Hot Dogs – investigating the epidemiology of canine heatstroke presenting to UK primary care veterinary practices

The Hot Dog’s team (Emily and Anne) are now working with Dan O’Neill from the Royal Veterinary College on a UK wide canine heatstroke study. The study will use data from the Vet Compass™ database to review the clinical records of over 900,000 dogs registered with UK primary-care veterinary practices for heatstroke events. As well as canine risk factors (e.g. breed, age, sex and bodyweight), additional information will be collected to establish the incidence, fatality rate, seasonality and underlying causes for canine heatstroke. Understanding the risk factors of heatstroke specific to the UK dog population will provide evidence to better support educational campaigns aiming to reduce or prevent this potentially fatal condition.

This project has been funded by a Dogs Trust Canine Welfare Grant.

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The results of this (likely two year) project will be published in an open access journal, so the link will appear here on the Hot Dog’s site as soon as it is available!

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Canine Activity Survey Links!

Thanks to some fabulous people we now have our activity survey available to complete in several different languages! If you know anyone with canine friends/family or businesses who speak the following languages please share 🙂

Deutsche (German):

An alle Hundebesitzer! Haben Sie 5 Minuten Zeit, um eine Umfrage über die Bewegungsgewohnheiten Ihres Hundes auszufüllen?

Español (Spanish)

Se convoca a todos los dueños de perros: ¿tienen 5 minutos para rellenar una encuesta sobre los hábitos de actividad de su perro?

Magyar (Hungarian):

Felhívás minden kutyatulajdonos részére: tudna szánni 5 percet arra, hogy a kutyája napi mozgástevékenységét felmérő kérdőívünket kitöltse?

Nederlands (Dutch):

Oproep aan alle hondenbezitters, kunt u 5 minuten vrij maken voor de activiteiten gewoontes van uw hond.

Português (Portuguese):

Chamando todos os proprietários de cães, você tem cinco minutos para completar um questionário sobre os hábitos de exercício do seu cão?

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The Wonder of Bone.

We recently attended an incredible talk by Dr Martin Fischer on the wonders of Dogs in Motion. This frankly blew our tiny minds. So we’d like to share some of the incredible work being done on bones and explain how this links with canine heatstroke.

Dog breeds and bones

It all comes down to the skull. Firstly, a bit of background on how selectively breeding dogs for skull shape impacts the skeleton as a whole.

Dogs with a shortened nose (brachycephalic breeds) often also have a shorter, squarer pelvis. This has a cascade effect. It impacts how they walk, which in turn impacts the forces on their leg bones, which impacts the shape of the long bones. Tall, slender dog breeds tend to walk with their legs underneath their body, like a model on a cat walk stepping one foot in front of the other. This is the most efficient method of moving if you are a dog. As soon as the dog becomes broader, the chest becomes more barrel shaped, the dog walks with the feet either directly underneath the shoulder joint, or, in very barrel chested dogs they may even walk with the feet wider than their body, like a cowboy. This is not an efficient way of moving, but may be necessary for fighting. Traditionally, selective breeding aimed to develop a dog with a purpose. Sight hounds were bred for speed to catch prey, bull breeds were developed for their jaw strength for fighting.

Two very different dogs

This altered skeleton structure also causes the legs to move differently. In a Greyhound or Whippet, the legs simply swing back and forth, like a pendulum. The bones grow in an elliptical shape as this provides the best strength to withstand the force of trotting, running, jumping and landing. This again is streamlined and efficient. In a barrel chested breed, the legs don’t just swing back and forth, they twist and rotate to provide the same stride length. This twisting and rotating causes the bone to grow in a perfect circle, which is less aerodynamic and reflects the less streamlined motion. This means a barrel chested dog, which includes almost all brachycephalic breeds, has to work harder to move the same distance as a non barrel chested breed. This increased work, requires increased effort, which generates more body heat from muscle activity. They also tire faster, meaning exhaustion occurs more quickly.

What do bones have to do with heatstroke?

Dogs only sweat on their paw pads, so they rely on their breathing for temperature regulation. A dog’s long muzzle (nose) is a key method of cooling. Inside these long muzzles, are the nasal turbinates (see below), as series of scroll like bones that are coated in tissue similar to the surface of the lips and gums. These nasal turbinates hugely increase the surface area within the muzzle. This means a huge area of wet tissue is available for air to pass over every time the dog inhales. This functions to trap particles and potentially dangerous microbes like bacteria within the mucous in the nostrils to reduce the risk of respiratory infections. But most importantly, passing cool air over a wet tissue, allows evaporation and cooling.

