Summer is a horseman/horsewoman’s favorite season; longer riding days, dry trails, and not having to wear layers or rain boots for barn chores creates for the perfect opportunity to get out and ride. However, with the high heat and humidity, it is also a good time to review management practices to help our hoofed friends enjoy themselves and beat the heat. To start off our discussion, we will briefly review the horse’s normal physiological mechanisms to dissipate heat. We then will review four key management practices we can employ to help with cooling and, finally, we will review the most common clinical signs associated with heat stroke and what you can do while waiting for the veterinarian to to care for a horse in the heat of summer days


Normal core body temperature for horses range from 99.0 – 100.9°F. Heat generated during exercise, especially during hot, humid days, can cause an increase in body temperature to 102.0 -106.0 F. However, when the horse’s body temperature reaches over 104.0°F, metabolic systems begin to shut down and a temperature exceeding 105.0°F can cause other organ systems to shut down with circulatory collapse becoming a possibility. Horses, much like humans, utilize a mechanism called evaporative cooling (sweating) to help try and dissipate most of this heat. During evaporative cooling, horses lose a lot more water than normal and, in order to make up for this, their water intake needs to increase dramatically. On average, an adult horse will drink about 8-10 gallons of water on a cool (< 70°F) day. During hot summer days, horses may drink 20-25 gallons per day or more! With this in mind, it is easy to see how the horse’s normal cooling mechanism can be quickly outmatched on high temperature, high humidity days leading to heat stress. This is where additional management practices can help to promote evaporative cooling for your horse, decrease ambient temperature of their environment, and encourage increased water intake to help in keeping your horse cool.


The four management keys to keep your horse cool on these hot, humid days include: 1) Air, 2) Hydration, 3) Planning, and 4) Monitoring. I like to think of this as the ADAPT approach to heat management.


Making sure barns are adequately ventilated can have a huge impact on keeping your horse cool. This increased airflow will help increase your horse’s evaporation rate and result in a faster cooling and better maintenance of cooling. Opening doors and windows, use of industrial fans (will caution against at home box fans as these can short out and cause fires), and providing room in sheds with adequate space for all horses can help to increase air flow.

Hydration (ADAPT)

This is where the saying “you can lead a horse to water but can make them drink” comes from. Some horses may not drink while you are near or next to them. Offering your horse fresh water frequently and allowing them to have access to fresh water at all times is crucial. Checking automatic waterers, cleaning troughs daily (or even twice daily during hotter days), and walking away from your horse after leading them to the water source may help this. Dominant horses can chase more submissive horses away from water troughs or will lurk around water trough enough to intimidate and prevent these horses from even attempting to drink. The easiest way around this problem is to provide multiple water sources. Adding additional mineral supplementation to their pasture or over their hay/grain in the form of salt blocks or loose ionized salt will also encourage water intake. There are also many electrolyte powders and pastes you can add to a bucket of water. The key for these is to be sure to follow label instructions as well as continue to offer your other normal water buckets (horses just like people can be picky about their food and drink choices).

Plan (ADAPT)

Planning your rides or training sessions to take advantage of cooler times during the day. Instead of training midday, plan on the cooler times of the day such as early morning or later in the evening to get the most out of your time with your horse and ensure their health and safety.

Monitor (ADAPT)

Careful monitoring of your horse’s hydration, temperature, and attitude is key. There are a number of ways to keep a careful eye on your horse’s hydration. One easy way is to do a skin fold hydration test. You can do this by lightly picking up a piece of skin near your horse’s shoulder then letting go of the skin and counting how many seconds it takes for that skin to slip back. If a horse is adequately hydrated, this should take 1-2 seconds. Slower times (~4 seconds) may indicate moderate dehydration. As mentioned previously, a normal, healthy horse’s temperature range is between 99.0 and 100.9°F. Following work or exercise, horses may a slightly higher temperature but temperature should not exceed 102.0°F. A horse’s rectal temperature can easily be obtained during barn chores or following exercise and is a useful gauge of how your horse is tolerating the heat. Lastly, monitor your horse’s attitude for changes such as: 1.) not greeting you as they normally do at the gate; or 2.) stumbling while walking to you; as these can be indicators of lethargy and heat exhaustion.


Rapid identification of heat stroke is accomplished by careful monitoring and observation. Horses that are suffering from heat stroke need immediate veterinary attention and treatment. Some of the most common clinical signs of heat stroke include: increased rectal temperature (>102.0°F), increased respiratory rate (> 32 breaths/min), ataxia (loss of control of body movements), and/or weakness (horses which are stumbling or abnormally unsteady on their feet).

Some immediate management practices which you can do if you suspect heat stroke in your horse are:

  1. Call your veterinarian immediately.
  2. Record your horse’s rectal temperature.
  3. Move your horse to a shaded area.
  4. Begin to cold hose your horse with focus on key points of heat dissipation (armpit, jugular vein in neck).
  5. Place a fan near your horse to increase air flow.
  6. Continue to record rectal temperatures every 15 minutes until your veterinarian has arrived.

Prevention of heat stroke is accomplished through appropriate management practices and careful monitoring. Immediate veterinary attention is required of any horse that is suspected to be suffering from heat stroke.


If you any questions or concerns with your horse or barns heat management strategies. Please feel free to contact our office at: 319-366-6441 or emergency pager line at: 319-368-0487. Thank you for your time and happy riding!

Author: Jeremy M. Servantez, DVM