Equine Asthma - When Horses Run Out of Breath: Cause, Diagnosis and Treatment

Equine asthma: This often means breathless, sometimes seriously ill horses and desperate, helpless horse owners. What is behind this disease? To what extent are we responsible for it?

In this article, we will shed some light on the darkness. When exactly do we talk about Equine Asthma? What are the symptoms? What treatment options are available and when do they make sense?We look at the uncomfortable topic of responsibility. What are the (man-made) causes and how can we protect our horses? What measures can horse owners take to keep horses healthy? And, if the child has already fallen into the well, how can horses be supported in the best possible way in case of illness?

Equine asthma: What exactly is it?

Equine asthma is defined as a chronic, non-infectious disease of the deep airways, which is increasingly diagnosed in horses. One can definitely talk about a disease of civilization.

While it is absent or low in free-ranging horses, it is in the high double-digit percentages in our domesticated horses. According to studies, up to 80 percent of all horses, especially younger ones, suffer from low-to-moderate equine asthma. This primarily affects horses kept in stalls, but horses kept in open stalls and paddocks are also affected by this disease. Horses suffering from high grade equine asthma are severely ill. They try to avoid any movement as much as possible, because it costs too much energy. This makes living together in a group difficult to impossible. The breathing problems and the lack of air can make the horse panic as a flight animal and the well-being suffers considerably.

Different names - one disease?‍

Even the different terminology of this disease creates confusion. Let's take a closer look at the different abbreviations:

• EA (Equine Asthma. This is the internationally used generic term for chronic, allergy-related respiratory diseases in horses.‍
• COB (Chronic Obstructive Bronchitis). This term describes an inflammation of the bronchial tubes lasting longer than six weeks.
• Chronic: a condition that persists for more than 6 weeks.
• Obstructive: A narrowing of the airways, resulting in difficulty breathing.
• Bronchitis: The inflammation affects the bronchi (airways of the lungs)

‍This term says nothing about the severity of the disease.

• COPD: Chronic Obstructive Pulmonary Disease, a term originated in human medicine. It was used for a short time. It was thought to see parallels in treatment and progression. However, the causes and risk factors are completely different in horses and humans (especially smoking), so it was discarded at the beginning of 2000. The term COB‍ was then used again.
• IAD (Inflammatory Airway Disease) This term refers to a mild form of the disease that primarily affects younger horses and is characterized by symptoms such as lack of performance and persistent respiratory distress after exercise.
• RAO (Recurrent Airway Disease) It tends to affect older horses and is the name given to the moderate to high severity of the disease.
• Summer Pasture-Associated Obstructive Pulmonary Disease or SP-RAO (Summer Pasture-Associated Recurrent Airway Disease): This special form of RAO occurs seasonally in summer and is often referred to as summer bronchitis. It is triggered by allergens from grasses or trees to which horses react asthmatically.
  

Causes of equine asthma

The development of equine asthma is a complex interaction of various factors. Dust contamination in stables from bedding and roughage, as well as molds and feed mites, are particularly frequently responsible. In the seasonal form, SPAOPD, plant pollen also plays a role.

Inadequate ventilation and the formation of ammonia often contribute to the deterioration of the stable climate, especially in stables with mattress bedding. Bedding the stalls and sweeping the stable aisles can also lead to increased dust formation. 

Another reason is the increasingly poor quality of roughage. Incorrect storage and excessive humidity favor the formation of mold spores and storage mites. They favor the development of equine asthma.

In the dry summer months, exercising horses in dusty riding arenas and indoor arenas with inadequately watered floors can aggravate the situation.

Another major factor is the lack of exercise and the resulting inadequate ventilation of the lungs. This reduces the self-cleaning function. Mucus, bacteria and foreign substances are deposited.

All these above mentioned factors can lead then to the fact that the bronchial tubes of the horses gradually narrow. The increased mucus production makes breathing difficult, plus bronchial obstruction (automatic constriction of the muscles around the airways). Up to this stage, the disease is still curable. As the disease progresses, the airways are then "remodeled." Experts call this process "remodeling." During this process, the collagen fibers lose their elasticity, the lungs can no longer expand to meet demand and take in air only to a limited extent.

Equine asthma is caused by the interaction of suboptimal housing conditions and lack of exercise. 

The involvement of heredity and genetics in equine asthma is currently the subject of intense research.

