Heat Stress and Dehydration in Horses – Prevention and First Aid
Is heat stress and dehydration in horses dangerous?
Like us, horses are susceptible to heat stress and dehydration, particularly in hot and humid weather. This can have serious consequences for their health.
In this post we discuss heat stress and dehydration in horses – the signs and symptoms and also First Aid measures, and preventative care.
What is Heat Stress and Dehydration In Horses, And Humans?
Heat stress occurs when a horse’s body temperature rises faster than it can cool itself. It can happen easily in high humidity when the moisture in the air hinders sweat evaporation.
Dehydration sets in when a horse loses fluids through sweating and isn’t able to replenish them quickly enough. It can lead to electrolyte imbalances and other health risks. Further, it can also create a vicious cycle, as dehydration reduces the amount of fluid available for sweating, which further worsens heat stress.
Even in high humidity, when sweat evaporation slows down, fluid loss can still be significant because the horse’s body continues to produce sweat to cool itself down. The unevaporated sweat drips off the horse’s skin, taking fluids with it.
How sweating cools horses, and us, down…
Sweating produces liquid on the surface of the skin. Body heat (energy) vaporises the liquid, turning it into a gas that ‘floats’ away from our skin.
This transferral of body heat to the liquid removes the heat from our body. As a result, our temperature lowers, and we cool down. Thus, the more sweat that evaporates on our skin, the more body heat it uses, and the cooler we get. This process is thermoregulation.
However – when the surrounding air is full of moisture, like on a humid day, the evaporation process is less efficient. The liquid simply can’t evaporate so readily, which means less body heat is transferred. So, sweat pools on the skin rather than evaporating, making us even hotter and sweatier.
We continue to produce the sweat though, and if we’re not replacing those fluids fast enough, we dehydrate.
The same thing also happens with horses.
What Are The Signs Of Heat Stress In Horses?
Heat stress can be a serious concern for horses. Therefore, it’s important to recognise the signs indicating a horse is experiencing heat stress. These commonly include –
Excessive Sweating
Like us, horses regulate their body temperature on hot days through sweating. So – if you notice profuse sweating even when the horse is at rest, it may be an indication of heat stress.
Rapid Breathing and Increased Respiratory Rate
Horses with heat stress often exhibit rapid or shallow breathing as their body tries to cool down. You may notice their sides heaving or their nostrils flaring more than usual.
Elevated Heart Rate
Heat stress can cause heart rate to increase. Check the pulse by placing your hand on the horse’s chest, just behind the elbow, or by feeling the pulse at the base of the jaw.
Weakness or Lethargy
Horses experiencing heat stress may become lethargic, unwilling to move, or also show signs of weakness. They may appear dull or disinterested in their surroundings as well.
Dry or Sticky Gums
Normally, a horse’s gums should be moist and slick. In cases of heat stress, the gums may appear dry, sticky, or tacky to the touch.
Dark Urine or Reduced Urination
Heat-stressed horses may produce dark-coloured urine due to dehydration. Additionally, reduced urination or a decrease in the frequency of urination may also occur.
How Can I Keep My Horse Properly Hydrated During Hot Weather?
Proper hydration is vital to prevent heat stress and dehydration in horses. Here are some measures you can take to ensure your horse remains adequately hydrated –
Provide Ample Fresh Water
Ensure your horse always has access to clean, fresh water. In hot weather, horses can drink significantly more water than usual to stay hydrated. Check water troughs regularly to monitor your horse’s water intake. Also clean them to avoid contamination, and encourage the horse to drink more.
Soak Feed
Consider soaking your horse’s hay or providing moistened feed to increase water consumption. Products like beet pulp and copra can hold a lot of water, and are an ideal way to get extra water into horses that may not always drink enough.
Shade and Ventilation
Create shaded areas in your horse’s environment, such as using trees, shelters, or canopies, to provide relief from the direct sunlight. Adequate ventilation is also crucial to help dissipate heat and keep the air flowing.
Limit Exercise During Hot Hours
Try to avoid riding or exercising your horse during the hottest parts of the day when the sun is at its peak. Opt for early morning or late evening workouts when temperatures are cooler.
Cooling Methods
Use cooling techniques that will help your horse regulate its body temperature. Hosing down your horse’s body with water can provide instant relief, especially on hot days. Pay particular attention to the neck, chest, and legs, as these areas are more effective for heat dissipation.
Electrolyte Supplementation
During periods of intense heat or when your horse engages in strenuous exercise, electrolyte supplementation can help replenish the minerals lost through sweating. Consult with your veterinarian to determine the appropriate electrolyte formulation and dosage for your horse.
What Are Some Basic First Aid Measures For Heat Stress And Dehydration In Horses?
Despite taking preventive measures, horses can still experience heat stress or dehydration. Know what the signs are and how to provide immediate first aid to help your horse recover.
Remove from Heat
If you suspect your horse is overheated, move them to a shaded area or into a well-ventilated barn. Provide a cool breeze with fans if available.
Offer Water
Allow your horse to drink small amounts of cool water at regular intervals. Avoid giving large quantities of water all at once, as it may cause further complications.
Wetting and Cooling
Use water to wet your horse’s body gradually, starting with the legs and moving up to the neck and chest. Avoid using ice-cold water, as it can shock the system. Use a sweat scraper to remove excess water and improve evaporation.
Monitor Vital Signs
Take your horse’s rectal temperature regularly to track their progress. Normal rectal temperature for horses ranges between 37.5°C to 38.6°C. Contact your veterinarian if the temperature remains elevated or if other concerning symptoms persist.
Consult a Veterinarian
Contact your veterinarian immediately if your horse’s condition does not improve or if they exhibit severe symptoms like rapid breathing, weakness, or collapse. Heat stress can escalate rapidly and require professional intervention.
Frequently Asked Questions About Heat Stress and Dehydration in Horses
We answer some common questions about heat stress and dehydration in horses.
What should I do if I suspect my horse is experiencing heat stress?
Move your horse to a shaded area or a cool, well-ventilated space immediately. Offer water and gently hose the horse down with cool water. Contact your veterinarian for further guidance.
Can I give my horse ice-cold water to help cool them down?
Giving horses ice-cold water is not recommended as it can constrict blood vessels. So offer cool, but not excessively cold, water. Apart from which, horses often won’t drink icy cold water!
Are there any specific cooling methods for an overheated horse?
Yes, you can use various cooling methods for treating overheating, heat stress, and dehydration in horses. Wetting the horse’s neck, chest, and legs with cool water, using fans to promote airflow, and also applying cool towels to the horse’s body can all effectively help cool the horse down.
What is the ideal temperature range for horses?
Horses are comfortable within a temperature range of 4 to 27 degrees Celsius. Extreme temperatures outside this range can increase the risk of heat stress.
Can horses sweat?
Yes, horses do sweat. Sweating is an essential mechanism for thermoregulation in horses, allowing them to cool down.
How long can horses go without water?
Horses should not go more than a few hours without access to water. Dehydration can occur quickly and lead to serious health complications.
Key Takeaways About Heat Stress and Dehydration In Horses
Learn to quickly recognise the signs of heat stress and dehydration in horses. Provide ample access to clean water. Offer electrolyte supplements as needed, and create a comfortable environment with shade and ventilation.
If you notice signs of heat stress and dehydration in your horse, acting quickly is important. Contact your veterinarian for professional assistance if their condition does not improve.
