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Beef up plans for managing heat stress
Alicia Boor
Alicia Boor

A Kansas State University veterinarian is urging cattle producers to beef up their plans for managing heat stress, a challenge that costs the cattle industry up to $370 million in losses.   

A.J. Tarpoff, a beef veterinarian with K-State Research and Extension, said heat stress decreases the reproductive efficiency and performance of cattle grazing on pasture. In confined facilities, heat stress causes cattle to eat less, which negatively affects their performance.   

The human body cools itself by sweating, called evaporative cooling. But cattle sweat only 10 percent as much as humans, and panting is their primary way of dissipating heat.    

Doing so, however, causes cows to eat less, setting them on a path to poor growth and future performance.   

“This all has to do with heat load,” Tarpoff said. “The internal temperature of cattle will peak two hours after the hottest point of the day. So our strategy for keeping cows cool needs to be built around knowing that.”   

Another factor is that cattle produce heat by digesting food, typically four to six hours after eating. “So if we feed animals within the wrong period of time, we can actually increase their heat load because the heat of digestion and the heat from the environment are building on top of each other.  

Tarpoff listed some best management practices:   

• Handling. Receive, ship, or move cattle preferably before 10 a.m. 

• Feeding. Feed 70 percent of the animals’ ration as late in the evening as possible, which puts the peak heat of digestion overnight when temperatures are likely cooler. 

• Managing heat. Reduce stocking density. Maximize airflow by removing obstructions around facilities, including weeds. If feasible, install shade structures. Install sprinklers to wet cattle down at night or early morning so as not to increase humidity.   

Then, of course, there is the importance of providing water. Lots and lots of water.    

As a rule, he said cattle should consume “about five times the amount of water as the dry matter they are consuming.”   

“Cool, clean and readily-available water is critical during heat stress events. We may have to increase the water tank capacity within a pen to meet these needs.   

Tarpoff said he follows two sources for help in making a decision when to put a heat stress management plan into full effect.  

The U.S. Meat Animal Research Center (MARC) maintains a seven-day forecast tool for the United States, taking into account temperature, humidity and solar radiation.   

“The other tool I use is the Kansas Mesonet, which provides an animal comfort index,” he said.   

“I know that if we don’t have those night-time cooling hours, the animal won’t be starting each day at thermo-neutral, so they’re more at risk on the second or third day,” Tarpoff said. “That’s when we should start putting in some of these management strategies.” 


Alicia Boor is the Agriculture and Natural Resources agent with K-State Research and Extension – Cottonwood District. Contact her by email at aboor@ksu.eduor call 620-793-1910.