What can be the cause for patchy re growth/bald patches ?

I think that most groomers have encountered dogs with bald spots or patchy hair loss in their salons.
We sometimes also get accused by the client of causing it with our grooming techniques, and the question pops up on a regular basis in grooming groups on Facebook.
I will try to address the most common issues that we see in this blog post- how they look, the cause of them, and what we can advise the owners.
Remember that we are not vets – so we don’t diagnose. But we can tell the owners what it  “looks like” and also adapt our grooming routine based on what we find.
This is not a scientific write-up as that would be too long -this is just a brief overview of the topic.

You will notice that many of them look the same. This is because the symptom of the problem, in most cases, is that the hair follicles are affected and either go into arrest or are deformed. But the reason for the problem can be different things.

Patchy regrowth after a clip off on a spaniel type of coat.  

Springer spaniel with patchy regrowth

You clip the dog for years without a problem and then one day the clients turn up with the dog for an appointment and the hair on the loin/croup area hasn’t grown back. It is as short as on the day when the dog went home.

This is NOT caused by the clipping in itself or the fact that you reverse clipped ( it happens when you clip with the grain as well )  This is down to the hair follicles in that area being stuck in the resting phase and not shedding and then moving on to the growth phase. That paused cycle will be visible when the coat is clipped.

The cause for this is 9 times out of 10 a medical issue.  It can either be a thyroid problem- the thyroid hormone is part of the signals that trigger a move to the growth phase /creation of new hair.
If the dog lacks enough of that hormone no signal will be sent to the hair follicles to start the process of creating new hair/ actively growing hairs.
A thyroid problem can sometimes be visible as a general bad regrowth of hairs or sometimes as this patchy regrowth.

Treatment with steroids can also cause this as they suppress the signals and the dog ends up stuck in one phase and not moving forward to the next.

The reason why other medical problems can cause it is that the body will reduce the nutrition to the coat if it’s needed elsewhere in the body to fight an illness.

The coat and skin need around 30 % of the nutritional intake -but as it is the less important organ of the body it gets whatever is left once the others have had what they need. And if the dog is sick – the body will redirect all nutrition to that area to help fight the illness and the coat growth is shut down to save energy/reduce the use of nutrition.  Old age also slows down coat growth. 

We can also see this if the dog has been treated with a Fentanyl patch. A Fentanyl patch is a sort of pain reliever that you apply to the dog’s croup area. It works like a nicotine patch. You must shave the area for the substance in the patch to be able to be released onto the dog’s skin.
A side effect is that Fentanyl has shown to affect the hair follicles and they seem to go in to arrest. There have also been reports of change of color on the hair in the treated area.

Cavailer clipped with a 7F with the grain. This picture is taken 8 weeks after the last groom and as you can see that no hair has grown back on the body. It emerged shortly after this picture was taken that she had a liver tumor.
Photo :Shauna Kerin

The guard hairs grow in a mosaic pattern.  If you were to pull them all out they would first come back over the shoulders and on the croup. The next step will be on the neck, back, and loin area. And then the new hairs gradually start to show up on the sides of the body -slowly spreading down on the sides.

This is why they can get this defined empty “ square” over the croup/loin. If the hair follicles were in the resting phase when we clipped the dog and the dog has a medical problem – the hairs won’t be shed and no new hairs will start to grow. The hairs we cut off are just left in limbo. 

How can we prevent this from happening?
We as groomers can’t prevent the dog’s health/age issues – but one thing that we can do in order to reduce the “damage” is to wash and dry and de-shed the dog before we clip it.  Make it into a habit of carding your short clipped spaniel type of coats after the clip off as well.
By doing that we remove all old hairs and signal to the body that it’s time to create a new hair as the hair follicle is empty. By reducing the number of hairs in each hair follicle we also allow for more nutrition to the hairs that are left. 

What advice can I give the owner?
Tell them to make an appointment with the vet to check the thyroid function and also to do a general check-up.
They can also stimulate blood circulation in the area by brushing the dog with a bristle brush – the increased blood flow helps to transport more nutrition to the hair follicles in the area. And it aids in removing old hairs.
Advise them to look into the dog’s nutritional intake – as I said before – the skin/coat is the largest organ of the body and demands 30% of the nutritional intake in order for optimal function. But it only gets the leftovers – so we need to make sure there’s enough left over to cover the need.
So changing to a high-quality food or adding an extra high-quality protein to the current food can help improve the growth once the initial problem is addressed.

The difference when you switch to high-quality food.
You can see the patchy regrowth in the right picture – the picture to the left is 3 months later.
It will take time to see a complete difference as we can only affect the hair that is created after the change of food. So we need to give it time to emerge above the skin in order for us to notice the difference.
Photo :Barbara Kavanagh.

Patchy regrowth/coat funk on a so-called “ double-coated breed “ 

Patchy regrowth on a collie that’s been clipped with a 5F with the grain or a 3F in reverse for several years. He gets done 2-3 times per year and most of the time it is patchy -but once every 2nd year it grows back fine.

Dogs have 2 main types of hairs that create the coat – undercoat /wool and guard hairs. They share the same hair follicle – but have two separate growth cycles. The cycles are run by several factors like hormones, temperature, daylight, nutrition, stress, and genetics

There is 4 stages in the growth cycle:

Anagen or Growth Phase

The anagen phase is the first phase of new hair growth. Dogs that do not tend to shed heavily have a longer anagen phase. Dogs that continuously shed have shorter anagen phases. The amount of time the hair follicle stays in the anagen phase is genetically predetermined.  Poodles for example spend almost 98% in the anagen state – their coat grows more or less constantly. Other breeds with short hair spend only a short time in this phase.

Catagen or Regressing Phase

The catagen phase is the transition phase. This phase begins when the cell creation signals to stop. Hair stops growing during this phase and the outer root sheath attaches to the hair.

Telogen or Rest Phase

Telogen is the resting period. This period varies depending on the type of coat the dog has – in most breeds this is the longest period in the cycle. Breeds with a “Nordic” type of coat – as Huskies, Elkhounds can spend several years in this phase. This is nature’s way of using the nutrition/energy in a good way – in a cold climate, you need the energy to keep yourself warm – not to grow a coat.

Exogen or Shedding Phase

The final phase, exogen, is the shedding phase. This phase occurs when the hair falls out and the follicle moves back into the anagen phase. The length of this phase depends on the season.

A new phase has lately been introduced when we talk about coat growth phases – ‘‘kenogen’’: It applies to hair follicles that have passed the telogen stage, lost their hair fiber (exogen), and remain empty for a certain time before a new anagen phase is starting.

The hair follicles are all in different stages all over the dog – some are resting – some are preparing to shed –some shed and some are creating new hair. There is a practical reason for that – creating new hairs demands a lot of nutrition so if all hairs fell out at the same time there would be a huge amount of nutrition needed to create a full coat again – and it’s going to be tough to fill that demand.
But if some hairs are resting while others are created the nutritional demand will be much lower.

We would also lose the purpose of the guard hairs if they all fell out at the same time – that would leave the dog without a “weather shield “ and exposing the wool to the elements.

As I mentioned above – some breeds guard hairs can be in the resting phase for 4-5 years – while the undercoat usually has a 6-month cycle on most breeds  –they shed and grow new undercoat twice a year as the undercoat is there to keep them warm in the winter and gone in the summer to keep them cool.

During spring they shed the thick winter wool and set thinner summertime wool and then in the autumn is time to shed the summer wool and set thicker winter wool again.

The shedding of the wool is much more synchronized and usually happens all over at the same time – at least it feels like that when it happens ….

When we clip a so-called double-coated breed there is a high risk that the guard hairs won’t grow back for a long time and the dog will look really stupid during that time. It all depends on where in the growth cycle the hair is when we clip the dog.  It can grow back just fine but in the worst-case scenario it can be at its start of the resting phase and it will be 2-3 years before all hairs are out in normal length. Or the dog is elderly and the body decides that the nutrition is needed for more important things than hair….

A lot of elderly dogs also suffer from medical problems and that will also affect the growth as the body needs the nutrition to battle the sickness – not to create hair. And it’s sometimes an underlying medical problem that suddenly gets visual when you clip the hair.

A 14-year-old Tibetan spaniel has been clipped with a 7F twice a year for many years and always grown back fine. But at 14 years of age, it didn’t come back after the last groom. The hair growth has slowed down with age and we can see that the hair follicles on the back and sides haven’t moved to the growth phase this time.
Photo : Valerie Power

There are also medical conditions that can cause the hair follicles to go into a permanent resting state. You won’t see it until you clip the dog as the hair isn’t growing – but it’s not the actual clipping that caused it – it just made it visible.

So there is a risk that the hair never grows back again….The body can also decide to put the hair follicles in a permanent resting phase when we clip them short. This is most common in the ” nordic type” of breeds – but it sometimes occurs in other breeds as well.
The cause of this is still not known – one of the theories is that the cooling of the skin when the hair is gone gives a signal to the body to reduce the blood flow to the skin to keep the core heat and that affects the hair follicles growth cycle. Another theory is that hormones disrupt the growth cycle. 


What can we do to prevent this?
Always wash and de-shed the dog before clipping it in order to remove as much of the hairs that are ready to come out as possible. That will signal to the hair follicle to create new hairs. You will also have fewer hairs competing about nutrition.
Do another round of carding once you have clipped the dog.

Don’t clip the dog too short – try to leave at least 1 cm so the skin doesn’t feel the chill that can trigger a shut down of follicular activity. That will also protect the skin and reduce the risk of thickening of the skin that can affect the hair follicles.

What advice can we give to the owner?

Always warn them about the risk if they ask for a “Boo clip” on a pom or shaving their collie for the summer. Just so that they are aware and can’t blame you for it.

If the problem occurs – tell the owner to brush the dog on a regular basis to remove the “dead” undercoat and to feed high-quality food to allow for more nutrition to the coat. Brushing also increases the blood flow to the hair follicles.

What can I do in the shop if the problem occurs?
Bring the dog in on a regular basis for a wash and de-shedding session. Don’t use any aggressive coat rakes as they tend to cut some of the hairs –
The undercoat is usually like Brillo as it changes in texture due to suddenly being the main protection for the body.
Use a light silicone-based conditioner to soften it to prevent matting.

Clipped pomeranian – you can see the area on the croup and flank where the guard hairs are missing. This is the exact pattern for the mosaic pattern I talked about. If we left the coat untouched for another year -the coat would in 9 times out of 10 come back in those areas as well.
Photo :Lisa Curran

Alopecia

Alopecia means hair loss and it can be caused by a wide range of factors as genetic, hormonal, and medical. Sometimes we don’t even know why it appears.

The most common we hear about is Alopecia X . . This name was coined a few years ago to refer to the following disease(s): pseudo-Cushing, adult-onset growth hormone deficiency, hyposomatotropism of the adult dog, growth hormone-responsive alopecia, castration responsive dermatosis, gonadal sex hormone alopecia, sex hormone/growth hormone dermatosis, hypogonadism in intact males, biopsy responsive alopecia, post-clipping alopecia (of plush-coated breeds), adrenal sex hormone imbalance, adrenal hyperplasia syndrome, Lysodren responsive dermatosis, follicular dysplasia of Nordic breeds, Siberian husky follicular dysplasia, follicular growth dysfunction of the plush-coated breeds and black skin disease of Pomeranians.

