Summer can place extra demands on horses, particularly during periods of high temperatures and humidity. Heat stress and dehydration can develop quickly, especially when combined with exercise, travel, limited airflow or heavy sweating.
Understanding how horses regulate their body temperature, recognising the early warning signs and making a few simple management changes can help keep your horse comfortable and better able to cope with hot weather.
How Horses Cool Themselves
Horses primarily regulate body temperature through sweating and respiration. As temperatures rise, the body works harder to release excess heat.
Horses can lose significant amounts of fluid and electrolytes through sweat. If these losses are not adequately replaced, dehydration can develop and the horse's ability to cool itself may be reduced.
High humidity can make this more difficult because sweat does not evaporate as efficiently.
What Can Contribute to Heat Stress?
Heat stress occurs when a horse is unable to lose heat as effectively as it is producing it.
Factors that can increase the risk include:
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High temperatures and humidity
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Intense or prolonged exercise
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Limited shade or airflow
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Inadequate water intake
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Heavy sweating and electrolyte loss
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Poor recovery between workloads
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Travel or floating
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Physical or emotional stress
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Over-rugging or inappropriate rugs
Heat stress isn't limited to competition horses. Paddock horses can also struggle during prolonged periods of hot weather.
Signs of Heat Stress in Horses
Recognising changes early is important. Signs can include:
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Excessive sweating or an unusual lack of sweating
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Rapid or laboured breathing
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Elevated heart rate
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Lethargy or weakness
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Reduced appetite
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Standing still or seeking shade
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Poor recovery after exercise
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Restlessness or signs of discomfort
More severe heat stress can cause marked weakness, distress, uncoordinated movement or reluctance to move.
A horse that appears seriously unwell, particularly if it is not recovering after being moved to a cooler environment, needs prompt professional assessment.
Dehydration and Electrolyte Loss
Dehydration is an important concern during hot weather because water losses can be substantial when a horse is sweating.
Dehydration can affect circulation, muscle function, gut motility, appetite and the body's ability to regulate temperature.
Sweat also contains electrolytes, including:
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Sodium
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Chloride
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Potassium
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Magnesium
Horses that sweat heavily, exercise regularly or experience prolonged hot weather may have greater electrolyte requirements.
Providing constant access to fresh water is essential. Electrolyte supplementation may also be worth considering for horses with significant sweat losses. Products such as Hi Form ElectroPlus can provide additional electrolyte support when appropriate.
How to Keep Your Horse Cool in Summer
Simple management can make a significant difference during hot weather.
Provide Plenty of Water
Make sure your horse has constant access to clean, fresh water. Check troughs regularly during hot weather, as warm or dirty water may discourage drinking.
Provide Shade and Airflow
Natural shade, shelters and good airflow can help horses dissipate heat. In paddocks without much natural shade, consider how shelter can be provided during the hottest part of the day.
Adjust Exercise
Avoid strenuous exercise during the hottest part of the day. Consider exercising in the early morning or later in the afternoon and allow plenty of time for recovery.
Workload may also need to be reduced during periods of extreme heat or humidity.
Pay Attention to Rugging
Rug management is particularly important during summer. An inappropriate or unnecessary rug can trap heat against the horse's body.
Consider the temperature, humidity, wind, coat and individual needs of your horse rather than relying on the calendar alone.
Take Care When Travelling
Transport can increase heat and stress levels, particularly when horses are confined in poorly ventilated conditions. During hot weather, consider travel times, airflow, rest breaks and access to water.
Cooling After Exercise
Hosing with cool water can help remove heat from the coat after exercise or during hot weather.
After rinsing, avoid automatically scraping every drop of water from the coat. Leaving some water on the coat can support evaporative cooling, particularly when there is good airflow.
Some Horses Need Extra Care
Individual horses can respond very differently to hot weather. Extra attention may be needed for:
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Older horses
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Overweight horses
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Horses with PPID
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Horses with heavy coats
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Hard-working or competition horses
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Horses that sweat heavily
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Horses that have previously struggled in hot weather
It's important to consider the whole picture rather than temperature alone.
Supporting the Whole Horse
Heat stress doesn't occur in isolation. Hot weather can add to the overall physical and emotional stress load on a horse, particularly when combined with changes in pasture, insects, travel, exercise or diet.
Supporting your horse through summer means looking at the whole picture — hydration, nutrition, pasture, exercise, environment and stress.
Small changes in management can make a big difference during prolonged periods of hot weather.
Not Sure if Your Horse is Coping with the Heat?
Every horse responds differently to summer conditions. If you notice changes in behaviour, energy, performance, sweating or recovery during hot weather, it may be worth looking more closely at their overall diet and lifestyle.
Our Quick Horse Questionnaire can help identify areas where additional support may be beneficial.
Final Thoughts
Heat stress and dehydration are important summer considerations for every horse, not just those in heavy work.
By providing adequate water, managing exercise, monitoring sweating and recovery, and making sure your horse has appropriate shade, airflow and rugging, you can help them cope more comfortably with hot conditions.
Pay attention to your individual horse. Changes in behaviour, sweating, energy or recovery can be useful signs that they need a little extra support.