by: Glenn Selk
Oklahoma State University Professor Emeritus
Understanding and avoiding heat stress in cattle can be a valuable management tool for summertime in Oklahoma. According to the 1997 Oklahoma Climatological Survey most areas of Oklahoma have 10 or more days each year above 100 degrees and 70 or more days with high temperatures above 90 degrees Fahrenheit. This means that most cow/calf operations will be working cattle on days when heat stress to cattle is possible. Cattle have an upper critical temperature approximately 20 degrees cooler than humans. When humans are uncomfortable at 80 degrees and feel hot at 90 degrees, cattle may well be in the danger zone for extreme heat stress. Humidity is an additional stressor that intensifies the heat by making body heat dissipation more difficult.
Over heating is sporadically encountered in cattle, but is really a rare problem. High humidity contributes to the likelihood of heat stroke or prostration because water evaporation from the oral and nasal cavities is decreased, in spite of rapid panting. At an environmental temperature of about 88 degrees, heat dissipation mechanisms such as sweating and evaporative cooling must take place to prevent a rise in body temperature. Sweat gland activity in cattle increases as the temperature goes above the thermoneutral zone. Panting is an important heat regulatory device in cattle.
The signs of overheating may develop suddenly and depend upon the environmental conditions -- and the health of the cattle exposed to the heat. Panting often occurs at rectal temperatures at or above 104 degrees F, but may begin even at lower body temperatures. Some animals manifest restlessness, excitement, and spasms of certain muscles. However, other animals may be dull and depressed. A protruding tongue may be covered with saliva, and frothy mucus discharged at the nostrils. Rectal temperatures of overheated cattle have ranged as high as 107 to 115 degrees F.
Overheating in cattle can be prevented under most management conditions. Allowing animals access to cool water and mineral supplements is a must in very hot summer weather. Shade and free air circulation should be provided if at all possible. Avoid working cattle during very hot parts of the day. Very excitable cattle will be even more prone to heat stress if handled at high environmental temperatures. If animals are going to have limited access to water under stressful conditions such as shipping by truck or trailer, they should be allowed water prior to further stressful situations.
If weaning calls for cattle to be gathered and put through a working chute for immunizations, implanting, or other operations, then a few common sense rules should be followed.
1) During hot weather, cattle should be worked before 8 am, if possible. Certainly all cattle working must be complete by about 10 am. While it may seem to make sense to work cattle after sun down, they will need most of the night cooling before enough heat is dissipated to cool down from an extremely hot day. Recent research at Oklahoma State University with rumen temperature boluses has shown that the core body temperature of beef cows peaks at two to five hours after the highest daytime temperature. On a hot summer day the highest daytime temperature is often late afternoon. Therefore the peak body temperature of cattle may occur at 6 p.m. to 11 p.m. (Source: Pye, Boehrner, and Wettemann. 2011 Page 104; Abstract 285 http:/ /adsa.asas.org/midwest/2011/Midwest_Abstracts_2011-revised.pdf.)
2) Cattle that must be handled during hot weather should spend less than 30 minutes in the working facility. Drylot pens and corrals loaded with cattle will have very little if any air movement. Cattle will gain heat constantly while they are in these areas. Therefore a time limit of one-half hour in the confined cattle working area should limit the heat gain and therefore the heat stress.
3) Make every effort to see that cool, fresh, water is available to cattle in close confined areas for any length of time. During hot weather conditions cattle will drink more than one percent of their body weight per hour. Producers need to be certain that the water supply lines are capable of keeping up with demand, if working cattle during hot weather.
Written by Gallagher Electric Fencing
by: Heather Smith Thomas
A good dog can be as much or better help than another rider or two—bringing up stragglers, keeping the herd together, rounding up a herd-quitter, getting cattle out of the brush or in any other terrain that may be difficult to get through on a horse. When working by yourself, dogs can be invaluable, especially when moving a challenging group of cattle. On a hot day, however, it's important to make sure you don't overwork your dogs. Just like horses and humans, they may overheat when working hard. Making sure they have adequate water during the job, and a chance to cool off now and then, can help avert dehydration and heat stroke.
Don Hatch, a stockman near Tendoy, Idaho, has always depended on good horses and good dogs to help handle cattle, since he is often moving cattle by himself. “I've killed a few really good dogs from heat exhaustion, moving cattle in hot weather. Every time it's happened, I've been moving cows by myself and overworking my dogs. On some of this lower range country, water sources are a long ways apart and there is no shade; even the sagebrush is short,” he says.