Dog skull cross section

Dogs with a short muzzle, have a smaller area available for air to cool within the nasal turbinates. If the dog with a short muzzle also suffers from brachycephalic obstructive airway disorder (BOAS), they also have smaller nostrils, so the air cannot flow into the nasal turbinates as quickly. They then have narrowed air passages in the throat and whole windpipe, meaning both inhalation and exhalation is slower, and requires more effort. Remember these dogs are also using more effort and energy to move their limbs than a normal dog, add to that increased heat generated by the respiratory muscles having to work harder too.

Nose length comparison
Compare the length of the muzzle on the two skulls. The brachycephlic breed on the left has a much shorter muzzle, so significantly less surface area of nasal turbinates for cooling.

So, not only do brachycephalic breeds over-heat more quickly because simply walking and trotting they use more energy than a longer legged, longer nosed dog, but they also have a significantly less effective cooling mechanism because of their short nose. At the talk by Dr Fischer we were told that in Germany, Bulldog owners are advised to actively cool their dog as soon as ambient temperature exceeds 25oC. French Bulldog owners are advised to actively cool their dog above 28oC.

Altering bone, alters a dog’s risk of developing heat stroke.

Bone and insulation

The wonders of bone continue. People often think of a bone as a permanent, fairly fixed body structure. You suffer growing pains during adolescence whilst your skeleton grows and develops, then you reach your adult size and that’s about it. However, bone is continually growing, developing and changing right up until you reach middle age. Bone reacts to the stresses placed upon it. If you do a lot of high impact activity like aerobics, running, jumping or cross fitness, your bone responds to this by strengthening and changing in structure. If you are, as Dr Fischer put it, a “sofa pumpkin” (aka a couch potato, but we MUCH prefer this term!) and subject your bone to very little strain and load, bone will become less dense as you age.

sofa dog

How does this affect body insulation? Active bone, releases a hormone called osteocalcin. This hormone alters how cells respond to insulin in both mice, and humans. A failure to respond to insulin causes type 2 diabetes mellitus. In humans this condition is associated with a sedentary lifestyle, excess intake of carbohydrates and obesity. Mice with no osteocalcin are more likely to develop both type 2 diabetes and obesity. Mice with high levels of osteocalcin are almost resistant to developing type 2 diabetes and obesity. The link between a sedentary lifestyle and an increased risk of both obesity and diabetes mellitus type 2 is partly due to bone.

So, a dog doing very little high intensity exercise that involves stressing and loading the bone (just walking and mainly being a ‘sofa pumpkin’) is at greater risk of becoming obese and developing type 2 diabetes. The obesity is a big problem. An increased layer of fat under the skin acts as insulation, so the dog loses less heat into the surrounding air. This means the dog needs less energy to maintain body temperature (dogs typically use around 70% of their energy intake from food just to maintain their body temperature, this increases if the dog is in a cold environment). So if their diet remains the same, they will be consuming too many calories for simply maintaining their body, so the excess energy will be stored as, you guessed it, more fat. This becomes a vicious cycle.

Sofa Pumpkin

Whilst dogs lose heat through their respiratory tract, in particular using their nasal turbinates, they also lose heat through conduction and convection into the air and the floor in contact with their skin. If they are overweight the extra fat beneath the skin reduces this heat loss. These dogs are then heavily reliant on using their respiratory tract to cool, so you might notice they pant more than a less overweight dog, at lower ambient temperatures. Obese dogs are at increased risk of heatstroke, and are more likely to die from the condition.

How do bones impact activity?

Anyone who has ever experienced osteoarthritis or a fractured bone will know the answer to this question all too well. A painful joint or bone is horribly unpleasant, so we avoid using it. Not using a bone, especially a bone in the leg, will impact loading on that bone. This impacts bone strength, the release of osteocalcin, and also the health of cartilage that lines our bones in joints. Cartilage relies on loading to supply nutrients to the deeper layers, no nutrients, the cartilage thins and calcifies into new, abnormal bone. This contributes to osteoarthritis development.

So the less you use your bones, the weaker they become, and the more likely it is that you will develop painful joint disease. This makes you less inclined to use your bones, because they are painful. Which starts the cycle all over again.

So what should we do?

Body composition and skeletal health is hugely important for your dog’s overall health and welfare. Musculoskeletal disorders, including osteoarthritis, are among the top three causes of death in dogs, alongside cancer and neurological  problems.