The symptoms of equine asthma

The symptoms of EA are often complex and gradual. In the beginning, they are mild and barely noticeable. Coughing and nasal discharge, which are the most obvious signs for most horse owners, often appear only at an advanced stage of the disease.

A classic example is the occasional coughing at trotting, which is often not taken seriously. In many cases, even this symptom is absent, and the horses show no abnormalities at rest. They do not cough in the stable or in the pasture, and their respiratory rate is unremarkable. 

Only when the horses' performance gradually deteriorates and they are exhausted more quickly than usual do they become aware of the problem. The horses show less willingness to exercise and take longer to recover after work. Sometimes increased snorting is noticed at the beginning of work, and the horse may sweat more.

Athletic horses or those that are systematically trained often develop performance problems more quickly, which can be detected by close monitoring of training and performance. Fast and early treatment here can nip the disease in the bud.

In recreational horses that are exercised only occasionally or moderately, a decline in performance can often go unnoticed. It is estimated that the subtle symptoms of this condition are not recognized by owners in 95 percent of mildly affected pleasure horses. These horses therefore remain exposed to allergens and sources of irritation. Also omitted is the establishment of systematic training to activate self-cleaning of the lungs. 

To make matters worse, many horse owners whose horses are boarded have limited ability to influence housing conditions. They are not free to choose the type or quality of bedding and feeding, which can lead to compromises that unfortunately often have an unfavorable effect on the horses' health.

All these factors contribute to the fact that the disease can develop unnoticed from a mild, reversible form to a moderate to severe disease with limited curability. As a rule, the veterinarian is not consulted until the symptoms are obvious: regular to frequent coughing, difficult breathing with increased respiratory frequency and nasal discharge. 

In severe cases of equine asthma, horses may even be observed at rest with distended nostrils , with respiration assisted by the use of abdominal muscles. The increased abdominal breathing leads to the development of the characteristic space between the abdominal muscles known as the"vapor gutter".

• Cough
• Nasal discharge
• Coughing during trotting
• abnormal respiratory rate
• Deteriorated performance/lack of performance
• Prolonged recovery time after stress
• Low movement readiness
• increased snorting
• distended nostrils
• Increased abdominal breathing
• "Steam channel"
• from no abnormalities to severe asthma symptoms

Diagnostics according to plan for equine asthma

"Before therapy, the gods have set the diagnosis." Franz Volhard (1872-1950).
This quote still holds true in many areas, but especially with EA, many stumbling blocks lie here for the horse owner. Diagnosing equine asthma is often a challenge. Precisely because the onset of the disease is so subtle, the transitions from prevention with herbs and supplements to the point of chronic progression are often fluid. Also, the extremely increased scale of fees for veterinarians (GOT) ensures that one does not want to or even can call the veterinarian with "every little thing" or with a "vague suspicion".

In addition, many horse owners can only improve the way their horses are kept to a limited extent. The efforts to optimize something within the scope of possibilities (feed, bedding, grazing times, etc.) are often slow. This means that valuable time is often wasted. 

Veterinarians like to propagate how important early detection of the disease is, but unfortunately the reality is different. The "blame" does not always lie with the horse owners. Time pressure and lack of personnel in the field of veterinary medicine also lead to insufficient examination and incorrect assessment of symptoms in equine health.

Every concerned horse person knows this: Something is wrong with the horse, but there are no reliable data and facts. One argues from the "gut feeling" (my horse has something), is often laughed at for it and feels not taken seriously in his feeling, because the horse often stands well and does not make a "sick" impression.
Every good diagnosis is preceded by data and facts. That is why it is advisable to keep a health diary for your horse. This is as labor-intensive as it is informative when it comes to the complete tracing of symptoms. More about this in the chapter: "What you can do for your horse yourself". 

If you as a horse owner suspect the onset of EA, it is important to contact specialists, especially at this very early stage, so that they perform examinations according to plan and concept. This is important in order not to experiment around forever in the 1st stage, but to carry out the diagnostics quickly if necessary, so as not to prolong the disease.

The Step-by-Step Plan in Diagnostics at a Glance: 

‍

These stages are the approximate order of examination, which may of course vary according to the severity and stage of the disease. Not every horse needs to go through the entire diagnostic process. What is important is the success of treatment and, if necessary, the repetition of the appropriate steps. Therefore, diagnostics for respiratory diseases need not and cannot follow a fixed scheme . After each step, it is important to evaluate the findings and then consider what procedures might be useful next.

