b'HANDLING THE HEATbodily events that trigger the brain to tellFerry. Only transport your horses duringvasodilation, sweating, and breathing. the horse, Im thirsty, thus driving him tothe coolest times of the day or at night,Consider body temperatures up to 101.3 replenish the water supply by drinking.and ensure good air circulation. If youdegrees F normal; beyond that, the horse Normally, horses find electrolytes inmust tie your horse outside on a hot day,is starting to experience hyperthermia, or plants or soil, says Mejdell. But whensuch as to the trailer at a competition, tryheat stroke, says Ferry. horses are performing in the heat, be- to find a place with shade and a breeze.At 105.8 degrees F vasodilation calls ing transported, or otherwise dealingexcessive blood away from the organs to with hot conditions, they might needShade Structures the skin. This is a major emergency and supplementation.Studies have shown that when given thecan lead to death, she says. Electrolyte supplements come aschoice while at rest, horses seek shade onAbove 108.5 degrees F, proteins in the powders or pastes, which are particularlyhot days. We saw frequent, brief (aboutbrain (and other organs) risk coagulation, useful for athletes needing to replenishsix-minute) bouts, with horses going in forsays Dahlborn. If the brains thermoregu-electrolytes lost during exercise. Other- short stays about 17 times a day, mostly inlation control centers fail, thermoregula-wise, horses should have regular accessthe mornings, says Holcomb.tion fails, she says. to a salt/mineral block or loose salt, espe- However, poorly ventilated shaded ar- Ferry says other warning signs of heat cially during extreme heat, says Ferry. eas might not be cooling enough to temptstress or stroke include:horses to spend time in them, she says. Constantly increasing respiratory rate, The Exercise Factor even 30 minutes after exercise.Horse muscle is powerful stuff, burning Dry, sticky gums.a lot of energy. That energy comes fromWhen horses exer- Gums that take longer than one second the muscle cells high metabolic capacity,cise, about 20% of theto turn pink again from white after which generates physical activity, as wellyouve pressed them with a fingertip as all that heat, says Dahlborn.metabolism in the (capillary refill time).When horses exercise, about 20% ofmuscle cells is used forA general unwell appearance, possibly the metabolism in the muscle cells iswith muscle soreness or colic signs.used for work, and the remaining 80%work, and the remain-I n advanced stages, increasing heart becomes heat, she says. The addeding 80% becomes heat.rate, red mucous membranes, loss of heat isnt wasted, however; it heats theconsciousness, and falling down.body when its cold outside, and it keepsDR. KRISTINA DAHLBORN If you notice any of these signs, stop muscles warm while working. working the horse immediately and place Still, this means most cases of heatBoth man-made buildings and naturalhim in a cool, shady, well-ventilated stress occur following intense and/or longvegetation (trees) can provide appropriatearea, ideally with fans, says Ferry. Offer exercise sessions in hot environments,shade, says Jrgensen.fresh water and cool him however you Ferry explains. Good planning can helpFor best practices, shade should becan, hosing or pouring cool water on the protect your horse from overheating.made available at all hours of the day dur- neck, chest, legs, head, and poll, which Avoid intense work during the hottesting hot, sunny weather, says Holcomb.houses the nerves responsible for sensing times of the day, she says. Aim for earlythermoregulation. Use a sweat scraper mornings when the air is still cool, andTipping the Bodys Limits to avoid reheating the body, she adds. hose and sweat-scrape your horse after. Generally speaking, horses have evolvedIf you follow these steps, the horses to live in ambient temperatures rangingtemperature should drop 2 degrees C (3.6 The Airflow Factor from -40 to 104 degrees F, says Dahlborn.degrees F) within 10 minutes, says Ferry.Horses thermoregulate better inBut the scope of temperatures they canIf the horse doesnt recover within that environments with good airflow, becausetolerate is probably more restricted,period, call a veterinarian immediately. fresh air can remove heat from the horse,depending on their breed, health, bodyHe or she will probably provide intrave-says Kathy Holcomb, PhD, retired profes- condition, and even colorwith darkernous fluids and/or administer rehydration sor from the University of California,horses absorbing more of the suns rays.liquids by nasal tube.Davis, School of Veterinary Medicine.Still, if we consider this range as withinIf the organs were affected, expect Free-roaming horses or domestictwo extremes, we find that most parts ofthem to take awhile to recover, says horses on large pastures with varied ter- the world likely reach the upper (hotter)Ferry. The horse will probably have to be rain migrate during severe heat to spotslimit more than the lower. While manyoff work for a prolonged period of time.with good airflow. But confined horsesowners stress about their horses getting have less choice, she says. cold in winter, Mejdell says the heat of theTake-Home MessageFans can keep air circulating withinsummer is the greater risk.Most horses can cope with hot condi-barns, says Jrgensen, as can air inletsMeasure if a horse is getting too hot bytions if they have access to self-cooling and outlets, mesh stall fronts, and openchecking his temperature with a rectalopportunities, says Mejdell. Our role as windows and doors. thermometer, say Holcomb. It will rise ifowners is to provide our horses with ways Pay attention to stagnant hot air inhes experiencing heat stroke because theto thermoregulate properly while at rest trailers and poorly ventilated stalls, saysbody can no longer dissipate heat throughand stay cool when in work.h14August 2020The Horse|TheHorse.com'