Features of thermoregulation in labradors make them very susceptible to heat. Dogs in natural conditions in the heat have the opportunity to go into the shade or hide in a hole. Vessels located close to the surface of the skin expand, the volume of blood flow increases, and heat transfer to the environment increases five to six times. All higher mammals in the skin have glands that produce sweat. The evaporation of moisture from the surface of the body is enhanced. Dogs cool more often by breathing. Under normal conditions, a dog inhales and exhales air twenty to forty times per minute. At high temperature, she makes three to four hundred breaths per minute. Not only the respiratory rate changes, but also its “structure”: almost all exhaled air passes through the mouth, where moisture evaporates from the surface of the walls of the oral cavity and tongue. If this is not enough, then the skin temperature rises. With prolonged and severe overheating, the dogs begin to break down the proteins that make up the membranes, which play a crucial role in the work of a variety of internal organs. When overheating, and sometimes it reaches 44 degrees, the proteins begin to “curl up.” This occurs in the protein structures of the liver, kidneys, spleen, as a result of which these organs simply fail. The danger of prolonged exposure to heat stimulates the loss of potassium, magnesium and sodium.
For the occurrence of heat stroke it takes a little. If your dog is mobile, then it is enough for half an hour to run in the bright sun. The opposite situation is also possible – the dog settled down to sleep in the sun. Thirty to forty minutes of the dog staying in a closed car or bag is enough to cause severe hyperthermia. What temperature is critical for a dog depends on a lot: on age, state of health, fatness, coat length, body size. First of all, elderly dogs suffer, as well as patients with various viral infections (parvovirus disease is especially dangerous in this state). In young as well as in adult dogs with cardiovascular failure with respiratory system lesions, the fatal temperature is lower. Below it is in obese dogs experiencing overwork. Long and thick coat slows down heat transfer. Therefore, during this period, it is useful to use, in addition to water consumption, also salt, which slightly salt the water, but not higher than the isotonic state. You should also wet the dog several times a day from the hose. Going somewhere in the heat by car and taking animals with you, you need to take a thermos with water and pieces of ice. Shade the dog’s seat. In very hot weather, you can use the drug rinbronkh. It is given with a drink of 20 grains.
The first signs of heat stroke: rapid shallow breathing, whitened or blood-stained whites of the eyes, pale or strongly colored (literally burgundy) tongue and gums. Pallor or “bloodiness” depends on whether the dog’s blood vessels have expanded or narrowed due to overheating, a very weak, hard-to-feel pulse (it is better to determine it on the femoral artery). The pulse is threadlike, sometimes intermittent, when the heart, as it were, “pauses”. The following series of symptoms is caused by cerebral hypoxia: the dog becomes lethargic, has poor eyesight on moving objects, and responds poorly to commands. The breath is intermittent, wheezing. There may be pulmonary edema, convulsions occur. The dog faints or coma. It is quite simple to distinguish fainting from coma: if, during fainting, the dog’s pupils react to light (narrow), then with a coma, this reaction is also absent. Coma is the ultimate state of the body, then death occurs. Death occurs mainly due to circulatory disorders. After heatstroke survivors, after several hours of severe hyperpexia, signs of irreversible brain damage may remain, and the dog may suffer symptoms of disorientation for the rest of its life.
In addition to heat stroke, animals also have sunstroke. Under the influence of direct sunlight, dogs with dark hair heat up especially quickly: they absorb more radiant energy. Dogs caught in the sun are affected by radiation. It is best tolerated by those whose brain is protected from the penetration of long-wave heat rays. For sunstroke, unlike thermal shock, the suddenness of the disease, which often occurs at normal body temperature, is characteristic. The mucous membranes are reddened. The dog is anxious, agitated, convulsions are possible. During a sunstroke, under the influence of direct sunlight, brain damage occurs, hyperemia occurs – plethora, caused by increased blood flow to the brain, as a result of which its work is disrupted, the work of important centers of the medulla oblongata. The dog may also develop heat exhaustion (heat prostration, collapse, or fainting). The main symptoms are lethargy, heavy breathing. Amid thermal exhaustion, fainting may occur.