The diversity in names is mostly based on a description of the symptom and based on the differences in endocrine evaluation results and/or clinical responses to various treatments.

So as you can see – it can be a wide range of diagnoses for the same visual symptom.
This is why it is important that a dog that starts to show signs of alopecia gets checked by a vet and not just get put into the bracket ” ooh you clipped him so you destroyed the coat ”
You as a groomer can’t promise to get the coat back with shampoo treatments if it is an underlying medical condition.

The typical Alopecia X patient is a Spitz or Nordic breed such as an American Eskimo, Chow Chow, Pomeranian, Alaskan Malamute, Elkhound, or similar. Poodles have also been over-represented. Hair loss begins in early adulthood, usually by age of three years.
They first lose the long guard hairs, leaving a fuzzy, puppy-like coat but eventually, that goes, too. The bald skin becomes hyperpigmented but is not itchy, and the skin does not usually get infected.

There is no set cure for this condition as there can be different causes for it – hormonal, genetic, endocrinal, and in some cases, there are no clinical findings at all.
Some dogs respond well to neutering. But the problem tends to come back a couple of years later. In other cases, vets have had success with melatonin treatment – but again – the problem tends to come back again.

This condition in itself is not caused by clipping – but can be visible due to clipping. Clipping of so-called double-coated breeds can cause a similar problem – but rarely the complete hair loss that we see with Alopecia X. Clipping causes more of a patchy regrowth – but not a naked dog.


White toypoodle with Alopecia X.
photo: Sofia Nandrup

Colour dilution alopecia – appears in any dog that has a blue/steel grey color. The cause is unknown. The hair breaks and no new hair growth appears. The skin can be thickened and scaly. It usually appears when the dog is from 6 months to 2 years of age.
What can we do in the salon? : Avoid heavy scrubbing as that will increase the breakage of the hair. Shampoos like benzoyl peroxide remove scales, and hydrating sprays or rinses improve the skin appearance.

Seasonal alopecia/flank alopecia/
Canine flank alopecia is a localized, often cyclic, disease of the hair follicles resulting in hair loss over the flanks of affected dogs. It is also known by the names cyclic flank alopecia, recurrent flank alopecia, and seasonal flank alopecia, but these terms are not always accurate as the condition can appear at various times of the year, vary in duration, be continuous or be sporadic in nature.

Science doesn’t know the full cause of this condition. One theory is that it is linked to daylight as it seems to follow daylight cycles and that melatonin has seemed to help in some cases.

It usually appears when the dog is 3-6 years of age. It can affect all breeds but Airedale, British Bulldogs, Boxer, Schnauzer are common breeds that get affected.

This is mainly a cosmetic condition.

What can we do in the salon?
The skin in affected areas can be thickened and a bit scaly, so use a remoisturizing conditioner to soften the skin.

Seasonal flank alopecia in a labradoodle. She have a similar patch on the other side .

“Curly coated breed alopecia “is not the scientific name – but it explains what breeds are involved –   It is caused by hair follicles that are misfunctioning due to structural abnormality.  It is a genetic disease  that affects   Portuguese water dog, Spanish water dog, Lagotto Romagnolo, Irish water spaniel, curly coated retriever
its believed to be linked to the curly coat gene.
They get progressive hair loss around the eyes, flank, and saddle. This starts around 2-4 years of age.

What can we do in the salon?
As this is down to a structural problem inside the hair follicle it’s not much we as groomers can do.
We have to be careful during the groom as the hairs break easily and they won’t grow back. So make sure you treat the coat with a conditioner to keep the hairs soft. Don’t do any excessive brushing/scrubbing.


Symmetrical hair loss due to medical conditions :
Cushing’s syndrome and Thyroid problems: Dull, dry, brittle, easily removed hair coat – fails to regrow after clipping. It usually starts occurring in a symmetrical pattern – at the back of the back legs, sides of the neck, and on the sides of the chest. It then gradually involves the whole body – but the head and legs stay hairy. So, a similar pattern to Alopecia X.
You will also see an increased pigmentation of the skin and the skin usually looks dry and a bit scaly. The dog will also start to get a more pronounced belly.
Cushing’s is a condition where the body produces too much cortisol ( that is a natural steroid) and what we see is the same side effects as a high dose of steroids for a long time would give the dog.

What to advise the owner: Tell them to see the vet for further investigation. There are medications that can ease the problems.

What can we do in the salon? : We can choose products that rehydrate the skin and makes the coat softer to prevent breakage.

Hormonal changes :
Hormonal changes due to tumors or hormonal imbalance can cause alopecia. How it manifests itself can be different depending on the cause of the problem.
We can see a gradual loss of guard hairs in areas where there is friction, symmetrical hair loss on the sides of the chest or the back of the back legs, or in the front.
There is usually no itching or skin problem visible.

What can we do in the salon? It is not much we can do – use a moisturizing conditioner to reduce the hair breakage.

Spanish water dog with progressing hair loss in patches on the body.
The coat on the neck has started to thin out and she has lost some hair on her face as well.
Photo: Jane Ashbrook

Pinnal Alopecia – a fancy name for a condition that mostly affects Dachshunds – but it is also seen in Whippets, Boston terrier, chihuahua, Italian greyhounds, miniature poodles, and Portuguese water spaniel
They get a progressive hair loss on the ears – it starts at the edges and they then gradually lose all hair on their ears and they become completely naked.
It usually starts when the dog is around 12 months of age- but can occur later in life. The cause is unknown.
It usually doesn’t affect the dog – it’s normally no itching or skin irritation. But they can sometimes develop irritation at the edges of the ear due to inflammation in the blood vessels. The skin becomes crusty and can bleed.
The owner needs to protect the skin from cold/strong sun and seek veterinary advice if the dog develops skin damage on the edges.

Smooth haired dachhund with completely naked ears .
photo: William O’brien

A big Thank You to my groomer friends that have allowed me to use their pictures !

Day 3 and 4 of the journey to Groomania in Belgium- a very delayed update :)

I know it’s a very late report from the trip – I got hit by the flu/sinus infection and have been sick for 2 weeks now. Its amazing how much its affecting your brains ability to function ha ha ha ha ….But better late than never- so here we go 😊

Day 2 of Groomania gave us more great seminars –
Sonia Enrico showed show grooming of wire haired foxterrier – interesting to see the differences between countries on how its done.

And talking about hand stripping – I tried out the Karhi hand stripping machine. Being a hand strip person, I must admit that I have been quite sceptic when I first came on the market. But this was the first time I had a chance to try it out my self and I was surprised that it actually worked quite well.
It´s very slow! I think it would do my head in using it LOL – but it’s a great option for groomers with damaged hands that still wants to offer the service. Due to the slow pace it also causes less irritation to the dog and several groomers that I have talked to says that they see a huge difference in the dogs when using it. So, don’t dismiss it- it definitively has a niche in the market.

I watched William Gallharde from Brazil in the afternoon doing a shih tzu in a Brazilian take on Asian Fusion.
He didn’t only shared grooming secrets – he also told us about the everyday life of Brazilian groomers, and it was amazing to hear the difference between Europe and Brazil… Lots of people bring their dog to the groomer every week! Or at least every second week – he found it hard to understand how we coped with the 10-12 weeks dog that we usually do.
This is why I like to go to events like this – you not only learn grooming tricks – but you learn about the differences in the industry in different countries.

There was off course also competition going on during the day – I watched the poodle classes and you could see some amazing grooms – a Japanese lady – Momoko Hatakeyama-did a white toy poodle and I said halfway thru the class that this one will go far – she ended up winning Best in Show at the end 😊I liked her way to handle her dog – a lot of poodle people forget that it’s a dog and once the dog is sprayed up they carry it in the head and tail in order no to mess up the hair ☹ But when her name was called she scoped up the dog into her arms and headed for the podium – not a worry in the world about any “damage” she would do to the “ sculpture” that she just had created.

If you go to Groomanias official Facebook page you will find all the winners and lots of photos from the weekend – https://www.facebook.com/groomaniabelgium/

You don’t go to Groomania without intent to do serious shopping LOL – and I am no different….
I never spend a lot of money on shoes and clothes – but I didn’t hesitate to buy a comb for 109 euro!
And -yes… its gold coloured……

How can you justify paying that much for a comb you say ?? …… well -it’s a huge difference between combs… And I must admit that I have been a bit reluctant to spend that much myself. But I tried the comb earlier and realised that it is actually different to other combs.

I will do a separate post later about the comb and why I like it.I also got myself a set of model dog/training wigs and a head so that I do creative styling/colouring / Asian fusion to train and have fun.
I have a couple of the old type of model dogs – but the “hair” quality has improved a lot the past year and its much easier to work in the new type compared to the old one. There will be a couple of evenings spent now brushing them when I watch the telly…

And then I got some less exciting but necessary shopping done – things that you actually need 😊 – like wheels that doesn’t collect hair for the stool and dryers and new blingy grooming smocks.

The finals for the competition was the end of the day – it’s a long and slow process- and it always goes on until late in the evening. This year was no exception – the clock was well over 8.30 in the evening when it was over.This is truly an international event – the Best overall groomer came from Colombia and the Best in Show winner came from Japan.
It was in total groomers from 34 different countries attending the event !

By the time it was over it was too late for us to head to our favourite Italian restaurant, so we had to stick to McDonalds.

Monday was spent touristing a bit more in Kortrijkand do a bit more shopping ha ha ha. We found a dangerous shop filled with hairstyling items from all over the world- wigs, extension’s, clippers, dye, products for afro hair and more…. Let’s say we were not empty handed when we left that shop 😊

Once at the airport I couldn’t resist heading into the Tintin shop…. Belgium is the home country of Tintin and with his dog Milou being a fox terrier type of dog there is always tempting items to buy for a fox terrier fan.I did find a lovely figurine of Tintin and Milou in a blue urn from the book The blue lotus.
But I couldn’t justify spending 275 euro on it …. So I settled for a more modest priced figurine with Milou sitting on a throne with a golden crown – probably very accurate if you ask the fox terrier ha ha ha

The last leg of the journey ended up making me feel like I was part of the second Die Hard movie ….
Heavy rain and winds and clouds made it impossible for the plane to land so we had to circle around in the air above the airport for 20 minutes ….. it felt just like in the movie ha ha ha ha
I then just waited for the pilot to tell us that they would divert us to Cork or something ( which is in the other end of the country for you that doesn’t live in Ireland. ) My sinuses where at that point completely blocked and my head felt like it was going to explode – so I didn’t look forward to a prolonged flight followed by several hours in a bus to get back to Dublin.
But just as I was going to give up the pilot declared that he had been given green light to land the plane and I was happy despite the bumpy approach to the runway.

The date for Groomania 2020 is 26-27 September – mark the date in your calendar and start to plan your journey – you won’t regret it!

Groomer adventure- the trip to Groomania in Belgium day one



Getting up at 03.30 is great! – said no groomer ever 😂 Its horrible! But thats the price you pay in order to attend a great event ..

Groomania is a grooming event that includes everything a groomer need- 2 days filled with seminars/demos ,world class competition, shopping,vine,belgian pastry and mingle with groomer friends from all over Europe .
Its a fantastic event thats been around since 2005 and I think this is the 10th time I attend it.

