What is Heat Stress?
Heat Stress, also called heat stroke or heat exhaustion, is a potentially life-threatening condition caused by an extreme elevation in body temperature. This increase typically occurs as a response to a trigger, such as a hot environment, but stress and an inability to lose heat can also contribute. When dogs are exposed to high ambient temperatures and excessive humidity, heat stress can result. This is largely because dogs do not sweat through their skin like humans, which is our primary method of heat loss and core body temperature regulation. Instead, dogs release heat primarily by panting with only a small amount of sweating through the footpads and nose.
Heat stress occurs when panting is not sufficient to cool the body down and the core temperature becomes dangerously elevated. Once the dog’s temperature reaches 41° Celsius, damage to the body’s cellular system and organs may become irreversible, leading to serious organ damage or death.
Signs of Heat Stress
Signs include: excessive or heavy panting; hyperventilation (deep breathing); increased salivation and drooling early and then eventual drying of the gums/mucous membranes; weakness, confusion or inattention; Vomiting or diarrhea that may be bloody.
Common behavioural changes are: Agitation; Whining; Barking; and Other signs of anxiety.
In the end stages of heat stress, a dog can become listless, dull, weak, and recumbent. It may have increased difficulty breathing, and ultimately may have seizures, collapse, lapse into a coma and die.
Preventing Heat Stress
Ensure transport is sufficiently cool before greyhounds are loaded for transportation to the track. It is a good idea to hose or towel down greyhounds before travel ensuring excess water is removed from the dog’s coat.
Transportation trailers and vehicles must have good ventilation and airflow and/or air-conditioning.
Try to arrive at the track as close as possible to the opening time of kennelling.
Greyhound clubs should make sure kennels have appropriate cooling or air-conditioning systems.
Note that large, dark-coated dogs or more nervous/ ‘stressed’ dogs may be at increased risk of heat stress and these greyhounds should receive particular care in hot weather.
It is difficult for greyhounds to remain cool when being transported to racing venues in hot weather (when the temperature exceeds 35° Celsius), particularly if the trailer is not air-conditioned. Participants should ensure fluids are given to their greyhounds before/during and after the journey, both to and from the track and, and they must carry adequate water and drinking containers in case of delay during the journey. In addition, they should ensure a good airflow is maintained through the vehicle while travelling to reduce the build-up of humidity.
Once on the racetrack, and after the greyhound has been given fluids, it is advised to kennel the greyhound as quickly as possible.
Treating Heat Stress
Do not attempt to force greyhounds to drink if they are affected by heat stress. Hose the greyhound down as soon as possible until the dog shows signs of a decrease in its panting. Hosing the greyhound’s feet, chest, back and groin is advised. Remove excess water and repeat as necessary.
If dogs cannot be cooled effectively, begin to vomit or have diarrhoea or are listless, dull, weak, or become recumbent, emergency veterinary treatment must be sought immediately.
QRIC stewards pay close attention to the temperature on race days, as the temperature gets hotter, they provide extra water and ice for racing greyhounds.
On hotter days dogs are kept in their air-conditioned kennels for as long as possible before racing and on occasion parading greyhounds before the race may be cancelled to keep dogs out of the heat for as long as possible.
Extra veterinarians are also on site at the track to ensure any dogs exhibiting heat stress are taken care of and if the temperature gets to 40° Celsius a decision may be made to cancel or delay races until it is cooler.