Environmental temperatures that exceed the thermoneutral zone (TNZ) of dogs are considered hot.
When we talk of TNZ, this is the temperature range wherein a dog produces heat (to keep warm when it’s cold) and loses heat (to keep cold when it’s hot) at an equal rate.
To determine the TNZ of dogs, we need to factor in the breed, coat density, coat length and skin insulation. Studies have estimated that the TNZ of dogs are:
1. Longhaired breeds – 15 to 20°C
2. Shorthaired breeds – 20 to 25°C
3. Alaskan sled dogs (breed for very cold areas) – 10 to 15°C
Generally, heat stress starts when environmental temperatures exceed 25°C. 30-35°C is mild heat stress while 35-40°C is severe heat stress. Dogs exposed for a long time to severe heat stress levels are prone to heat stroke.