Cool Aid: Beating the Heat With Working Horses
Anyone who has worked or played in high heat knows how exhausting it can be. High, fluid-sapping desert heat can drain you in no time as you sweat away volumes of fluids and electrolytes. Then there’s the suppressive, sweaty, heat-and-humidity combination where the air is so heavy you practically swim through it. Given how lethargic, uncomfortable, and sometimes a little ill we humans can feel in high heat when we only need to cool our relatively limited muscle mass, imagine how carrying around a 1,000 pounds of steaming muscle and body heat and hair coat feels to our equine partners.
Washing horses with cold water is an effective, safe say to cool the horse during hot weather or after competition.
Races and heats and rounds and shows are held in all kinds of weather, and if we want our horses to do their best while competing in the heat, then we have to do our best to condition and acclimate them to withstand high temperatures.
Spring Into Summer
As cool weather gradually gives way to hot weather, most horses acclimate naturally with little problem. Acclimation is more difficult, however, when temperatures change suddenly, such as when traveling from cooler to hotter climes. The abrupt change can stress body systems not used to the heat.
There is little one can do when spring temperatures spike 60 degrees in a 24-hour period. Reports Bruce Saunders, a veteran Standardbred trainer at The Meadowlands racetrack in New Jersey, "We don’t train any horses on a day that goes from 30 degrees to 90 degrees, and we give the horses two or three days to get acclimated to the change. We’ll back off on the exercise levels, get the work done before the heat and humidity come in, make sure they have plenty of cool water and their fluids stay up, and just use good common sense to not stress them out."
Those who ship their horses, especially performance horses, from temperate to hot climates can prepare their horses in advance for the new environment. Shelley Bridges, an endurance competitor/trainer with Trinity Training Barn, Aubry, Texas, used to live in California before moving to steamy Texas. She says, "When going from a cooler climate to compete in hotter weather, I’d train my horses about two weeks ahead of time with a light summer blanket on to make them get hotter and help their bodies change to the sweating conditions of the heat. Initially, I’d shorten their work periods, then work up as the horses got used to the heat. I also increased their electrolytes to accustom them to start drinking more before they left."
Upon arriving in the hotter area, Bridges would add fluids to the horse’s feed—a half-gallon of water to the grain or a beet pulp mixture—to keep more fluids in the gut.
One also can arrive early at competition and allow the horse to acclimate naturally, says Catherine Kohn, VMD, Professor of Veterinary Clinical Sciences, The Ohio State University, and a researcher who participated in the 1996 Olympic studies on the effects of heat on horses. "We recommend they arrive about three weeks ahead of time: One week to get over the transport and a couple of weeks to acclimate to the heat." Kohn notes, "This assumes long transport—12 hours by road or plane; acclimation is not necessary for a three-hour trip. Also, this recommendation assumes top level competition in very hot weather."
But even acclimated horses can suffer from heat stress and heat stroke if pushed too hard. Fortunately, a handler can reduce the risk through conditioning and careful management.
A fit horse in good health and condition is better able to withstand the stress of heat. Conditioning builds the circulatory and respiratory systems so the horse can cope with the additional stresses of heat during exercise.
"Conditioning changes the horse’s ability to utilize oxygen and blood flow in the muscles," explains Ann Swinker, PhD (physiology), Extension Horse Specialist, Colorado State University.
Adds Saunders, "Good conditioning is crucial. It takes a long time to get a horse finely turned and properly conditioned. But once they get like that, they have the capability to handle more stress both physically and mentally. You can gradually get them conditioned to where they’re comfortable in handling the stress of the work level and the severe temperature levels."
In conditioning a horse, Bridges suggests you work slowly and consistently. "Slowly work them in the heat to get them used to it. Start out just walking them for four or five days, depending on the heat and the condition of the horse. For some backyard horses, walking a half hour in the heat is a really good work-out!"
Interval training--which is gradually increasing work/rest/work segments at the trot and canter--is considered a good way to increase fitness and conditioning.
Kohn cautions, "How hard you train the horse depends on what you’re trying to do with it and how fit it is. You definitely want to work up the horse’s fitness slowly if you’re asking him to become both fit and heat-acclimated at the same time."
