Heat stroke is unfortunately a common occurrence I see in the emergency room during the summer months. Unless very prompt and aggressive treatment is obtained, many of these dogs will die. Personally, having been a veterinarian for many years and seeing all kinds of dogs affected by heat stroke, I must say that I believe our giant breeds, i.e. mastiffs, are more prone to heat stroke due to their size....
First off, our mastiffs (and all dogs) perspire through panting and through their nose and pads of their feet. We sometimes forget that we, as humans, perspire all over, thus creating a moist skin environment, which has a cooling effect. So, our dogs will pant heavily when hot. That is not to say that heat exhaustion is occurring, it is a normal fact. I know you know mastiffs that pick out the cool concrete or wood floor or tile floor in your house to sleep. That is because of the cooling effect of these surfaces.
Heat stroke occurs when the body temperature is 106 degrees of higher and it does not take long to literally boil the internal organs. If this should occur in your mastiff, the first thing to do is to remove the dog from the environment where they overheated. I say environment, because heat related problems are not always due to a mastiff being outdoors. Being in cars, EVEN with the windows cracked, can be a death trap, even if it is only for 5 minutes. Or being in a kennel in an unairconditioned area, or in an area not subjected to good air circulation. So, take the dog to a shaded area or area with a fan as soon as possible. You may have to get help to move the dog, since collapse is possible with severe overheating. The first thing most people do is put ice cold water on the dogs. This is wrong. You use cool water, i.e. hose water or tap water but not ice cold water. Ice cold water causes the blood vessels in the skin to constrict or get smaller and thus will decrease the amount of coolness that can get to the inner core of the body which is what you want to cool down. If possible take their rectal temperature. Begin to cool the dog by wetting with cool water poured over the body. It is best to direct the water to the auxiliary areas (armpits) and groin areas since these areas are thin skinned and will absorb the coolness faster. I use a hose if possible and I will get towels soaked with cool water and put them in the groin and auxiliary areas. DO NOT LET THEM DRINK. Spray water in their mouths and put a cool towel over their heads to cover their nose, but not enough to restrict their panting. If available, apply alcohol to their pads of their feet, as the evaporation of alcohol cools even faster. Direct a fan at the dog to help with the evaporation process.
The second most important thing is to get them to a veterinarian as fast as you can.... Click here to read the full article