NOW that we are into May I had intended to write a piece on heat stress in animals, but having listened to another dismal forecast it seems appropriate to include comment on the effects inclement weather might have as well.
Many of us are aware of the RSPCA campaign ‘dogs die in hot cars’. Some may be less aware of heat and cold stress in other species.
Wild animals have evolved to thrive in the environment of their habitat. A biology exam question asks for comparisons between the anatomical adaptations of the arctic and fennec fox to their environments. The arctic fox is squat, stubby with short limbs and small ears so it has a small area of skin and heat losses are minimised. Conversely the fennec fox (a North African desert mammal) has long limbs and huge ears, hence a vast area of skin with lots of surface blood vessels from which surplus heat can be dissipated.
All animals have physiological and behavioural adaptations suited to a particular temperature, humidity, altitude and rainfall.
It took generations of breeding at lower altitudes before chinchillas could be brought from the high Andes and shipped to Europe, but they remain prone to heat stress and are happier in temperatures of 18C or less.
Another consideration is ‘am I providing my animal with the opportunity to change its behaviour to control its temperature?’ Herpetologists’ (reptile keepers) animals can only control their body temperature by changing behaviour so they must have an environment in which they can warm up and cool down as required. The same is true with all our pets: A dog can survive a warm day if it has access to shade and water, but not in a boiling car; a hutched rabbit will cope with a cold night, but only if deep, dry and plentiful bedding are provided.
One warm day last week, a farmer presented me with a sheep he assumed had pneumonia — its breathing was very rapid, shallow, noisy and getting worse. It was suffering from malignant hyperthermia in which the body tries so hard to get rid of heat through panting and pumping blood that more heat is generated and the situation becomes life-threatening. The sheep had a temperature of over 110F/ 43.5C, but thankfully made a full recovery with a thorough soaking, a cold-water enema, sedation, anti-inflammatories and a recommendation for immediate shearing.
Dogs do die in hot cars, but so do guinea pigs in runs without shade, fish in tanks with broken heaters and rabbits in damp hutches with no bedding. Even sheep in full fleece can do a good job of cooking themselves without any help from Jamie Oliver.
SAM PRESCOTT, Director and Senior Vet