Look critically at your dog. Can you see their ribs or can you feel them? If not, your dog could probably lose some weight. This will also allow them to be more flexible and active. Being more active, will prolong their bone and joint health. Ultimately, this will reduce their risk of heatstroke.

If the wonder of bones has gripped you as much as it did us, we thoroughly recommend Dr Fischer’s book, Dogs in Motion. A sneak preview in the video below.

Dog’s in motion (opens video in new window)

 

Cold as ice: Keeping hot dogs cool.

The heatwaves currently sweeping the UK, Canada and Japan this year have already resulted in the loss of both human and canine lives. The UK’s Environmental Audit Committee warns the frequency of such heatwaves is likely to increase in the UK , with the number of human deaths potentially increasing three fold. We have been warned that society needs to be “better prepared” for such heat, so here at Hot Dogs Canine Research we’re starting now!

Firstly, some “false news”

Ice cubes are not dangerous to dogs, provided they are used appropriately. There has been a lot of misinformation on social media regarding ice cubes, with a recent story suggesting that a vet warned owners ice cubes could kill their dog. This story has been misinterpreted. A dog with heatstroke should not be cooled with ice. We’ll come on to why later in the post. A dog in a heatwave, getting fed up with the hot weather, can absolutely have the odd ice cube. Or iced dog food popsicle, or frozen cream cheese lick mat! A fit and healthy dog, will not suffer any ill effects from consuming frozen food or ice cubes, in the same way that we suffer no ill effects from ice lollies. They should be provided in moderation, and they should not replace constant access to clean, fresh, cool water.

Cooling a playful dog

If you have a dog that is a little too stupid to realise it is too hot to play (see Stevie below for a classic example), you should consider active cooling methods to stop them overheating. Stevie is partial to a hosepipe. He gets to play in the jet of water for a couple of minutes, then the hose is switched off. Dogs have died from water poisoning, so it is important to not encourage your dog to drink excessively when it is hot. Avoid lots of toy chasing/retrieving, or allowing dogs to snap at running water for prolonged periods. Stevie gets a couple of minutes, then the hose is switched off – moderation is the key.

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Swimming or sitting in water is also a great way of keeping cool. Dog proof paddling pools are great – the inflatable ones often succumb to punctures from claws – and some dogs will choose to just climb in and lie down. Swimming in open water is not only a great way to cool down, but also excellent exercise for hot dogs. Sadly during summer blooms of blue-green algae can render small lakes and ponds dangerous to dogs, so keep an eye out for warning signs and learn how to recognise the problem here.

Cooling coats and mats are becoming increasingly popular, but be aware there is no robust evidence to support their use, yet. We are in the process of evaluating one, so watch this space for updates!

Cooling a hot dog

If your dog is hot from exercise, you may want to consider actively cooling them on a regular basis. Dogs do not sweat (apart from their paws) so they rely on panting, and losing heat from their body through radiation into the environment, or conduction to colder surface or liquid.  There is some evidence that dogs may continue to overheat AFTER they have finished exercising – our study investigating cooling in dogs supports this finding in canicross dogs – so the risk of heatstroke doesn’t end just because the exercise had.

There is very little robust scientific evidence to support any specific cooling method.

Studies have been done cooling dogs with heatstroke, but none to date simply cooling dogs post exercise. Our advice at the moment, is to first know your dog and trust them. If they are dragging you to the nearest puddle, lake or water bucket, chances are they are looking to cool themselves down. Let them. Most dogs will get out when they’re comfortable.img_1733

If like Murphy here (on the paddle board), your dog likens water to a dog eating monster, you may struggle to get them into a paddling pool or stream for a quick dip. Applying water with spray bottle, or sponge to the legs, inner thighs, belly and neck is the next best advice. Dogs with a heavy coat and become water logged, and can take an age to dry, so targeting the areas with less hair, like the belly and thighs, can provide some relief, without causing too much of a wet dog smell.

Murph on a paddleboard

Allowing your dog to drink is incredibly important. Dehydrated dogs get hotter when exercising , and are at greater risk of heatstroke. If your dog has been unwell, especially with diarrhoea or vomiting, they are more likely to be dehydrated, so ideally don’t allow them to exercise until they are fully recovered. Allowing your dog to drink tap water (typically between 10-15oC depending on the time of year) will help them to cool, and maintain hydration. Again you need to know your dog. If they are likely to drink a 2 litre bowl dry in one sitting and ask for more, you may need to stagger their intake, but most dogs will drink as needed.