When I get up this early I am always amazed how people can look so flawless when I see them at the airport…How do you manage to have perfect hair and makeup at 04.30 in the morning ??? I am happy if I manage to remember to bring my suitcase and get dressed and not turn up in my pyjamas 😂😂

Once at your destination  airport the first thing you usually see are the toilets- and this trip where no exception.  The toilet doors at Brussels airport have a very strange attachment

It instantly raises a lot of questions in my weird brain and the possibilitys are endless- it goes from some SciFi movie inspired theory to something more practical like register if the door is open or closed..  I am going to go to the Info desk one day and ask 😄

I met up with my swedish groomer friends Cilla and Sussie and to our suprice we managed to get coffe, get to the train station, buy tickets and find the right train in 10 minutes- quite an acchivement I must say. 

We could now finally sit back and relax and officially start our holiday 😎

Travelling by train is nice- you are able to see the landscape and buildings in a completely different way compared to when you drive.
I love the houses in Belgium- cute and quirky and train stations are many times like small castles.
Brussels in it self is a mixture of complete opposites- ultra modern glass buildings and then tiny houses stuck together in lots of different colours and textures.

The traintrip also involved interesting discussions like how to snap someones neck like they do in the action movies and how do you train to get the right “snapmove” ?? I hope non of our fellow passengers understood swedish 😂

Our home for the weekend is Hotel Focus- a nice small hotel/hostel just minutes from the train/bus station. Its the third time I am staying here and its nothing fancy-but nice staff,clean and a good price.Its not even a telly in the room- but we are not here to watch tv – wont be time for that 😅

As we arrived early today we had plenty of time to stroll around in Kortjirk and do some non grooming shopping and eat nice food ,taste lovely belgian beer and admire the old church St.Martins churchI love old buildings and when you go into a church thats been there for centuries you get humble- someone built this masterpice with no help from heavy machinery and all the detailed artwork is amazing.

We managed to find dog connections inside the church- 2 painting where the dogs had quite a focal point.First the painting of the holy martyr Catharina of Alexandria – she is just about to be beheaded and if you look to the lower right corner you see two dogs thats just about to start a fight.

Then it was a painting “Legend of Saint Martin” and again in the lower right corner is a dog ☺️ Looks like a cocker spaniel type of dog.

At the end of the afternoon we where told by the FitBit that we had walked 13000 steps and our feets said that it was time to get back to the hotel.

We said we where going to have a bit of rest and then go out for dinner- but at 8 in the evening we realised we where not motivated enough to go anywhere -so no dinner.

Now sleep and gather some energy for tomorrows adventure 💤

A deeper look into the coats role in the dog’s thermal regulation

We have already established in the earlier post that every breed has the same thermal regulation – there is no special rule for so-called double-coated breeds.  And we know what risks that is involved for the look of the coat if we clip them – so let’s take an extra look at the coat’s role in the thermoregulation process.

           Is the undercoat actually keeping them cool like some people claim?


Before we go into the thermal properties of the coat – let’s go back in history for a while.
In order to understand the coats, we need to remember that all breeds originate from dogs that had a special purpose. Evolution created specific dogs for specific needs in different parts of the world.
Man didn’t have dogs as pets – they all had a working purpose and had to cater to their own needs. They didn’t have clothes or shelter – the dogs got a body and coat that was adapted to the environment where they lived. Dogs that didn’t survive the climate they lived in didn’t reproduce.

(Description of coat characteristics, breed development and history from FCIs breed standards www.fci.be , general properties of different coats from the book Ecological and environmental Physiology of mammals)

 

samoyed
(Photo by Dhyamis Kleber from Pexels)

Dogs that developed in arctic climates had a thick coat with hairs standing straight up – the undercoat is very thick and super efficient as a heat preserver to make the dog withstand temperatures down to -40/50C.
The coat forms a shield around the dog making the snow unable to get down to the skin. The snow gets stuck on the surface and due to the insulating properties of the undercoat, no heat is released out to the environment causing the snow to melt and make the dog wet. The thick undercoat also prevents winds from getting into the coat and release the warm air that is stored within it.
The average downpour is these areas are snow.

All areas of the dog are covered in thick hair to prevent heat loss and the ears are small and the nose short for the same reason ( Devito,Russel-Revez &Fornio 2009 ) . They are all on the bigger side as it’s easier to keep the heat in a larger body mass than in a small.

The temperatures in the areas they were developed in varied from -50 to +15 (sometimes up to 20 but that’s not the norm) – so the main purpose of the coat is to keep them dry and warm.
The artic breeds are our average sled dogs, but they are also used for hunting.

herdehund
Photo by Djordje Petrovic from Pexels)

Dogs developed in areas with mountains got a coat that is slightly different. It must be able to withstand both rain and snow and sun radiation. There is also a difference in the temperature variation depending on where in the world they are – but you seldom have that extreme cold as in the artic area. The breeds are mainly used for herding /guarding livestock and a lot of them lived with the livestock 24/7.

The coat consists of thick long guard hairs that lay down -following the dog’s body contour. There is a thick slightly longer undercoat -but not as thick as on the artic breeds
The thick long guard hairs that lay down prevent water from getting deeper into the coat. Water will be transported away from the body by the hair shaft and fall down on to the sides of the dog. Like on a slate roof. The hair on the shoulders and the back are thicker for that reason – it acts as an extra umbrella.
When the wind blows – the hair is moving and is releasing some of the heat trapped inside the coat. But the flat angle of the hairs prevents the wind from getting deep into the coat and the undercoat can still preserve a layer of warm air close to the skin.
They have a thicker undercoat in the winter for extra heat prevention and a thinner undercoat during the summer.
The thick coat also acts as a shield against damage from predators that attack the heard.

The temperature in these areas is not as extreme as in the artic as the mountains keep the climate on a more “normal” level.  It’s still off course a bit of variation depending on where you are – but the average would be around -5/-10 C in the winter and +20/25 in the summer.
It’s more rain than in the artic areas as the temperature is higher and this is why the coat is lying flat rather than standing up.
The dogs are big as they are meant for protection and it is also easier to keep a big body mass warmer during cold weather. The ears are quite small and have hair on them on the outside -they hang down to protect from heat loss but are easy to move to capture noise from threats.

saluki
(Photo by Milica Popovic from Pexels)

We then have the hunting breeds developed in warm dry desert climates. They are large but thin-bodied with long legs – so the body mass is usually lower than on the artic breeds. The coat has silky shiny guard hairs and a thin undercoat. The warmer the area they are developed in -the shorter the coat is.

The shiny guard hairs reflect some of the sun rays away from the surface- and the reduced amount of undercoat coat will allow for wind to release the heat within the coat.
Their thin bodies make it easier to keep cool as a smaller body mass is easier for the thermal regulation system inside the body to keep the core temperature. They don’t have a lot of body fat as the fat prevents heat loss. The long legs are developed for hunting, but they also allow for heat loss as the hair on the legs is thin.
The coat on the stomach and under the chest/armpits is very thin to make conduction of heat to the ground easier.

Some of them have big ears that stand straight up – making it easier for heat to evaporate from the skin.

The temperatures in the areas vary from +1 to +28 in Afghanistan (Afghan dogs are hairy) to +25 – +35 C in Yemen (Salukis have a little bit of silky longer guard hairs but not a lot) and all in between.
Their bodies have also adapted to the heat, so the thermal system is able to deal with a higher heat burden than an artic breed without causing heat stress. This is down to generations of evolution. (Blood Chemistry Changes in the Saluki Dog Exposed to High Environmental Temperatures  Author(s): Stephen Krausz, Jacob Marder and Uri Eylath Source: Physiological Zoology, Vol. 51, No. 1 (Jan., 1978), pp. 33-41)
 

basenji
 If we then finally look at some other breeds made for extreme climates, we have basenji – developed in Central Africa with a temperature around +25-28 C. They are small with short fine guard hairs and almost no undercoat. Again – adapted to heat with the small body mass and almost no guard hairs that insulate.

They are part of a group of breeds labeled as “pariah dogs” or primitive dogs that originates from Afrika, the Middle East, South Asia, South Europe, and Latin-American.
They all share the same body type but differ slightly in size and coat thickness depending on the average temperature in the area they are from.

(Photo by Edvinas Bruzas on Unsplash)

The look of the pariah dogs really shows how nature adapts the dogs to the environment they are in and that the warmer it is – the shorter/thinner the coat is. ( DeVito,Russel-Revesz & Fornio 2009)


     There are of course more breed types with coats adapted for their purpose – but I have chosen to show the ones that are mainly adapted to weather conditions to keep the text from being too long.

If you move a dog from its original climate to a completely different climate you will over time see that the body adapts to the new surroundings and the coat will change. It doesn’t happen overnight – but a dog made for a warm climate will after several years of living in a colder climate have a different type of coat compared to when it first arrived.
( Shield 1972 –studies of dingoes moved to a cold climate)

          All these breeds were fine in their natural habitats until we started to move them around – we brought arctic breeds to hot climates and dogs made for hot climates to cold areas. And we started to “develop “them. With dog shows came an urge to change and exaggerate them usually by adding more hair…….

If we look at pictures of long-haired collies when the breed started to evolve and how they look today – we can see that there is twice as much hair on them now. But their thermal regulating system is still the same. The system will only change if we let evolution rule – only the ones that survive will be able to breed. But modern breeding allows for the weaker individuals to produce offspring and there is, therefore, no need for adaption of the system.
And with the habit of changing the hormonal influence on the coat by neutering – we interfere even more in nature’s way of dealing with heat/cold. Neutering changes the coat structure and thickness and a lot of neutered dogs carry too much weight.

             So if man had let the breeds stay in the climates they were made for and we hadn’t interfered in evolution with dog shows and neutering – then this discussion about the right or wrong in clipping them would never have arisen …..


Moving on from this – let’s see now how nature has intended the coats function in the thermoregulation process.

Dogs generate heat internally thru metabolic heat production. The internal body temperature is independent of the environmental temperature as the thermoregulating systems keep it on around 38 all the time unless the system is put under hard pressure. 
If it is cold/hot the system needs to work harder and that will put a strain on the dog in the long run. 

One of the ways dogs gain heat is muscular use – if the dog is moving around inner heat is created thru the energy released from the muscle movement. Muscular movement creates heat that is also released for a time even after the movement has stopped. This makes exercise a high-risk factor to heat stress and it doesn’t matter if the dog is long or shorthaired.
(Investigating factors affecting the body temperature of dogs competing in cross country (canicross) races in the UK Anne J. Carter⁎, Emily J. Hall)

The coat’s main function is to prevent heat loss and protect the skin. The coat changes throughout the season to adapt to the environmental temperature.
All animals change between summer and winter coats. We can read in Korhonen H., Harri M. & Asikainen J., 1984: Moulting and seasonal pelage variations in the raccoon dog. Acta theriol., 29, 7: 77—88  how the coat goes from shorter and thinner in the summer to longer and thicker in the winter.
The change allows for an effective heat loss during the warm period and effective insulation during the cold period.

