A. Having lived in Northern California for many years during large wildfires, I understand your concerns firsthand. A horse’s respiratory system is the main limiter of performance.
While it’s possible to improve cardiac function and muscle mass, as well as the strength and skill to perform certain expectations, the respiratory system cannot be greatly improved through exercise. The ability to transfer oxygen across lung membranes into the bloodstream sets the upper limit on how much oxygen is available to reach muscle tissues. Muscles need oxygen to metabolize fuel stores of fats and carbohydrates using aerobic metabolism.
When a horse is asked to work hard and when adequate oxygen isn’t available, the body recruits anaerobic metabolism, which provides less total energy and can only use carbohydrate as a substrate. So, a horse with a reduced ability to bring in and transfer oxygen might have to switch to anaerobic metabolism sooner than a horse with a greater ability to deliver oxygen to muscle tissue. Any lung tissue damage will, therefore, have a negative impact on that horse’s performance capacity, so we should consider airway health in horse management, especially performance horse management.
Smoky air leads to breathing in tiny airborne particles. The horse’s respiratory system has mechanisms that reduce the risk of particles reaching the sensitive lung tissue, but smoky conditions might overwhelm. Additionally, smoke particles are tiny, often smaller than 1 micron in diameter, which means they can reach the deepest lung tissues.
These small particles can cause coughing and wheezing, as well as increased airway mucus production and, thus, nasal discharge as the body tries to expel the foreign particles. The horse’s immune system is also impacted, which might lower his ability to handle more normal day-to-day irritants such as pollens, dust, and mold.
When smoke is obviously in the air, it’s important not to ride and place additional stress on the horse’s respiratory system. From a nutritional standpoint, make sure your horses have access to fresh, clean water to keep them hydrated, which in turn keeps their airways moist and more able to expel inhaled particles. If not grazing pasture, horses tend to drink more water if it’s placed near their hay. Encourage adequate water intake by feeding salt.
Consider soaking hay to reduce inhalation of dust particles that might further irritate the airways. Soaking will also reduce inhalation of mold, fungi, and pollen from the hay. Try limiting dust, mold, and fungi exposure in the rest of the horse’s environment by using dust-free bedding such as hemp. Use of fans (always use fans designed for barns and properly installed and maintained to prevent barn fires) in the barn can help keep air moving, which is important because smoky air is often heavy and sits, becoming stagnant.
Lung irritants can cause inflammation in lung tissue, so consider feeding a supplement that helps support a healthy inflammatory response. The most basic of these would be an omega-3 source, because research shows omega-3 fatty acids might benefit horses with respiratory conditions.
For horses that already have respiratory conditions such as equine asthma, talk to your vet prior to fire season to see whether you should have something like a nebulizer on hand. Horses negatively impacted by smoke may need support from bronchodilators, nebulization, and intravenous fluids.
If your horse starts to show symptoms of respiratory distress because of smoke inhalation, contact your veterinarian immediately. Know your horse’s normal respiratory rate, and check it regularly to see whether his breathing rate has increased in an attempt to supply more oxygen. When unsure if your horse is suffering from the effects of smoke this guide from the University of California at Davis is a helpful resource.