Cooling a dog with heatstroke

Again, there have been several stories on social media regarding cooling dogs with heatstroke, very few backed by up solid science.

What we do know, comes from the dark days of science well before the Animals in Scientific Procedures Act 1986 legislation. Dogs were heated to the point of collapse, or unconsciousness. This study found that comatose dogs cool differently and much slower than conscious dogs with heatstroke. We know that dogs presenting to vets in a coma tend to have a poor prognosis for survival, likely due in part to their inability to effectively cool.

A conscious dog with heatstroke was found to cool quickest when immersed in water at 15-16oC. These dogs climbed out of the water baths themselves once they had recovered.

Stevie in the lake

The comatose dogs cooled much slower than the conscious dogs, largely because they stopped panting. Their rate of cooling was similar in water temperatures ranging from 1 to 16oC, however, two of the dogs cooled with ice water died immediately following immersion in the water. These dogs started shivering once they were place in the ice water bath, which could have caused further elevation in body temperature contributing to their deaths. When placed in water above 18 degrees, the dogs cooled more slowly.

In an emergency situation, the current best available advice for treating heatstroke is to continuously pour tap water over the dog, with as much air movement as possible, a fan or air conditioning is ideal. Do not delay getting the dog to a vet, especially if they are already comatose. These dogs need emergency care to maintain their blood pressure and try to save their brain, kidney and liver function. Cool the dog quickly, then transport them whilst maintaining air flow (windows down or air con on in the car) to the nearest available vet.  Try not to lay things over the dog, like wet towels, as this could restrict air flow to the skin and could reduce heat loss.

The single most effective way to ensure a dog’s survival, is to prevent heatstroke from happening.

Once heatstroke has occurred, rapid action is required. If the dog is still conscious, allow them to drink a little, and cool them with tap water. Seek veterinary care quickly. If the dog has already lost consciousness, every single second counts. Rapid cooling, then ideally continue cooling on route to the vet.

If its hot outside, chill out! Lie back, put your feet up, and enjoy a nap like Monty here.

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Dogs don’t just die in hot cars.

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Hopefully by now, most people have seen the warnings that dogs die in hot cars. They die of heatstroke because trapped within a car, with little or no air flow, they get hotter and hotter. Once their internal blood temperature exceeds 41oC their internal organs become damaged and begin to shut down. This can take minutes.

But hot cars are not the only reason dogs die from heatstroke. Increasingly, hot countries are reporting that exercise is the major reason dogs get taken to the vets with heatstroke. Now in the UK we’ve been lucky.  Traditionally, the UK doesn’t see much hot weather, and when we do, it usually doesn’t last long before we get rain, wind, sometimes even the odd summer snowfall!

But this is changing.  Climate change is increasing the number and frequency of abnormal weather events.  Look at 2018, at home in the Midlands in March it was -7oC. Three months later it hit 32oC on my driveway. Three months is 90 days.  Heat acclimatisation takes around 60 days.  I remember de-icing the car on Easter weekend, so before the prolonged period of heat hit, we didn’t have 60 days to acclimatise to the heat, and neither did our dogs. Already there have been reports of dogs presenting to veterinary practices suffering from heatstroke following exercise, one dog lost their life following a walk in the heat.

Heatstroke happens when exercising dogs get too hot and stay hot.

Dogs and temperature

Unlike horses and people, dogs can’t sweat.

Unlike horses and people, dogs come in an enormous range of sizes, colours, coat types and length, breeds and personalities. Ok, people and horses are also pretty variable, but you don’t often see a x40 difference in body weight like you do in dogs.

Dill hot in mud.jpg

Because dogs can’t sweat, and because they are so variable, there is NO SAFE TEMPERATURE.  In our research we saw dogs reaching a critical temperature (over 40.6oC and up to 42.5 oC when measured with an ear thermometer) at every race we attended over a two year period.  At every race.  Some races it was snowing, the hottest race was 15.4oC. We’ve spoken to canicrossers (people who run with their dog in harness) who have seen dogs collapse from heatstroke with snow on the ground (on-going project so no reference yet!). Yet we’ve also seen dogs competing in long races in the middle of summer crossing the line safely.

There is no easy way to predict which dogs will overheat.

You need to know your dog. Some dogs will tell you when they’ve had enough. They’ll lie down, or seek shade, or just flatly refuse to move! But some dogs will run until they drop, so they need to be managed with exercise only in the cooler mornings and very late evenings.

A cautionary tale

Danny lost his beautiful dog Brodie in June 2018.  The temperature was 19oC. Brodie wasn’t working hard.

