When air becomes scarce – COB, COPD, or RAO?

The causes of chronic coughing in horses are very diverse and their significance has not yet been clearly established. Initial triggers can be acute infections of the respiratory tract with viruses, bacteria, or even lungworms. The mucous membrane of the respiratory tract swells and increased amounts of mucus are produced, which can no longer be transported away properly. Breathing becomes difficult due to the narrowing of the small airways and the horse tries to cough up the excess mucus. Other causes include environmental allergens that come into contact with the horse's lungs. These include mold, pollen, mites, and hay or straw dust. Animals whose airways are already weakened by infection are particularly susceptible. Harmful gases, such as poor stable air with excessive ammonia concentrations, can also act as physical irritants and lead to impaired lung function. Another factor can be a lack of exercise, as the lungs' cleansing function is not sufficiently activated when the horse is not exercised enough.

Two factors cause the small airways to narrow. The stimuli described above lead to increased production of bronchial mucus. At the same time, the ability of the cilia (tiny hairs that move the mucus) to transport the increasingly thick mucus decreases. Secondly, the airways become hypersensitive to certain stimuli, leading to a spastic overreaction of the small bronchi. Without veterinary treatment, irreversible damage to the lung tissue can occur, making normal lung function impossible. The increased formation of connective tissue between the alveoli causes the lungs to permanently lose their elasticity, a condition known as pulmonary fibrosis. The term "asthma," which is now incorrectly used to describe any respiratory disease, strictly speaking only describes the final stage of RAO, which is characterized by pulmonary emphysema, overinflation, and destruction of the alveoli.

In the initial stage, only a slight cough is sometimes noticeable, which in some cases only occurs at the beginning of exertion. In some cases, the horses also have nasal discharge, which is initially watery but can later become whitish-yellowish. Affected horses show reduced stamina and tire more quickly. Even at rest, a significantly increased respiratory rate with sometimes audible breathing sounds is noticeable. In advanced cases, shortness of breath and fever may occur.

The affected horses have visible difficulty breathing, and their respiratory muscles have to work much harder than those of a healthy horse. If the abdominal muscles are also actively used to assist exhalation, an indentation between the rib cage and the abdominal muscles becomes visible. This so-called "steam channel" is familiar to most horse owners and indicates a serious respiratory problem. The high energy expenditure involved in breathing therefore also leads to weight loss in the horse if the condition persists. So don't waste any time if your horse is coughing. Contact a veterinarian right at the onset of the illness to determine the cause.

A good preliminary report is essential for the veterinarian to make an accurate diagnosis. This means that you must provide them with detailed information about when and how the horse coughs, how it is kept, and whether there have been any changes in its living and feeding conditions. During the examination, the veterinarian will listen to the horse's lungs and may also tap them. If the symptoms are not very clear at first, it may be necessary to listen to the horse again after exercise or respiratory stimulation. Further examination methods may be used to confirm the diagnosis. X-rays, blood gas analysis, or endoscopy of the respiratory tract can sometimes even be performed in the stable. Samples taken during these procedures are then examined in the laboratory.

Even though RAO is generally considered incurable, the first step, in addition to medication, is to review the horse's posture and feeding regime and adapt them to the condition. It should be noted that even if the symptoms subside, the hypersensitivity of the bronchial tubes remains and will accompany the horse throughout its life.

The focus should always be on optimizing the air quality for the horse in question, as a significant improvement in symptoms can be observed simply by reducing all dust-producing factors. For box stabling, low-dust bedding should be chosen and only wet hay or haylage (pressed, lactic acid-fermented hay, packed in airtight containers) should be fed. Window boxes, paddock boxes, or, ideally, year-round open stables/exercise stables with optimal fresh air supply are preferable for horses with RAO.

Another essential aspect in the treatment of horses with chronic coughing is continuous exercise, as this is the only way to remove stuck mucus from the bronchi and lungs. Free movement is at least as helpful as targeted lunging, riding, or walking. Always ensure that the exercise program is moderate, as your horse is still ill and should not overexert itself.

Medication aims to relieve bronchial spasms and liquefy the thick mucus so that it can be transported out of the bronchi. Mucolytics and antispasmodic and bronchodilator preparations are the preferred treatments for this. Inhaling certain medications can help to liquefy the thick bronchial mucus. Your veterinary practice will draw up a detailed treatment plan for your individual case and can send you the medications for your horse digitally via petsXL, so that you can find all upcoming medication doses in your timeline and set reminders for yourself.

Although all these measures and treatments cannot cure the disease, they can keep it well under control. Maintaining optimal conditions remains the top priority. Only then can your horse breathe deeply again and enjoy its life to the fullest together with you.