Heat Stress a Problem, Even for Northern Plains Cattle

Heat stress can be a serious hazard for cattle, even in northern Great Plains climates.

The past week’s extremely hot and humid weather conditions have resulted in some reports of heat stress problems in beef cattle, particularly from feedlot operations in regions where the weather has been especially humid.

Cows and nursing calves are less susceptible but also can be affected by the high temperatures, says Greg Lardy, the North Dakota State University Extension Service’s beef cattle specialist.

Symptoms of heat stress include rapid breathing or panting, increased body temperatures, drooling, salivation or foaming at the mouth. Cattle will tend to stand grouped together during the early onset of heat stress. In severe cases, cattle will breathe with their mouth open and stand with their tongues protruding from their mouth. Along with the heavy, rapid breathing, cattle will appear to be pushing from their flanks. In the latter stages of severe heat stress, cattle will stand with their head down and may be away from the herd.

Heat stress usually is more severe when nighttime temperatures do not cool. Night cooling allows animals a chance to dissipate excess body heat that built during the day.

Lardy says solutions for combating heat stress include:

• Changing the cattle’s feeding time from morning to late afternoon or evening
• Sprinkling the animals with water
• Providing shade

Changing the feeding time shifts the heat produced during fermentation to night, a when cattle are better able to dissipate the heat.

Sprinkling usually is the most immediate solution. It should begin in the morning prior to the heat of the day. Producers should sprinkle the cattle and the mounds or surfaces of the pen where they lie.

“Providing shade will also help,” Lardy says. “However, this is a longer-term investment and is generally not something which can be done immediately.”

Dark or black-hided cattle are more susceptible to heat stress because their coat color absorbs more solar radiation; however, cattle of all hide colors can succumb to heat-related stressors and suffer from heat stress. In addition, cattle nearing market weight and carrying the most body fat or condition also are more susceptible because they are less able to dissipate excess body heat due to their fat cover.

Water requirements also increase dramatically during heat stress. In some cases, producers may need to add water spaces to provide the extra water cattle need.

Lardy recommends producers refrain from processing, moving or working cattle when ambient temperatures are high or heat stress is a potential problem.

“Working cattle in the early morning hours or waiting for relief from the heat wave is the best option,” he says.

Producers also should use fly control to provide cattle relief from the pests during periods of high temperatures.

NDSU Agriculture Communication