WEST LAFAYETTE, Ind. — Heat and humidity are returning to
the eastern Corn Belt after weeks of unseasonably cool temperatures, meaning
cattle producers need to be on the lookout for signs of heat stress in their
Heat stress in cattle is a concern because it can reduce
breeding efficiency, milk production, feed intake and weight gain. Extreme cases
can be fatal, said Ron Lemenager, Purdue Extension beef specialist.
Heat stress affects all cattle, but hide color plays a role
in determining which cattle might be more susceptible. Black-hided cattle absorb
light, making them more prone to heat stress, whereas cattle with lighter
colored hides, such as cream or red, might not become heat stressed as
“The good thing is that here in the eastern Corn Belt, we’ve
actually had some pretty cool temperatures through the early part of the
summer,” the specialist said. “We don’t have the heat stress we had a year ago
when we were experiencing the 2012 drought.”
According to Lemenager, it usually takes a combination of
high temperatures and high humidity to cause heat stress, but cattle also can
experience heat stress in lower temperatures if humidity is high.
Cattle seeking shade is an early sign of heat stress. Having
enough shade available is one key to prevention.
“The smaller the shade area, the worse the congregation of
animals,” Lemenager said. “That’s probably not a good thing with cattle huddling
together, obviously, because heat can be transferred from one animal to
Another risk is fly infestation. A high population of flies
around a herd causes animals to huddle together more frequently. Flies can be
managed with dust bags, insecticide-impregnated ear tags, insecticide sprays,
pour-on insecticides or some combination of these.
Panting also can be a sign that cattle are heat
“They probably will have their tongues hanging out like a
dog, and that panting is a way to get rid of some excess heat,” Lemenager
Cattle standing in ponds or creeks also could be caused by
In some cases, cattle can fall down or have convulsions.
These are signs of severe heat stress, which can be fatal.
Lemenager recommended that producers make sure cool, fresh
water is available to cattle at all times and use more shaded pastures during
the warmer months. Sprinkling cattle with water also can help to dissipate heat,
but it shouldn’t be excessive.
Producers also should be careful to keep cattle away from
muddy areas, because hot mud could cause scalding where the skin comes in
contact with hot mud.