‘Now then, Rusty’, I told the little terrier. ‘Just relax for a moment while I take your temperature’. As I popped the thermometer into the dog’s rear end, I thought that perhaps it was just as well that animals do not understand human words. Dogs and cats would not appreciate advance knowledge of the fact that the vet was about to take their temperature!
The temperature of a dog’s body is a very useful indicator of the state of health. The normal body temperature of any species of dog can be well defined within a narrow range. If a dog’s temperature is above or below that range, it shows that the body is reacting to a disease.
Unfortunately, few dogs would calmly accept a thermometer under their tongue. As a result, dog’s temperatures are routinely taken per rectum. The thermometer must be held in place for approximately a minute, which can be tricky enough with a squirming, wriggling cat or a nervously aggressive dog.
Dog’s temperatures can vary considerably due to hot weather and exercise. For example, I have seen some perfectly normal dogs with high temperatures caused by the journey to the clinic in a hot car. Finally, if a dog is in pain for any reason, a high temperature may develop.
A dog’s high temperature usually hides underlying illnesses. Bacterial or viral infections are the most common causes. Sometimes a dog has physical symptoms, such as a discharge from the eyes, or a cough. In these cases, it can be easy to identify the site of the infection.
In other cases, there may be few or no physical symptoms. The owner may have simply noticed their dog behaving differently – not eating, lying around, seeming very quiet. On physical examination by the vet, the only sign of illness may be a high temperature. In these cases, it is often necessary to carry out further tests such as blood tests, urine samples and X-rays.
It is less common for dogs to have body temperatures, which are below normal. I saw a typical example of such a case today. He was a 2-year-old Collie who had suffered from a severe attack of gastroenteritis. He had become very dehydrated, and his body was becoming weak and debilitated. As a result, his temperature was slipping below normal. If he had not been treated, his temperature would have continued to fall, and he would have eventually slipped into a coma. He was given warm intravenous fluids, and wrapped up in a blanket. He is still very ill this evening, but his temperature has come back into the normal range, which is a very good sign.
Vets often include temperature taking as part of their standard physical examination. If routine procedures such as vaccinations are being undertaken, it is important to be certain that a dog is as healthy as it appears to be.