Dangers of Rising Mercury


Dr Amol Yamgar
Dogs can tolerate rising environmental temperature quite well. However, with the temperature rising, the danger of heat stroke in dogs also increases. Know how you can protect your pooch and keep them cool and safe in summer! –by Dr Amol Yamgar

More than 70 percent of the total body heat loss in dogs and cats is due to radiation and convection from the body surface. Static air around the body is soon elevated to body temperature, and surface heat loss is blocked. However, when the body temperature exceeds 104°F a breakdown of the animal’s thermal equilibrium begins. At 106°F the brain gets involved and it may cause long term damage. Inadequate ventilation is one of the most critical factors that cause heat stroke in dogs.

Thermal homeostasis occurs when there is a balance between ‘heat load’ and heat dissipation. Heat load is defined as the summation of environmental and metabolic heat. Heat stroke occurs when heat load markedly exceeds the ability of body compensatory mechanisms to promote heat loss. It is characterised by hyperthermia (above 105°F), often complicated by alterations in many systems and organs such as acid-base balance, kidney, liver, cerebral edema and blood clotting mechanism.

Main causes of heat stroke
Pets who are confined by chain outdoors are more susceptible to developing a heat stroke. Often they are unable to get into the shade or have no or limited drinking water available. In these cases, excitement and exercise associated with animal fights appear to have precipitated heat stroke. Although exercise and excitement can significantly contribute to the induction of heat stroke in confined dogs, heat stroke is rare in dogs who run free, regardless of air temperature. Long distance traveling in hot climate is another factor that may trigger a heat stroke in your pet.

In contrast to human heat stress, humidity has less of an effect on canine heat stress, primarily due to the poor development of canine sweat glands. However, high humidity may contribute to the likelihood of heat stroke because evaporation of water from the oral and nasal cavities is reduced in spite of maximal panting.

Other predisposing factors include –

  • Lack of availability of fresh drinking water
  •  Brachycephalic anatomy (brachiocephalic breeds – Pug, French Bull Dog, British Bull Dog, etc)
  •  Length of hair coat
  •  Obesity
  •  Decreased heat tolerance associated with young and old age, body weight (greater than 15 kg)
  •  High environmental temperature and humidity

Sense the symptoms
and keep your pet safe!

The onset of heat stroke in three-fourths of cases is acute, with clinical signs developing fairly rapidly.

Initial symptoms include – panting, drooling, tachycardia, bright red oral mucosa and hyperthermia, dullness, loss of consciousness, uncontrolled movement, and chances of collapsing.

Instead of sweating dogs eliminate heat by panting. When panting is not enough, your pet’s body temperature rises. The pulse becomes rapid and weak. As the disease progresses, your pet might become stuporous due to the development of cerebral edema. The extremities become hot and dry to the touch. The bright red oral mucosa becomes pale, due to either peripheral vasoconstriction or decreased circulatory volume or both.

Massive diarrhoea and vomiting may occur at a later stage. If the diarrhoea becomes bloody, disseminated intravascular coagulation (DIC) may be a complication. Progression of cerebral edema to terminal stages leads to coma and respiratory arrest.

Easy first aid steps can save your pooch
External cooling methods, this can usually be accomplished by spraying your pet with cool water, draping a cold and/or wet towel over their body and making them sit near the fan to cool off. Take your pet’s temperature every 5–10 min while you continue water cooling until their body temperature drops below 103°F (39.4°C).
Ice packs or rectal palpation sleeves containing ice slush can also be placed around the neck regions, but should be removed if shivering occurs or after 15 – 20 minutes. Let your pet drink as much cool water as he wants. Take your pet to the vet for best care.

A little care goes a long way
Knowing about the risk for heatstroke during summer is the key to prevent this fatal disease. During acclimation periods to hot and/or humid weather, dogs should not be permitted to run or play outside, especially during afternoons. Pet parents are advised that acclimation is partially complete within 10 to 20 days, but it can take up to 2 months for animals to fully acclimate to warm temperatures.

Never leave your pet in the car for any amount of time, even if the car is parked in shade or is well-ventilated. The temperature rises rather quickly due to glass windows which can lead to severe heat stroke.

Make sure your pet has access to fresh and clean drinking water at all times. If you notice any of the signs of a heat stroke, head to the vet immediately.

Heat stroke can be avoided; you just need to be cautious. Don’t tie your pet in direct sunlight, give him a cool place to laze around, keep him hydrated with water and summer fruits, and do not force your pet to exercise or take him for a walk in the afternoon when the temperature is highest.

Take it slow and easy and enjoy the summer days indoors with a cold drink and lots of snoozing!

(Dr Amol Yamgar, BVSc & AH, MVSc (Surgery), PhD, is a pet practitioner currently based in Mumbai)