He moved to this area from Utah 18 years ago. “I never had a problem with this in Utah, but up here I've killed two really good dogs,” says Hatch. This particular range has steep areas that are very short on shade and water. In steep country, and with cattle not wanting to move because of the heat, it's easy to overwork your dogs because you are using them a lot.
“The first one I killed was the best dog I ever had. He was the best help corralling cattle, in the corral, or out on the range. When heat stress hits, it seems like it happens quick,” he says. You may not realize the dog is in trouble until it's almost too late. But as soon as you see the first signs of a problem, if you can get the dog cooled off, you can save him.
“It's always happened to me in the heat of the day where there hasn't been much shade—where the dogs weren't able to get in some shade once in awhile, and a long ways between water. If you get an hour or two from water, they can overheat and die,” he says.
“I saved one two years ago; he went into convulsions after working too hard. I tried to load him on my horse, and the horse wouldn't let me, so I took my shirt off to blindfold the horse, then loaded the dog on and climbed on too, and jerked the blindfold off. I took him as fast as I could, about a mile and a half to a water trough, put the dog in the water and got him cooled off quick enough to save him. The average person might not try that, but my dogs are very valuable to me and I wanted to save that dog!”
“The best advice I can give anyone is to pack water along. Take a canteen, or bottles of water in your saddlebag, so that if a dog gets in trouble you can pour water over his head and mouth. Give the dog a drink and wet him down. If you're working in an area with no water, stop once in awhile and dump a little in their mouth and on their head and rest them a few minutes. This can help avoid problems. Usually, however, I get too intent on what I'm doing and don't worry about them enough until they're in trouble. In the past 18 years I've gotten dogs in trouble about 6 times, and twice it's killed them.”
Just as in humans, the dog's body can only function within a narrow range of temperature. If it gets too high, the brain is damaged. “They start staggering and acting disoriented. If you see that, you know you've got a serious problem,” he says. Only fast action at that point can save the dog.
“If you're out all day in the heat—and it seems like black dogs are the worst because they get hotter—and it's up in the 80's or 90's, they will overheat if they keep working. I had a couple other dogs I've saved that went into convulsions; there was no water close enough to get them to, but I got them to stay there and lie in some shade. The dogs were smart enough to know there was a problem and they stayed. I left the cows and hurried home to get water. The dogs were where I could drive with a truck so I brought water that way since I could get back to them a lot quicker. I got some water into them and was able to save the dogs,” says Hatch.
A tough cattle drive is easier on a dog if there are accessible streams, mud bogs or troughs. “Any place a dog can drink, and get into some water and get his belly in it and get cooled off, will really help. I try to move cattle in the mornings, but sometimes it takes longer than you figure and you end up in the heat,” he says.
Michael Thomas, a rancher near Salmon, Idaho, also depends on dogs whenever he's moving cattle, especially on the range. The dogs were invaluable August 16, 2003 when he and his wife and father were desperately trying to get all the cattle out of their high range pasture ahead of a fire. They wore out the horses and dogs but with 2-way radios (for constant communication regarding the fire's progress and where the cattle were), they managed to save all their cattle—gathering them in three hours out of an area that usually takes two or three days.
That day there was no time to rest the dogs or worry about water. But as a general rule Thomas feels fortunate that most of his range has shade, and not very long distances between water. “We've had some days moving cattle that if we hadn't gotten to a trough or a creek when we did, our dogs would have been in trouble,” he says.
“We always try to take time when we get to a water source to let the dogs get a drink and get wet. With the stock troughs you sometimes have to teach dogs to get in them, especially the young ones—if they haven't been in a trough before. Sometimes they're a little timid because when they get up on the side of it and look down in there they are afraid to jump in. The first few times, I get off my horse and lift them in, so they can get a drink and get completely wet. If you do that every time you pass a trough, when the weather is hot, they won't get into trouble,” says Thomas
A dog working hard in hot weather needs to drink every chance it gets, since it will dehydrate just from water loss via panting while trying to stay cool. “If it's real hot and you can't avoid working cows that day, you have to always keep in the back of your mind to try to not overdo them. It's easy to overwork dogs before you know it,” he says.
“Last summer we had a couple young dogs that went along with us to learn the job. One day we were down in the low country in July gathering some cattle that had gotten through the fence down into a neighbor's place that had a lot of gates open--going clear down to the highway. On the long drive back up to the range pasture, the young dogs were falling behind and trying to crawl under any little sagebrush for shade, and even trying to get under our horses. By the time you realize they are too hot, you definitely have to stop and give them a break. The 3 dogs that had been going every day with us were ok, but the young ones that hadn't been going every day were the ones that were in trouble,” he explains.
