Is heat stress impacting your horse?

Temperatures are on the rise as spring is quickly turning to summer. We might not be thinking about it yet, but heat stress could already be impacting the health and performance of our horses.

Horses tend to be more susceptible to heat stress than their human companions. With considerably larger amounts of active muscle mass generating heat, as well as having a larger body overall, it’s more difficult for a horse to release excess heat.

It’s not just the heat or temperature that may impact your horse, however. Humidity is an important factor as well. On hot, humid days, much of the sweat produced by your horse does not evaporate. It stays on the skin or drips from the body – either way, it does not cool the body efficiently. To put it simply, if you’re hot, your horse is likely hotter.

When overheated, horses often go off feed and blood flow to the GI tract is reduced. This can lead to Leaky Gut Syndrome (LGS), allowing harmful pathogens and toxins in the gut to leak into the bloodstream. The immune system is then activated and energy that would go to performance, growth or reproduction is now used by the immune system. Worse yet, if the leaks become large or chronic the result could be sepsis, organ failure or even death.

Calculating risk

One way to identify the level of heat stress risk is to add the temperature and relative humidity together. The sum of these two measurements can provide some general guidance on when and how much your horse should exercise. For example, if the temperature is 88°F and the relative humidity is 45%, the total score would be 133. According to the chart below, your horse is at a medium risk for experiencing heat stress. You can ride or train normally – just make sure to include breaks for rest and cooling.

What else can you do to reduce the impact that the heat and humidity have on your horse? Make sure there is adequate airflow in stall or in the trailer if traveling. Ensure access to plenty of clean water – an average adult horse needs 5–10 gallons of water per day in normal circumstances. Also be sure to provide your horse with an opportunity to get out of the sun. It typically feels 10–15 degrees cooler in the shade and the risk for sunburn is decreased.

A nutritional approach: how can KemTRACE® Chromium help?

Evidence suggests that insulin action is a key component of the heat stress response. Chromium improves insulin function and results in efficient clearance of glucose into the cell from the bloodstream. Increased glucose uptake may improve thermal tolerance in heat stressed animals.

By increasing glucose uptake in immune cells, the immune system is better positioned to mount a defense against any pathogens that may have entered the bloodstream due to LGS. Not only does this improve immune efficacy, but also results in more energy for other needs such as physical or reproductive performance. Chromium has also been shown to reduce levels of cortisol – a stress hormone – in horses.

Visit to download a free informational poster and to learn more about heat stress and how KemTRACE Chromium may help.

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