Excessive heat warnings were in effect until Wednesday evening, with a heat advisory to continue until Saturday night, the National Weather Service said.
Highs on Wednesday were expected to exceed 110 and heat indices were expected to be 115 or above.
Ensuring an adequate water supply should be at the top of the high-heat management list for horse owners, Mark Russell, extension equine specialist with the University of Arkansas Division of Agriculture, this month.
"Horses need lots and lots of water and if they can get under shade and out of the direct sun, that would be a good thing to do," Russell said. "In the evenings, spray them down with a water hose to give them some way to cool their entire bodies."
Pat White, executive director of Hearts and Hooves, a therapeutic riding center in Sherwood, said Wednesday: "We have put all of our horses on electrolytes, refill the water troughs more frequently and reduced their physical activity.
"We also monitor for respiration," she said. "We have one horse that doesn't sweat, so he comes in at midday or earlier, is hosed off and stays in his stall under fan until evening."
Forage, too, is high on the critical list. Like cattle producers, some horse owners are seeing their pastures wither into the dirt. And like cattle, some horses will graze plants they normally ignore.
"Yesterday morning I had a producer come in and he said he had buried three horses for a lady in Nevada County," said Jerri Lephiew, Ouachita County extension agent for the University of Arkansas Division of Agriculture. "She had perilla mint and didn't realize it could be fatal to horses."
Perilla mint, a purple, square-stemmed mint family member, contains a ketone that can cause respiratory failure. There's no antidote, and the best defense is to remove the plants so horses and cattle can't get to them.
Blister beetles are another summertime threat to horses -- especially if they are baled up in alfalfa hay, Russell said. "It's almost guaranteed that if a horse ingests a blister beetle, it will die," he said.
Blister beetles have popped up in home gardens in northwest Arkansas and have made appearances in fields in north-central Arkansas. The beetles are narrow-bodied and about three-quarters of an inch long. They vary greatly in color from dark gray or black to yellow with black stripes. Russell warned horse owners to check all hay to be sure it's beetle-free.
Ray Vogelpohl of Diamond TR Ranch near the Perry-Pulaski county line, said training and riding has been suspended.
"They're hot to start with and you get out there and put a blanket and a saddle on them with a rider weighing 120-150 pounds -- they don't need any of that," he said.
Vogelpohl said the horses are turned out in grass, which doesn't reflect as much heat back on to the horses as sand or other surfaces, and the air can circulate freely around the horses.
"The grass soaks up some of the heat and they've got shade trees to get under," he said. "And they've got plenty of water. We have an automated watering system that we check twice a day for leaks or other issues.
"The water fountains are insulated, so they're about 20-30 degrees cooler than the air temperature," Vogelpohl said. The horses "get a little boost when they drink that water."
So far, his grass pastures are holding up, thanks to a pair of much-needed showers in July.
Vogelpohl said he's altered his routine a little too. "We're doing what we have to, to make sure the livestock are doing well," he said, otherwise, "We're pretty well staying inside."
For more information on livestock care, visit www.uaex.edu , or call a county extension office.