A Vet’s Guide to Navigating the Impact of Wildfire Smoke on Horses' Health
In recent years, there’s been a surge in the frequency and intensity of devastating wildfires across the globe. Beyond the immediate danger of death, the aftermath of wildfires can greatly harm a horse's health in the long term.
By Dr. Keaton Massie, DVM
Wildfires fill the air with smoke that leaves lasting consequences on the respiratory systems of horses long after the skies are clear, from lung problems to infections and other complications. The potential impact of smoke-polluted air on our beloved companions is starting to become a significant concern for horse owners.
What is in smoke?
Depending on what is burned, smoke has different chemical compositions. For instance, smoke from a house fire contains different chemicals compared to smoke from a wildfire. Wildfire smoke usually contains carbon dioxide, carbon monoxide, particulate matter, soot, hydrocarbons, and various organic materials, such as nitrogen oxides.
The biggest worry here for our horses is the particulate matter because these particles are incredibly small (less than 2.5 microns in diameter) and can penetrate deep into the lungs.
Effects of Smoke on Horses
When animals breathe in smoke, they inhale a dangerous mix of gases like carbon monoxide and hydrogen cyanide, along with tiny solid and liquid particles called particulate matter. All of these elements enter their throat, nose, and lungs, blocking air passages and inducing swelling in the airways.
This can result in asthma, respiratory illnesses, and infections. Smaller particles can reach the lower airways and cause even more harm, affecting the lungs' ability to clear irritants effectively.
Normally, a horse's lungs expel pollutants like dust and pollen within about 24 hours. When particulate matter finds its way into the lungs, however, it can linger there for weeks. Horses in close proximity to wildfires face a higher risk of immediate harm, including death, due to the toxic gases present.
During exercise, the effects of smoke inhalation become even more pronounced. You see, animals breathe in much more air when they exercise, and horses have an enormous lung capacity that can inhale as much as 2,200 liters of air every minute during vigorous exercise. With this massive volume of air, just about any tiny pollutant can lodge within the bronchioles and alveoli of the lungs, leading to inflammation and sometimes pneumonia. This reduces horses’ stamina, makes them tire quickly, and affects their overall performance.
Assessing affected Horses
Horses react in varying degrees to wildfire smoke. High concentrations of particulates in the air can lead to various respiratory symptoms in horses, like repetitive coughing, increased nasal discharge, flared nostrils, wheezing, and labored breathing.
When at rest, a horse typically takes between 12 to 24 breaths per minute. Any horse that takes close to 30 breaths per minute is in respiratory distress and should be seen by a veterinarian immediately.
Protecting Horses from Air Pollution
First, I always advise horse owners to stay informed about the Air Quality Index (AQI) in their area at all times. The AQI is a measure of air quality that rates how clean or polluted the air is. It is reported on a scale from 0 to 500 in countries like the USA and Australia, with 500 being the most hazardous level of air pollution.
Although the AQI is primarily designed for human health, it can also provide valuable insights for safeguarding the well-being of horses. Generally, it is recommended to keep animals indoors when the AQI is over 150 for multiple days in a row.
Here are practical steps to keep your horses safe during and after wildfires:
Limit outdoor physical activity when smoke is visible or the AQI is above 150. At levels above 200, avoid all forms of exercise altogether.
Soak forage and hay before feeding them to horses. This helps to reduce the dust and allergens that might be present.
Hydration is Key. Make sure they always have access to clean, fresh water. Water keeps the airways moist and aids in the removal of inhaled particulate matter.
Place fans with misters in the barn to humidify the air
Feed Vitamin E (3000-4000 IU's per day per 1000 pound horse)
Feed omega fatty acids.
Contact your veterinarian if your horse seems to be in respiratory distress. They can recommend appropriate treatments based on your horse's needs.
Pay extra attention to horses with underlying respiratory diseases like asthma. Keep them indoors at AQI levels above 100.
Regulate exercise after wildfires. Even when the smoke seems to have dissipated, opt for lighter workouts and keep a close eye on their breathing rate and overall well-being.
Allow your horse sufficient time to recover from airway damage. This usually takes about 4-6 weeks.
Stay Informed by keeping an eye on local air quality reports and wildfire updates.
When Can My Horse Return to Work?
Foreign particulates are moved deeper into the lungs during exercise. Here are two charts from Dawn Sherwood, Assistant Professor at Oregon State University, to help guide you in deciding when to return your horse to work post smoke exposure.
As we navigate the increasingly frequent occurrences of wildfires, horse owners need to be proactive in preventing serious respiratory issues that arise from smoke inhalation. I believe the tips listed above will help you properly care for your horses. If you have further questions about handling horses affected by wildfire smoke, reach out to me below.