There are 3 different ways in where the coat is involved in the heat loss/gain/preservation                                                                                                                                                                                        convection                                      radiation         conduction

To explain it in simple terms
Conduction is when the
heat is transferred from a hot solid object/non- moving fluid (still air is considered a fluid ) to a cool solid object/non- moving fluid in direct contact with each other.

Convection is when the movement of air removes the heat from a warm area to a cooler area

Radiation is transfer of heat from an warmer object to a cooler by infrared radiation without direct contact.

The coat is also indirectly involved in the heat loss thru evaporation –this is when heat leaves the body thru fluid. In this case, its heat loss thru fluid leaving the skin.
But its very little heat that leaves the body this way – the main heat loss thru evaporation is done by panting – and that the most important part in the heat loss process once the environmental temperature reaches a certain degree – but I won’t talk about that now as the coat is not directly involved in that.

(Read more in the book Ecological and environmental physiology of Mammals by P.Withers, C.Cooper, S.Maloney, F.Bosinovic,A.Cruz-Neto )

The total heat loss/heat gain is a combination of all of them – we can’t just look at one and draw a conclusion based on that number. A dog can for example have a thick coat and gain heat from environmental high temperatures -but at the same time lose heat thru conduction to a cooler surface that it lays on due to a shaved stomach. And then top it up with a wind that increases the heat loss thru convection

                 This is why simple formulas like Newton’s law of cooling aren’t applicable when we discuss this subject as the parameters are different. (A Heat Transfer Analysis of Animals: Unifying Concepts and the application of Metabolism Chamber Data to Field Ecology, G.Bakken)

 Klein writes in 2012 “The body temperature is dependent on a balance between heat inputs from the internal and external environment and heat outputs. The ambient temperature will determine the heat input from the external environment. If the ambient temperature exceeds the body temperature, the dog will absorb heat from the environment .”

Conduction happens in two ways in the thermoregulating process.

1) When the dog’s skin is in contact with a surface/non-moving fluid ( as air ) that is cooler/warmer than the dog’s body temperature – heat loss will occur if the dog lays on a cool surface like tiled floors or fresh grass. If the surface is warmer than the dog’s core temperature – the dog will instead GAIN heat from it. Warm concrete will heat the dog in the same way as a heating pad for example.
This is the main way conduction affects thermoregulation in dogs.


conduction hund
The first dog is laying on a surface that is cooler than the body – that will make the heat from the body being transferred to the colder surface. The second dog is laying on a surface that is warmer than the body which makes the heat from the surface being transferred to the body.

Conduction will also happen within the coat –heat from warm air within the coat will move to areas where the air is cooler.
The insulative value of the coat is more a property of the air held within the coat layers rather than on the coat properties it selves – but some heat is transferred up thru the coat by conduction along the hair shaft and that conduction varies depending on the hair quality.
utan underull
The first picture illustrates how it looks when the air close to the skin is 28 C- and the air further out in the coat is 20 C – the heat from the warm air will be transferred to the area with cooler air and heat it up. The air close to the skin will then decrease in temperature unless radiation from the skin reheats it.

The second picture shows the opposite situation – the air close to the skin is 20 C and the air further out in the coat is 28C  – the heat from the outer layer will now be transferred down to the cooler area close to the skin and heat it until the temperature in this area has reached the same temperature in the outer layer.
Once the temperature in all layers is the same the transmission of heat will stop.

This is how the law of conduction works if you don’t have any barriers that prevent it.

How is the coat preventing heat loss thru conduction? :

Air is trapped in a layer of still air close to the skin thanks to the undercoat – the thicker/denser the undercoat is – the more still the air is. This will prevent heat from leaving the coat and the thickness will prevent cold air from being transferred down into the coat as still air is a very effective barrier/insulation.  Increased thickness of the coat reduces the conductive heat transfer according to Berglund 2009

condution med päls

The coat’s main purpose is to KEEP the heat inside the body so there are only a few so-called “thermal windows” on the dog that allows for direct conduction to the ground. Those are areas where the coat is thin so that heat transfer is made easy.  It’s the pads and on the stomach and in the armpits and sometimes the ears.
When it’s cold – the dog curls up so that those areas are not in contact with the ground and no heat transfer is done – but when the dog is hot they lay flat so that the thin-haired areas are in direct contact with the cooler surface and heat can be transferred.

Conduction is usually considered the less important mechanism for heat regulation due to the limited parts of the body that is affected on animals like dogs.

How is the coat preventing heat gain thru conduction? :

radiation från mark
A thick layer of hair prevents the direct transfer of heat from the ground to the skin – but the heat from the ground will heat up the coat surface and that heat will then be transported deeper into the coat. But the direct heating will be delayed compared to direct contact between the skin and the ground.  

Once the temperature at the surface of the coat is higher than the temperature close to the skin heat will be transferred TO the air layer at the skin and then onto the skin as the rule for conduction is that heat will go from the hot area to the cold one. But that will take longer than the direct transfer that will occur when the skin is in direct contact with the ground.

Radiation:

When the thermoregulation systems detect that the core temperature is rising it sends a signal to the brain that it’s time to get rid of some of the heat in the body. That is done by the heat transported thru the blood to the skin surface and the heat is then released into the skin and the heat is radiating into the cooler air that is trapped close to the skin inside the coat.

Once that has happened – convection and conduction take place and continue to move the heat away from the body.

A major obstacle for heat loss thru radiation is fat.  Fat is a poor conductor of heat – so if the dog has a thick layer of body fat -a lot of the heat will be stored in the fat instead of radiating out from the skin.

Nature has used this to its advantage when creating animals that live in cold climates – they have a thick layer of fat that insulates and prevents heat from leaving the body. And the opposite is done for animals that are created for hot climates – they have very little body fat to make sure a maximum amount of heat is evicted thru radiation. (Do you remember the sighthounds from desert areas – they have very little body fat – but wolfhounds that are also classed as a sighthound but originate from a colder climate have a completely different body type)

When we allow the dogs to go fat we disturb the thermoregulating process. The body won’t be able to release excess heat thru radiation and that puts a bigger strain on the other heat release systems in charge. Systems that use more energy to work – and a by using the energy they also produce heat….

If the dog is old or weak from any type of health issue they may lack that extra energy that is required, and their body will also suffer quicker from the excess heat than a young healthy dog.

The coats role in heat gain thru radiation:

The dog can gain heat thru radiation from an object that radiates heat. Normally that is the sun or a radiator.  As we can control the heat that is coming from the radiator I will only discuss radiation from the sun.

radiation

Solar Heating of Mammals: Observations of Hair Transmittance by N. A. 0ritsland and K. Ronald     tells us that 70% of the solar radiation heating at a wind speed of 0.5m/s is down to coat length – the longer the coat is – the less of the heat is transported down to the skin. Only a small amount was down to reflection.

(They only measured how much heat that the hairs were able to transport down to the skin – not how much that was stored inside the coat.)

Dawson,Webster,Maloney concludes in their paper The fur of mammals in exposed environments  (2013) that a really thick well insulating coat restricts the heat flow from solar radiation and that the impact of coat colour is negligible. (The general rule is that dark colour absorbs more heat than light colours) However –when the coat insulation decreases colour increasingly influences the heat inflow from solar radiation.

So both of the papers show us that a longer coat delays heat gain from direct sun radiation. It won’t prevent it as once the outer layer of the coat is heated by the sun -conduction will occur and heat will be transferred down to the cooler air closer to the body – but it will be delayed.

We also learn that when the coat gets shorter or thinner the solar
radiation will heat up the body quicker if the coat is dark compared to a light coat.

The coats role in heat loss thru radiation:

A thick undercoat will form an isolative layer that captures the heat radiating from the body and prevent it from leaving the body.
The thicker the coat – the more still air is trapped within it and the more heat will be kept within the coat.

A study done by C-J Chesney done indoors on 6 Landseer coloured Newfound lands (The microclimate of the canine coat: the effects of heating on the coat and skin temperature and relative humidity C. J. CHESNEY ) showed that when the outer layer of the coat was heated that led to an increased temperature within the coat and a raised skin temperature.

The mean skin temperature started out at 35 C and the mean coat temperature was 28.5C. The room temperature was 23 C. After 25 minutes of heating from the infrared lamp the mean skin temperature was now 39.4. The mean temperature within the coat was now 40.9 C.
The radiation from the infrared lamp had heated the surface of the coat and the heat was then transported down into the coat thru conduction – heat is transferred from warm areas to cold.
This lead to an increase in the coat temperature and you can see that the difference between the coat temperature and the skin temperature is only 1.5 degrees compared to the start when the skin temperature was 35 and the coat temperature was 28.5. At this point, heat is going DOWN to the skin and heating the dog.

They also measured the skin and coat temperature on 9 black and white border collies that was outside playing on a sunny day with an environmental temperature of 21 C.

The mean skin temperature on them was also around 39 C – and the mean coat temperature was 38.5 C.

The difference in the coat temperature can be contributed to wind convection on the outdoor dogs and due to the difference in between the coat characteristics- length/thickness

We can see that even thus the environmental temperature is only 21C – the temperature inside the coat is 38.5 which shows that the coat DOESN’T catch cold air. If you have radiation that heats up the outer layer of the coat – that heat will be transferred down into the coat after awhile.

If the dog moves around some of the heat will be released thru convection.

Convection – is the transfer of heat due to the movement of air. There are 2 types of convection: free and forced.

Free convection occurs when the heat that is radiating from the body heats up the air close to the skin- the warm air then raises away from the skin.

Forced convection is when an external force moves the air – like wind or you are moving your hand thru the coat or when the dog moves, and the hair is moving due to that movement.

Free convection plays a small role in the total heat transfer while forced convection can have a great impact on it.

bondary layer

A so-called “boundary layer” develops at the surface of the skin and thru out the coat – the layer starts at the skin where the air temperature is the same as on the skin and it ends above the coat surface where the air can mix with the air that surrounds the dog and reach the same temperature as the environment.

In fancy wording – Convection is conductive heat transfer thru the boundary layer.

näst näst sista
The warm air from the skin raises up -meets the cooler air that is in the coat higher up from the skin – heat is transferred to that cooler layer by conduction and then it continues to be transported up thru throughout the layers of coat until it meets the air that surrounds the dog – once the temperature is the same in two areas there is no more transmission happening
If the undercoat is thick and a large amount of air is trapped within it  – less heat will be transferred thru it as the air is a bad conductor of heat.




    If the air temperature is higher than the skin temperature heat will be GAINED by convection    
(stockman 2006) –so the coat can’t “catch” cold air if it’s a warm day.

The body temperature will also increase on a hot day as the dog breaths in warm air that heat it from the inside.

A lot of things affect the heat transfer thru the layers – the thickness of the coat-the length of the coat – the shape of the dog/area the heat is radiating from, the difference in the temperature within the layers, winds that blow thru the coat – how strong it is and from what angle is blowing, the dog’s movement and more….

There are equations made up where you can predict the heat loss thru convection -but as there are so many factors that you have to consider -the equations are just a theory and you need to do a “real life” experiment to come to a more accurate conclusion for each individual case.

A dog can regulate the thickness of the still air layer by raising the guard hairs so that there is room for more air within the coat.

