The heat is on Print
News - Rubrieke
Tuesday, 21 November 2017 21:48
Untitled Document

Dr Liesel van der Merwe is a small animal medicine specialist. Send her your questions: This e-mail address is being protected from spambots. You need JavaScript enabled to view it .

Dr Liesel van der Merwe

The summer sun is blazing and I think it’s time to remind you to look after your pets in this heat.

Dogs can’t sweat; they cannot cool down by evaporation. They only have a few sweat glands in the footpads, but these are too few to really help reduce heat. The only way they can cool down is by panting. If panting isn’t enough their body temperature rises. This can be fatal as it can cause major damage to the body organs if exceeding 41°C.

Cats are very unlikely to develop heatstroke unless enclosed in a car. Certain breeds of dogs are predisposed to developing heat stroke: those with thick fur, short noses or those suffering from medical conditions such as laryngeal paralysis and obesity.

All the brachycephalic (flat-nosed) dogs are at risk because they have very “crowded throats” with extra pharyngeal tissue, which limits the amount of air they can move, which in turn limits the amount of heat they can lose by evaporation during panting.

Dogs that enjoy constant exercise and playtime, such as working dogs (Labradors, golden retrievers, springer spaniels and border collies), should be closely monitored for signs of overheating, especially on hot days. They just don’t know when to stop.

Never under-estimate how hot it can become in a closed car, even if one or two windows are open a sliver. If you must leave your dog in the car for a few minutes, park in the shade and open your windows at least half way.

It is not only exercise and closed cars which cause heat stroke, sometimes the humidity is high during a hot spell and this reduces the dog’s ability to lose heat by evaporation. I have seen small dogs like Pekingese overheat while sitting in the shade on a very hot humid day, purely because of the thick coat combined with the flat nose and the high humidity and temperature.

Symptoms of heat stroke can progress rapidly and even if you move the dog into the shade, temperature continues to rise for a while. Symptoms are panting, drooling with thick tacky saliva and reddened gums. As the temperature increases, the heart rate increases and develops irregular beats.

Muscle tremors develop and a wobbly, uncoordinated or drunken gait develops. Bloody diarrhoea and vomiting may occur due to bleeding into the gut. Shock develops and your dog will become unconscious.

Note that overheating (hyperthermia) is not the same as a fever. Giving aspirin or parasetamol will not help and may cause more harm to the kidneys and gut.

Treatment is urgent and a visit to the vet is recommended. As the temperature rises, the small cells lining the blood vessels become damaged and thus all the organs become affected and the dog develops clotting problems.

If the heat stroke is severe, the most important treatment is intravenous fluids to prevent circulatory collapse. In severe cases intensive therapy is required and may still not be sufficient to prevent organ failure.

There are a lot of practical things you can do at home to help your dog. Immediately move the dog into a cool space. Let him lie on cool tiles and place a fan on him. Wet the entire dog with cool water, soaking to the skin. If your dog is not afraid of water, put him in the bath. This will cool the blood moving through the skin.

Do not use iced water as this will cause the blood vessels in the skin to constrict and slow down heat loss. Icepacks or packets of frozen veggies wrapped in paper or towels can be placed in the groin and armpits to cool down the blood moving in the big veins. They are too big to constrict with the cold.

Alcohol can be placed on the more hairless areas, which causes the temperature to drop due to evaporation.

Allow access to water but do not force water into the mouth as your dog might aspirate. Use cold water and a cloth to rinse the mouth out and cool the surfaces in the mouth down.

Prevent heat stroke by: Cutting/shaving dogs with thick coats; exercising in the early morning or evening; free access to water; and plenty of shade.