COPD in Horses

Chronic Obstructive Pulmonary Disease is also known as Heaves, Equine Asthma, Emphysema or Broken Wind.

For all of their bulk, courage and majesty horses have finely tuned and delicate internal systems which go wrong very easily.

Respiratory problems cause coughing, increased respiration and laboured breathing. A yellow nasal discharge may also be present. Breathing can so severe that the horse appears listless, may wheeze and can develop a muscular ‘heave line’ along the horse’s barrel from taking a double exhalation. Usually, the appetite is normal unless the condition is so severe the horse has extreme difficulty breathing.

COPD  is caused by environmental problems such as dusty or mouldy hay, dust and moulds in bedding, or pollens, dust and other irritants in the environment. When airborne allergens get down into the airways, they irritate the cells and cause mucus secretion, which will trigger a snort or cough. However, if the horse is allergic to one or more of these particle types, inhaling them will also cause inflammation. Large numbers of white blood cells move into the area. Some of these cells secrete chemicals that cause swelling. Others produce antibodies to the allergen(s) which causes even more inflammation.

Because of the mucus and inflammation, less air can get through. The smooth muscles in the walls of the lower airways constrict to prevent the allergens from passing further down into the lungs which reduce the amount of total air space in the airways and lungs. Wheezing and coughing occur, which then worsen the irritation and inflammation in the lungs, causing a vicious circle in which the body’s own defences ultimately cause the most harm. 

COPD is on the extreme end of the respiratory allergy scale. It is most likely to develop in colder climates, and in horses over age 7 that are stabled in the winter rather than pastured. A stable is usually a dusty place, and that dust can contain many allergens. Straw bedding and hay are primary sources of a wide variety of allergens. When a horse is breathing this dust for hours at a time, problems can arise. Even clean hay contains small amounts of mould, dust mites, pollen, and other debris; mouldy hay, of course, is even more contaminated. In damp or humid conditions bacteria and mould in the hay can grow increasing the risk.

Any but not all horses exposed to respiratory irritants may develop COPD. The longer they are exposed the more severe the condition may become. Horses kept stabled may be at higher risk. The usual picture of a horse at risk is one, usually over 7 who is stabled during the winter, basically most horses. Housing, feed, bedding, weather, and activity are all factors that influence the risk. Horses involved in high-intensity activities are particularly susceptible, especially if they live, train, or work in cold-weather conditions.

Cold weather itself may be a significant problem for many horses. Exercising in very cold temperatures has been shown to cause inflammation in the lungs and airways, and maybe a large factor in the development of respiratory problems. 

A study of horses of varying ages housed in a conventional stables found that although they appeared perfectly healthy, were performing well, and had no outward signs of lung problems all of them had microscopic evidence of inflammatory airway disease. This suggests that any horse can develop respiratory problems. 

Being aware of the likelihood of COPD can help if owners are aware of the subtle signs of the beginning of the illness. If recognised early enough management changes may slow or even prevent its onset.  If the horse is continually exposed to the irritants the disease may progress to the point where the horse is unable to thrive.

There isn’t good news for owners of horses who live outdoors either. Even horses on pasture can sometimes become allergic to certain moulds or pollens and develop “Summer Pasture Associated Obstructive Pulmonary Disease (SPAOPD).” About 10% of COPD horses also have SPAOPD.

Good management practices can help avoid or control COPD. Try to ensure there is a good flow of air into the stables and ensure any fodder and bedding is mould and dust free. Muck out frequently as the ammonia fumes from stables can also further irritate the respiratory system. 

However, horses need to be out of the stables while they are cleaned and kept out until the dust settles. Hay should be stored away from the stables and kept as dry as possible. Hay stored in the same barn with COPD horses was shown to rapidly cause heaves symptoms and worsening of lung function. Wood shavings, shredded paper, or rubber mats should be used for bedding instead of straw, to minimize dust; good quality straw may also be less dusty.

There are drugs available to help alleviate symptoms and some owners find various herbal or natural remedies effective. The bad news is that there is no sure cure; once a horse has COPD it will always be at risk of further lung damage, but with good management should be able to work and live a fairly normal life.  Conventional medicine treatment generally includes anti-inflammatory steroids and bronchodilators which reduce the muscular spasms in the lungs.

Unfortunately, these drugs have serious side effects including laminitis and also suppress the immune system, making the horse more susceptible to viruses and other infectious diseases. Inhaled steroids deliver a smaller dose to a more focused area, but require daily or twice-daily administration using a special mask. Conventional drugs may not be suitable for long-term management of the problem because of potential side effects and also because they contain prohibited substances under the rules of various equine sport governing bodies.

There are holistic treatments available. Essential fatty acids, with their antioxidant and healing properties, are one such option. Herbs can be a safe, effective alternative to drugs for COPD. Many herbs would help with some of the symptoms of the disease. Yarrow is often used for upper respiratory complaints. Herbs used need to include an antioxidant which will reduce inflammation-causing molecules in the body that contribute to asthma. It also needs to be antifungal, to inhibit mould particles that commonly cause COPD, immune-modulating, to decrease the over-reactive immune response to allergens, have anti-inflammatory properties to protect the lungs from the harmful effects of inflammation.

You may be able to find Funtumia Elastica, a Traditional Asthma Remedy in health food shops.  This native African plant has important antioxidant, antifungal, anti-inflammatory, and antibiotic properties. It is traditionally used in its native environment, to treat asthma, allergies, and other respiratory issues, as well as malaria. It has no known toxicity and is not barred by any equine sport governing body.

With careful management, whether you go down the herbal route, or stick with conventional medicine and good stable practices there is no reason why a horse with breathing problems shouldn’t have a full and useful life. 

Precautions: This article is an advisory post only.  It is solely your own responsibility when feeding natural supplements to animals. If you are giving any other type of drug or medication to your horse, please check with your vet to make sure it is still safe to administer.

by Jacqui Broderick

Image credits: Pixabay