b'endotoxin, were referring to infectivelast bit of oxygen when theyre galloping.bacteria, but were not actually talkingIn those horses, she says, youre going about an infection at all, says Mazan.to notice equine asthma before you hear Were talking about little portions, espe- a cough or see nasal discharge. Usually, cially of Gram-negative bacteria, that endtheyll be a bit slower than previously. And up in the environment. Its in manure, allin a racehorse, just 1/100th of a second types of grain and pelleted feeds, in hay,can mean the difference between winning in s havingsits everywhere. And beta-and placing several horses back.glucans are anywhere theres hay andYoull also see that they have more where theres mold of any kind. Again,trouble paying back their oxygen debt were not talking about fungal infection;when they stop workingthey may run were talking about the bits and pieceswell but not recover well, she adds.of the structure of mold that are highlyWhat about horses at a performance inflammatory in the respiratory system level thats a step down from racingboth in horses and humans. high-level show jumpers, for example, that We think of asthma in people asarent pushed until theyre a bit older and being an allergic disease (involving antrain longer and slower? When theyre 6, immune-system response to irritants),7, or 8 years old, they wont have quite the but actually theres an enormous compo- brilliance they once had, or there might be nent of human asthma thats far more likean intermittent cough or clear or mucoid what we think the majority of horses arenasal discharge, says Mazan.getting, which is occupational asthma, Stepping down another notch, she says she adds. This can involve irritation fromthe moderate-level dressage horse might inhaling particulates and toxins in the air. have had a little bit of a cough and nasal Julia Montgomery, DVM, PhD, Dipl.discharge and suddenly around age 10 ACVIM, associate professor of largehas become what she calls a respiratory animal clinical sciences at the Universitycripple: He cant move; hes breathing of Saskatchewans Western College ofhard. We dont know what triggers the Veterinary Medicine, concurs. When ithorse that has had moderate equine asth-comes to asthma, managing the environ- ma to become this horse with the typical, ment is the most important thing; drugsold-fashioned term heaves, which most alone will never fix it, she says. If youaccurately describes it: They stand there dont address air quality, nothing else willwith their sides heaving, and they work work long-term. extraordinarily hard to breathe.To that end, she and her colleaguesThe type of asthma your horse has also work with each client who owns a horseaffects his performance, says Mont-with asthma in three areas: What isgomery. There are two formsmild or environmental; what is appropriate; andmoderate and severe. Severe presents what is feasible. She advises keeping awith clinical signs at rest: abdominal journal to pinpoint a horses triggers, thenmovement and coughing. Mild to moder-addressing those areas. For example, if aate asthma doesnt display many clinical dusty arena heightens a horses asthma,signs at rest, but the horse will cough clients can address that at home. But ifduring exercise and perform poorly.they travel to shows, she might talk toThe most commonly ignored sign is them about options for when theyre away. coughing, she adds. Dont ignore your SHELLEY PAULSONhorses routine coughing; there may be Asthmas Effect on Performance more to it.So how does equine asthma affect your horses performance? That depends on hisEvaluate Your Barns Air Qualitycompetition level and type of asthma. To determine where to start with reme-She says those airborne particles areRegarding performance level, Ma- dial efforts, you can hire an environmental the No. 1 cause of equine asthma, andzan considers how much of the horsesengineer to measure your barns air qual-the particulates with the worst effectrespiratory reserve his job requires. Aity, or you can work with your veterinar-are those containing endotoxins (whichracehorse needs every last little bit of itsian or researchers at a veterinary school to bacterial cells release as they disintegrate)respiratory reserve, she says. All horsesdetermine areas for i mprovement. and beta-glucans (which form a part ofthat gallop become markedly hypoxemicIn a study Mazan was involved with the structure of common molds). (low on blood oxygen), and their CO 2levelabout 10 years ago, the investigators Anybody with a background in biol- rises. But racehorses live on the razorfound that 10 hours of barn exposure ogy may think that when we refer toedge of sustainability. They suck up everycould increase human and horse risk for TheHorse.com|The HorseFebruary 202017Asthma_USE.indd 17 1/3/20 10:32 AM'