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| Summer Heat threatens your pet
In order to understand why pets get heat stress/stroke, we should take a moment to discuss how they cool themselves. Dogs do not really sweat to cool themselves. Instead, they rely primarily on panting and to a much lesser degree to vasodilation (opening of the blood vessels near the skin) to help lose heat via radiation away from the body. When dogs pant, a large amount of heat is removed from the body through the removal of warmed water vapor from the lungs, and evaporation from the tongue. This process has its limits and cannot continue to work effectively when the temperatures start to soar. Rabbits tend to reduce their heat load by vasodilation of the blood vessels of the ears. This is not nearly as effective as panting. When you consider the relative inefficiency of this system and the high insulating properties of their fur, it is easy to understand why they are subject to heat stress. Cats will cool them selves through a combination of grooming themselves (to allow the saliva to evaporate from the skin which is cooling) and panting. Cats also have more effective kidney systems than dogs and can retain more body water in the heat. With less dehyration they are less subject to heat stress/stroke. These issues coupled with the fact that more cats tend to live indoors explain why we don’t see as much of a problem with cats as dogs in the summer. Who is at risk? Heat stress can affect most of our pets, however, dogs and rabbits tend to be the most common victims. Pets that are housed out of doors are much more liable to develop heat stress, especially if they do not have access to water and/or shade. Breeds with darker hair coats are more prone to heat stress because their dark coats absorb more solar radiation than do lighter coated breeds. Breeds with impaired respiratory systems (snub nosed, or brachycephalic breeds) such as English bulldogs, Boston Bulldogs, French Bulldogs, Shi-tzus, Lhasa Apsos, Chow Chows etc are much more prone to heat stress because of their impaired ability to effectively pant. Heavy coated breeds such as Chow Chows, Malamutes, Samoyeds etc have trouble dissipating heat through their heavily insulated coats. All Rabbits are prone to heat stress, especially if they are enclosed in cages without any shade and/or cooling system. Heat stress occurs when the animal is unable to maintain its internal temperature with in the normal range for the species. In dogs and cats this temperature should be between 100 and 102.5 degrees on average. Bunnies have slightly higher resting temperatures and can range from 101 to 103 and still be normal. As the body overheats, the pets become dehydrated, lethargic, sleepy and anorectic. As the internal body temperature continues to rise above 105 degrees, the pets become at risk for heat stroke. Heat stroke is a syndrome wherein the pets become so dehydrated that their blood becomes concentrated and does not flow smoothly through the cardiovascular system. Oxygen is not delivered properly to all the organs and carbon dioxide and other waste products are not removed from the tissues adequately. Frequently, the clotting system of the body gets out of whack and thromboembolism (clogging of blood vessels) can occur. If left untreated, the pet will go into shock and frequently will die. What can you do to protect your pet?
What should you do if you suspect heat stress/stroke?
Other heat related problems: Every summer we see a rash of dogs coming in with burned paws from running on the street during the heat of the day. If you’ve ever tried to walk on concrete or asphalt on a 100 degree day, you know that you can burn your feet in a heartbeat. Dogs that are accustomed to walking on concrete all the time build up hard callous which helps protect them. But pets who are on grass or in the house most of the day are prone to blistering their foot pads on the hot roads. This is particularly true of puppies who have not had enough time to develop calluses. To help protect them, take your walks/runs only in the early AM or early evening hours. Feel the sidewalk before starting out and see if it is dangerously hot. Solar radiation problems: Pets can get sunburn too! Mostly this occurs in white coated or pale coated breeds. The areas affected often include the eyelids and nose (in non pigmented pets) and the underbelly (where there is less hair). Unfortunately, with continued exposure, it is common for pets to develop skin cancer (squamous cell carcinoma). This cancer may first appear as red ulcerated spots and then develop into more raised tumors. Squamous Cell carcinoma is an aggressive tumor which invades deeply into the adjacent tissues. It can also spread to other parts of the body (metastasize) via the lymph system or blood system. Early detection and surgical excision gives the best long term prognosis for these pets.
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Summer in Southern California can put your pet at great risk of heat related injury. With temperatures routinely hitting the 90s and often breaking 100, it is important to understand heat stress and heat stroke and what you can do to help protect your pets.