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  • Writer's pictureMireille Doffegnies

Horses and Air Quality

RESPIRATORY CONSIDERATIONS FOR HORSES IN SMOKEY ENVIRONMENTS By:  Dr. Sylvia Ouellette, DVM DABVP (Equine) Sr. Veterinarian, Oakhurst Equine Veterinary Services

Image Design by: Alta Equine Sports Medicine Dr. Sylvia Ouellette, DVM wrote a very informative article about caring for your horse in smokey environments given all the wildfires in Oregon, Washington, California and other places in the US (and around the world), and resultant poor air quality.  Let's continue to pray for all the people and horses affected . Thank you Dr. Sylvia!! Due to all the wildfires in the region, we have been fielding a lot of calls regarding when it is considered unhealthy for horses to exercise or be outdoors. There have been a few great articles written within the last few years regarding this issue. One of the key considerations is to look at the Air Quality Index (AQI) to determine what is considered unhealthy or unsafe. Equus Magazine created the chart below listing the AQI colors and ranges and what they mean for horses.1

In case you are wondering what the numbers mean, the EPA calculates the AQI for five major air pollutants regulated by the Clean Air Act: ground-level ozone, particle pollution (also known as particulate matter), carbon monoxide, sulfur dioxide, and nitrogen dioxide. The higher the AQI value, the greater the level of air pollution and the greater the health concern.

The bottom line is when the AQI goes above 151 (range 151-200), it is unhealthy for any horse, whether they have underlying respiratory issues or not, to do any exercise outdoors. Keep in mind our equine friends have to live outside 24/7 in this air! Unless you have a barn that can be fully closed off from the outside environment with a separate source of air, most barns are still considered "outside" environments. During the fires in Oregon, for example, a lot of our AQI’s have reached into the mid to high 400’s and have been in the mid 200’s for days. The University of California, Davis also put out a great article quoting air quality index and how it pertains to human athletes, and stated that "All athletes should be removed from outdoor practice or competition venues at AQI of 200 or above. 2 " They "recommended 2 weeks off based on the AQI which was over 400 and took more than 10 days to resume normalcy." According to the UC Davis publication, "The effects of smoke on horses are similar to effects on humans: irritation of the eyes and respiratory tract, aggravation of conditions like heaves (recurrent airway obstruction), and reduced lung function. High concentrations of particulates can cause persistent cough, increased nasal discharge, wheezing and increased physical effort in breathing. Particulates can also alter the immune system and reduce the ability of the lungs to remove foreign materials, such as pollen and bacteria, to which horses are normally exposed."2 What Can You Do For Your Horse? A lot of people want to know what they can do to keep their horses comfortable. For now, if your horse is otherwise healthy and does not have any underlying respiratory diseases, here are some suggestions:

1) Keep your horse calm and limit exercise, especially when smoke is visible. 2) Wet down the hay or area that they live in to further reduce inhaled particulates. 3) Make sure your horse has fresh clean water available at all times. 4) The lungs have a normal ciliary apparatus that allows it to clear particles from the environment that gets trapped in the lower airways. Coughing is then utilized to help clear the subsequent mucous that develops. A mild cough will be normal in these circumstances and should not be suppressed. What About Using A Nebulizer? Chronic nebulization can alter the above mentioned pathway and should be avoided in normal horses. Nebulization can be a useful tool for horses with respiratory issues, but in normal horses, can open the airways to allow more particulate matter to settle deeper into the lungs. Additionally, you need to know what you are nebulizing with as some drugs that are nebulized can have harmful side effects if your horse has an underlying problem. Also, you need to make sure the nebulizer machine has been properly sterilized in between horses in order to prevent the spread of diseases, including introducing bacteria that may cause pneumonia. If your horse is showing signs of respiratory distress such as chronic cough, nasal discharge, difficulty breathing or abdominal breathing, fever, keeping head and neck extended to try to breath, pale or grey mucous membranes, then please call your veterinarian immediately and seek treatment. When Can My Horse Go Back To Work? Dr. Pinkerton, from UC Davis, recommends that horses return to exercise no sooner than 2 weeks post smoke-inhalation, following the clearance of smoke from the atmosphere. Going online and checking the air quality index in the area where your horse lives is a good idea. It will help you to make an informed decision on when you feel it is safe to start introducing exercise outdoors for both yourself and your horses. Please consult with your veterinarian if you are concerned about your horse’s respiratory health during these times. Thank you so much for making a commitment to your horse’s health and well-being! 1 Equus Magazine: What you need to know about the air quality index. Christine Barakat with Melinda Freckleton, DVM Sept 5, 2018 2 UCDAVIS: Guidelines for Horse Exposed to Wildfire Smoke. Dr. Kent Pinkerton. December 13, 2017

About Dr. Sylvia Ouellette Dr. Sylvia Ouellette (pronounced Wool-let) graduated from the University of California at Davis in 1991 with a Bachelors of Science in Zoology and a Doctorate of Veterinary Medicine in 1995. She began practicing in Southern California at the Racetrack circuit upon graduation. In 2001, Dr. Ouellette left the racetrack to open her own practice in the Los Angeles area, specializing in lameness in sport horses.  After practicing for 10 years and successfully completing an extensive application and examination process, in 2005, Dr. Ouellette became board certified as an equine specialist with the American Board of Veterinary Practitioners (ABVP).  Several years ago, Dr. Ouellette decided to leave Los Angeles for a great opportunity to work in the Pacific Northwest with Dr. Jack Root’s practice.  She specializes in complex lameness and back issues as well as general equine medicine.

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