We are all too sadly familiar with some of the classic reasons for a dog dying of heat injury and every summer brings about more tragic stories of preventable incidents.
Here in Part Two Simon helps us understand both the classic and some other reasons for canine Heat Injury.
Physical Exertion ‘Heat Injury’ – When heat production from exercise or exertion is greater than the heat loss?
Simon – “Exertional Heat Injury is a serious risk and does not necessarily depend on hot climatic conditions, risk factors can be a rapid change in ambient temperature but also fitness related such as long periods off work, overweight or recent weight gain or muzzle work as the muzzle may restrict the canines mouth opening and on occasion the handlers overestimation of dog’s fitness level”
Signs to Look for
Early signs of thermal stress?
- Shade seeking
- Limiting voluntary movement, resting in place
- Sitting or lying, more than usual, without command
- Delaying return to the handler ( this might be seen as disobedience)
- ‘Self out’ of reward objects
- Panting smile, increased tongue length visible and more exposure of cheek teeth.
Signs of heat injury? If the handler is seeing these then it has already occurred!
- Excessive panting
- Staggering, incoordination
- Bloody diarrhoea
The Treatment – Active Cooling
Rapid immediate cooling is required – Cool first then transport. The target is to cool the core temperature to 1020F in 30-60 mins. Canines should be carried out, not walked to transport.
- Remove from heat threat, direct sun, vehicle, crate etc.
- Cool as fast as possible to 1030F (39.40C) to decrease heat threat time. Stop active cooling here to avoid hypothermia occurring.
- Any available reasonable method
- Cold water (any water less than 900F) on the coat with air blown over causes evaporation and cooling. (just wetting coats is not very effective in canines got to have air movement over coat as well)
- Ice/iced water, there is no evidence that ice or ice water is detrimental in heat injury, so long as the active cooling is stopped at 1030F
- Wet towels/ ice packs
If trained to give subcutaneous fluids, i.e. inject fluids under the skin this may help with any dehydration which may be a complicating factor (500mls every 2hrs on three occasions. Can be given in advance before threat)
Following heat injury the canine’s temperature may be unstable for hours to days, often prolonged recovery period. However there is no evidence in canines that suffer from heat injury, that they will be more prone to it in future, unlike humans. They must however receive veterinary follow up care.
What are considered to be causes of classic heat injury in working dogs?
- excessive temperature inside a confined space such as a vehicle or crate/kennel box
- inadequate/ reversed heat gradient
- AC failure, flat battery, faulty equipment
- Alarm failure, many transmit to a pager kept on the handler
- Alarm misuse/disuse, dis-alarming the system
- Distraction, handler carrying out routine admin duties away from the dog
- Negligence, leaving the canine unattended in crates or vehicles for prolonged periods, not necessarily in direct heat/sun
How do handlers prevent this?
- Handler primarily, but also working colleagues around the canines
- Be familiar with vehicles limitations, prevention is better than cure!
- Training focus on back up/buddy system awareness in case of equipment failure/ handler distraction
Recurrence and prevention?
If nothing has changed since occurrence then canine is still at risk. If the heat threat changes then re-evaluate the situation. Always try to pre plan with deployment threat assessment. Try to allow acclimatisation to the area of deployment. Regular health checks, fitness checks and a balanced diet and level of hydration will all help prevent heat injury.
Prior planning may well save your canines life.
For the purpose of this article I have not included disease or pathological forms of heat injury such as malignant hyperthermia.
S. G. Newbery BSc BVetMed MSc Forensic Science MRCVS