Breeds developed in artic areas already have a coat that allows for maximum air layer as their guard hairs and undercoat is already standing straight out from the body and the undercoat is very thick/dense – this shows how nature has adapted the coat to the environment – the body doesn’t need to use vital energy to create the shield – it is already there.

Breeds from areas where you have a mixture of warm and cold climates have a coat that lays flatter and they must make a larger effort to raise the guard hairs when it’s cold and lower them when it is warm.
The increase in the insulation layer by raising the guard hairs is partly offset by the greater openness of the coat. More heat is lost through this more open hair layer because of increased penetration by wind and subsequent convective heat loss. So it’s not that effective if there is a strong wind present and especially if the undercoat is thin.

Approximately   95% of the volume of the hair coat is occupied by entrapped air and this greatly affects the insulation of the coat (BIANCA, 1968).

Convection has important consequences for the heat exchange – if, for example, the air temperature is lower than the skin temperature, an increase in the wind speed will make the coat move more and more heat is lost thru the boundary layer inside the coat. That will lower the skin temperature and give a signal to the body to either produce more heat if the skin temperature goes below a certain degree or stop the heat radiating from the skin if the skin temperature is a correct level.

The coats role in preventing heat loss from convection:

The dog’s coat reduces heat loss by trapping a layer of still air close to the skin (still air is one of the best insulations available as it’s a poor conductor of heat) The more dense and thick the undercoat is – the more air is trapped within it and more heat is stored – it’s also harder for the wind to get into the thick dense coat.
The longer the coat is – the harder it is for the wind to reach in and release the heat.
Increasing the hair coat depth increases the boundary layer which in turn increases the amount of air trapped within the coat.

The higher the environmental temperature is – the less heat is lost thru forced convection/wind as no transfer occurs. (If the temperature within the coat and the environment is the same there won’t be any transfer)

        One theoretical study showed that by increasing the coat length from 1 cm to 2 cm the heat loss dropped by 80% at a windspeed of 1m/s. For a 20 mm hair coat depth, increasing wind speed by a factor of 10 increased heat loss by 58%, but for a 30 mm hair coat, heat loss increased by only 14%. – so the longer the coat is – the less heat is lost thru convection  (A MODEL OF SENSIBLE HEAT TRANSFER ACROSS THE BOUNDARY LAYER OF ANIMAL HAIR COAT  K. G. GEBREMEDHIN )

The higher the wind speed is – the more important the coat thickness is to prevent heat loss according to Tregear´s study from 1965 – The heat loss from the skin of a naked pig was I0 times that from a rabbit skin with hair on in strong wind – while in still air the ratio was only 4.

The coats role in preventing heat gain thru convection:

The coat is NOT catching cold air despite popular belief amongst dog groomers – the air that blows thru the coat releases hot air trapped inside the coat and therefore reducing the temperature inside it. But once the environmental temperature and the coat temperature are at the same level no heat exchange will happen.

näst sista bilden


The picture shows how the temperature inside the undercoat is 39 – the heat is then transferred up towards the colder part of the coat and decreases. But when the air temperature is 35 the heat from the environment will now be transferred down INTO the coat towards the area with the lower temperature – reheating it.


Evaporation thru the skin:
Heat loss by evaporation from the skin depends on the difference in temperature on the skin and the surrounding air. The rate of evaporation will depend on the air movement. If the air close to the skin is still the air quickly will have the same temperature as the skin and no transfer occur. If the air is exchanged more evaporation will occur as the air, then continues to be cooler than the skin – if the environmental temperature is lower than the skin temperature.

When you have a dog with a long thick coat there won’t be that much evaporation thru the skin as the coat will prevent the exchange of air and therefore keep the air temperature close to the skin at a high level.

If you on the other hand have a dog with a short thin coat and areas without or very little hair the exchange of air will be much bigger, and more heat (and moisture) will be lost this way.

When the effective environmental temperature is equal to or greater than body temperature, evaporative heat loss is the only kind of heat loss possible. The evaporative heat loss is now done by panting rather than thru the skin – the warm blood heats the tissue inside the nose and mouth and evaporation occurs and heat is transferred out from the body.

        Radiation, conduction, and convection contribute to an increase rather than a reduction in body temperature in a warm environment as the heat is going down in towards the body rather than away from it – this is important to remember! (Hahn, 1994;Fuquay, 1981). However, if the relative humidity is also high, evaporative cooling is less effective (Hahn, 1994; Fuquay, 1981; Mount, 1979) and the risk of heatstroke increases rapidly.

So what conclusions can we make from all these studies/scientific facts that I have listed when it comes to the discussion about if we should /should not clip a dog when it’s warm weather?

We must -again- first and foremost remember that all breeds have the same thermoregulation. There is no difference between a poodle or a golden retriever or a short-haired Jack Russel.
So everything that we have found applies to all of them.
There are breeds that thru evolution has become more heat tolerant – but they still have the same thermoregulating system.

All breed types have a coat/body shape that is adapted to the environment they originally lived in. Humans have then altered the coats on many of them to become longer and thicker to please the eye and we also alter the properties of the coat by neutering.
By moving the dogs from the environment, the coat originally was adapted to – we force them to deal with climates they are not meant for. And the coat’s initial purposes can suddenly be a burden instead of an advantage.
This has impacted their possibilities to regulate their body temperature in the way nature had originally intended.

If we in this discussion only focus on the role of the coat in the thermoregulation process – not its protective properties from damage to the skin or the fact that negative changes can occur to the coat in it when it’s clipped on certain coat types – the following can be concluded:

       –   The coats main function is to PREVENT heat loss. The thicker and longer the coat is – the better isolative properties AGAINST heat loss.

There is a direct correlation between coat length and thickness and the coat’s ability to KEEP the heat within it when you apply a wind. The thicker and longer the coat is – the harder it is for the wind to penetrate into it and release the heat that is stored within it.

Berglund .et.al 2011 did a computerised model that showed that a short clipped dog tolerated heat better than a longhaired dog in the absence of convection by wind.

Studies, literature reviews, and field trials on animals with the same type of thermoregulation and the same type of coating all conclude the same thing :

 – The shorter the coat is – the easier it is for the animal to release the heat from the body

– The thinner the coat is – the easier it is for the animal to release heat from the body

– Less wool/undercoat reduces the coats ability to store heat

Direct heat gain from solar radiation can be delayed by a thick coat – but a high environmental temperature adds to the thermal burden and the heated air on the surface of the coat will eventually heat the air inside the coat. By having the coat shorter – heat will disappear easier due to the air movement within the coat.
UV rays from the sun can cause irritation to the skin – by leaving a short protective layer that problem can be avoided.

               So, if we only look at hot weather it’s beneficial to be clipped – but we need to leave a protective layer for the skin to avoid damage from UV rays.

But if it’s cold and wet – then it’s not beneficial at all to be clipped short.
Water breaks down the boundary layer inside the coat and the insulative air layer will be destroyed and the heat within the coat will now leak out and cold wind can get down directly to the skin as the coat is left open by the water. 
This means that we must either plan for winter when we clip – as in giving the coat plenty of time to grow back – or make sure the dog has proper protection from the elements when winter arrives.

This won’t be a problem if you have a breed that has a coat that isn’t affected by clipping. But the so-called double-coated breeds might have a delayed re-growth or no re-growth at all – and you are at risk of having a dog with a short or sparse coat when winter arrives.

If you live in a country with mild winters and the dog is living indoors you don’t really need to bother about it – but if the dog is living outdoors or you live in a country with cold winters – then you need to weigh in the benefits of the short coat during the summer with the risks of lack of protection during the winter.

You can always put a jacket on the dog if it’s cold or wet and windy to replace the shield the coat is supposed to give the dog. But we need to be aware that a jacket can have a negative effect on the environment within the coat/skin if left on too long.

We can also do an “in-between” if it’s a double-coated breed  – instead of clipping the coat short all over the dog  – leave the coat in its natural length on the upper part of the body – but clip the stomach/chest and armpits short. Make sure that you de-shed the dog so there is only a little undercoat left that can form that insulative layer that keeps the heat.
That will make the “thermal window” larger and it is easier for conduction to occur to the ground. You can even clip it shorter under the chin and down on the throat. That is an area that is naturally shorter in many breeds. 
This can work well for dogs that are not overweight and don’t have a reduced thermal regulating ability due to age/health. 

förnackdelar

Long hanging guard hairs and thick undercoat act as a shield against rain and wind.
The long guard hairs prevent the wind from getting down into the coat and release the heat.
This is great if it’s cold and rainy – but if it’s hot and no wind the dog will quickly become heated as the high environmental temperature will heat the air inside the coat and the thick coat will prevent the heat from leaving it.

The other side of the dog is clipped short – this is beneficial if the air temperature is high – the heat from the body can now instantly disappear. The heat will now disappear quickly from the body as there is no coat that prevents it from leaving.
If there is a slight wind the radiation from the sun won’t be a problem either as the heat is quickly blown away by the conduction of the wind.
BUT….. If you have a low air temperature there is nothing that prevents the heat from leaving the body. And if it rains the water will quickly get down to the skin and chill the dog and if it’s windy the cold wind will instantly get down to the skin and release whatever little heat that is present.

        This shows that both sides have their pros and cons and you need to determine what is most beneficial for each individual dog that you see and its circumstances – body condition, living conditions, general weather conditions, and more.
                                            There is no black or white  
😉

To shave or not to shave – a look into the literature about dogs thermal regulation,coat growth and more……

Every summer comes the heated debate about clipping so-called double-coated breeds. The debate has been going on for ages and it is like a religious debate where you have 2 fundamentalists discussing who´s God is the right one.

Its been flaring up on the internet in different forums long before Facebook. But with Facebook, there is an added element of different “factual” articles being shared. Mostly from the No side and they all claim to show why it is wrong using different claims that very seldom have any scientific backing.

The latest one is a thermal camera picture of what we are told – a golden retriever in a lion trim and the claim is that we could see in the picture that the clipped area is warmer than the longhaired one and that proved that it was bad to clip them.

But there was no information about the picture – where was it taken? Indoors? Outdoors? Is the sun shining on the dog? Is it hot or cold around the dog?  Is the dog dry or wet? Clean or dirty? Had the dog recently been running around?   Those are all factors that affect the outcome of the picture.

The picture shows how much heat that is radiating FROM the surface of the dog ….. and it will off course be more heat coming from the clipped area than the long-haired one as the coat insulates and KEEPS the heat from slipping away from the dog.  ( read more about thermal images of dogs  in this paper – Mari Vainionpää Thermographic Imaging in Cats and Dogs Usability as a Clinical Method,2014)

It would have looked the same if we took a picture of a boxer with a towel over his shoulders……

So the picture showed that the coat was doing its work properly – it kept the heat from leaving the dog while the clipped area was allowing heat to leave the body faster. It actually showed what the Pro side says – clipping dogs keep them cool as it allows heat to leave the body.

The important temperature to know is the dog’s core temperature – the temperature INSIDE the dog. That is the temperature that actually shows us how the dog is doing.
The temperature on the outside is irrelevant as that only shows what the temperature is on the surface of the skin and that is depending on the environmental temperature, radiation from the sun, and much more.

