Page 102 - July 2022

VETERINARY VIEWS
SUMMER HAZARDS
by Nancy S. Loving, DVM
Summertime has a particular set of issues that can befall a horse whether it is exercising or lolling about in the paddock or pasture.
HEAT STROKE
Climate change is bringing hotter summertime temperatures to many parts
of the country. Riding in hot weather can
tax horse and rider, particularly if heat and humidity conditions, difficult exertions and speed, and/or challenging terrain push a horse past his ability to compensate. Over half of the energy used for muscular activity and locomotion in a horse is converted to heat, and if this heat continues to rise, all body tissues, including the muscles, demand more oxygen. Eventually, the horse’s condition deteriorates due to muscle fatigue and exhaustion. This is known as heat stress or stroke. Although climatic conditions like high ambient temperatures and humidity contribute, heat stress is usually a result of overexertion and/or prolonged exercise that causes the horse to overheat rather than being caused directly from intense sunshine.
The persistence and duration of a horse’s sweating process contributes to heat stress due to on-going losses of body fluids and electrolytes in sweat. You may see a racehorse lathered in sweat after running a mile-long track – in that sweat is a combination of body fluids and electrolytes. But for that horse,
the exertion is quickly over and what is lost is quickly replenished. In contrast, protracted exercise such as occurs with endurance riding, Eventing, or polo, leads to continued
Effective cooling techniques to
help your horse in difficult summer weather can include:
dehydration and electrolyte imbalances as heat from the working muscles is eliminated as copious amounts of sweat.
Besides learning specific athletic skills, an essential training ingredient important to the success and well-being of any athletic horse is fitness of the cardiovascular system. As the muscles condition to better efficiency, less work is needed to
achieve a certain level of athletics,
with less heat generated by the body. Conditioning also improves body
condition and turns fat into muscle. Similarly, body clipping removes
insulating hair that interferes with
effective heat dissipation.
Recognition of how well a
horse is coping with exercise
is instrumental in averting
development of heat stress. Learn
how to monitor your horse’s vital
signs, including heart rate recovery
– no matter the intensity of an
exercise effort, once exercise has
stopped, both heart and respiratory
rates should recover to at least 60 beats per minute (bpm) and 60 respirations per minute within 30 minutes. For moderate exertions, recovery HR should return to less than 60 bpm within 10 minutes.
Learn about and implement effective cooling techniques to help your horse in difficult summer weather – use cold water soaks, ice boots, shade, fans, and make sure there is ready availability of ample drinking water. Precautions should also be taken when hauling in hot weather – transport of a horse in
Iceboots
“Over half of the energy used for muscular activity and locomotion in a horse is converted to heat, and if this heat continues to rise, all body tissues, including the muscles, demand more oxygen.”
Shade and fans
an enclosed van in hot weather contributes to dehydration and heat stress.
If a horse succumbs to heat stress, treatment with intravenous fluids may be necessary not only to restore hydration to maintain circulatory health, but also to cool the internal organs and muscles.
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100 SPEEDHORSE July 2022
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