Adapt And Adjust
While exercise and work-outs can be maintained during periods of high heat, one might have to alter the time and intensity of the work program and keep a watchful eye on the horse to make sure that it’s not overheating.
In the cool of the morning. Kohn says researchers found that in hot, humid areas, the best time to work a horse is early in the morning. "Unless you’re in a desert situation, in most places the humidity is very high in the early morning and the temperature is lower. When the sun comes up, the humidity goes down and the temperature goes up. We found that horses handled high humidity with lower temperatures better."
Solar radiation and the effects of the sun beating down on horse and rider are less intense in the morning, as well.
"Horses can’t take the continual stress of working out in the heat every day," says Saunders. During the winter, Saunders gets out on the track around 7:30 a.m., but when a summer forecast calls for hot, humid conditions, Saunders begins working the horses at 5:30-6:00 a.m., with all the serious work completed by 8:30 a.m.
Another choice, particularly for horses which have to compete during the heat of the day, says Swinker, is to alternate work-outs so the horse is worked during the morning on one day, then in the heat on another day. "See how the horse responds to working in the heat of the day," she says, "then gradually increase the amount of time working in the heat."
Cut back. Kohn’s study also found that it’s important to decrease the amount or intensity of work the horse does during hot, humid weather, as a shorter work-out in high heat and humidity is the stress equivalent of a longer work-out under gentler conditions. This is why the distance and efforts on the roads and tracks phases of the 1996 Olympics courses were reduced by 30%. "One needs to realize that asking a horse to go just as far and just as fast in the heat of the day may be asking a lot if it’s a hot, humid day," Kohn says.
Bridges says that on extremely hot days, she opts to reduce the pace of the work-out. "My horses usually get out on two 10-mile rides and one 20-mile ride a week," she says. "In the heat, we go the same distance, but we’ll go slower and take longer." Ditto for actual races. "A 50-mile endurance race in the winter could take four hours; that same race in the summer could take six."
Kohn says it’s helpful to plan rest pauses in the work-out to help facilitate heat dissipation.
Warm-up and cool-down.Although it might be tempting to skip warming up a horse when the weather is hot, the horse’s muscles still need to be stretched and warmed before starting a training session. "I don’t want to push them too hard, too fast, and have the heat catch up with horse and cause overheating," says Bridges. "I start out slowly to let their bodies adjust to how hot it is. Normally, I might take a mile to warm up; in the summer, that could be 11¼2 miles."
Naturally, thorough cool-downs are very important for the horse’s health. When the horse is trying to dissipate body heat and sweat into a hot and humid atmosphere, the cooling-off process takes much longer. Says Saunders, "We alter cool-downs significantly in the summer. In the heat, horses don’t recover as quickly from stress. They’ll blow much longer, drink more water (and the intake has to be moderated so they don’t take too much fluid too quickly), and take longer to cool down their bodily functions and body temperatures. Sometimes it takes an hour to 11¼2 hours of cooling and watering before we’re comfortable that the horse’s body temperature has returned to normal and we can turn him lose in the stall."
Cooling techniques.When cooling down a horse during hot weather, forget about using a cooling sheet. Says Kohn, "Sheets just act as heat insulators. If you put a wet towel on the horse’s back, very quickly that towel heats up to the temperature of the horse, and then it’s actually making it harder for the horse to cool off. Instead, put the horse in a cool or shady area, let them stand in front of a fan or misting fan, or wash them down with cold water."
Kohn says studies have proven there are no adverse affects to treating hot horses with cold water. In fact, hosing a horse down with cold water might be one of the most effective ways of cooling the animal.
"In experimental studies we did, we found that if you poured 55-degree water from a hose on top of the horse, it comes off the bottom of the horse at 75 degrees. A tremendous amount of heat can be transferred in the water."
Putting ice in the rectum to cool a horse can help, says Kohn, "but the problem is then you can’t get a correct temperature. So, for that reason, I don’t recommend it."
Saunders uses a combination of techniques to cool his horses--walking, multiple cold baths, and taking the horse to where fans or a breeze will cool and circulate the air. Remember these cooling techniques are important for hot horses (rectal temperature 104 degrees) working hard in hot weather, and are not necessary when horses are cooler.
