How To Prevent Heat Stress in Horses

Learn about the signs, treatments, and how to prevent heat stress in horses.

You take your horse for a ride on a warm, summer day, and it isn’t long before both you and your horse are soaked with sweat. The pace of your ride gradually slows down as your horse struggles to maintain energy. Is he/she simply being lazy or is there something more going on? In this situation, it’s important for you to be aware that horses can develop heat stress if they become over-heated and dehydrated.

Heat stress can lead to severe health complications. It can even be fatal, if not treated, which is why Blain’s Farm & Fleet and Nutrena are providing a guide on recognizing, preventing, and treating heat stress.

What Causes My Horse to Get Heat Stress?

This is probably the first question on your mind and the most crucial in order to prevent heat stress from becoming a problem. Some common factors that can lead your horse to developing heat stress are:

• Dehydration
• Hot, humid weather
• Poor conditioning
• Inability to sweat normally
• Heat generated in muscles
• Transporting in hot conditions
• Insufficient oxygen intake
• Riding too fast for horse’s fitness level
• Exhaustion
• Insufficient time to acclimate to warm weather
• Intense exercise

It’s important to note that all horses are different, which means heat can affect some horses more than others. You must look at your own horse’s situation (fitness level, age, health status, the climate they are used to) to determine how easily they can develop heat stress.

What are the signs of heat stress?

This is probably the next question on your mind and an important one in order to notice the signs of heat stress before it becomes too severe. Refer to the list below for conditions that may arise if your horse develops heat stress and signals that may indicate that your horse is starting to become over-heated.

Visible Indicators of Heat Stress:	Conditions Caused from Heat Stress:
Rectal temperature over 103.5ºF	Reduced tolerance to exercise
Sluggishness/weakness/ poor posture	Poor recovery after riding
Hot/dry skin or inability to sweat	High/irregular heart rate
Sunken eye sockets	Severe dehydration
Rapid breathing/flared nostrils	Colic
Refusal/disinterest in food or water	Cramping, spasms, or loss of muscle control
Falling/stumbling	Seizures
Reduction of skin elasticity
Refusal to move

If you notice your horse exhibiting any of these signs or conditions, it’s imperative that you stop your ride immediately and get your horse into a cool, shaded place. If your horse shows severe symptoms or a rapid decline in health, contact your veterinarian.

How do I treat heat stress?

You notice your horse is exhibiting signs of heat stress, so what can you do? The following steps will take you through a course of action to help bring your horse out if its heat stress state.

Step 1: As mentioned above, stop exercise immediately and move your horse into a shaded area with a light breeze or fan, if possible, and offer him/her water.

Step 2: Using a hose or sponge, apply cool (not cold) water onto your horse. Start by running the water down his/her legs, then move up to their neck, back, and any areas with large veins that are close to the skin. Scrape away excess water, as it heats up, with a sweating blade.
*Refrain from using a cooling towel or blanket on your horse as this can trap the heat that’s coming off your horse’s body.

Step 3: Massage your horse’s major muscle groups to encourage blood circulation and to help prevent cramping. You can also use liniment gel, if your horse is not in a severe stage, to help soothe their muscles.

Step 4: Monitor your horse’s rectal temperature frequently until it recedes to 101ºF. Once recovered, hand walk your horse for about 15 minutes to further prevent cramping.

Step 5: Administer electrolytes and monitor your horse for several hours. Make note of any changes to his/her condition. If your horse is in a severe state of dehydration or shock, you can administer intravenous fluids. However, if you don’t know how to administer fluids intravenously, it’s suggested to let your vet do this step.

Step 6: Refrain from giving your horse any further medications until your horse is re-hydrated and fully recovered.

If your horse does not improve with these steps, or his temperature exceeds 104ºF, call your veterinarian immediately.

How do I prevent heat stress?

While heat stress is hard to predict, there are preventative measures you can take to help reduce the chances of it occurring.

• Let your horse have the day off when temperatures are too high. A good rule of thumb to follow is no riding if the temperature and humidity combination gets above 180ºF. If you need to ride in those temperatures, take the time to get your horse acclimated by going on short rides and avoiding terrain and speed that is beyond your horse’s fitness level.
• Adjust your riding practices to include frequent breaks and proper cool-down techniques. Improving your horse’s fitness level will help them tolerate the heat while being ridden.
• If your horse isn’t used to the climate, avoid riding until they adjust.
• If your horse has a long/thick coat, due to age or recently coming from a cool environment, clip their hair to a shorter length.
• Provide your horse with constant access to cool, clean water by filling their trough or feed pan several times a day. Also, be sure to provide them with water immediately after riding. Just make sure the water isn’t too cold. Drinking ice cold water right after exercising can lead to muscle cramping and colic.
• Provide your horse with extra nourishment by giving them electrolytes and supplements.

The thought of your horse getting seriously ill from heat stress can be a scary thought. If you educate yourself, get to know your horse’s tolerance, and take some extra time to care for your horse, heat stress can be preventable. For more information on heat stress, you can check out Nutrena’s Heat stress guide and talk to a trusted veterinarian.

Blain’s Farm & Fleet knows how much your horse means to you. In addition to this guide, we also offer a large variety of horse care products in our stores and online to make sure you have access to everything you need to keep your horse healthy. For more horse care guides and tips, check out our horse and hobby farming blog.