News Update

Heat Stress Could Become Problem for Livestock
July 19, 2006

With a heat wave blanketing most of the United States this week, officials at the University of Kentucky (UK) Agricultural Weather Center warn of the potential danger to livestock. Heat indices there have soared into the 100° F to 105° range.

“Livestock become uncomfortable when the heat index reaches about 90 degrees,” agricultural meteorologist Tom Priddy said. “With heat indices at this range, it’s critical for producers to be aware of what’s going on with the animals.”

The heat index is a combination of air temperature and humidity and is used to describe how it feels outside. The Agricultural Weather Center regularly monitors heat indices across Kentucky and provides an index of its own — the Livestock Heat Stress Index — to help producers know when heat stress could create a problem for their animals.

The county-by-county index indicates three levels of heat stress: no stress, danger stress and emergency stress. Despite an expected cooldown this weekend, Priddy said stress conditions will continue to hover near the danger category for much of the state.

“Unless those producers minimize that heat stress, it becomes a potentially serious situation,” he said.

Periods of heat stress call for livestock producers to be vigilant in making sure their animals are able to withstand the conditions. One of the most important things producers can do is provide cool, clean drinking water, said Robert Fehr, Extension professor at the UK College of Agriculture.

“Providing an adequate source of cool, clean drinking water is essential to help keep animals’ internal body temperatures within normal limits,” he said.

Fehr cautioned that unless aboveground waterlines are shaded they can act as solar water heaters and make the water too hot to drink.

Bill Crist, UK Extension dairy specialist, said it is also important to provide shade for the animals and to keep buildings as open as possible for adequate ventilation. Sprinkler systems that periodically spray a cool mist on the animals can be beneficial.

To keep cattle from becoming overheated, Crist advises producers not to work the cattle during periods of heat stress.

“Certainly, you do not want to work cattle with this kind of weather — veterinarian work, reproductive checks or vaccinations ... anything that makes them move for some reason,” he said.

Producers should avoid transporting livestock during a danger or emergency period, Fehr said. When livestock must be transported, he recommends doing so with fewer animals per load. Planning trips so the animals can be loaded immediately before leaving and unloaded quickly upon arrival can likewise help minimize the risk.

Kentucky producers who want to keep close tabs on the livestock heat stress index can access the Agricultural Weather Center Web site at wwwagwx.ca.uky.edu or go to their county Extension office’s Web site and click on the weather link. The heat stress index, along with other agricultural forecasts, is updated regularly by Priddy and his staff.

“We are utilizing technology to provide the most up-to-date ag weather information available,” Priddy said. “Now, the farmer’s still got to make the decisions. We’re not trying to tell them you’ve got to do this or that. What we’re trying to do is provide them the information that allows them to make the decisions.”

— by Terri McLean of UK College of Agriculture, which provided this article