[Videos – click the links to view]

WARNING this may be distressing to hear: Danny after Brodie collapsed

This is what he was doing before he collapsed; listen to Brodie’s breathing at the end of this video, something wasn’t quite right: Brodie training

Brodie collapsed shortly after this video was taken.  Tragically he died from heatstroke.

Danny has kindly allowed us to share Brodie’s story, because like us, he would like to see canine heatstroke become a thing of the past.  Heatstroke kills dogs. Veterinary hospitals report mortality rates of up to 63% in dogs with heatstroke.

Your dog won’t die from a missed walk, or run or training session.  If they get heatstroke: flip a coin. Heads you win, tails they lose.

coin toss Stevie.jpg

Dog’s cool in a number of ways.

Like us, dogs have a number of ways to cool down if their core temperature gets too high.

  • Radiating heat into the air around them – the hotter the air, the more humid the air, the less this happens.
  • Conducting heat to their surroundings – if the ground is hot this won’t happen.
  • PANTING! Air in the lungs is moistened, meaning water evaporates as the dog pants. If the dog can’t move enough air, or if the dog is in a humid environment, this becomes ineffective.

So if it is hot and humid dogs will struggle to cool.

But even if it’s cold and dry, if your dog can’t move air, their main cooling mechanism isn’t working.

Panting, some key facts

In order to pant, dogs need to be able to move air.  Anything obstructing air flow, will limit the effectiveness of panting and therefore cause the dog to overheat more quickly (see below for respiratory disease).holly panting (2)

  • Brachycephlic breeds
  • Laryngeal paralysis (see below)
  • Tracheal collapse
  • Any respiratory disease, or heart disease that affects normal breathing.

In order to lose heat through panting, dogs need enough water in their body to moisturise the air.   A dehydrated dog will conserve water and produce less saliva, and not moisturise the air in their lungs as much as a well hydrated dog.  Unsurprisingly, they get hotter quicker when exercising.

  • Vomiting
  • Diarrhoea
  • Anorexia (not eating)
  • Being in a hot environment
  • Urinating more frequently (diseases like diabetes, Cushings, hypothyroidism, renal disease can all cause this)
  • Not being given enough to drink or something nice to drink

Anything that could make your dog even slightly dehydrated could increase their risk of heatstroke if they are exercising. The same as people!

How do I know if my dog has a respiratory condition?

Usually, this is fairly obvious. If you’re sat on your sofa watching television, can you hear yourself breathing? No? Good, this is normal! Noisy breathing happens when there is turbulence in the respiratory tract.  This could be a narrowing, a flap of tissue, or liquids like mucous or pus. Narrowed airways may cause wheezing, or whistles. The classic noise is snoring.  If you can hear your dog breathing when they are at rest (and awake), this isn’t normal.

holly on a beach

However, this isn’t always the case. My family dog Holly (the Goldie here) had laryngeal paralysis (LP).  This is a disease one respiratory specialist vet described as “something that can be diagnosed whilst walking past a dog in the street”. They’re normally noisy.

[Videos – click the links to view]

Extreme laryngeal paralysis – this is an advanced case.

Cyanotic dog with laryngeal paralysis – note the blue tongue!

LP dog at the vets – not so obvious, panting, but listen to the forced exhale.

Holly wasn’t a noisy breather. She panted quite a lot but never made ANY noise.  I am a vet, and I missed it.  She started collapsing on walks. She would go very pale, collapse, and then about 5 minutes later get up and be fine! I checked her, found nothing. Checked her again, found nothing.  Then one day I was there, her heart rate was over 300 beats per minute and that’s not normal! So I referred her to a cardiologist thinking she must have a heart problem, they eventually examined her airway with an endoscope and found her LP. Her diagnosis was made almost by accident.

Because we then knew she had a respiratory problem we were careful with her.  We kept her cool, we kept her walks short, we kept her weight as low as we could. Because of my background, I knew she was at an increased risk of heatstroke, so I made sure she wasn’t put at risk.

If you are worried about your dog, get them checked by a vet.  If they find nothing, but you are still worried, get them checked again.  Don’t be afraid to ask for unusual things.  If your dog’s problem happens during or after exercise, ask if you can walk them in the car park and have them examined during and after exercise.

If you know, or suspect, that your dog is suffering from any kind of respiratory problem, be extra careful. Keep your dog cool in the warm weather and don’t risk exercising during the heat.

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Thinking of monitoring your dog’s temperature?

