July 5, 1999 | By: Ellen Brightwell

Humans aren't the only ones suffering from the heat and drought this summer. Farm animals are feeling the heat, too. Be sure livestock have abundant cool, clean water, adequate feed and plenty of shade to help them deal with heat and drought conditions, say scientists with the University of Kentucky College of Agriculture.

"Providing cool, clear water is probably the most important thing livestock producers can do to help animals overcome heat stress. Shade is a close second," said Patty Scharko, Extension veterinarian at the College of Agriculture's Livestock Disease Diagnostic Center.

"Livestock seeking shade beneath trees often seek any source of green. And since grass doesn't grow well beneath shade, animals might graze on poisonous plants. This is one important reason to put hay close to animals gathered in the shade of trees," Scharko said.

Horse owners can reduce heat stress by scheduling activities during the cooler part of the day and giving horses plenty of water, according to Laurie Lawrence, equine nutritionist.

"Transport horses during the cooler hours of the morning or evening and try to avoid roads with slow, stop-and-go traffic," Lawrence said. "To reduce the risk of dehydration and heat stress, give horses access to water before, during and after transportation in hot weather. And schedule work periods for cooler times of the day to minimize heat stress problems in working horses, particularly unfit horses."

Heat loss for all horses becomes difficult when temperatures exceed 90 degrees, so avoid exercising them during very hot periods. When humidity is high, temperatures much lower than 90 degrees can pose problems, according to Lawrence.

Offer horses frequent drinks of water during work in hot weather. Allowing them to drink during work helps maintain water balance and relieves the urge to drink a lot of water after exercise. After a hard workout, water horses out gradually.

Even non-working horses will double their water intake during hot weather, so be sure plenty of water is available to horses in pastures, paddocks and stalls.

Lactating mares will have especially high water requirements because they are using water for milk production and heat loss.

Hot weather also will increase horses' need for salt because salt is lost during sweating. Heavy rains can "melt" salt blocks in pastures, so salt licks should be checked.

Beef cattle need plenty of cool, clean, fresh water during heat and drought stress situations, according to Darrh Bullock, Extension beef cattle specialist. Water consumption goes down if all animals have is warm, dirty water such as that from a shallow farm pond.

Heat stress also reduces beef cattle's feed consumption. Cattle that don't eat as much don't gain as much weight. Cattle need to be kept out of the sun--whether beneath shade trees or a built structure.

"In Kentucky, we have added concerns because of the endophyte problems in fescue," Bullock added. "When animals graze endophytic fescue, their body temperature increases. And heat stress just compounds this problem. The combination of endophyte toxicity and heat stress reduces the reproduction rate and lowers cattle rate of gain and milk production.

"You can reduce the effects of tall fescue endophyte in future years by seeding clover into fescue pasture. This will dilute the effects of endophyte toxicity."

Dairy cattle should be close to feed and water because the main loss from heat stress is lower milk production due to reduced feed consumption, according to Bill Crist, Extension dairy management specialist.

"Cattle don't consume as much feed when they're hot. Those on pasture typically stay in the shade; they won't go out and eat. So it's also important to locate their feed and water near shade whether natural shade such as trees, or a manmade structure like a barn," he said.

Crist said producers can lower heat stress dramatically by taking the sides off barns. If more cooling is needed, use fans to move air in the same direction as prevailing winds. For additional cooling, use a sprinkling system to sprinkle cows every three out of 15 minutes. An alternative is to install shade cloth in an area with good air flow and close to feed and water.

"Using a free-stall barn is a very easy way to help cows combat heat stress," he added. "Be sure the barn is high at the eaves--at least 10 feet tall--and has a good slope on the roof--four inches of rise in every foot of run. It also should have an open peak and open sidewalls."

"Since swine don't sweat, their respiration rates will increase to get rid of excess body heat resulting from heat stress," said Merlin Lindemann, swine nutritionist. "Their food intake decreases because the digestive process creates more unwanted heat, resulting in a lower rate of gain and lower milk production in sows. Any methods to help animals eliminate heat, either by air movement from fans or water from foggers or sprinkler systems, will improve their comfort. This will restore their feed intake and reduce production losses."

Sources: Laurie Lawrence (606) 257-7509

Patty Scharko (606) 253-0571

Bill Crist (606) 257-7543

Darrh Bullock (606) 257-7541

Merlin Lindemann (606) 257-7524


Writer: Ellen Brightwell (606) 257-1376