When horses cough, immediate action is needed


If your horse starts coughing, it needs to be investigated and diagnosed without delay, as management can be key to preventing further damage caused by equine asthma, researchers say.

Prevention of airway problems is the best way to protect your horse from equine asthma, but if this is not successful, early intervention is paramount, a group of researchers from around the world noted in Frontiers in Veterinary Science.

Equine asthma, commonly referred to as heaves, Recurrent Airway Obscruction (RAO) or Inflammatory Airway Disease (IAD), starts off with a hypersensitivity reaction to particles in the air (e.g., dust, mould). These particles cause inflammation in the airways and restrict airflow.

The horse will struggle to breathe even at rest. The “heave line” develops along the lower edge of the ribcage as the horse has to work harder to breathe, due to inflammation and airway obstruction. The chest muscles must work harder during each breath taken by the horse. If a heave line appears, the disease has already progressed to advanced stages.

Intervention is recommended at the first sign of coughing, and more so if the cough is repetitive or persistent. Triggered by the microscopic particles that cause airway inflammation, common signs of equine asthma include coughing, nasal discharge, exercise intolerance and breathing difficulties. Equine asthma can affect horses at any age in any discipline of riding.

The importance of prevention

Veterinarian Renaud Leguillette from the University of Calgary says that feeding horses from a round hay bale can potentially double the risk of developing equine asthma. Horses are picky eaters and do not hesitate to bury their heads deep in the round bale to look for the most desirable hay first. In doing so they inhale all sorts of dust, mould and particulates.

Many stabled horses are exposed to exponentially more inhalable irritants than horses kept outside. Keeping a horse at pasture is often the best option for those suffering from equine asthma. Every precaution to reduce dust in the environment should be taken. Low dust bedding, turning horses out before sweeping, cleaning stalls regularly to keep ammonia levels low and clearing out any mould under stall mats are just some of the effective measures that can be taken. Maintaining arena footing to minimize dust, making sure the barn is well ventilated and feeding steamed hay and soaked concentrates are all environmental factors within the farm owner’s control.

Causes and diagnostics

If asthma is suspected, the veterinarian will be looking closely at the horse’s environment to determine what is causing the irritation in the lungs. They will be looking at all potential causes which could include: Dusty environments, smoke inhalation, pollen or other allergens and particles in the pasture or hay.

One cannot jump to conclusions at the first sign of a cough. The vet will need to rule out upper airway diseases and bacterial or viral infections. Bronchoalveolar lavage (BAL) is the gold standard diagnostic test for asthma.

Corticosteroids administered with or without a bronchodilator may be prescribed to help the horse recover from bouts of equine asthma, but environmental improvement is the key to long-term management.

Always bring in the veterinarian to check a horse that repeatedly coughs. It is vital to prevent the debilitating progression of asthma.

Equine Asthma: Current Understanding and Future Directions. Laurent Couetil, Jacqueline M. Cardwell, Renaud Leguillette, Melissa Mazan, Eric Richard, Dorothee Bienzle, Michela Bullone, Vinzenz Gerber, Kathleen Ivester, Jean-Pierre Lavoie, James Martin, Gabriel Moran, Artur Niedźwiedź, Nicola Pusterla, and Cyprianna Swiderski. Frontiers in Veterinary Science. doi: 10.3389/fvets.2020.00450

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