Monitoring. Generally, a horse which has adequately cooled off will breathe normally, won’t be sweaty, and will look alert. However, a better way of knowing that the horse has cooled off sufficiently is by monitoring its vital signs.
The most important way is to monitor the horse’s temperature. Know what your horse’s normal temperature is at rest—a healthy, adult horse usually has a temperature around 99.5-100.5° F, Kohn says. "If you exercise your horse, even in the winter, the body temperature will go up because of the heat produced as a by-product of energy production. You need to determine how hot your horses get. Many horses’ temperatures go up to 103° or 104°. That is not a dangerously high temperature, but put your horse in the shade and cool him off with some water to make him more comfortable. On the other hand, if his temperature goes up over 105°, you’re talking about seriously wanting to cool the horse off."
Check the heart or pulse rate prior to and right after exercising to ascertain stress, and know what is normal for your horse and how long he usually takes to recover. You can feel the heartbeat against the left side of the chest immediately behind the left elbow. You can feel the pulse rate under the curve of the jawbone. The normal heart rate for a horse at rest is between 36 and 44 beats per minute. During exercise, a horse doing pleasure types of activities might have a heart rate of 120 to 150 beats a minute, while a racehorse might have a maximum heart rate of 220 to 240 beats a minute. Within a short period of time, the heart rate of 120 to 150 beats per minute should come down to a recovery heart rate of around 60 to 70 beats per minute. In less fit horses, the heart rate could remain elevated for as long as 30 to 60 minutes.
"If your horse normally recovers to a heart rate of 50 in 15 minutes, and the heart rate is 70 a half-hour to an hour later, then there may be a problem," warns Kohn.
Check the respiration rate by counting how many times the flank rises and falls in 15 seconds, then multiply that by four to get the respiratory rate per minute. A normal resting rate in temperate conditions is around 12 to 16 breaths per minute; after exercise on a hot day, it can rise to over 80, but should decrease to less than 40 within a half-hour.
"As horses lose some heat through the respiratory system, some may pant," says Kohn. "Sometimes people put too much of an emphasis on panting or rapid, shallow breathing. The respiratory rate should decrease as the horse cools off; if the horse is hot, heprobably going to keep panting."
Bridges uses a 60/40 respiration/heart rate standard for her horses. "If I’m doing a good work-out and it takes my horses more than 10 minutes to come back to a 60 heart rate and their respiration to come down to 40, then I’m working them too hard. I also don’t like to see their body temperatures getting over 102 degrees."
Managing The Heat
Coping with high heat might call for changes in the barn, pasture, supplements, and water. Use your turn-out to acclimate the horse, but be sensible about it. "If it’s very hot and humid and the horse is turned out, that’s fine, as long as he has access to shade," says Kohn. "Most people around here turn their horses out at night, but what we recommend for acclimation to the heat is two or three hours during day. You don’t need to keep your horse out for long periods of time to get the beneficial effects of heat acclimation. Take them out early in the morning to start with, and then maybe toward midday."
Notes Bridges, "When I do a 100-mile endurance race, I ride all day and half the night, so the horse has to be used to being out in the heat and sun. The turn-out is part of the acclimation."
Be sure the turn-out area has shade--a stand of trees, a shed, an awning, or the shady side of a building.
Try to make the barn a comfortable, airy respite from the heat by keeping the air circulating with good ventilation or stall fans. "Ventilation (even in cold weather) is really important for horses housed inside," says Swinker. "Don’t put a fan directly on the horse; that puts them in drafts and makes them uncomfortable." Make sure stall fans are securely mounted and that electrical cords are out of the horse’s reach.
When it’s extremely hot, many horses don’t eat as much. "In temperatures over 100, horses reduce consumption of feed and spend more time in comfort behavior searching for the coolest or breeziest place," Swinker says. Kohn indicates that horses love to stand in front of the fan and it doesn’t hurt them.
As far as changing the diet, Kohn says there is debate but no definitive answers. "Some horses do better on higher fat diets in the heat, but some horses find high fat diets not very palatable," she says.
