Be safe in the heat

Watch for heat-related illnesses on the farm

Summers are getting hotter. According to the Environmental Protection Agency (EPA), heat waves are starting to occur in any season. In 2021, a record-shattering drought and heat wave in the western United States claimed 221 lives. And records kept by the National Oceanic and Atmospheric Administration (NOAA) show that 2023 was the hottest year on record. It’s likely that for the foreseeable future, hot seasons will be hotter and — in places like the Midwest — drier.



You may think that heat stress, heat exhaustion, and heat stroke are just different words for the same malady. They’re not. Heat-related illnesses exist on a continuum, and to properly protect yourself, your workers, and your livestock, it’s important that you know the difference.


Heat stress or “heat strain” is one of the least severe conditions. That doesn’t mean you can ignore it, however. It starts when, because of inadequate access to ventilation, water, or moderating factors such as air conditioning, water misting, or ice packs, the body’s natural thermoregulating systems begin to get overwhelmed.

It begins with mild overheating but can quickly escalate to something more serious. Symptoms include mild to moderate discomfort, hot skin, and profuse sweating. Heat cramps can begin to appear at this stage, as can rapid breathing.


If heat stress goes on too long without relief, the result can be heat exhaustion. Sweating is the body’s natural method for controlling the core temperature in the body. With heat exhaustion, though, excessive sweating can lead to dehydration and electrolyte depletion. This in turn can affect blood pressure and heart activity.

In addition to excessive sweating, symptoms of heat exhaustion include irritability, headache, fatigue, muscle weakness, dizziness or lightheadedness, and even fainting. As electrolyte levels plummet, other signs that heat exhaustion may be taking hold include worsening muscle cramps, muscle spasms, nausea, and vomiting.


Heat stress and heat exhaustion can progress to heat stroke gradually, but this much more serious condition can also occur quickly. However it manifests, it’s important to act quickly to relieve it. Untreated heat stroke can damage the brain or other organs, leading to disability or death.

One of the hallmarks of impending heat stroke is a rise in the body’s core temperature, to 104 degrees or higher. This may bring on an altered mental state or changes in behavior, including confusion, agitation, slurred speech, irritability, delirium, seizures, and, if untreated, coma. While excessive sweating may occur with heat stress and heat exhaustion, the skin of someone suffering with heat stroke may feel hot and dry. 


The first thing to do for a human or animal suffering from heat-related illness is to remove them from the heat. Get them into air-conditioning or shade and provide plenty of cool drinking water. If the person does not start feeling better within one hour, loses consciousness, or is unable to drink, call 911 immediately, as they may be nearing heat stroke.

While you’re waiting for emergency personnel to arrive, avoid providing alcoholic or caffeinated beverages, even if the drinks are cold. Both can contribute to dehydration.

The National Safety Council recommends removing outer layers of clothing and immersing the person in a pool or bath or, if that’s not possible, applying ice bags, wet cloths, or cold packs to the person’s neck, armpits, and groin to help reduce body temperature.


The best way of handling heat-related illness is preventing it from happening in the first place. Here are some guidelines from the National Institute for Occupational Safety & Health (NIOSH). And these apply to any outdoor workplace:

  • Reschedule work for earlier or later in the day to avoid midday heat.
  • Provide cool, potable water. People working in the heat should drink 24–32 ounces of water every hour.
  • Require sunscreen usage.
  • Allow time for water and rest breaks.
  • Require protective clothing like hats and lightweight, light-colored clothing.
  • Increase the number of workers on tasks that involve being outside.
  • Closely supervise new employees until they are acclimatized to working conditions.
  • Train supervisors and workers on the prevention and signs of heat illness


Because heat-stressed livestock can’t tell you what they’re feeling, detecting and treating their heat-related illnesses can be harder. For example, did you know that cattle’s digestive process produces heat in their bodies? When the mercury climbs into dangerous territory, take extra measures to keep your animals safe and comfortable.

  • Avoid handling, transporting, moving, or processing cattle on overly hot days. If you must do it, then do it during the early morning hours, when conditions are cooler.
  • Cows do sweat as do horses, but cows have few sweat glands and mostly stay cool through respiration, drinking water, or staying out of the sun. Provide easy access to plenty of water, cooling fans, and shade.
  • Speaking of water, make sure your herd has plenty available. If your pasture only has a single cattle tank, consider increasing your tank’s capacity, or adding another. It’ll also help if the water’s cool —between 40–65 degrees Fahrenheit. That’s the temperature cattle prefer so it can help increase their water intake.
  • Watch for abnormal behavior. Delirium, irritability, and sudden awkwardness in movement are signs of heat-related illness livestock just as they are in humans.


Sources: The Centers for Disease Control and Prevention; the Mayo Clinic; the National Safety Council; Michigan State University Extension

The information included here was obtained from sources believed to be reliable, however Grinnell Mutual Reinsurance Company and its employees make no guarantee of results and assume no liability in connection with any training, materials, suggestions, or information provided. It is the user’s responsibility to confirm compliance with any applicable local, state, or federal regulations. Information obtained from or via Grinnell Mutual Reinsurance Company should not be used as the basis for legal advice and should be confirmed with alternative sources.

 Updated 5/2024


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