The Horse:Your Guide To Equine Health Care provides monthly equine health care information to horse owners, breeders, veterinarians, barn/farm managers, trainer/riding instructors, and others involved in the hands-on care of the horse.
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A52 TheHorse.com/AAEP2017 AAEP Wrap-Up THE HORSE March 2018 YOUR GUIDE TO THE 2017 AAEP CONVENTION SPONSORED BY Melissa Mazan, DVM, Dipl. ACVIM, a professor at Tufts University Cummings School of Veterinary Medicine's Hospital for Large Animals, in North Grafton, Mas- sachusetts, reviewed how veterinarians can best treat and manage equine asthma. Treatment goals for RAO and IAD are similar, Mazan said, with a few key differ- ences. Goals for RAO should include: ■ Relieving bronchospasm that causes coughing and labored breathing; ■ Reducing lower airway inflammation; ■ Preventing acute episodes in the long term by controlling lower airway in- flammation and obstruction; and ■ Returning the horse to athletic function. Treatment goals for IAD should include: ■ Eliminating bronchospasm; ■ Reducing mucous production and airway obstruction; ■ Reducing airway reactivity; and ■ Preventing recurrences. "Treatment of these diseases entails a team approach and an acceptance that this may be a lifelong problem that may be modified, but that is unlikely to go away," she said. "One of the most impor- tant aspects to successful treatment is the establishment of a reasonable definition of return to athletic use," she added. While a young IAD horse might return to full function, an older RAO one might only be suitable for light pleasure riding. It's also important for veterinarians to consider the horse's history (Is the condi- tion seasonal? Worse indoors than out?) before implementing a treatment and management plan, Mazan said. Regardless, veterinarians have a few pharmacological therapy options: Corticosteroids Mazan called these drugs the cornerstone of successful treat- ment for both IAD and RAO. Researchers have shown that systemic oral or inject- able corticosteroids work well for treating horses with heaves, but they appear less effective in IAD horses. Veterinarians use prednisolone and dexamethasone most frequently. They can also administer inhaled corticosteroids. Vets commonly prescribe the aerosolized drugs flutica- sone and beclomethasone for owners to administer via a metered-dose inhaler, such as the Aerohippus or EquineHaler, she said. Depending on how severe a horse's clinical signs are, a veterinarian might choose to begin treatment with systemic medications or with a combination of systemic and inhaled aerosolized medica- tions, said Mazan. With a chronic case the vet might opt for aerosolized delivery. "The decision as to which delivery method is preferable may be influenced by a number of factors, including finan- cial, given that aerosolized drugs and their delivery devices are quite expensive." Bronchodilators Veterinarians often use aerosolized bronchodilators because they produce fewer side effects, Mazan said, but systemic options are also available. The two types of bronchodilators include β -2 agonists (e.g., albuterol, clenbuterol) and parasympatholytics (e.g., ipratro- pium, hyoscine butylbromide). "A very important caveat is that using corticosteroids (and bronchodilators) without remediating the environment is like using hand sanitizer without wash- ing your hands," Mazan said. "It's better than nothing, but much less effective than removing the actual problem." The root problem might be within your very own barn. "The barn environment is replete with organic particulate matter, respirable endotoxins, molds, and volatile gases such as ammonia," Mazan said. She offered tips for improving RAO and IAD horses' environments: ■ Hay is notoriously dusty. If possible, switch to pelleted hay, complete feed, or silage. If you must use hay, soak or steam it and feed from the ground. ■ Avoid storing hay above stalls, or place a tarp beneath it to reduce downstairs dust and allergen exposure. ■ If your grains and concentrates are dusty, wet or soak them prior to feeding. ■ Use wood shavings and other low-dust beddings rather than straw. ■ Dampen aisleways before sweeping, and avoid using leaf-blowers. ■ Remove horses from the barn before performing chores. ■ Keep barns and stalls free of cobwebs and other materials that collect dust. ■ Leave barn doors and windows open when possible for air movement. ■ Use low-dust footing in arenas, or reduce current footing's dust by adding a humectant or hygroscopic agent. Medical treatment and environmental management go hand-in-hand when car- ing for horses with asthma. Mazan encour- aged practitioners to monitor treatment outcomes to ensure horses are improving. Lack of improvement could suggest an infectious disease and the need for addi- tional diagnostics and treatment. h ISTOCK.COM If your horse has asthma, take steps to keep his environment as low-dust as possible. e Visit TheHorse.com/AAEP2017 ■ Evaluating Horse Airways: At Rest, During Exer- cise, or Both? TheHorse.com/40199