Chromium, Heat Stress and Your Horse

Summer temperatures, competitions, and time in hot trailers or stalls can impact the health and performance of your horse.

How Vulnerable is Your Horse?

If you're complaining about the heat, it's likely that your horse is already suffering from the effects of heat stress.

Due to their large bodies and high percentage of muscle mass, horses generate a tremendous amount of heat. Additionally, only about 25-30% of their sweat evaporates, removing the heat. In humans, that number is closer to 50%. The result? Horses can succumb to heat stress 3-10 times faster than their riders.

Horses are at a higher risk of heat stress if they are:

  • Poorly conditioned
  • Not acclimated to the heat or humidity
  • Active or competing
  • Overweight
  • Heavily muscled
  • Unable to find shade
  • In poorly ventilated trailers or stalls

It's Not Just High Temperatures

It's not just the heat or the humidity, it's both. Using the Horse Heat Index can help you decide whether to ride or take the day off. Simply add the temperature (°F) to the relative humidity (%). The sum of those two values can help to identify the risk. Download and print the Equine Temperature-Humidity Index poster here.

Reducing the Risk

There are several ways to reduce the likelihood your horse will suffer from heat stress.

  1. Use the Horse Heat Index to decide your activity level for the day. Riding in the early mornings or evenings can be safer and more comfortable for you and your horse. 
  2. Provide access to shade. Being in the sun directly heats the skin and makes it more difficult to cool off. Additionally, it can feel 10-15 °F cooler in the shade.
  3. Ensure adequate air flow in stalls or trailers. Air flow helps your horse cool down.
  4. Provide plenty of clean water and train your horse to drink water with added electrolytes. This can help prevent dehydration and an electrolyte imbalance.

KemTRACE® Chromium and Heat Stress

Evidence suggests insulin action is a key component of heat stress response

A trial conducted at the University of Melbourne indicated that feeding chromium could reduce body temperatures and respiratory rates during heat stress in swine. Swine heat stress indices demonstrate pigs may become heat stressed at a lower combination of heat and humidity than the horse. However, the head conditions demonstrated in this trial would still negatively impact the ability of a horse to cool. 

The chromium group exhibited both a lower rectal temperature and reduced respiratory rate. Chromium has been shown to increase insulin sensitivity in horses and researchers believe there is a connection between increased insulin sensitivity and improved capillary function in the skin.2,3 The result is increased blood flow, and ultimately, an increased amount of body heat dissipated.

The chromium group exhibited both a lower rectal temperature and reduced respiratory rate.




Chromium, Heat Stress and Your Horse


Summer temperatures, increased activity and reduced air flow in trailers or stalls are some of the conditions that can lead to heat stress in horses. Chromium has been shown to reduce body temperature and respiratory rate during heat stress.


Equine Temperature-Humidity Index Poster


Download this free poster today and help keep your horses safe in the heat. The poster includes temperature-humidity calculation methods, suggested activity levels for your horse, as well as useful heat abatement tips.




1St-Pierre, N. R., Cobanov, B.,Schnitkey, G. (2003). Economic losses from heat stress by US Livestock Industries. Journal of Dairy Science, 86.
2Spears, J. W., Lloyd, K. E., Siciliano, P., Pratt-Phillips, S., Goertzen, E. W., McLeod, S. J., Moore, J., Krafka, K., Hyda, J., & Rounds, W. (2020). Chromium propionate increases insulin sensitivity in horses following oral and intravenous carbohydrate administration. Journal of Animal Science, 98(4).
3Liu F;Cottrell JJ;Wijesiriwardana U;Kelly FW;Chauhan SS;Pustovit RV;Gonzales-Rivas PA;DiGiacomo K;Leury BJ;Celi P;Dunshea FR; (n.d.). Effects of chromium supplementation on physiology, feed intake, and insulin related metabolism in growing pigs subjected to heat stress. Translational animal science. Retrieved April 29, 2022, from

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