Avoiding Heat Stroke

Today is opening of prairie grouse season here in South Dakota and one that brings a mix of emotions as a hunting dog veterinarian. As a hunter I live most of the rest of the year for what this day means, as a veterinarian I often dread these early season hunts. Today dawned cool and nearly perfect for an opening day. As I worked around the house, catching up on a week of neglected chores I breathed a sigh of relief for the conditions. Too often these early September days, and even into October, can mean heat and humidity which can translate into a deadly combination for hunting dogs.

Every season we lose dogs to heat stroke and the hard, simple fact is that we cause it and we are responsible for preventing it. While today’s grouse opener was cool, the rest of the week is forecast to be much warmer. Please take care in the field to ensure your dogs stay safe. Recognize the early signs of overheating, how to reverse it and when to seek veterinary care. Here is  an article I wrote years ago after a tragic pheasant opener here in South Dakota where we lost far too many dogs:

Overheating, or heat stroke, is a common problem in hunting dogs, and as we found out during South Dakota’s pheasant opener last year, a deadly problem as well. Overheating is a condition that develops from the body’s inability to regulate temperature. Basically, the heat being produced by the body is greater than the heat being dissipated.

The causes of heat stroke in hunting dogs are numerous, but at the top of the list is a lack of conditioning. Too many guys take their dogs from the couch or the kennel straight into the field without any thought about the dog’s level of conditioning. This would be akin to taking most of us on a given day and demanding us to run a marathon…at the drop of the hat. The difference is that we’re able to say no and are in tune with our bodies enough to know when to stop. These dogs love to hunt and love to perform, and by the time they are showing signs of a problem it is often too late.

Other causes of overheating include lack of acclimatization, high humidity and high temperatures. A rule of thumb used by many dog trainers down south is that if the ambient temperature when added to the humidity is greater than 150, you probably shouldn’t be running your dogs. You can still have heat stroke develop at lower temps, but this is when it becomes particularly dangerous. You’ll also see heat problems with too much exercise too soon. Also an obese animal is going to be much more prone to overheating than one running at a lean body weight. Previous episodes of overheating will also predispose a dog to overheating again, because overheating can cause the body’s internal thermometer to become “out of whack” and make the dog more susceptible to future episodes.

It’s also important to know a dog in water can still have heat stroke. This is particularly true in the summer months and early fall when many of the shallow bodies of water have had time to heat up. At these times it can be like swimming the dog in a hot tub. Just because they’re wet doesn’t mean they’re cool. Basically, you should always try to be smart when working your dog in any type of heat.

Signs that your dog may be getting close to overheating include panting and/or extreme hyperventilation. These dogs aren’t just hot; they are trying to move as much air as possible in an often futile attempt at removing heat. Many of these dogs will also be hypersalivating. They’ll come back with long ropes of drool coming out of their mouths, or puddles of saliva around them. They also will have an altered mental state and appear glassy-eyed. Often when you look at these dogs they look like they are in trouble, almost as though no one is home when you look them in the eyes. Many will become ataxic (i.e. stumbling and incoordination) and show muscle weakness. Often, but not always, you will see vomiting and diarrhea develop. From here it may progress to total collapse.

At this point you are probably wondering what temperature the body has to reach to fall into the category of heat stroke, and unfortunately there isn’t one. The normal body temperature of dogs is 100-102.5 F, but in normal working dogs, without heat stroke, we can have temperatures during and immediately following exercise that get up around 106-107 F without causing a problem. But these are the same temperatures that we start worrying about heat damage starting to occur with heat stroke.

This is where having a thermometer in your emergency kit becomes important, because if the temperature does not begin to fall immediately, or worse it continues to climb, after the exercise is stopped, your dog is in trouble. As corny as it may sound, I would recommend taking you dog’s temp after a day of hunting or while out training when you are not even close to crossing the overheating line. This will give you an idea at what temp your pup typically runs while at work and will allow some sort of baseline if you get into trouble out in the field.

Basically during heat stroke all the body systems are being affected. The tissues of the body are essentially cooking themselves. When we get these dogs into the clinic they have severe blood chemistry abnormalities, they can go into respiratory distress and this is one condition that can quickly lead to death.

As far as starting treatment in the field, the biggest thing is to get them cooled down. If there is water around get them a cool water bath or spray them down. If you are going to cool them in standing water be sure to wade in with them and hold on to them, as they could collapse and drown or get out too deep and not be able to make it back. Apply ice to the hairless portion of the belly and especially deep in the armpits and groin, as there are some very large blood vessels in these areas that help cool them down fast. You can also get them in the vehicle with the A/C on high with the fans blowing directly on the dog.

The whole while during the cooling process you need to be monitoring the dog’s temp and stop cooling them when the temperature reaches 103 F. This will also allow you to make sure you are not cooling them too fast. It is very easy to over-cool these dogs and drop them down too low and end up causing hypothermia…remember the internal thermostat is no longer working correctly.

If it appears that your dog got more than just got a little warm, you need to get him to a vet. Continue attempting to cool him down while transporting them to a vet, though. Hospitalization, monitoring and supportive care are very important in order to save these dogs. Many of the dogs that survive may have long-standing problems, and the sooner you seek veterinary care the better.

Another problem that can contribute to heat stroke and may cause death all on its own is hypoglycemia or low blood sugar. It is also termed exertional hypoglycemia, hunting dog hypoglycemia, or sugar fits. We see this condition when the blood glucose levels fall below 50.

The cause of hypoglycemia is similar to heat stroke: a lack of conditioning. Hypoglycemia occurs when your dog does too much work too soon, and it occurs early in training and often with over-anxious young dogs. Many of the dogs we worry about are those dogs that are constantly trying to go. They’re wild in the box, excited before they’re released, and some of them have gone through an entire workout without ever getting off the truck.

Some of the signs you may see with this problem are an altered mentation where the dog just doesn’t seem to be acting right and is confused and almost dazed. There can be trembling or shaking as well. Many of these dogs will have a nervousness and anxiety about them and most dogs will exhibit weakness and ataxia or stumbling, as they can no longer walk normally. In severe cases it can lead to collapse, seizures, coma and death.

Treatment consists of getting simple sugars into the dog. Oral simple sugars are absorbed from the gums and thus do not need to be forced down the dog. I recommend carrying a bottle of 50% Dextrose or Karo Syrup in the first aid kit. You can draw up a syringe of the dextrose and administer is slowly until the problem resolves. If using syrup you can just take some and rub it on the gums until the dog responds If you do not have these items you can also use honey or REAL fruit juice…the key being real fruit juice as too many juices contain artificial sweetners that will be of no value in treating the problem. In a pinch items like Pepsi or Gatorade could be used. Just be sure to take it slow and rub them on the gums as many of these dogs may not be able to swallow, and you don’t want to pour pop down the wrong pipe. If the dog recovers uneventfully, I wouldn’t send them back out to perform. I’m big on running bloodwork with any type of collapse, and although likely everything will be normal at the time of the work-up, it will allow you to rule-out other possible causes of collapse.

Many of the emergencies we see in hunting dogs can often be prevented with preseason conditioning, nutrition and getting to know your dog. With a little education on what to do when an emergency occurs you can also prevent these problems that crop up from being a season ending, or worse yet, life ending condition.


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