Know your limits!

This applies both to your ability to accurately use the thermometer you have chosen (see below for tips on some of the more sensitive ones), and also to interpret the reading in front of you.

What is a normal canine temperature?

This isn’t an easy question to answer. Google normal dog temperature and you will find a huge variety of temperature ranges reported by various sources.  When you look at the range, does it tell you who established it and in what population of dogs?  So far we have only found one source that answers those questions, and it was a German study, using 62 healthy dogs presenting to a veterinary hospital. The range they suggest is “normal” for a dog in the vets is 37.2 to 39.2°C (Konietschke et al. 2014).  Keep in mind, these were dogs in the vets, so your dog at home in a non stressful environment is likely to be at the lower end of this limit.

Consider your dog’s state when you take their temperature.  Are they excited, have they just been fed, have they just been walked/run/chased the cat, have they just spent the last hour lying in front of the fire?

After exercise, you dog’s temperature could be anything from low (if they got very wet in cold weather), right up to around 42.5°C – this is seriously hot. If you dog’s temperature is over 40°C after exercise, considering cooling them or at least check it again after 5 minutes.  If a dog’s temperature remains over 41°C for any length of time this is when heatstroke becomes a very real (and possibly fatal) possibility.

The options.

If you’re going to go to the trouble of monitoring your dog’s temperature, make sure you understand the risks and limitations of the thermometer you choose to use.

Mercury glass thermometers

These are the traditional thermometers you may remember from science classes at school.  They are rarely used in the UK anymore, due to the very real risk of the glass breaking and mercury poisoning! (Emily – I can remember an order of 10 mercury glass thermometers arriving completely smashed, and having to close the vet practice I was working in for the day, evacuate all staff, clients and patients so it could be professionally decontaminated!)

If you only have access to this type of thermometer, you need to be aware of three important things:

  • Firstly, you’ll need some lube. You can’t ask your dog to hold this under their tongue for a minute, so it’s going into the other end I’m afraid! Forget lubrication, and this is the last time your dog will ever let you anywhere near their bottom.
  • Secondly, once you’ve found some lube, you need to shake the mercury back into the bulb. Otherwise you won’t know if the measurement you get is today’s temperature, or the last temperature recorded.
  • Finally, you do need to leave them in for at least a minute.  Remember there is risk of breaking the glass, so seriously consider if this type of thermometer is worth the risk.

glass thermometer

Digital predictive thermometers

There are now far more common in both human and veterinary practice.  The major advantage of these thermometers is speed.  Not as accurate as simple digital thermometers (the hints in the name, predictive), but readings usually in under 10 seconds.

If you are looking for a cheap, reliable, safe and accurate option for monitoring temperature, this is your best bet.

Things to remember:

  • I’m going to say it again, LUBE.
  • Often these come with disposable plastic thermometer covers to help reduce disease transmission.  It’s up to you if you want to use them, single use plastic waste should be avoided where possible, so if you opt to go down the sustainable route remember to disinfect your thermometer after every use.
  • If you can, go for the models with a flexible probe, if you dog sits down, they’ll thank you!

 

Ear thermometers

So far, we’ve found these to be the best alternative to rectal thermometers in terms of both accuracy and tolerance.  You do need to use a veterinary model, so thats either the Vet-Temp or the Pet-Temp, which means you’re looking at around £100+ for the thermometer and you definitely need a supply of probe covers.  Ear wax completely blocks the thermometer’s sensor so you can’t scrimp on using a new probe cover each time I’m afraid.

Ear thermometers are not as accurate as rectal thermometers.  There are more things to go wrong: correct positioning, ear wax, hairy ears.

If you are going to use an ear thermometer, train your dog to accept ear handling and gradually introduce the thermometer.  We’ve found most dogs tolerate the thermometer really well, but it does beep loudly.

Also, if you’re going to use an ear thermometer, use an ear specific normal temperature range.  We suggest 36.6-38.8°C (see references below).

FINAL Rectal vs tympanic membrane temperature in exercising dogs

Link to published version

FINAL Establishing a reference range for normal canine TMT

Link to published article

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Monty the dog having his ear temperature taken

Non-contact infrared thermometers (NCITs)

If something sounds too good to be true, be wary.  Human medics and nurses have found these thermometers to be both accurate and safe, reducing the risk of disease transmission between patients as they require no physical contact with the patient. Sadly so far the situation in veterinary medicine is very different. Animals are typically covered in fur, so obtaining an accurate temperature by measuring the animal’s skin surface temperature isn’t currently possible.