Stage 1 - Initial diagnosis of equine asthma: 

The 1st stage of diagnosis in equine asthma, which includes history and clinical examination, is critical for initial assessment of the horse's condition.

Classic anamnesis: Here, all relevant information about the horse is collected first. This can take the form of a standardized questionnaire filled out by the veterinarian or horse owner. This facilitates the recording of previous illnesses, husbandry conditions, feeding habits, amount of exercise and symptoms.

Use health diary: If you have already recorded data on the horse's disease history, you have a clear advantage here. Ideally, this diary should contain detailed records of symptoms, behavioral changes, abnormalities in training and all relevant data. This can provide valuable information to the veterinarian.

Clinical examination: It starts with an examination of the whole horse. How does the horse breathe? Does the horse flare its nostrils when breathing at rest and show clear signs of respiratory distress? Is the horse in pain or stress, which would explain a higher respiratory rate. Are ribs and belly in normal proportion? Is increased abdominal breathing noticeable or is the vapor trough visible on the side of the abdomen?

The training condition of the horses plays a significant role in the level of the respiratory rate. Very fit sport horses or very young animals can have a largely normal respiratory rate despite acute respiratory problems. Since thermoregulation of horses is via respiration, the external temperature at the time of examination is important. Thick robust horses with dense winter coats will try to cool down their body temperature by breathing at higher outside temperatures.

What is the texture and color of the mucous membranes should be included in the examination. Blue or purple colored mucous membranes may be a sign of intoxication or lack of oxygen in the horse. Heart failure could also be causative here. 

Swollen lymph nodes in the lower jaw are more likely to indicate an upper respiratory tract infection.

Listening with stethoscope: Both sides of the ribcage and the trachea are listened to. A slight noise on inhalation is normal, but exhalation should not be heard. Rattling, whistling or a crackling sound are indications of pneumonia. 

Exercise examination: In sport horses or horses that only cough under exercise, it is necessary and often very informative to listen to the lungs during and after exercise. In old horses or animals that are already struggling with severe respiratory restrictions, listening under stress should of course be omitted or only performed with the necessary sense of proportion.

But beware!!!

Stuck, viscous mucus does not cause any sounds or only sounds that are difficult to hear, even under stress. Negative findings, even after repeated listening, do not necessarily mean that everything is in order. Therefore, the significance of the examination is limited. Examination by endoscope can provide certainty here.

Provocation test: As the name implies, coughing is provoked here and triggered by pressure on the larynx. If the horse coughs several times in response, this indicates an overstimulated airway. 

Blood gas analysis: It is an objective method for more accurate assessment of respiratory disease and can be performed easily and quickly using a blood sample. Many mobile veterinarians now have the necessary equipment to do this. Blood gas analysis shows oxygenation in the blood, i.e. how effectively the horse is breathing. But - and you guessed it - in fit sport horses, you will find good values here even if there is an incipient respiratory disease. ‍

Stage 2 - Further diagnostics for equine asthma: ‍

If all the examinations of the first stage could be done mobile and in the stable, the horse has to go to a clinic for the next examinations.

Upper airway endoscopy: Endoscopy, also called bronchoscopy or reflection, provides images of the condition of the upper airway. The examination can be performed on a standing horse. However, it should be sedated for this purpose to avoid defensive reactions and the triggering of irritable coughs that can lead to injury. 

A tiny camera now provides information about the condition of the upper area of the lungs. In addition to mucus and secretions, inflammatory processes such as redness and swelling can be detected here. More rarely, tumors or foreign bodies are the cause of the cough.

A sample of the mucus, the so-called tracheobronchial secretion (TBS), can now be taken. More detailed examination for pathogens and inflammatory cells then takes place in the laboratory. The cell content in the mucus provides important information regarding the severity and duration (acute - subacute - chronic) of the lung disease.

Subsequently, the so-called bronchoalveolar lavage (BAL) is recommended. Often, it is not performed until the next examination stage, which, however, means additional stress for the horse. It is much gentler to perform both examinations together. In order to be able to penetrate deeper into the lungs, the endoscope tube is dipped out. A small amount of saline solution is then introduced and directly aspirated again. The saline reaches the alveoli, the air sacs in the lungs. Since equine asthma is a disease of the lower respiratory tract, this examination provides a much more accurate picture of the severity, degree of disease and whether allergy may be present. The level of certain cells such as neutrophils, mast cells or eosinophils can be determined in the obtained lavage sample. 

