June 19, 2018 | By: Aimee Nielson

Summer hasn’t officially begun according to the calendar, but Mother Nature has already been bringing the heat and humidity. In fact, Kentucky experienced the warmest May on record, and livestock are feeling it. Producers have options to keep livestock thriving in the summer heat.

“When you get a combination of heat and humidity, it can cause concern for livestock,” said Matthew Dixon, agricultural meteorologist for the University of Kentucky College of Agriculture, Food and Environment. “We go by what is called a ‘livestock heat stress index’ to determine what level of concern farmers and pet owners need to have for their animals.”

The index helps producers know when heat stress could create a problem for their animals so they can be even more vigilant in making sure animals have the necessary resources to combat and withstand the conditions. The state has already experienced days in the dangerous and emergency livestock heat stress categories.

“The most important thing producers can do is provide cool, clean water and shade,” said Jeff Lehmkuhler, UK beef specialist. “It’s also a good idea to avoid working or transporting animals during periods of danger or emergency heat stress.”

Horses have difficulty regulating their body temperature when temperatures exceed 90 degrees. If humidity is high, the temperature doesn’t even have to reach 90 degrees to make life uncomfortable for horses.

“Horse owners can reduce heat stress by scheduling activities during the cooler part of the day and making sure horses have plenty of water,” said Bob Coleman, UK equine extension specialist. “If you do transport horses during the cooler part of the day, give water before, during and after transportation to reduce the risk of dehydration.”

Coleman added that even non-working horses will double their water intake during hot weather. Owners should allow them to drink often to help maintain water balance.

“If you let them drink often, it can relieve the horse’s urge to drink a lot of water after exercise, and they need to gradually drink after a workout,” he said. “Also, remember lactating mares have special water requirements, because they are using water for milk production as well as body temperature regulation.”

Hot weather also increases horses’ need for salt, because they lose the mineral during sweating.

For dairy cattle, it is important to keep buildings as open as possible to allow air to circulate. Fans can make a big difference, and sprinkler systems that periodically spray a cool mist on the animals are also beneficial.

Poultry are especially prone to heat stress. Mortality during extreme heat can be significant, and egg production and hatching rates can drop.

“Since the birds don’t have sweat glands to help get rid of excess body heat, they have to pant to cool down,” said Jacquie Jacob, UK poultry extension project manager. “It’s important to make sure chickens are in well-ventilated areas and they have access to clean, cool water at all times.”

Dixon said that while he doesn’t expect the index to reach the emergency category the rest of the week, temperatures and humidity levels will keep conditions in the dangerous category during the afternoon and evening hours.

The UK Agricultural Weather Center provides statewide and county-specific weather information, alerts, livestock heat stress conditions and more. To view the index for a specific location, go to http://weather.uky.edu/ukawc2.php or click a specific location from the Kentucky map at http://weather.uky.edu.


Matthew Dixon, 859-218-4363; Jeff Lehmkuhler, 859-257-2853;

Bob Coleman, 859-257-9451; Jacquie Jacob, 859-257-7613