Here is an illustrated explanation on the subject from Dr Melissa Starling:

” Thermal cameras detect infrared radiation and convert it into an image. Radiation increases with temperature, so these cameras can be a nifty tool for looking at temperature. However, they do not measure temperature per se. They measure radiation. For example, the image below is of my short-haired dog Kestrel in a cool environment. At the time, Kestrel had a shaved belly due to her recent sterilisation surgery. You can see clearly where her hair was clipped because it is much warmer than the rest of her.

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This doesn’t mean that it’s the hottest part of her. Other parts are covered in a thin layer of fur, and even that is enough to reduce the amount of body heat she radiates, as it traps some of that heat against her skin where the camera cannot “see”. Her extremities are quite cool, which probably does reflect her skin temperature in comparison to, say, her back, which also has a thin layer of fur.
The second picture is of Kivi in the same environment, who has a great deal of fur. His body has a lot of blues and greens, indicating he is radiating less heat than Kestrel is. This is the whole point of dense coats. His cooler coat does not mean he is cooler at this moment. It means his coat is doing a great job of trapping his body heat well away from the air and not a lot of heat is escaping from his body.

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If the ambient temperature were a lot warmer, would this change his thermal image? I can’t show you an example, but yes, it would, to a degree. For example, if he stood in the sun, it would warm up his coat. Would that mean his skin and body were also warmer? Probably to some degree. We can see that some heat at least can escape his coat, so presumably, it goes both ways.”

( many thanks to Melissa for allowing me to use her pictures and texts. Visit her Facebook page about canine behavior https://www.facebook.com/DrMelissaStarling/ )

Another interesting fact during the discussions is that all the claims only apply to so-called double-coated breeds. Apparently clipping a poodle with a 5F or stripping a border terrier down to its undercoat is fine – but loads of bad things will happen if you clip a “double-coated” breed. The logic is gone – they are all dogs and the same rule for thermal regulation applies to all of them – so-called “ double-coated” breeds are no magical creatures that have their own set of rules.

So what is right? Will they die from heatstroke if we clip them as we mess up their thermoregulation? Will they get burnt by the sun and get skin cancer? Are we causing them unnecessary suffering if we clip them? And will the coat be destroyed and never grow back again?

As a former vet nurse now grooming my world is ruled by scientific facts – not myths/old housewife tales – so I decided to dig into the subject from the scientific point of view – gathering facts produced by professionals rather than from various written pieces from laymen like dog rescues or Jane Doe that decided that they wanted her 15 minutes of Facebook fame.

I am going to try to explain how it works and then it is up to you as a groomer to decide if you want to do it or not. All claims that I do will be supported by information on where I found the facts so that you can check it out yourself.
And then you will be able to do an educated decision based on proven scientific facts that can be verified rather than pseudoscience and myths.

         My take on this subject from the start was quite clear and black and white – but while digging into it I realized that is more complicated than I thought and I had to review my standpoint a bit.

It is not as easy as the NO side claims ….. it’s a complicated issue that depends on a lot of factors and this is why this piece is looooooooooooooooong……..

I have tried to use a layman language so it’s easy to understand even if you don’t have any medical training.

   

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So grab your coffee and start to read – it is going to be a long journey ……


The basics  – A simplified explanation 

( more info can be found in Muller and Kirks Small Animal Dermatology )
The coat is there to protect the skin from damage from the environment and to keep the dog warm.

The term COAT describes the mass of hair that covers the dog  – and the term HAIR is the individual hairs that form the coat.

There are primarily two types of hairs that make up the coat – guard hairs and wool/undercoat.
( Dogs also have tactile hairs  – what we usually call whiskers  )

The guard hairs can be of different texture depending on the breed of the dog. And the dog can have different types of guard hairs on different body parts – as collies for example that have short guard hairs in their face and on the part of the legs and then long guard hairs on the body.
The wool is shorter and softer in texture and mostly looks the same all over the body.


If we start with the basic – What is a double coat?

Every breed is in fact double-coated – all dogs have a shorter woolly undercoat to keep them warm and stronger longer guard hairs that are aimed to protect the undercoat from being wet and dirty. But thru selective breeding, we have changed the coat in some breeds and it can nowadays be hard to see the difference between the wool and the guard hairs – as in poodles for example. We have also aimed for less undercoat in some breeds and they can for the naked eye appear as single coated – Yorkies is one of them.

guardhairs poodle
Guard hairs on a poodle

Spaniels, terriers, schnauzers all have a typical “ double coat” that works just like nature intended – strong shiny guard hairs that protect the short thick wool that keeps them warm – but they are not for some strange reason included in the term “ double-coated” in the discussions.

The breeds that traditionally are classed as “ double-coated” in grooming terminology are the ones that have longer wool and longer guard hairs – but there is still a clear definition between the wool and guard hair and the hair lays down. They are seldom styled – most of them are left natural and just get a tidy up. A typical example is Golden retrievers, Tibetan spaniels, and New Foundlands. Included in this group are the “Nordic type” breeds as well – dogs that have a spitz-type coat with thick short wool and longer stronger guard hairs and both the wool and guard hairs are standing out from the body rather than laying down. The naming Nordic type comes from the fact that most of them originate from cold climates – Siberian Husky, Norwegian elkhound and Samoyed are some of them.

Now when we have established what a double coat is – let´s look at how the coat works.

As mentioned before – all dogs have a double coat – wool and guard hairs. They share the same hair follicle – but have two separate growth cycles. The cycles are run by several factors like hormones, temperature, daylight, nutrition, stress, and genetics

There are 4 stages in the growth cycle
Anagen or Growth Phase

The anagen phase is the first phase of new hair growth. Dogs that do not tend to shed heavily have a longer anagen phase. Dogs that continuously shed have shorter anagen phases. The amount of time the hair follicle stays in the anagen phase is genetically predetermined.  Poodles for example spend almost 98% in the anagen state – their coat grows more or less constantly. Other breeds with short hair spend only a short time in this phase.

Catagen or Regressing Phase

The catagen phase is the transition phase. The catagen phase begins when the cell creation signals to stop. Hair stops growing during this phase as the outer root sheath attaches to the hair.

Telogen or Rest Phase

Telogen is a rest period between the catagen and anagen phases. This period varies depending on the type of coat the dog has – in most breeds this is the longest period in the cycle. Breeds with a “Nordic” type of coat – as Huskies, Elkhounds can spend several years in this phase. This is nature’s way of using nutrition/energy in a good way – in a cold climate, you need the energy to keep you warm – not to grow a coat.

Exogen or Shedding Phase

The final phase, exogen, is the shedding phase. This phase occurs when the hair falls out and the follicle moves back into the anagen phase. The length of this phase depends on the season.

A new phase has lately been introduced when we talk about coat growth phases – ‘‘kenogen’’: It applies to hair follicles that have passed the telogen stage, lost their hair fiber (exogen), and remain empty for a certain time before a new anagen phase is starting.
( The Hair Follicle: A Comparative Review of Canine Hair Follicle Anatomy and Physiology. Monika M. Welle and Dominique J. Wiener ,2016 )

The hair follicles are all in different stages all over the dog – some are resting – some are preparing to shed –some shed and some are creating new hair. There is a practical reason for that – creating new hairs demands a lot of nutrition so if all hairs fell out at the same time there would be a huge amount of nutrition needed to create a full coat again – and it is going to be tough to fill that demand. But if some hairs are resting while others are created the nutritional demand will be much lower. ( approx 30% of the nutritional intakes goes to the skin and hair – but as this is the less important part of the body organs it gets the leftovers after the heart, lungs, brain, and other organs have had their share )

We would also lose the purpose of the guard hairs if they all fell out at the same time – that would leave the dog without a “weather shield “ and exposing the wool to the elements. Wich does happen when we clip them short ( regardless of breed ! ) -So clipping them short has its downfall – but it also happens when we strip down wire-haired dogs as border terriers and jack russels or clip a shihtzu ……

And remember now that there is one cycle for the guard hairs and one for the undercoat/wool.

As I mentioned above – some breeds guard hairs can be in the resting phase for 4-5 years – while the undercoat usually has a 6-month cycle on most breeds  –they shed and grow new undercoat twice a year as the undercoat is there to keep them warm in the winter and gone in the summer to keep them cool.
During spring they shed the thick winter wool and set thinner summertime wool and then in the autumn is time to shed the summer wool and set thicker winter wool again.
The shedding of the wool is much more synchronized and usually happens all over at the same time – at least it feels like that when it happens ….

When we clip a so-called double-coated breed there is a high risk that the guard hairs won’t grow back for a long time and the dog will look really stupid during that time. It all depends on where in the growth cycle the hair is when we clip the dog.  It can grow back just fine but in the worst-case scenario, it can be at its start of the resting phase and it will be 2-3 years before all hairs are out in normal length. Or the dog is elderly and the body decides that nutrition is needed for more important things than hair….

A lot of elderly dogs also suffer from medical problems and that will also affect the growth as the body needs the nutrition to battle the sickness – not to create hair.

patchy regrowthPatchy regrowth of the guard hairs on a collie – you can see how there is mostly wool and then single guard hairs here and there.
This dog is clipped with a 7F roughly 3 times per year – he mostly looks like this when coming in for his groom – but every second year his coat is back to normal. 

patchy regrowth spaniel

Patchy regrowth on a spaniel – this is common in spaniel type of coats ( springer spaniel,cavalier ,cocker spaniel ) when the dog gets older or has a medical condition.
Thyroid problem is a common cause for this type of patchy regrowth. Lack of thyroid hormone delays the start of the growth phase.

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Patchy regrowth of wool on a collie – you can see the new guard hairs coming up in the short area.

And it’s sometimes an underlying medical problem that suddenly gets visual when you clip the hair there are medical conditions that cause the hair follicles to go into a permanent resting state. You won’t see it until you clip the dog as the hair isn’t growing – but it’s not the actual clipping that caused it – it just made it visible.
So there is a risk that the hair never grows back again….

The body can also decide to put the hair follicles in a permanent resting phase when we clip them short. This is most common in the ” nordic type” of breeds – but it sometimes occurs in other breeds as well.  The cause of this is still not known – one of the theories is that the cooling of the skin when the hair is gone gives a signal to the body to reduce the blood flow to the skin to keep the core heat and that affects the hair follicles growth cycle. Another theory is that hormones are disrupting the growth cycle. ( A Colour Handbook of Skin Diseases of the Dog and Cat UK Version, Second Edition,Patrick J. McKeever, Tim Nuttall, Richard G. Harvey)

So YES- you might “destroy” the coat by clipping it short. Or to be correct – in most cases, you destroy the look of the dog. The coat isn’t destroyed as it’s just following its natural cycle – but the dog will look crap during the time. But there is a risk that underlying medical problems suddenly get visual or that the hair follicle goes into a permanent resting state and the hair never grows back again.  This is why it’s so important to inform the owner of how the coat growth cycle works and make them sign a paper that they are aware of what can happen.

And remember that this can happen to other breeds besides the ones we call “double-coated” –  but the problem is more common in them.

So we now know how the hair grows and what’s affecting it – but what about the thermal regulation?
How do dogs keep their body temperature at the right level?

( Read more in Guyton and Hall Textbook of Medical Physiology )

All warm-blooded animals have the same basic thermoregulation system – dogs, cats, hamsters, humans, birds….. the basic is no different. Once you look into different species there has been adaption done during evolution to adapt to the different environments/circumstances. But within the same species it’s all done in the same way  -so no difference in between different dog breeds for example.

