This past week has been very trying for all of us. I am concerned about you and your horse and have put together the following information to assist you in returning your horse to work.

Wildfire smoke causes air quality to be poor. The Air Quality Index (AQI) is used to gauge the safety of exercise for human athletes. The AQI can also be used as an index to assess the safety of equine exercise in smoky environments. Moderate to intense exercise should be reduced or limited in sensitive horses when AQI is over 100. AQI over 200 is considered extremely unhealthy, and training or competition should be postponed or canceled. Standing in and breathing smoke-filled air with an AQI over 200 will cause inflammation and damage to your horse's airway.

Airway damage resulting from wildfire smoke takes 4-6 weeks to heal. Ideally, plan on giving your horse that amount of time off from the time when the air quality returns to normal. Attempting exercise may aggravate the condition, delay the healing process, and compromise your horse's performance for many weeks or months.

After the smoke has dissipated and the AQI is under 100, the following return to an exercise program can be started.

Week 1 & 2 – pasture turnout and slow hand walk daily for 20 minutes.
Week 3 – Brisk hand walk daily for 30 minutes.
Week 4 – Ride at a walk
Week 5 & 6 – Ride at a walk and trot
Week 7 – Return to regular exercise

Your horse will need to be examined if any of the following clinical signs are observed. Call on the emergency line.

Resting respiratory rate more than 30 bpm,
Obvious flaring of nostrils,
Wheezing or noisy breathing,
Increased effort of breathing with the development of a "heave line" along the horse's lower abdomen,
Repetitive or deep coughing,
Abnormal nasal discharge, or
Non-pink mucus membranes

The following additional management aids will be helpful to your horse.

Wet the hay to decrease dust
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.
Platinum Performance is already high in omega fatty acids.

Please know that other veterinarians and I are not making the restricted return to exercise recommendations lightly. There is a 2019 research study by Bond et al., published in the Journal of Veterinary Internal Medicine, measured the inhalation and aerobic capacity in exercising polo ponies that had wildfire smoke inhalation from the Calgary wildfires. The aerobic capacity, or oxygen uptake, of an exercising horse, is measured by the maximal oxygen consumption or VO2 max. Bond's study conducted VO2 max measurement with wildfire smoke in the air and then again after two and a half weeks of wildfire smoke-free air. The horses had a 15% increase in speed with a similar increase in VO2max after being in smoke-free air for two and a half weeks. This research shows the profound effect of smoke on the horse's lung function and performance.

Oregon Equine is here to help you and your horse get through this trying time and back to enjoying your activities together. Please call with questions or concerns.

Sincerely:

Dr. Janine M Wilson DVM, CAC

503-631-4100