Emphysema is not a death sentence. Konniy Mir (Horse World), #1-2004
What will you do if your beloved horse starts coughing? In 99% of all cases you will shut the stable door tight, seal all of the seams, cracks and air vents, stop turning the horse out and wrap your favorite warm scarf around his neck. When I try to persuade the horse owners in the opposite - keep the horse warm with a horse blanket, open all doors and widows or even arrange to keep the horse outside, they either argue with me, or pretend to agree and do the opposite when I'm out of sight. It is very hard to combat prejudice.
You can find coughing horses in almost every stable. Poor ventilation can very often lead to one of the most common diseases of stabled horses - acute or recurrent airway obstruction (RAO; COPD, heaves). In our country this condition is also known as emphysema, heaves, horse asthma or allergy.
The relationship between stabling, hay feeding and respiratory disease has been recognized for over 300 years. Poor ventilation and stall maintenance, grooming horses in their stalls, hay dust have shown to negatively affect the equine respiratory tract. The stable air is filled with minute dust and fungal spores, dead skin sells, dust mites, etc, which act as irritants and allergens to the airways. Affected horses develop a hypersensitivity reaction to the dust, resulting in an asthmatic reaction, primarily characterized by chronic coughing, which is true for 80% of all COPD-affected horses. At the same time, the absence of cough unfortunately doesn't mean the absence of inflammation.
Research conducted in Switzerland showed that 50% of horses without visible signs of COPD are nevertheless affected by the disease. No clinical symptoms may be present (the disease is diagnosed via endoscopic examination) or they may result in poor performance, coughing, increased nasal discharge, wheezing or labored breathing, etc. In severe cases the horse may develop a muscular "heave line"* along his barrel.
*"Heave line" represents the thickened edge of hypertrophic external abdominal oblique muscles, caused by forced expiratory efforts.
What Happens in the Lungs?
The majority of inhaled dust particles deposit within the upper airway. However some fungal spores, particularly Aspergillus fumigatus and actinomycete Faenia rectivirgula, are small enough to reach the bronchioles, where they cause irritation to the respiratory tract, leading to increased mucus production, smooth muscle contraction and therefore narrowing of the airways.
The inflamation is able to reach the alveoli (thin-walled air-filled spaces surrounded by a capillary bed), where gaseous exchange occurs. Oxygen diffuses from the pulmonary alveoli into the hemoglobin in the red blood cells, which carries respiratory gases throughout the body and releases carbon dioxide into the alveoli. The inflammation of the alveoli causes them to be flooded with liquid, thus reducing the efficiency of the gas exchange process.
It is unnecessary, I suppose, to explain the influence of reduced oxygen availability over all body systems - the blood level of carbon dioxide increases and the level of oxygen decreases, causing major damage to vital organs. It must be obvious, that a horse in such a poor condition is unable to work.
Disease is Easier to Prevent Then to Cure
It is impossible to remove all dust from the air, however in 95% of all cases preventive measures can help combat the problem.
Never neglect any of the above-mentioned rules. Keep in mind that medical treatment is not effective without lifestyle changes and cannot be combined with improper treatment.
How to Recognize the Disease
Veterinarians often mistakenly diagnose a coughing horse with bronchitis or pneumonia. However, horses do not easily catch a cold or the flu - 95% of coughing horses have COPD.
It easy to distinguish COPD from respiratory tract infection without calling in a veterinarian - you need to take the horse's temperature. In bronchitis, the cough is usually accompanied by high fever, while COPD doesn't lead to an elevation of the body temperature. If your horse is running a fever, call a veterinarian right away.
First signs. At first affected horses do not have a temperature and appear well in themselves. After a while you will notice a loss of exercise tolerance, and then the other signs will follow:
As the condition progresses:
The affected horse may develop severe respiratory difficulties, similar to acute asthmatic attacks. The coughing becomes continuous; the animal breathes with flared nostrils. The horse will expand the flanks dramatically when inhaling and contract them spasmodically when exhaling. The animal's labored breathing is loud enough to be heard from a distance - sometimes you can hear the COPD-affected horse on entering the stable.
There may be some temporary improvements, followed by sudden deterioration in the condition. Asthma attacks will eventually lead to the death of the animal.
As for exercising a COPD-affected horse - if the stable hygiene is good and the horse has a mild case of COPD (1-5 coughing spells during the exercise), he can exercise in fresh air. Be careful to avoid fatigue.
A light workout will help keep the horse's respiratory tract toned. If the horse is coughing during exercise, stop and allow the horse to clear the airways! If the horse is heaving or coughs more than 10 times during the exercise, he should not be exercised and should only be allowed to walk.
The owners of COPD-affected horses are often misled by incompetent veterinarians. Don't let them treat your horse with trimediazine and antibiotics if the horse is not running a fever! These medicines may bring temporary improvement, but the condition will relapse without fresh air and changes in stable management. Don't ever read "ancient" Soviet books on equine medical treatment!
Bronchodilators (ventipulmin) are used when the above-mentioned measures are not effective - it is useless to treat the horse with ventipulmin without proper management practices! Ventipulmin relaxes the smooth muscle of the airways.
Mucolytics reduce the viscosity of mucus and help clear the lower airways.
Antibiotics are used if secondary infection is suspected.
Hormone-based medication - corticosteroids - is used only in severe cases.
Corticosteroids suppress inflammation, but cannot be used over a long period of time as they cause serious side effects, including laminitis.
Sodium cromoglycate can give a 20-day protection against exacerbation of the disease. The drug is usually given by inhalation: several drops of the medicine are inhaled through a special nebulizer mask; the treatment course lasts 4 days.
The fungal spores may not be the only trigger; the horse may also be allergic to foods or various other things. More than 30 allergens have already been listed. Western scientists are developing vaccines against COPD.
If you asked me whether the condition is curable - I would give a definite "yes, with proper stable management practices, timely diagnosed and treated". The latest scientific research has produced encouraging results - it has been proved that damaged alveoli can actually be restored.
Even the most severe chronic cases are curable. Lethal outcomes which are not rare in our country are mostly due to ignorance and negligence of horse-owners and veterinarians. The fact is that the disease can be prevented and cured with no medication whatsoever.
It hurts me to say that of course there may be cases so severe, that the only possible way to relieve the suffering of a poor animal is euthanasia...
To prevent the disease - keep your horse as natural as possible. The horse must not live in the stable! Thie horse is created for fields!