Heat Stress Awareness in Horses

HEAT STRESS AWARENESS IN HORSES What is heat stress? Heat stress occurs when the horse's body's means of controlling its internal temperature starts to fail. As a result, a number of clinical problems , including anhidrosis, rhabdomyolysis (tying up), synchronous diaphragmatic flutter, heat stroke, exhaustive disease syndrome, and sudden death can occur. Horses more at risk of heat stress Signs Skin is hot to touch Rectal temperature above normal range of exercising horse (above 103.5°F) Horses grazing on endophyte-infect- ed fescue Horses recently moved from a cooler climate Older horses Foals treated for Rhodococcus equi using a macrolide antibiotics Distressed appearance Rapid, shallow breathing Muscle tremor Slow capillary refill Dark mucous membranes Dehydrated horses Horses with Larger horses Trailered horses Profuse or no sweating anhidrosis Decreased performance Dark urine Collapse Overweight Darker col- Out of shape horses When the humidity index is >180 Horses ored horses What to do if you suspect heat stress Contact a veterinarian immediately if your horse displays any signs of heat stress. You'll need to rapidly cool the horse Move the horse into a shaded, well-ventilated area. Apply cold water or ice over their body concentrating on the neck area. Use alcohol baths if cold water is not available. Keep hosing and scraping off the water until the water is no longer heating up the horse or you take its temperature to confirm its back to its normal body temperature. Do not force the horse to walk although voluntary movement in the shade is fine. Stand the horse in front of a fan or misting fan if avail- able. Do not use wet towels or any fabric cover because these prevent heat convection. Offer all three of the following: cold, lukewarm, and electrolyte-supplemented water. Do not withold water. If a horse is prone to tying up, do not directly apply ice water to the large gluteal muscles in the hind end, but focus on areas where blood vessels are more superficial (i.e. head, neck, back and rib area). Methods to prevent heat stress Mg P Na Fat WORK PRE-COOLING THE PROVIDE LET THEM ROLL FEEDING A MODIFICATIONS HORSE ELECTROLYTES IN THE SAND HIGH-FAT DIỆT In sweating, a horse losses salt, potassium and magnsium from its body. Supplementing with electrolytes will help offset these losses. Using fat as an energy Keep horse in good con- Prior to starting any work, while the horse is still at its normal body Rolling in sand helps dition. Reduce the redistribute the heat source produces less length of time spent warming up. Take fre- quent breaks. Do not work horse beyond its fitness level. Keep work light in warm weather. reserves from their gut metabolic heat for the temperature , hose the horse's body with cold and enhances heat energy produced, then shedding from their carbohydrates. It water. coat which increases results in the horse the evaporative surface having less heat to up to 100%. dissipate. STOP ALLOW TIME TO DONT WORK IF WATER ALWAYS TURNOUT HORSES PROVIDE SHADE ACCLIMATE TOO HOT AVAILABLE AT NIGHT OR SHELTER It takes 15 - 21 days for Don't ride in the middle Always be sure to If an indoor stable is Provide horses the a horse to fully accli- mate moving from a cool or drier climate to a hot , humid enviroment. of the day. Adjust your available, allow horse option to get relief from the sun by allowing provide horses with schedule to ride earlier fresh, clean and cool to rest in a stall with a in the morning or later in the evening when its cooler temperatures. fan during the day and turn out at night. water so they don't access to shade from become dehydrated. trees or buildings. Also be aware horses drink more when its warmer. Sources http://www.extension.umn.edu/agriculture/horse/care/manag- ing-horses-during-hot-weather/index.html http://aces.nmsu.edu/pubs/_b/b-711/welcome.html http://www.equestrianwa.org.au/site/equestrian/wa/down- loads/Dressage/Helping_horses_handle_heat_191210.pdf http://www.ncbi.nlm.nih.gov/pubmed/8847243 http://animalscience.ag.utk.edu/horse/pdf/HorseExpress/HrseExp%20V.21%2ONO.3.pdf Horse DVM com