight than underweight.

Bedding is a prime source of mould in the stable environment. The best solution is to have no bedding at all, and use rubber matting instead. Stables with rubber matting must be well drained to avoid pooling of urine.

If you use conventional bedding, try mould-free products such as shredded paper or cardboard, bearing in mind that these materials must be well mucked out or they become as mouldy as the worst straw beds.

Mould from other stables or nearby hay and straw stores can be a source of contamination. As a result, the horse’s entire environment must be considered when formulating a minimum-dust policy.

Your vet is the best person to advise you on this and other aspects of minimum-dust management.

Q: My six-year-old part-bred Thoroughbred has been diagnosed with a mild case of COPD, which she developed before I got her. One of the symptoms is doubled expirations.

Could you explain what causes her to do this and if it causes any discomfort to her during exercise?

Jo Holmes MRCVS replies: Your mare has developed Chronic Obstructive Pulmonary Disease (COPD) which means that she has become allergic to some of the dusts and fungal spores found in hay and bedding.

The condition is also known as ‘heaves’ because one of the first signs of the problem is an increased respiratory effort and shortness of breath after exercise. The horse’s chest heaves in and out to pull in oxygen.

Healthy horses and humans breathe similarly; inspiration is active as the diaphragm (a large muscle separating thechest from the abdomen) contracts to allow air into the lungs.

Expiration is normally passive, requiring no effort, since the elastic recoil of stretched muscle propels air out of the lungs.

Horses with COPD are generally trying so hard tobreathe that expiration becomes active and other chest muscles have to be recruited to try and help with the expulsion of air from the lungs.

Sometimes a double expiratory effort is seen as the horse tries to remove the used-up air from itslungs before inhaling fresh lungfuls of oxygen.

COPD is similar to the conditions of asthma and farmer’s lung in humans – it is caused by exposure to dust and mould (allergens) in forage but some horses are more likely to develop it.

The internal lining of the lung becomes inflamed when exposed to allergens and swells up in a typical inflammatory response. This swelling narrows the airways and disrupts the passage of air containing vital oxygen.

Other clinical signs include achronic, soft cough and sometimes a ‘heave line’ where intercostal muscles around the rib cage have overdeveloped to assist expiration.

In acute cases, an increased respiratory rate may be seen even at rest in the stable. Normal respiratoryrate for a resting horse is eight to 12 breaths per minute but a horse suffering an acute attack of COPD may breathe more than 20 breaths per minute.

Your horse may show some intolerance to exercise since she is only likely to go at a speed at which she can cope. However, as long as you don’t try and push her beyond this, she shouldn’t experience too great a discomfort.

The best way to help her is to remove the causes of her allergy and change her environment. If you can keep her in a field at all times she will not be exposed to bedding allergens; soaked hay can supplement her grass diet if necessary. If she’s stabled, paper bedding and dust-free, vacuum-packed shavings are best.

If she still has problems when exercised, or you cannot change her stable management, there are various drugs that can help – speak to your vet for advice. I have had success with commercially available herbal feed supplements designed to boost respiratory function which are as effective as drugs.

The only other treatment involves allergy testing to find out exactly which fungal spores she is allergic to. Once identified, samples of the allergen are injected at regular intervals to desensitise the body and encourage it to develop an immunity. This procedure can take several months to work. One treatment may work better than another, on individual horses, so you may need to experiment.

It is likely that your mare will always be allergic to certain dusts andspores and you will have to ensure she is not exposed to them.

Read more expert advice about COPD:

• Coping with COPD
• Coughs understanding the causes
• How to cope with coughs

Chronic Obstructive Pulmonary Disease (COPD), which is also known by the term Recurrent Airway Obstruction (ROA), is an allergy.

The small airways of the lung are irritated by dust, moulds or pollen resulting in respiratory distress and noise. Because COPD interferes with the free flow of air to the lungs, affected horses often show more severe symptoms during exercise.

Traditional veterinary advice

Solutions to COPD are part-management, part-veterinary. Reducing the amount of foreign bodies in the air which might irritate the lungs is veryimportant, so keep the horse’s environment as dust-free as possible by:

• feed soaked hay or haylage from the ground
• ensure the stable is well ventilated
• turn your horse out regularly or full-time
• use low- or no-dust bedding such as paper or rubber matting.

Veterinary treatment involves increasing the damaged lung’s capacity for gaseous exchange in a similar way to human asthma inhalers. Drugs such as Ventipulmin and Sputolosin help loosen mucus and help the horse clear the discharge. In the short term, administering anti-allergy drugs such as steroid inhaler will calm lung irritation.

Alternative therapies

Herbs such as garlic are antiseptic and expectorant, encouraging the expulsion of mucus, while liquorice is soothing.

Homeopathic remedies might include Bryonia for a dry cough which is worse for movement, or Arsenicum Album for a wheezy cough in a chilly, anxious animal.

Hay or flouve essential oils can be administered internally to reduce the allergic reaction. Alternatively, massage the throat and underside of your horse’s neck with a gel containing one or a combination of the following, depending on your horse’s preferences:

• lavender (anti-bacterial, stimulates the immune system)
• eucalyptus (antiseptic, expectorant)
• yarrow (anti-inflammatory).

For more advice on coping with winter ailments, including rain scald, mud fever and galls, see the February issue of HORSE magazine, now on sale.