The body has an advanced system that is in charge 24/7 to keep the body temperature –core temperature – at a correct level. For dogs, this level is 38.5 ( +-0.5 ) When the temperature goes above or below that level the system kicks in to restore it back to the correct level – more or less like your average thermostat in your boiler system or AC unit.

thermostatic system

This system is not fully developed in young individuals and is less efficient in old dogs – so they are more vulnerable to changes in the surrounding temperature – both heat and cold.

It’s important to keep the core temperature at a correct level as the dog’s body is made up of cells that contain a vital fluid known as protoplasm. This protoplasm contains proteins and vital nutrients, enzymes, and hormones necessary for life function. Chemical reactions necessary for life are occurring in the cells and if the core temperature is too high or too low those reactions will be altered and damage will occur to the whole body and in the end death as the system collapses.

Nature has put a great deal of thinking into the anatomy of animals to adapt to the environment they live in. You see for example that animals that live in cold environments are usually larger than animals that live in hot environments as it’s easier to keep the core temperature at a correct level in a larger body volume in a cold environment and vice versa.

adorable animal beach canine
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The coating of the body – with feathers/hair is there to insulate and prevent heat loss and to protect the skin. The hair insulates and prevents the heat from leaving the body – and you see an example of that on dogs that is from cold environments – they have small ears that are very hairy – and on the opposite –  dogs from hot environments have large smooth-haired ears to make it easier for heat to evaporate from the skin.

dog chihuahua sobel
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You can also see that animals that are developed for cold climates have thicker coats than animals from warmer climates.
Some dog breeds that are developed in warmer climates might have a longish coat (but it’s thin)compared to breeds that are developed in cold climates.

We must also remember that we have changed the breeds thru out the years to please our eyes…..

golden retriever in grayscale photography
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Golden retrievers are a typical example of that – they used to have a     coat that consisted of short thick wool and longer shiny guard hairs. When they got wet from retrieving birds in the water they dried quite quickly.  Nowadays they have heavy long coats consisting of lots and lots of long wool and it gets even more if you neuter them.

Neutering causes changes in the coat growth cycle and changes the    coat. Lots of breeds get twice the amount of undercoat that nature Intended and the undercoat is not shedding in the same way it used to do.

   So we have messed up the system that nature once created  – but     nature hasn’t changed the thermoregulation system -so it still works in the same way and now faces bigger obstacles with more hair that insulates the body.

In order to maintain a constant body temperature if the environment is warm heat must be transported from the core of the body and released into the environment in several ways  :
(Heat Production and Heat Loss in the Dog at S-36°C Environmental Temperature
H. T. HAMMEL, C. H. WYNDHAM2 AND J. D. HARDY )

Conduction: occurs when the body is in contact with a cooler surface, thereby allowing heat to be transferred from the dog to that surface.  You can notice for example that dogs prefer tiled floors when it is warm rather than a fluffy carpet. Or they dig a hole in the ground and lay in it rather than on the grass.
Most dogs have a thinner coat on the stomach so it is easier for the heat to leave the body when in contact with a cooler surface –that’s why they lay flat on the stomach on the ground or tiled flooring for example.

Some heat is also transported from the skin thru the hair shaft to the outer layer of the coat if the environmental temperature is lower than on the skin.

Convection: the removal of heat from the body as air passes over it, as is seen with a fan or with wind or when the dog moves and the hair moves.
The movement of the hair allows the heat trapped inside the coat to escape. (  –if the dog is brushed so that the hair can actually move – a matted compact coat won’t move and therefore won’t release any of the heat )

The amount of heat that is released is depending on the length and thickness of the coat and the strength of the airflow. The longer /thicker the coat is – the less air is released. 

If you have a short coat – or no coat at all like us, humans – the wind will cool the skin as it passes over it unless the wind is warmer than the body. This is why it feels cooler to be by the sea on a sunny day compared to being stuck inside the city with no wind -even if the environmental temperature is the same.


Radiation
: when the body releases heat into the environment.

How is that done?
When the body’s heat production is stable, the blood flowing into the skin is regulated depending on changes in the surrounding temperature. The purpose of this regulation is to ensure that the difference in temperature between the skin’s surface and the environment remains constant, thus regulating heat loss and maintaining an almost constant body temperature. When heat production increases, blood flow to the skin increases, which, in turn, increases the heat lost from the skin to the same rate as the excess heat production.
Blood flow to the skin can vary depending on the requirement for heat loss or conservation. This blood flow is regulated by the sympathetic nervous system. An increase in core body temperature causes the blood vessels to expand, which in turn, increases the blood flow to the skin and therefore heat loss.

If the core temperature is getting too low the blood vessels shrink and the blood flow is decreased to minimize the heat loss.

A layer of air is trapped between the surface of the skin and the outer surface of the coat. Air has a low heat capacity and is a poor conductor of heat, therefore it serves as an insulator. The degree of insulation can be altered by increasing or decreasing the thickness of the air layer.
This is achieved by a small muscle that is attached to each guard hair and makes it possible for the body to move the guard hair closer or further away from the body.  If you need more warm air trapped into the coat the guard hairs raise so that there is room for more air and if you want less air in the coat the guard hairs lay more flat to minimize the space.
It is like when we get cold and get goosebumps and the hair on our arms/legs is standing straight out.

If the dog is fat the radiation will be less effective as the fat doesn’t transport heat well – so the fat will actually act as an insulation and keep the heat inside the body. (and keep the dog warm if it is cold) This is why arctic animals have a thick layer of fat to help them keep warm.

The first three mechanisms listed are only effective if the air around the animal is cooler than the temperature of the animal. At high environmental temperatures, the first three mechanisms are ineffective, and the animal must rely on so-called evaporative cooling mechanisms: sweating and increased respiration

Evaporation: the process when a fluid is changing to a vapor.  As the environmental temperature increases above 32 C, evaporation becomes the most important way for the body to release the heat and the heat radiation from the skin becomes less effective. 

It happens in the soft tissue of the upper respiratory system and mouth and is increased by panting. The hot blood reaches the tissue in the nasal cavity and condensation occurs when the hot blood meets the cooler air. To keep the air in the upper respiratory system cool the dog needs to pant when it reaches a certain temperature.

The main mechanism of heat loss during panting is by water evaporation from the moist soft tissue in the nose.
The heat of evaporation is removed from the tissues in the nose, cooling its blood supply. The cooled blood is collected in large veins and then passes through a small but dense network of blood vessels which functions as a heat exchanger, cooling arterial blood to the brain.

Under moderate heat stress, the dog pant with a closed mouth. Under significant heat stress, the panting increases and the mouth are open and the tongue is hanging out to maximize the heat loss.
The shorter the nose is – the harder it is for the dog to maximize the heat loss this way.
The cooled blood then returns to the body core and that will reduce the core temperature.

If the relative humidity is also high, evaporative cooling is less effective and there is a high risk of heat stress.

If the environmental temperature is lowering the core temperature the body needs to create more heat.

One way is to shiver  – this increases heat production as a chemical reaction called exothermic reaction happens in the muscle cells when stored nutrition in the cells is converted to energy. Shivering is more effective than exercise at producing heat because the dog remains still.  This means that less heat is lost to the environment via convection as the dog is not moving around.

They also raise their guard hairs to trap more air within the coat so that heat radiated from the body can keep the skin warm.

    

         So to make it short – at lower environmental temperatures body heat is lost thru radiation in the skin and that heat is then trapped in the air layer that is in between the hairs in the coat. If it’s windy/the dog moves most of the heat will disappear when the hair moves if the condition of the coat allows it. The longer/thicker the hair is – the bigger the air layer is and the more heat is trapped inside it and it’s harder for the warm air to disappear as conduction/convection won’t reach down into the long thick coat.
If the air trapped in the coat gets chilled – the system kicks in and produces more heat as the sensors in the skin react to the difference between the body temperature and the environmental temperature.

The main heat loss thou is done by panting – panting is more important for the total heat loss and the shorter the face is on the dog – the harder it is for the dog to lose heat in this way

Fat acts as insulation in both ways – it prevents the heat from leaving the body and it keeps the body warm when the environmental temperature goes down

Now when we know how the system works – what can we say about the effect of lots of hair on the dog ?

dog looking away
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The hair is there as insulation – to prevent heat from LEAVING the body. Air is trapped in between the hairs and that insulates as it prevents heat from leaving the body and cold air from reaching the skin. So the more hair – the less chance of heat leaving the body surface……unless it’s windy or the dog is moving around and the coat is well-kept – as the heat than can escape when the hair is moving. But it’s only a certain amount of heat that can escape and the longer/thicker the coat is the less effect we have from the hair movement.
That is why it is important to keep a long-haired dog well-brushed and to remove excess undercoat if we are going to keep it longhaired.

     Some of the No-sayers argue and say – the hair insulates FROM the heat as cold air is trapped inside  – but we will have to argue that point…..
Heat is radiating from the body – so it’s warm air that gets trapped inside the coat. And if the environmental temperature is high – where do you get the cold air from? If the air that surrounds the dog is warm – then it will be warm air trapped inside.

“Increasing the air temperature in the model caused the temperature through the depth of the hair coat to also increase. This causes the temperature gradients through the boundary layer to decrease and an associated lowering of the sensible heat loss from the skin surface. For example, at an air temperature of -20°C, the temperature at the hair-air interface was – 16″C, that is, 4°C higher than the air temperature. At 20°C, the temperature at the hair-air interface was higher than the air temperature by 2:C and at 35 C. by I°C (Fig. 2). The sensitivity of the temperature profile to changing ambient temperature and wind speed shows the effectiveness of the hair coat, the boundary layer, as a heat-conserving medium. ”

(A MODEL OF SENSIBLE HEAT TRANSFER ACROSS THE BOUNDARY LAYER OF ANIMAL HAIR COAT  K. G. GEBREMEDHIN Agricultural Engineering Department, Cornell University, Ithaca, NY 14853, U.S.A.)

K. G. GEBREMEDHIN also says in his article A model of sensible heat transfer across the boundary layer of animal hair coat from 1986  that: “ In the absence of solar radiation, the temperature profile through the depth of the hair coat decreased non-linearly from the skin temperature to the hair-air interface. The temperature at the hair-air interface is higher than the air temperature. “   So it is warmer inside the coat than it is in the surrounding environment.

Clipping the coat short decreases its insulating abilities by 50%   according to a scientific article written in 2011 (  Predicted thermal responses of the military working dog  (MWD) to chemical, biological, radiological, nuclear  (CBRN)protective kennel enclosure by Larry G. Berglund, Ph.D.Miyo Yokota, Ph.D.William R. Santee, Ph.D.Thomas L. Endrusick, B.S.Adam W. Potter, B.A.MAJ Scott J. Goldman, V.M.D., Ph.D.Reed W. Hoyt, Ph.D. )

Several studies on cattle, sheep, alpacas, and horses show that clipping the coat short reduces the heat stress in the body.
(Hair coat characteristics in Friesian heifers in the Netherlands and Kenya  by  H.Veenman
The effect of clipping the coat on various reactions of calves to heat. By W.Bianca
Effects of seasonal changes and shearing on thermoregulation, blood constituents and semen characteristics of desert rams  by Mohammed Suahir , M Abdelatif Abdalla
The effect of coat clipping on thermoregulation during intense exercise in trotters
K. MORGAN*, P. FUNKQUIST† and G. NYMAN ) )

                      So if we want the coat to insulate less heat  – clip it short


But the coat is on the other hand important to protect the skin from damage and it protects the dog from the elements.

