How Hot Can a Horse Get?
It doesn’t need to be a hot day for a horse to heat up as the exercise will heat up the horse, especially his feet and his tendons. 80% of aerobically created energy (uses oxygen) creates heat as a by-product. The sun will also create heat on the skin surface of the horse. It’s important to note that a horse’s hoof can reach 42℃ due to friction especially on artificial surfaces, the tendons also can reach 45 – 46℃ as heat is generated during stretching of the fibres.
How to Cool a Horse Down Safely
A horse will help themselves to cool down by sweating – up to 50% or even 60% of heat can be reduced by sweating. This results in loss of electrolytes which will need replacing, for more on electrolytes read our article ‘Electrolytes – Why, When, How’ at www.vetpro.co.nz. 25% of heat is lost via convection as the air flows over the body. A horse also breathes out heat in expired air and lastly heat radiates from their hot bodies.
However, it is important to help to cool down a horse as soon as possible after exercise. When the activity stops, the sweating suddenly reduces to 45% and so stops cooling the horse. A serious spike can occur at that time, creating the highest body temperature – so be ready to cool him. Cool- not icy cold water- hose all over, avoid very cold water it can cause shock and will close down the pores and you need to get the sweat out. If you can use warm water once he is cooler it will cleanse the skin and release the sweat from the pores better than cold. Scrape the water off as removing the water reduces the skin temperature. It is important to walk the horse around slowly, if possible in shade, so that convection will also act to cool him. Left standing the horse’s legs may have blood pooling in the lower regions. Cool the feet too, use cold water or a cool gel, especially on the sole. Cold bandaging can assist to quickly cool and improve tendon recovery. Avoid ice, it shocks the capillaries, restricts blood flow and a horses’ skin is sensitive enough to get freeze burn. An evaporative coolant that mimics and improves the natural cooling method like Arctic Blast Bandages or a gel like Aloe Cool Gel is ideal. Also if you are not near water then the new Arctic Blast Coolant Spray will bring down the surface temperature safely within minutes. Also get him to sip cool or tepid water, not in large amounts nor very cold. A horse is much likelier to want to drink tepid water than icy cold.
The Danger of Heat Stress in Your Horse
Be aware that heat stress is more likely to occur in high humidity, the level of humidity affects the sweat mechanism of the horse. High humidity of over 70% combined with an ambient temperature of 30℃ is the zone for caution and concern for heat stress.
It is important to monitor the respiration and heart rates, both should drop fairly quickly at the end of the exertion. If the respiration rate gets higher than the pulse it shows that the horse is very hot indeed. Panting is a sign of the onset of heat stress, maybe from a reduced sweat function or dehydration from a lowered fluid intake. Essential to keep washing down, scraping and walking him slowly to create air movement. If possible artificially create air movement with a fan, or even fanning him manually. A horse can become uncoordinated, weak and may even start collapsing, so check the day’s conditions, reduce the work and watch for signs.
Have on hand water or access to water, sponges, cool gel, sweat scraper and some evaporative coolant. Arctic Blast spray coolant and bandages are ideal as they are safer than ice, and create fast effective relief. The spray can be used all over the horses body if water is not available and Aloe Cool gel will cool the legs, joints and feet. A rapid safe cool down is going to improve recovery.
Pre- Event Cooling
It is becoming well known that cooling a horse prior to exertion can improve performance. The first scientific evidence on this was with human athletes. It is effective for endurance horses to be cooled in the breaks immediately prior to extra mileage, for showjumpers between rounds, for all horses that have two or more periods of exercise exertion in an event, for example dressage horses between tests.
These are science reports that show pre- event cooling can improve performance: 30 minutes pre-event cooling delayed onset of sweating by 19 minutes : Wilson TE, Johnson SC,Petajan JH, Gappmaier E, Luetkemeier MJ, White AT Dept of Exercise and Sport Science, Uni of Utah, Salt Lake City, USA – 2002.
38 minutes of pre-event cooling, prior to a 5km run, resulted in 13 sec improvement (100 metres), with a faster pace most evident in the last two thirds of the run : Arngrimsson SA, Petitt DS, Stueck MG, Jorgensen DK, Cureton KJ. Dept of Exercise Science, Uni of Georgia, Georgia, USA – 2004
30 minutes pre-event cooling, followed by a 70 sec cycle sprint, provided a 2.7% increase in power output : Marsh D, Sleivert G. School of Physical Educataion, Uni of Otago, Dunedin, New Zealand – 1999.
30 minutes pre-event cooling, followed by 30 minute run, lowered sweat rates between 10 – 23%, ALSO endurance times for running at 95% of VO2max were increased by 49 sec : Webster J, Holland EJ, Sleivert G, Laing RM, Niven BE School of Fabric and Textile Design, Massey Uni, New Zealand – 2005.
Halftime cooling (10 minutes) resulted in greater aerobic performance : Hornery DJ, Papalia S, Mujika I, Hahn A Uni of West Sydney, NSW, Australia – 2005.
Achieving 5 – 6 degrees of pre-event cooling, followed by 30 minutes of cycling, resulted in cyclists cycling 6% further – 0.9kms : Kay D, Taaffe DR, Marino FE Human Movement Studies Unit, Charles Sturt Uni, NSW, Australia.
In hot conditions 12.3% of horses are withdrawn from 3 Day Eventing due to heat strain, proactive cooling during the rest and recovery period was important to facillitate heat dissipation : Kohn CW, Hinchcliff KW Dept of Vet Sciences, Ohio State Uni, Colombus, USA – 1995.