“We slowed everything down, stopped periodically, but even after they recovered, it was short term. We couldn't go very far without having to let them rest again. We finally got to a creek where they could drink. Once they got some water (and were rehydrated and cooled off), they were able to go on home just fine. But from the point we realized they were in trouble, we had to consciously make stops, for them.”
It helps if a dog is in good physical shape and not carrying much fat by the time the weather gets really hot. “We are lucky in our situation, in that our first range pasture is fairly close to the ranch, relatively small, not very steep, and we're not riding all day long when we move cattle there. Even some of the older, experienced dogs are not in great shape in the spring. They do need to get in condition. Overweight dogs have a lot more trouble with heat,” explains Thomas.
Long hair is another factor. “If you have a hot climate you may want to consider a short-haired dog. Some people clip their dogs. I've seen some really hairy dogs that are shaved,” he says. Even though dogs don't sweat, they still radiate body heat (heat loss into the air, if it's cooler than body temperature), and a thick hair coat holds in heat.
“Every time you come to a mud hole or trough where the dogs get wet, they lie in it. If you clip the long hair they won't be packing around so much extra weight of mud and foreign material. The mud dries out and acts as an insulator to hold in body heat, too. There's a type of crossbred curly dog here in our valley that has a lot of thick hair, and almost everyone who has those dogs shaves them in summer,” he says.
“Our dogs, by the time we get into the worst heat of July and August, are lean and trim enough that if we just pay attention to hitting every water source we can, not pushing them too hard, we can usually get along fine. But our pastures are unusual in that we have a lot of water. On the other side of the valley where we leased range last year, there is a severe shortage of water and it's open country; vegetation/brush is short and there isn't much shade. It's a lot tougher on dogs. We try to ride really early in the morning and be out of there by mid-day—for the sake of dogs, horses and people. It's several hours between water sources, and some days, even though you start early in the morning with best intentions, you may get into trouble and not be done before it's really hot.” Sometimes you think it's going to be a routine check, but find something important you have to deal with, that takes longer. All of a sudden it's mid afternoon and 95 degrees.
On a day you know you'll have a long cattle drive, it's important to start early (for the sake of the cattle, horses and dogs), even at the expense of other chores and ranch work, so you might be on your way home by the time it is very hot. “A dog can travel a long ways in the heat, at the speed of your horse walking. But when they are working cattle they expend a lot more energy and more apt to become dehydrated and stressed.”
He's had both long haired (border collie crosses) and short haired (blue heelers). “One thing that helps us is that we use our dogs so much that by the time the weather is hot the dogs are not fat. They go all the time. It helps if a dog is never overweight. We have a few that don't go all the time (including some older semi-retired dogs) and they may join up with us voluntarily if we're moving cattle within sight or hearing of our house. They may hear us and come along. They're the ones that have the most trouble if we are out there all day. My suggestion to anyone who finds themselves out there with a fat dog is to be really careful. That's the dog you'll need to keep an eye on. If it's a long day and you are committed to getting the cattle moved without being able to go home, that's the dog you may end up packing home on your horse,” says Thomas.
A dog has less body mass (to dissipate heat from) than a horse and an in-shape dog can usually stay cool enough if he can keep drinking. “A good dog that's doing his job will generally go 10 times farther than your horse does in the average day. But you want a well trained dog that only does what you tell him to do, so he's not overworking himself. You also need to be conscientious about your use of the dogs. They often don't need to be working all the time unless it's one of those days when it's tough getting the cattle to move. Some days the cattle move easy and the dog doesn't have to work very hard, but other days you get into circumstances where cattle want to brush up or don't know the country and you have to drive them all the time—and that's when dogs may get overworked. There are some days you just have to stop and let the dogs rest. The most important thing is awareness. Pace the dogs, if you can. If you can periodically give them time to rest and have a good drink, they will be fine,” he says.
If a dog does start to suffer heat stress and becomes disoriented, staggering or having convulsions, it's imperative to cool him quickly. Wetting him down with cool water is probably the best thing to do, if you can. Be a little careful, however, if water is ice cold; cooling him TOO much can also be risky. Taking him to a very cold stream and immersing him, for instance, might not be best.
“In our area, the streams are small and not ice cold, especially by July or August when weather is apt to be hottest. In May or June, however, streams are colder if the water is coming right off a snowbank. And you could run into trouble that early in the year if your dogs are really out of shape. It's probably best to avoid extreme cold. Any water that is cooler than the dog will probably be effective,” says Thomas.