Experts do agree, though, when horses are sweating out fluids and electrolytes, they will need more of both. "Sweat contains salt, so when horses are working hard and are constantly training in hot weather, they will sweat a lot and lose a lot of salt," says Kohn.
Compensate for the salt loss by adding electrolytes to feed or water; if adding to water, make sure there is a second source of unalterated water. "Some horses won’t drink salt water," Kohn warns.
Kohn suggests avoiding commercial electrolyte supplements that contain a lot of sugar. "That doesn’t help," she says. She prefers supplements especially formulated for the replacement of electrolytes lost in sweat. "There are two I’ve used," says Kohn, "Summer Games, made by Kentucky Equine Research, and Perform & Win, distributed by Buckeye Feeds."
Besides commercial electrolyte formulas for her performance horses, Bridges makes up an old endurance recipe for use in the pasture: One part regular salt, one part light salt, and a half part dolomite. "It’s not as good as the high-tech store-bought ones, but it’s inexpensive."
Swinker cautions against overdosing electrolytes. "If the horses are stalled or corralled," she says, "and if they’re not being stressed or worked hard, you don’t need to provide them with as much as for a high-performance horse in training. Electrolytes are like minerals and vitamins—you can overdo it."
Obviously, access to plenty of clean, fresh, palatable water is important any time of the year. Swinker says that in normal circumstances, a horse will drink about eight to 10 gallons a day. But in hot weather, a horse--especially a working horse--can lose "to 13 quarts of sweat or 4% to 10% of its body weight per hour per performance. A lot of owners don’t think about that, and only provide the minimum. In hot weather, horses may need 12, 16, even 20 gallons of water."
Saunders says his horses always have two buckets of water in their stalls year around. "The buckets are topped off a couple of times a day in the winter. In the summer, we have to top them off more frequently."
Even when water is available, some horses don’t drink enough. As a result, says Kohn, "over time of training and showing in the heat, he may get a little dehydrated today, a little more dehydrated tomorrow, and a little more the next day until he has big problems."
To encourage a horse to drink, make sure the water is in a clean bucket (algae or scum in the water is not a flavor enchancer!) and that it’s cool. "Studies show horses really like fresh, cool water," Kohn reports. "If you change the water frequently and it’s cool, they’ll drink more. They also drink more out of buckets than automatic waterers, and they don’t like drinking with a bit in their mouth; they need to be taught to drink with a bridle on."
Salt or electrolytes added to feed will make them thirsty and encourage more water consumption. In some situations, where horses have become dehydrated and do not drink enough, rehydration must be accomplished via a nasal gastric tube or IV fluids. "For the majority of horse owners, that’s never going to be an issue," says Kohn.
It’s best to offer water immediately after exercise. Says Kohn, "Researchers from the University of Guelph found that if horses working very hard in hot, humid conditions were offered water right at the end of their bouts of exercise, there was a short window of time in which horses would voluntarily take a good slug of water." For horses which must continue working in the heat, drinking during pauses in the exercise program is important.
In extreme dry heat, horses can sweat off so much moisture that they become dehydrated due to loss of fluids and electrolytes. Where it’s hot and humid, sweat doesn’t evaporate because there’s so much water already in the air. Therefore, the horse doesn’t get any cooling effects from evaporation and continues to sweat, again resulting in loss of electrolytes and fluids.
The consequences of dehydration, high heat, and electrolytes losses are heat stress or the more serious heat exhaustion.
Because horses are more stressed when competing in the heat of the day, encourage organizers to schedule events during cooler periods of the day or in shady areas, or to cut back on intensity or effort.
Teach endurance horses to drink along the way. "If the horse is in the middle of a long event, it’s good if he takes in water, just like marathon runners have to drink as they go," says Kohn. "Encourage race and show horses to drink when they return to the barn."
Summer heat doesn’t have to end summer sports: By working and competing sensibly and appropriately, your horse can remain healthy and competitive.
About the Author
Marcia King is an award-winning freelance writer based in Ohio who specializes in equine, canine, and feline veterinary topics. She's schooled in hunt seat, dressage, and Western pleasure.
POLL: University Equine Hospitals