So far papers have explored using the eye (Kreissl & Neiger 2015), various anatomical sites including the ear, gums and hairless skin near the rectum in cats (Nutt et al. 2015) and the muzzle and forehead regions in dogs (Omóbòwálé et al. 2017). None of these papers support using NCITs in a clinical setting.

We have just finished a study comparing NCITs to rectal temperature in cats and to ear temperature in dogs, watch this space for the final results!

Leo NCIT 2
Leo the cat having his eye temperature measured with a non-contact thermometer (the Rycom device)

Temperature sensing microchips

Underused in my humble opinion! No, they don’t report the same temperature as a rectal thermometer, but guess what, a rectal thermometer doesn’t report the same temperature as blood temperature so it’s a compromise (Greer et al. 2007).

To me, your dog legally has to be micro-chipped (UK), why wouldn’t you have one that gives you the option to also monitor temperature?

You can pick up a temperature reading microchip scanner for around £55 on Amazon (Halo scanner) – incidentally, if you travel with your dog, this is worth buying anyway, with your own chip scanner you can check your dog’s chip is reading fine before you set off, and if you pack your scanner you know you can locate it at customs should they have a problem! The Halo scanner has the added benefit that if you regularly connect it to the on-line database, if you scan an animal reported as lost or stolen, this will flash up when you scan the chip. So if you regularly come across lost dogs, having one of these in your car can be useful.

These scanners are really easy to use, you just squeeze the handle (where it says Halo), wave them over your pet’s chip, they beep when they’ve found it and display the temperature.

halo scanner
The Halo microchip scanner can read temperature sensing microchips. Plus they come in a range of colours! I only have white, black, pink and purple so far…

How to stop your dog getting heatstroke – according to science

Published by The Conversation on-line, 21.06.2017 Available here.

Summer is a great time to get out and about with your dog. But dogs don’t tolerate the heat as well as their owners. When people get hot they start to sweat, but dogs are only able to do this through the pads on their paws. Dogs instead rely on panting as their main method of cooling.

But panting can only control body temperature up to a point. As temperatures and humidity rise, panting is no longer able to cool the dog. This leads to an increased risk of heatstroke in dogs, which is potentially fatal. It’s worth remembering that it can take around two months for a dog to acclimatise to high temperatures so it is important not to become complacent.

What is heatstroke?

Like humans, dogs can develop heatstroke in two main ways. Environmental heatstroke occurs following exposure to high temperatures, the classic example being a dog left in a hot car. Exertional, or exercise-related, heatstroke occurs during or following exercise and can happen at any time of the year. Heatstroke happens when an animal is no longer able to cool itself and its body temperature can no longer be controlled. When the dog’s body temperature exceeds 40℃, irreversible changes start to happen such as brain damage and multiple organ failure.

Every year, there are numerous reports of dogs dying in hot cars. Cars can get hot surprisingly quickly with internal temperatures reaching 40℃ within just ten minutes of being parked in full sun. Simply exercising or playing in warmer weather can also lead to heatstroke in surprisingly short periods of time, just a ten minute walk could be too much. Dogs that are working or competing in hot conditions are also at risk, so making sure they are kept cool is key.

Certain factors put some dogs at a higher risk of heatstroke. Brachycephalic (short faced) breeds, such as pugs and boxers, are more likely to suffer, as are animals with respiratory disorders. Male dogs and those with darker coats also tend to get hotter in warm weather.

Reducing the risk

Access to cool water is key. Shutterstock

Don’t leave your dog in the car and never leave dogs unattended. Even in the shade, car temperatures can increase quickly and as the sun moves and shade disappears the internal car temperature will rapidly increase. Leaving windows partially open has little effect on car temperature. If you are stuck in traffic or travelling, have the air conditioning on to keep the car cool and make sure windows are shaded from direct sunlight. Ideally, leave your dog at home in hot weather.

Try to exercise your dog in the cooler parts of the day. Avoid any strenuous exercise in the heat. And make sure you supervise activity – your dog may not know when to stop. Instead of exercising in full sun, try brain games in the house or walking in the shade, such as woodland.

All dogs need access to cool water and shade to keep their temperature down. If your dog is unfit, obese or suffers from a respiratory disorder be particularly careful exercising in hot or humid conditions.

As the weather becomes more unpredictable, the risks of being unprepared increase. Even in winter, dogs can be at risk with temperatures getting warmer than expected. The continuing changeable weather also makes it challenging to acclimatise to the heat, making sudden, unseasonal hot spells even more dangerous.