“When a dog is really in trouble, you need to give him water to drink and get him cool. It's better to see the early subtle signs. Out in the open where there's no shade you may not see the signs as readily because there's no shade for dogs to get into. If you stop traveling, however, you'll find them crawling under your horse for that little bit of shade. This is always a clue to pay attention to. A good dog may travel right behind your horse, but it's very unusual for a dog that knows his business to try to get under your horse. If he does that, he's desperate for shade. Another clue, if a dog is usually very energetic and exuberant and suddenly wants to lie down all the time, he's on the edge. If you see him lying down, it's time to stop. Or if he's usually right with you and is now back down the trail a ways lying down, you'd better pay attention.”
Written by Gallagher Electric Fencing
Participants in the Northwest Project Grass Grazing Field Day got a break in the rainy weather with blue skies and moderate temperatures — not a typical July day.
Held on two neighboring farms, the field day provided hands-on experience with the use of grazing systems with a large dairy herd and a cow-calf operation.
John and Amy Vanderstappen, owners of Van de Jersey Dairy Farm, use grazing to augment the total mixed ration they feed their registered Jersey dairy herd.
The participants in the field day were taken on three wagons through the pasture system to see the access road, watering systems and fencing that are used with the cattle. Vanderstappen pointed out that he had put in drainage tiles in many of his pastures.
“Tiling is important in pastures as well as on cropland,” he said. “It will pay for itself in three years. If we hadn’t tiled, we wouldn’t have been able to use many of these fields with all the rain we have had.”
Vanderstappen said he believes his cattle are healthier by being on pasture for half of the day. From April to September, the cattle are on pasture at night, and then in September they are switched to being on pasture during the day.
In late November, he brings all the cattle into the barns for the winter. He also doesn’t want his cattle in the pastures during deer hunting season.
Some of the cattle walk about half a mile from the barn to get to the pasture, crossing two roads in the process. Vanderstappen said the public is quite patient when the cows are crossing the road. Because they are the younger cattle, they move rather quickly.
“We only put the younger cattle on the pastures that are far from the barn,” Vanderstappen said. “We keep the older cattle in the fields close to home.”
Using a Natural Resources ConField
Day Shows Grazing’s Benefits, Whether Dairy or Beef
Photos by Carol Ann Gregg
John Vanderstappen explains the watering system in his heifer pasture that is fed by a nearby spring.
Ryan Miller points out assets and challenges in his beef grazing system.servation Service cost-share program, Vanderstappen improved the main road that leads to all the paddocks for the milking herd.
Vanderstappen and his crew did the laneway improvement by laying fabric then 2.5-inch stone, then 1-inch stone and then fines.
“You want the top soft so it won’t hurt the cows’ feet,” he said.
Vanderstappen talked about the benefits of the pasture system for his dairy, which is currently milking about 270 cows.
“I don’t see much change in milk production from when they are on pasture and when they aren’t,” he said. “There is about half the manure to haul in the summer. The cows receive about a third of feed from the pasture.”
Because the farm is successful raising calves, it has a surplus of high-quality Jersey cattle to market for dairy purposes. In 2013, the farm sold about 100 head to other dairy operations.
Vanderstappen said the farm’s calf-raising system has been changed to provide the calves with three-quarters of a gallon of pasteurized milk twice a day for three months.
Jersey heifers wait to be moved to another pasture.
The farm has moved from hutches to small groups of calves, and Vanderstappen said he is happy with the results.
“It is expensive to raise calves, but they are much healthier and bigger on this system,” he said.
Van de Jersey Dairy Farm is now using a new freestall barn with a liquid manure system. It is also using a custom manure hauler that Vanderstappen said is saving the farm money.
The new barn has a loafing area for cows about to calve.
There are four full-time and four part-time employees who see to the day-to-day operation at Van de Jersey Dairy Farm.
The field day continued at the beef farm of Ryan Miller. He began raising cattle with his dad more than 20 years ago. About six years ago, he purchased the farm where he and his family now live. They have 20 brood cows.
Miller led the tour through part of his pastures. He was concerned with how rough the pasture was after this past winter. He also talked about his system and how he can provide shade through an adjoining paddock during the heat of summer.
Because the system is relatively new, Miller was searching for input from other producers and agency staff who were participating in the field day.
While in the pastures, Extension educator Joel Hunter gave a presentation on the characteristics of different grass species with recommendations for seeding to provide a diverse stand of grass for the grazing animals.
Written by Gallagher Electric Fencing
