pet news

AUGUST 6, 2014

Large animal health in summer temperatures

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quarter horseOur cats and dogs aren’t the only animals that need special attention during the unbearable summer temperatures; horses and other large animals get hot too! Though they may not express it in the same way as our domestic pets, heatstroke is still common among large animals, and prevention is the best cure.

“The important things to consider during summer heat for animals are similar as for humans,” said Dr. Leslie Easterwood, assistant clinical professor at the Texas A&M College of Veterinary Medicine & Biomedical Sciences (CVM). “It is best to provide clean, fresh water at a rate higher than they would be losing due to sweat.”

The progression from dehydration to heat exhaustion and ultimately heat stroke can occur rapidly. Providing your large animals with access to plenty of water and shade is the most important way to keep their body temperatures under control. Just as with humans and other animals, the higher the temperature or activity level, the more water is required to cool the body.

“Most horses will consume between 5 and 10 gallons of water per day, and their daily requirement for maintenance is approximately 6 gallons for a 1000-pound horse,” said Dr. Easterwood.  “They will need more if they are exercising or if their housing conditions do not provide for shade or circulation of fresh air.”

Horses that are not sweating and are overheating can easily have their body temperatures rise to dangerous levels within minutes of exercising in the summer, and their large muscle mass allows them to generate a tremendous amount of heat, making them susceptible to a loss of water and electrolytes through sweat. As the amount of sweat increases, so does the imbalance of body fluids and electrolytes.

“The only increased nutritional requirements for hot weather would be the intake of electrolytes,” said Dr. Easterwood.  “Large animals that have access to mineral supplements will generally take in enough electrolytes to account for normal losses, but electrolytes can be added to their daily grain ration if the horse will be sweating excessively or exercising.” 

Since horses cannot tell us directly that they are overheated, we must pay attention to their appearance and behavior in order to distinguish their discomfort. Some signs to look out for are an excessive amount or absence of sweating, increased respiratory rate, depression, lack of appetite, apparent weakness, or disorientation.

“Horses that are not sweating adequately will start to breathe rapidly in order to try to cool themselves via their respiratory system” said Dr. Easterwood. “This condition is called anyhdrosis and can cause them to overheat while exercising.” She explains that these horses are literally trying to 'blow off steam' and cool themselves by taking in air that is cooler than their own body temperature while blowing out the warmer air.

While most horses and other large animals are able to cool themselves by sweating, taking in an adequate amount of water, and staying in the shade, you should still keep an eye out for signs of dehydration or heat exhaustion. Whether your pet whinnies or bleats, barks or purrs, they are counting on you to keep them healthy and comfortable during these hot summer months.

Pet Talk is a service of the College of Veterinary Medicine & Biomedical Sciences, Texas A&M University. Stories can be viewed on the Web at Suggestions for future topics may be directed to