You don’t need a lot of hair to protect the skin if your dog is an average pet dog  – only a short layer will do the job – look at all the short-haired breeds.  And your indoor dog will be protected from the elements by your house.
So use common sense and leave a short protective layer – don’t scalp the dog down to the skin.

     But it’s an important factor if you have a working dog –  a dog that is exposed to strong sun radiation/ harsh weather/bramble/bushes and maybe even attacks from other animals.  They do need a thicker layer to protect than a pet dog. 

abstract beach bright clouds
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One key heating factor is the radiation from the sun

We know that dark colors absorb more heat from solar radiation than light colours. You know yourself the burning feeling on your legs if you wear black jeans on a sunny day – this is why summer clothes have light colours 😉

IMG_20180625_122042

If you put a blanket over your legs to prevent the radiation from the sun to reach the black fabric it feels cooler. But it is going to be warm under the blanket after a while as it now prevents the heat from leaving your body.

It works in the same way with the dog’s coat –
A short dark coat will allow the solar radiation to heat up the surface much faster than a longer light-colored coat.

So the surface will be kept cooler on the dog with the longer light-colored coat – but the radiation will eventually heat up the surface on this dog as well.

But  –once the sun radiation disappears the short black coat will allow the dog to cool down quickly as the heat from the body can disappear thru the short coat quicker than on the dog with long hair.

The same goes for reflective hair – shiny hair will help in reflecting the solar radiation away from the surface (  just like the reflective sheets that you can put on a window )  and therefore prevent heating of the surface.
But  – Radiation can penetrate deeper into a white coat than into a black one (because it keeps being reflected), so some of it ends up being reflected onto the skin. With a dark coat, since the part that heats up stays closer to the surface, it can be removed more quickly by wind. With enough wind, a black-haired animal will actually gain less heat from radiation than a white-haired one.

But  – if we neuter the dog the structure of the hair changes and it usually goes duller/less shiny ( and we get more wool as well )  It’s the change in the hormones that affect the coat and alters the coat growth cycle so that the undercoat grows longer
( Spaying-induced coat changes: the role of gonadotropins, GnRH and GnRH treatment on the hair cycle of female dogs  Iris Margaret Reichler*, Monika Welle†, Christine Eckrich*, Ursula Sattler†, Andrea Barth*, Madeleine Hubler*, Claudia S. NettMettler‡, Wolfgang Jöchle§ and Susi Arnold. )
      And we then lose the shiny thin coat and get a dull thick coat instead that reflect less sun and insulates more 

Lots of breeds have been created to have fewer guard hairs and more wool -so there are very few shiny guard hairs left to reflect the sun radiation ( poodles and bichons are typical breeds )

So if you clip a golden retriever and leave 1 cm of hair and do the same on a poodle – they will have exactly the same negative effects of the clipping regarding the ability to reflect solar radiation AND protection from the environment. It’s no difference between the breeds.

The other heating factor is the environmental temperature.

animal arctic blur canine
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Lots of studies have been done on animals with the same thermal regulation as dogs and they all conclude that – “ Animals that live in environments where the temperature changes throughout the seasons get a long thick coat during the winter and a much thinner and shorter coat during the warm season.”
So it is obvious that a shorter thinner coat is what nature aims at in order to keep the animal cooler.

Dogs do adapt to the environment – if they spend a long time in a hot environment the body gets used to it and the thermal regulating process starts at a higher body temperature. But it takes time for the body to do this adaptation.

If the surrounding temperature is high but there is no direct radiation – like on a cloudy day or when you are in a car/indoors  – then the coat length/thickness is contributing factor to the ability to keep cool – the longer and thicker the coat is – the harder it is for the dog to keep cool as the heat radiating from the body wont leave the coat and it actually heats up the dog. 

Studies show that animals with shorter thinner coats deal better with heat than those that have long thick coats if there is very little wind that helps the heat from leaving the air that is trapped inside the coat.
(Effective thermal conductivity of the hair coat of Holstein cows in a tropical environment Alex Sandro Campos Maia2, Roberto Gomes da Silva3, João Batista Freire de Souza Junior2, Rosiane Batista da Silva2, Hérica Girlane Tertulino Domingos)

    Scientific literature concludes that long thick coats add to the risk of overheating, clipping the coat shorter improves the heat loss from the body and keeps them cooler if the dog is in a hot environment without any or little movement of the hair that allows the heat to leave the coat.

( ShortTechnical Report on Thermoregulation in Dogs and the Pathophysiology of Hyperthermia Jerilee A. Zezula, D.V.M
Heatstroke – thermoregulation, pathophysiology and predisposing factors  Carey Hemmelgarn DVM ChristI Gannon DVM  DacVecc )

“Accordingly, hyperthermia might become a problem in hot, humid areas outside of their original habitat. Several studies showed the beneficial effect of shearing against heat stress. In particular, fertility in males exposed to heat stress may be improved by shearing. Infrared thermography reveals that in shorn animals the heat is radiated across the entire body surface and is not restricted to the thermal windows. ”
Relationships between integumental characteristics and thermoregulation in South American camelids by M. Gerken

So what about protection from the elements – “ if you clip a double-coated breed you expose them to the elements “

Any breed that gets clipped/has their guard hairs removed will be exposed to the elements…..and so are the hairless breeds like Chinese crested and American Hairless terriers. There is no difference …..

So-called double-coated breeds won’t suffer more than a Chinese crested from being exposed to the elements – the suffering is equal.

           The guard hairs do have a purpose – ON EVERY BREED – not just on the double -coated ones.

That is why we for example prefer to hand strip wire-haired breeds as the wire guard hairs protect better than the soft clipped coat.


And what about skin cancer and sunburn??

Any dog that gets scalped with a 30 blade in reverse will suffer sunburn if we don’t allow the skin to gradually getting used to the sun and get a natural pigmentation to protect. But there are very few so-called double-coated dogs that get clipped that short …. there is, on the other hand, a lot of show poodles get done with that blade every year all over the world and no one says a thing about it…. And there are no indications that they have an increased ratio of skin cancer.

Solar dermatitis is not uncommon in dogs – and it’s the white-haired and non pigmented skin of short-coated breeds such as pit bull terriers, Staffordshire bull terriers, bull terriers, boxers, Dalmatians, and similar that gets affected but any dog with white or lightly pigmented hair and skin is at risk.
(Diagnosis and treatment of solar dermatitis in dogs  2007   Kimberly S. Coyner, DVM, DACVD )

No written papers that I read said anything about clipped double-coated breeds being of extra high risk  – they all mention naturally short-haired breeds – both for skin cancer and solar dermatitis.
But if you shave a golden retriever with a 30 blade in the middle of the summer -their skin will off course be as sensitive as the non pigmented skin on a bullterrier.

A dog can get severe burns from the sun if they are exposed to strong UV sunlight and high temperatures while in a high attitude for a prolonged time – its more common in short-haired dogs with a dark coat ( as the dark colour attracts the heat from the sun ) – but you can see it dogs with lighter coats as well.
( Dorsal thermal necrosis in dogs -a retrospective analysis of 16 cases in southwestern USA 2009-2016  Stephanne L Swartz,Anthea E.Schick,Thomas P Lewis ,Diana Loeffler )

But this means that all breeds with short dark hair are at risk – not just a clipped collie.  So every owner needs to take that into consideration if they live in a high-risk area – regardless of breed.

Have a look at the pictures below –

Here are 5 dogs done with the same blade – a 7F

               According to the No side –one of them will suffer – the rest will be ok –
“ as they have a different coat and thermoregulation. “……..

                                                Can you spot the one that will suffer?  

Probably not – as all of them will be wet when it rains and all of them will have an increased risk of getting cuts when running thru bramble –and a couple of them will have an increased risk of changes in the coat texture due to the clipping.

But they ALL regulate their body temperature in the same way – there is not a different thermoregulation system for double-coated breeds.


                                In the end, it is up to personal preferences what you do

First and foremost – we must remember that the heat/sun radiation/wind/humidity is different in different parts of the world. So what can be completely ok in northern Sweden might not work in Arizona.
Use common sense!

Yes –the dog might end up looking stupid for years in the worst-case scenario – but it won’t die from heat stroke because you clip it.

If there was an increased risk of heatstroke due to the clipping there would be lots of suffering dogs at the vet clinics and warnings in veterinary literature – dogs are clipped on a daily basis all over the world and we still don’t see any warnings in the scientific literature.
I did a search on Google scholar and didn’t get a single match when searching for “heat stroke clipped dogs “  – But I did get a lot of articles that said that one way of preventing heatstroke is to clip the coat short………

And Yes – for some dogs there won’t be a difference if you clip it short or just wash it and remove all the dead undercoat  – if it’s light coated dog like a long-haired chihuahua for example and the dog will look so much nicer in its natural style.

But a fat neutered longhaired chihuahua with a thick woolly coat like a Leonberger will probably feel much cooler in a short trim. But use common sense and don’t scalp it- leave 0.5-1 cm so that there is a layer of protection for the skin.

If it’s a working dog that is living outside 24/7 – like a dog that lives with a herd of livestock – they would need the long coat to be protected from the elements and the solar radiation. Most of those breeds are from areas where it is warm but windy – so you will have natural convection that moves the coat and releases the heat trapped inside.

On the other hand – working dogs that have shelter from the elements and do a lot of work in hot environments – like army dogs,agility dog,shultzhund – they benefit from being clipped short.
( The effect of coat clipping on thermoregulation during intense exercise in trotters
K. MORGAN*, P. FUNKQUIST† and G. NYMAN )

And for other dogs, the difference will be huge if you clip it shorter. Especially if the dog is overweight AND old as the fat acts as extra insulation and prevents the heat from radiating from the body and the old age makes their thermal system less effective.

Dogs with a thick coat that doesn’t get thinner due to brushing –  Like a thick-coated poodle or a neutered New Foundland for example – will definitely get relief from the heat if they are clipped shorter.  The thick coats won’t release any heat as it’s not moving in the wind like a thin collie coat and the guard hairs are either very few or dull due to neutering and therefore doesn’t reflect the sun radiation – so they won’t be missed if the dog is clipped short.

    So I am sorry to say –  the conclusion after all this reading is
– there is no ” one size fits all ” answer …….

You must look at each individual dog and make a decision based on this dog’s circumstances :
Is the owner prepared to have a dog that might look crap when the coat grows out due to the uneven regrowth?
Is it living indoors or outdoors ?
Young – middle-aged -old?
underlying medical conditions?
Fat – normal?
Thin coat – thick coat?
Owners purpose with the dog – working dog? What type of work is it doing?  Pet dog – is it a “living in the garden ” pet – or long walks by the sea dog ( that is constantly wet and therefore at a higher risk of hot spots … )

So educate yourself and then make a decision based on facts – not based on random memes/posts on Facebook.