The number of inflammatory cells in particular (up to seven percent are considered normal) thus provides an accurate value about the severity of the disease.

• low-grade disease: inflammatory cells account for about 20 percent
  At this stage, the disease is still completely reversible. 
• medium- to high-grade disease: inflammatory cells are above 20 percent
  At this stage, the disease is no longer curable.

The mucus samples from the endoscopic examination and the rinse sample can also show whether an allergy may be present. Both samples provide important information for assessing the cause, the severity of the disease. They also help to establish the individual therapy.

Bronchoalveolar lavage (BAL) should not be confused with therapeutically applied lung lavage! ‍

Stage 3 - X-ray and ultrasound

An X-ray shows the size and shape of the lungs. It is used to assess the bronchial walls and the lung connective tissue.
Fluid or abscesses that suggest pneumonia can also be seen here. Compressions of the lung connective tissue indicate tumors.

Ultrasound can be used to examine the lung surface more closely for changes. Possible abscesses and tumors can also be detected here. 

Cortisone - Therapy and Management‍

No one likes to treat their horse with cortisone, and certainly not lightly. It is THE bugbear in the medicine cabinet for many. And yes, one should not disregard the side effects and any responsible veterinarian will inform the horse owners about the risks and benefits and then together weigh the next steps.

If one looks at cause and effect, researches cause-oriented approaches and the effective fight against inflammation, cortisone quickly loses its bad image.

Often, expectorant drugs are prescribed in combination with bronchodilators at the beginning. But especially with the latter, caution is advised! They open the bronchial tubes, mucus can drain off, at the same time dust and mold spores can also penetrate more easily and deeply. If the posture management as the most important success factor (plenty of fresh air, sufficient daily exercise and a low-dust environment) has not been optimized in advance in the best possible way, bronchodilator drugs can even be counterproductive.

Mucus is a reaction and consequence of inflammation. The body protects the inflamed areas of the lungs by producing mucus. So the primary goal should be to treat the inflammation of the airways, not to eliminate the mucus. 

Cortisone is the most effective anti-inflammatory available in the field of internal medicine. Early and short use of cortisone can prevent inflammation deep in the lungs. In this way, the development of mild asthma into a severe form can be avoided and the horse can be spared further stressful therapies or a severely impaired life.

‍Discussthe use of cortisone with your veterinarian and weigh the chances and risks carefully!

Supportive therapies 

Acupuncture, Acupressure, Shiatsu

These forms of treatment belong to Traditional Chinese Medicine (TCM). Concepts such as meridians (energy pathways), acupuncture points, yin and yang, emptiness and abundance, and the free flow of vital energy (chi or ki) are important aspects of Far Eastern or Oriental health teachings. It can alleviate and cure existing diseases, but its greatest value lies in profilaxis.

TCM works holistically, always focusing on the whole individual - body, mind and spirit, taking into account the parasympathetic and sympathetic nervous system. Acupuncture points can be stimulated with needles, light (controlled laser acupuncture) or finger pressure. 

Inhalation Therapy ‍

Inhalation therapy is an important adjunct in the treatment of respiratory diseases. It offers a wide range of applications, including various mask systems that can also be used in the stable, brine chambers in transporters and permanently installed inhalation boxes. This form of therapy is generally well suited for horses and can help support the respiratory system and relieve symptoms.

Hygiene and Cleanliness are Crucial‍

Proper hygiene and scrupulous cleanliness are of utmost importance in inhalation therapy. The equipment, tubing, masks, nebulizers and inhalation boxes must be thoroughly cleaned and disinfected before and after each use. This is critical to ensure that dirt, dust or pathogens do not enter the horse's airway. Therefore, it is not advisable to interchange the devices between different horses or to use one device for different horses, especially in stable communities

Herbal Therapy (Phytotherapy)

Herbal therapy is a proven and natural method of treatment. Herbs belong to the oldest remedies and are the natural feed of our horses. Despite their impressive effects, they often do not have the status they deserve. Many herbs and medicinal plants, such as nettle, ribwort, wild carrot, chicory or dandelion, have unfortunately disappeared from the pastures. Yet they contain important vitamins, minerals and trace elements as well as special constituents such as tannins, bitter, pungent or mucilage. The latter are often found in typical cough herbs.

