Keep it cool: Avoid heat stress |

Keep it cool: Avoid heat stress

On a hot day cattle overheat quickly if they have to exert. Moving cattle is always safer during the coolest part of the day, starting early morning if possible. Horses and dogs may also suffer heat stress if they work too hard in hot weather. Heidi Carroll, Livestock Stewardship Extension, South Dakota State University, says the main thing is to be prepared. "It's important to have water available for horses, people, and any dogs involved."

"This may mean packing water along, or having some available along the way. Depending on distance traveled, cattle need water along the way or immediately available when you arrive. Dehydration is a major factor in heat stress," she says.

Dr. Ray Randall, veterinarian at Bridger, Montana, says one problem today is that most people now have black cattle. "They don't handle the heat as well as red or white cattle or Brahmans. But the main thing when moving any herd is to take them slow, and let them go their own speed. You don't want any chasing or yelling," he says.

Billy Greenough, a cowboy/farrier/horse trainer who rides for several large ranches south of Billings, Montana, was raised on a ranch on the Crow Reservation. "We ran several thousand steers and my dad was in charge of the cattle. When we trailed them to the Bighorn Mountains for summer pasture, it was a 35 mile drive, uphill. My dad always told us to make sure that every step those steers take is where you want them to go—no wasted energy. Let them go their own speed, and don't hurry them," says Greenough.

“If you know it will be a humid, hot day, consider postponing. Watch the weather forecast. Try to do the cattle drive before a heat wave rather than during it. If you can arrive at the new location and give the cattle one cool night to recover from a long drive before going into a stretch of heat, it is better than starting with cattle that already have elevated respiration rates and temperatures.”Heidi Carroll, Livestock Stewardship Extension, South Dakota State University

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"Those yearling steers would take off like a bunch of frisky horses, feeling good, and we'd have to try to hold them up. Pretty soon they'd slow down and we could line out. My dad always had guys ride along the edges of the herd, to keep them going in a straight line—always going the right way. A lot of people try to push the herd from behind—pushing too hard on the drag," he says. Pushing them all grouped up like that just adds more stress.

"When moving cow-calf pairs, make sure calves have time to get mothered up and nursed before you start moving the herd," says Carroll. "Calves won't be as likely to get dehydrated if they've had milk. Pay attention to how the calves are doing along the way. Calves often show signs of heat stress—panting and breathing with mouths open, or trying to lie down–before the cows do. Let the calves set your pace, and influence your decision regarding whether to stop. They may need a chance to rest before you continue," she says.

"When planning the move, pick the best day weather-wise, then do it early in the morning. If you can't move them until afternoon, be very proactive in reducing stress and taking them very slowly." Heat is cumulative for cattle if they can't dissipate it fast enough, resulting in a "heat load" and they will be very hot by the end of the day. Even after sundown with cooler temperature, those cattle will still be hot. They need rest and cooler temperatures (below 75 degrees) to dissipate heat from their body

Besides temperature, be aware of humidity. "If you know it will be a humid, hot day, consider postponing. Watch the weather forecast. Try to do the cattle drive before a heat wave rather than during it. If you can arrive at the new location and give the cattle one cool night to recover from a long drive before going into a stretch of heat is better that starting with cattle that already have elevated respiration rates and temperatures," Carroll says.

Julie Walker, Beef Specialist, South Dakota State University says the livestock weather hazard guide lists three conditions that will put cattle into heat stress, in addition to temperature, humidity, wind and solar radiation. "Those three things are heat index: first would be daytime heat index at 75 degrees or higher for 72 hours—because in our part of the country we have the blessing of night cooling, most nights; second would be heat index during a 48-hour period that is no lower than 79 during the day and no lower than 75 at night; third would be daytime heat index reaching 84 or higher for 2 consecutive days," Walker says.

"There are some apps available that give this weather information, and cattlemen can put these on their smart phone. One of them is called Thermal Aid but there are several. You can program it to alert you when there is risk for heat stress," says Walker.

Depending on terrain, try to make strategic stops along the way when moving cattle long distances. Stop in a shaded area, if possible, or a grassy meadow where the vegetation and shaded ground is cool, versus an open area with sun beating down on hard-packed bare dirt that reflects heat. If cattle can rest in a relatively cool spot it will help them recover a little from heat load.

"If you stop on a ridge you might pick up a breeze, which can also help dissipate heat and cool the animals. Especially on a humid day, finding areas with a breeze can be helpful," Carroll says.

There will be less dust (which causes more respiratory stress) if you allow cattle to string out single file, compared with a big mob being pushed and chased by riders and dogs. Any time cattle are grouped too tightly there will be more stress, more energy wasted in cows worrying about their calves, etc. Cows stay more relaxed if they can string out with their calves at side or following them, going their own speed, and the calves will also be less stressed because they know where mama is.

Pay attention to signs of heat stress in horses and dogs. If a dog doesn’t have water, it will dehydrate even more quickly than the horses, simply because it cannot sweat to cool itself.

“Dogs do a lot more running; they are traveling more miles than the cattle or the horses,” Walker points out. They can overheat quickly on a hot day if they don’t have some water along the way to flop into (like a stream or water tank).

Randall says dogs’ respiration rate goes very high because they can’t sweat; they have to pant faster to try to cool themselves. “Their body temperature can get so high that if they are dehydrated they will go into convulsions. Once that happens they die very quickly. If you have dogs that are really hyper, leave them at home on a hot day.” That’s when you need the dependable ones that won’t do anything extra without your command.

Horses are also susceptible to heat stress if you overwork them in hot weather. “If they are in good shape, and fit, they can stand a lot of work. But a soft horse on a hot day climbing hills and sweating a lot may get dehydrated and overheat,” says Randall. If it’s hot and humid, sweat doesn’t evaporate as readily, the horse doesn’t cool down, and sweats more to try to cool himself—and becomes more dehydrated.

“If the horse has been sweating, and has now stopped sweating, that’s a clue he’s too dehydrated to sweat. If you quit working him at that point, and get him cooled down, he might be ok, but if you keep asking him to keep going—and he’s been a long time without water—you may end up losing that horse,” Randall says.

Some people don’t let their horses drink when they are hot and sweaty, for fear of colic or founder, but horses need to drink or they become dehydrated. “We were taught to not water a hot horse, but water should not be withheld,” says Randall. A lot of cold water all at once can cause the gut to cramp, but warm water is safe.

“If water is cold, limit the horse to about a gallon and then give him a little time, and then give him another drink. Count swallows as the horse drinks, and limit the horse to about 15 swallows. After a break, let him have another dozen or so swallows—and keep spacing out his drinks,” advises Randall.

“When you get to a water source pour water over your horse to help him cool down. Get your saddle off and get water over his neck, back and croup, and the inside of the legs,” he says. This helps cool the horse by evaporation. Blood vessels near the surface of the body, bringing overheated blood from the core regions, can get rid of some of that heat if you keep putting water over the horse,” he says. F