The summer and warmth has finally arrived to the north. The sun brings the nature alive, but it troubles us as dog owners. The hot topics in public discussion this time of year are how dogs should not be left in a hot car, how to avoid tics and whether or not to shave a long coat down. These are all important topics, but there’s one more important topic that rarely comes up. That is how the heat affects a dog while it’s working.

Dogs cool themselves down by panting. They regulate their body temperature by breathing fast with their tongue out by exhaling the extra heat and by inhaling cooler air. A normal body temperature of a dog is about 38°C. 41°C is high fever and may cause serious and permanent brain damage and cardiac arrhythmia. If the temperature rises up to 42°C and more, it can be fatal. If the air temperature is too high, dogs can’t remove the extra heat from their body and their body temperature starts rising.
If the dog is panting its ability to sense odours decreases as the air does not effectively reach the olfactory epithelium, where the scent receptors are, deep in the nose.

When a dog is working inside, the temperature is often reasonable, if the space is used by humans. The sun heats up room space through plain windows as much as it does inside of cars, but the heat usually evens out in a bigger space and cools down because of ventilation. However, when a space heats up, its air currents changes, often radically. This affects a dog trying to pinpoint a scent in a space since the warm air rises up and the scents travel with it. The target scent may either fall down with cooler air in the opposite side of the space or travel straight through the air canals and out of the search area.

Furthermore, the heat affects the body temperature of a working dog. The hotter it is, the heavier the detection task is for the dog, since the ability to cool down by panting gets more difficult. Sniffing itself requires muscle work which increases the body temperature. Surrounding heat and effective sniffing makes the body temperature rise faster. If the dog is fit and has a strong muscles, it’s durability in work is also better.

When the dog works outside, the temperature may vary a lot depending on if you stand in the
direct sunlight or in the shade. Sun heats the asphalt burning hot even if the air temperature feels comfortable for us humans. While air temperature is 20°C on a sunny day, the ground temperature can be as high as 44°C! (Marvels of Mini Weather, The Science, 1965) The hot ground affects not only dogs’ paws, but also their noses close to the ground, again affecting the body temperature. The smaller the dog, the closer it is to the ground and the more its body heats!

In a book K9 Working Breeds: Characteristics and Capabilities authors Resi Gerritsen and Ruud Haak, who have long history with police, IPO and search and rescue dogs, introduce a study made on tracking dogs by Dr. Biewasser (Physical Stresses of Tracking, 1989, table below). Dr. Biewasser investigated two experienced tracking dogs tracking 1000 paces long tracks on a sunny day with temperature being about 20°C. They found out that the body temperature on those dogs rose up to 40,1°C (fever!) by the end of tracking.
The book also tells about a case where four unrelated belgian shepherd malinois of police died of exhaustion after training. The dogs had been tracking for at least 2,5 km and attacking a decoy in the end of the track. The air temperature during the training was about 20-22°C.
The study about body temperatures on tracking dogs by Dr. Biewasser would explain the sudden death of the police dogs. Their temperature had risen to severe levels after tracking of several kilometres and the attack in the end was too much. They had died of hyperthermia with body temperature of over 41°C. In the book they argue, that the optimal air temperature for practise is about 16-21°C.

Have you ever measured your dogs body temperature before and after performance?

Especially high drive dogs like malinois continue working despite the uncomfortable feeling or the fact that their body is overheating. If the motivation for the task is really high, it can be very dangerous for the dog to not stop working even though its body is overstressed. It’s then up to us as handlers and trainers to set the limit to the work and take care of our dogs’ wellbeing.

If you need to train or work with your dog at daytime, when the sun is shining and the humidity is high, you should work in short periods and assure your dog gets to rest often enough and its body temperature stays low enough. While resting, the dog should be able to get in the shade and cool down. You can use cooling mats, fans or something as simple as a wet towel. You should also offer your dog water to drink more often than you usually do. Some dogs won’t drink when working and then on possibility is to try flavoured water or ice cubes instead. Mix the water with some treats, some rehydration drinking powder (for dogs) or something else tasty to get the dog more interested in drinking. If you have a long search or track to do, remember to take breaks.

Professor Dominique Grandjean, head of K9 Sport/Work Medicine Unit in Alfort School of Veterinary Medicine in France, has worked decades closely with different types of working dogs. He argues that even light work doubles the loss of water on a dog. Hard working dog loses almost four times the amount of water compared to a house dog. Remember to take care of the hydration!

To avoid hot weather problems, try to train and work early in the morning or late in the evening, when the air cools down. Remember though, that the scents on a track are strongest in the early morning!

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