However, it is important to note that there is no master plan in herbal therapy. The herbs must be carefully selected and individually adapted to the needs of the individual horse. Since many herbs also have a high allergenic potential, mixtures of many different herbs are usually not suitable for asthmatic horses. Therefore, phytotherapy requires a deep understanding of the herbs and their effects, as well as an individualized approach.

It is advisable to have herbal therapy performed only by trained professionals who have the necessary expertise and experience to select the right herbs in the right dosage.

What can you do for your horse?

In order to get equine asthma under control, posture optimization is essential and has top priority. Drug therapy can only be successful if low-dust husbandry and adequate exercise of the horse can be ensured.

These measures have absolute priority

‍Alternative Bedding‍

Straw often contains mold, which is one of the main causes of asthma. Alternatively, bedding can be made with softwood shavings, linseed bedding or elephant grass

‍Improved Stable Climate

The greatest concentration of dust and irritant gases occurs during mucking, feeding and sweeping. The large particles settle within one to two hours, but the invisible smallest particles can still be measured in high numbers several hours later. Optimizing the air in the stables is therefore essential.

‍Sufficient Movement‍

Adequate exercise is not only important for the metabolism and the psyche, but essential for the cleaning of the airways (mucociliary clearance). Well-designed physical training adapted to the severity of the disease is the most important and effective non-drug measure. It serves to alleviate symptoms, increase exercise capacity, and significantly improve the horse's quality of life.

The type of exercise can be chosen freely and versatile (free running, free jumping, lungeingHowever, it must be adapted to the horse's state of training and health. 

• Lots of exercise in the fresh air 
• Avoid dusty halls, riding arenas and paths 
• A lot of canter work, as far as the health of the horse allows it
• Training with pulse and respiration measurement
• Avoid standing days 

It is recommended to keep a training diary.

Good Roughage

The best feed even for horses with respiratory problems is still good quality hay. Poor quality roughage cannot be turned into healthy, high quality forage by watering or steaming. However, you can bind dust particles, kill fungi and bacteria, and thus lower the allergenic potential.

Which method is best depends much on the practicalities (space, electricity, water, time, protection from frost and other weather conditions).

Both methods have advantages and disadvantages and affect the feeding behavior of horses in different ways. Heat and leaching also lower the nutritional value of the hay, so the supply of good mineral feed is necessary. 

Massage

Massages can be very relaxing and helpful for many horses with breathing problems. Especially when breathing must be supported by the muscles, pain and tension often arise in the diaphragm, the intercostal muscles, but also abdominal, chest, shoulder and back muscles are strongly stressed.

Especially the at first sight minimalistic techniques like the Masterson method or Shiatsu help the horses not only to relax muscularly, they also calm the vegetative nervous system. Good therapists are happy to provide assistance.

‍Documentation

In order to track abnormalities, possible symptoms, improvement and progression of the disease, it is helpful to document each day in detail. This helps to better understand the disease and provides important information for any further treatment that may be necessary or the effect of measures already taken. Also document the other values (temperature and pulse).

Do you know the PAT values for horses?

Be very accurate at this stage! Document the first signs of coughing!!! When and where did it occur, is there a connection with weather, feeding, training, dust exposure (stable, riding arena)? Together with other important data such as pulse and respiratory rate, this will give an overall picture, which can be of great value for further diagnostics.

• Horse pulse: 23-40 beats per minute
• Respiration in horse: 8 -16 beats per minute
• Horse temperature: 37.5 - 38.2 degrees

To get a better control of the horse's performance, devices for pulse and respiration measurement can be used during training. There are also numerous diary apps with which the health values of the horse can be recorded digitally in the cell phone. This often facilitates documentation (pen and paper are not always at hand and not everyone's cup of tea). The big advantage: photos, videos and voice memos can also be stored here. 

Conclusion

Equine asthma is a disease that can be prevented by optimal housing conditions. Good stable climate, plenty of exercise and good hay are the most important health factors. Early treatment in case of suspicion, a corresponding commitment of the horse owners, as well as careful stable and feeding management can prevent the incurable course of the disease, which significantly affects the quality of life of the horses.