Signs of heatstroke

Heatstroke can happen very quickly, starting with rapid breathing, lack of energy and decreased urine production. This can very quickly escalate to heavy panting, bulging eyes, and the tongue appearing excessively long and dark red. Collapse (leading to seizures or coma) and vomiting and/or diarrhoea can follow.

Both cooling your dog, and getting to the vet as quickly as possible are the two key ways to increase the chance of survival in heatstroke cases. Avoid using ice or very cold water as this can cause blood vessels on the skin surface to constrict and reduce effective cooling. It can also cause shivering which can create more heat from the muscles. Key areas to cool are the neck, abdomen and inner thighs with lukewarm water or water-soaked towels. It is important that you do not over cool your dog, as this can lead to shock – a lack of blood supply to vital organs – so using lukewarm water is important.

Out and about, cool surfaces, shade, air conditioning in cars and fans can also aid cooling. Even if the dog is cooled, veterinary treatment is still key to allow more targeted treatment and monitoring to occur. Heatstroke has been reported as fatal in 39-50% of dogs but those surviving more than 24 hours have a good chance of making a full recovery.

 

The Journey So Far

Thanks for joining us!

We have started this blog to share our research findings with the wider dog owning, dog working, and dog competing community.  Apologies for the lack of content at the moment, but we hope this will soon change!

For now, here are some of our recent research findings and publications in an openly accessible format, along with links to the published works (which are sadly mostly behind paywalls):

FINAL Heatstroke – providing evidence based advice to dog owners.

Link to published version

FINAL Establishing a reference range for normal canine TMT

Link to published version

FINAL Factors affecting canine temperature after canicross racing

Link to the published version

Our current study exploring activity levels in dogs is still open, click here to take part!

Our Conversation UK articles:

How to stop your dog getting heatstroke – according to science

If your New Year’s resolution is to get fit, your dog may be your perfect training partner

Dogs don’t just die in hot cars – here’s how to stop them overheating when exercising

If you have any concerns about your dog’s health please consult your veterinary surgeon immediately.  This site is designed to provide information and share knowledge regarding heatstroke, but is no substitute for veterinary care for your dog

 

parkrun: guidance for running dogs during the hot weather

A reminder to all dog owners that there is no “safe” temperature for running your dog, and anyone running with their dog today is personally responsible for ensuring their animal’s safety.

If it is a day with high humidity, or an ambient temperature approaching or exceeding 20 degrees, the risk of heatstroke to running dogs is high. To put that in context, dogs have developed heatstroke running in sub-zero temperatures with snow on the ground, and regularly exceed 42oC (a temperature that would normally be associated with heatstroke) at 5km races in the UK throughout winter.

Please take this risk seriously, and consider your dog’s safety:

  • If your dog is not a regular runner, is not fit, is overweight or has been out of regular training, seriously consider not running with them.
  • If your dog has been suffering ANY kind of illness that could result in them being even a little dehydrated (especially vomiting and diarrhoea) we recommend not running with them.
  • If your dog has any kind of heart or respiratory condition, we recommend not running with them – if you can hear the dog breathing at rest when not panting, this could be a sign of an underlying problem, safer not to risk it.
  • If you know your dog will go to the ends of the earth to please you, consider not running with them. They may not tell you they’re in trouble until it is too late.

If you make the decision to run your dog, you are responsible for their safety. Make regular water breaks to allow them to drink, if possible give them access to water throughout the race (streams/paddling pools if possible) or consider splashing their belly with lukewarm water. After the race, ensure you have somewhere cool, shaded, ideally with good air flow and access to water to allow them to cool down.

If you notice your dog starting to show any early signs of heat stress, stop, seek shade, water and call for help:

  • Furious panting: panting far more heavily than normal, with an extremely long tongue that may become dark red.
  • A change in behaviour: confusion, being unsteady on their legs, dragging their toes or tripping over, if they look like they’re drunk you’re too late and need to actively cool them and get to a vet ASAP.
  • Passing diarrhoea or vomiting.
  • Actively seeking shade/water or not wanting to run.

Consider empowering your race marshals with the ability to request a dog is stopped if they are concerned.

This advice sheet has been compiled using the best evidence currently available, and is subject to change. Further information and links to the sources of research supporting these suggestions is available at: Heatstroke.dog

Dr Anne Carter and Emily Hall MRCVS

parkrun advice sheet – downloadable version.

Sharing our research into canine heatstroke and heat related disorders.

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