Horses, for all their size and power, are delicate, sensitive animals. For sport horses and other equine athletes, the difference between a great performer and a disabled pasture pet can be a very fine line. While physical injuries and ailments like colic are easily recognizable, signs of respiratory disorders can be very subtle, especially in the early stages. Yet, respiratory disease can have as much or even greater impact on the horse’s well-being and performance than many more obvious problems.
The classic picture of risk is a mature horse (usually 6 or older) who is stabled during the winter. However, any horse can develop airway inflammation that can progress to serious disease over time. While it is always essential to watch your horse for subtle signs of illness, it is also important to understand that significant airway disease may be present long before obvious symptoms occur.
One study of horses of all ages housed in a conventional stable found that-although the horses all 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. Housing, feed, bedding, weather, and activity are all factors that influence the risk for any individual horse. Horses involved in high-intensity activities are particularly susceptible, especially if they live, train, or work in cold-weather conditions. Exercising in frigid temperatures has been shown to cause inflammation in the lungs and airways, and may be a large factor in the development of respiratory infections and asthma.
Signs of respiratory problems include poor performance, tiring more easily, taking longer for breathing to return to normal after exercise, increased breathing rate or effort, increased nasal mucus, increased snorting, coughing, and wheezing. These signs can be extremely subtle. They may be almost unnoticeable, since they can develop gradually over time. If your horse is not performing at its peak and no other reason can be found, respiratory disease could be to blame.
Equine respiratory diseases are usually environmentally based. Allergies to dust, mold, mites, or other airborne particles frequently occur. Hay and straw are the most common sources of these particles. When mold spores, pollens, mites, or other particles are inhaled, the respiratory lining cells secrete mucus to try to lift and discharge the particles, thus stimulating the horse to blow them out (snort) or cough.
Respiratory allergies develop when the horse inhales certain particles, including dust and storage mites, molds, and pollens, and the immune system reacts extra-strongly to them. Some allergies are present from birth, but others develop over time, with chronic exposure. This is why problems are seen most often in older horses.
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); this causes even more inflammation. Because of the mucus and inflammation, less air can get through. To make matters worse, smooth muscles in the walls of the lower airways constrict to prevent the allergens from passing further down into the lungs. This reduces 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. It is a vicious circle in which the body’s own defenses ultimately cause the most harm.
With mild allergies, symptoms may seem minor (or may not even be noticeable), and not affect the horse’s performance; but the problem tends to get worse over time. Therefore, it’s best to take preventive action early-before the allergic reaction gets worse.
It’s worth noting that every exposure to the allergen causes inflammation that lasts for days, so horses that are outside during the day and only exposed to dust and allergens in the stable at night or in the arena are still at risk.
If not brought under control, airway inflammation can lead to Inflammatory Airway Disease (IAD), Reactive Airway Disease (RAD, also called Chronic Obstructive Pulmonary Disease–COPD–or “heaves.”)
Environmental management is crucial to preventing and managing these horses. Excellent hygiene, good ventilation, and clean feed are the basics. Beyond environment, holistic care, such as giving herbs with antioxidant and anti-inflammatory properties can also be very helpful, and may go a long way toward preventing the development of career-ending respiratory disease.
Last update on 2021-06-19 / Affiliate links / Images from Amazon Product Advertising API