Trying to make heads or tails of it all !

On Christmas eve I finally recieved the MRI results for Belle, Smudge and Primrose after having them scanned the end of October. Smudge is a grade 2 for Chiari Malformation (CM) and a grade 1b for Syringomyelia (SM). Primrose is a grade 2 for CM and a grade 0b for SM. Belle is a grade 2 for CM and a grade 1c for SM.
Information about the British Veterinary Association (BVA) scheme for CM/SM can be found at this link http://www.bva.co.uk/canine_health_schemes/ChiariMalformationSyringomyeliaSchemeCMSMScheme.aspx
The grades for CM for Primrose and Smudge where to be expected and Primrose being 0b for SM is the best you can be at her age of three and a half years old and with Smudge being 1b for SM coming up to four years old that was not any thing to shocking  but I will not hide the fact that seeing Belle as a crossbreed with no change in her grade for CM from her mother was very disappointing  and that coupled  with a grade of 1c for SM when her Mum and pure half-sister are graded 0 for SM, either I was going to go into a hole of depression over Christmas, or put it to the side during the festivities and then tackle whether this is such a bombshell in the New Year.
Well its the New Year and I'm now going to try and understand what at first glance looks like a step back rather than a step forward. Dog breeding is a roll of the dice (which I will explain fully in the latter part of this blog) but you might be lead to believe other wise with all the talk of health tests, genetic break throughs but each thing we learn it also teaches us how little we know and in reality I don't think mother nature will ever relinquish all of her secrets to us, she's always going to keep a bit back to mess with our heads but I certainly think she is a good teacher as long as we are attentive pupils.
Lets take a look at Belle who is age two and is a cross between a Cavalier and Miniature poodle. She has been graded 2 for CM. CM is in Cavaliers is the most common cause of foramen magnum obstruction. The foramen magnum is a large opening in the occipital bone at the back of the skull and it is this hole that the spinal cord passes through from the brain to the neck and it is the occipital bone that is not formed correctly and this condition is described as a mismatch of brain size to skull size. This condition is not just seen in dogs but is also seen in a similar form in over three thousand children yearly and thus dogs are seen as an appropriate model to look at for the treatment in humans for this condition. Ever wondered why there is so much interest by the science community in dogs ? The recent stem cell break through with eye conditions come from being used on dogs, so ironically closing off breeding pools of dogs, that is proving deterimental to their genetic well being, has now provided large pools of genetic disorders we also suffer with, in them and gives us access to study these health problems better and help to manage them better and in some cases cure them in humans. So interest in canines by the scientific community has much wider implications.

Image showing a dogs skull and at the base a normal occipital bone

Image to show the foramen magnum in the dog compared with chimps and humans

Now Belle, as some will know is a dog we bred but was not expecting to  keep but  stayed with us through an unfortunate accident from one of our children accidently catching her foot in the patio door and chipping her radius, she has been left with an intermittant limp from the accident. Belle is a lovely dog  and her cranium is more towards the Cavalier than Poodle and keeping dogs back intentionally it may be best to retain ones that the cranium is starting to show a change and has started to lengthen in the cranium area. Belle is our first cross breed we have kept back and over one, so could be scanned on the BVA CM/SM scheme. The CM grade was the same as her Mum but the fact that her Mum at 6 is a 0c and Belle has been graded at two as 1c was not what I was hoping for and looks like a step back at a first glance.
What is a SM grade 1c ? The c indicates the age of scanning with c meaning scanned between 1 to 3 years old, b being scanned between 3 to 5 years old and a for scanning over 5 years old. The number indicates 0 for no sign of SM amd grade 1 is the dog has central canal dilation (CCD), which has an internal diameter of less than 2mm and then we go to grade 2 which is the dog has syringomyelia and a grade 2c is advised not to be bred from.
So what is central canal dilation (CCD) ? The best description I found for CCD and to understand its presence is a website dealing with the condition in humans  http://asap.org/index.php/medical-articles/dilated-central-canal/ , so if you read this article you will hopefuly understand that CCD can be a indicator that a dog may proceed to have syringomyelia especially if other conditions are present, such as CM but it also can be a benign finding and be present from infancy. Our Dolly is an example of a dog over 6 with CCD but it has not progressed to any thing more, a few dogs are first diagnosed with SM over six but it is thought that the dog had SM before then but symptoms where not clinical before then, as with scanning for breeding we are diagnosing problems often before clinical signs show and a dogs graded 2 for SM will in most cases show no clinical signs of the condition unless it progresses further. So for Belle it will be a rescan in a couple years to see if we are looking at a progression or a benign finding. I must look to the positives and although I have not seen what appears on paper an improvement in the skull, I though can see an improvement with my own eyes of the conformation of the skull especially in the the cranial facial features of Belle. The nose is longer with better dental alignment (at two Belle has no plaque on her teeth with just eating regular chews, with Cavaliers plaque will be seen by this age and around four most Cavaliers will benefit from a dental to remove plaque build up. Plaque build up is more common in short jawed breeds due to the shortening of the jaw and bad alignment of the teeth, same amount of teeth have to fit in not as much room) and with a longer muzzle a better ability to regulate body temperature, eyes are better positioned and unlike mum when she is asleep, no snoring, so this would indicate better anatomy to the soft palate and airway of the dog and lastly the ears are less heavy.
Do we record this as a negative ? At the moment Belle has been recorded with CCD, which may turn out to be a benign finding. The inheritance of CM/SM is inknown and Ysobel who is the Mum of Belle although at 6 is for SM graded 0a some of her litter siblings at one years old where MRI scanned by the breeder and at one had SM grade 2c and recently I was contacted by a breeder who had bought a Cavalier pup from a show breeder who both parents had been scanned SM free and at two the Cavalier has turned out to have SM grade 2c, so by the breeding protocol of the BVA, she should not be bred from but here is the sad bit, she  contacted the show breeder to let them know the dog they had bred at two had SM and he was taken aback but told the lady that she could still breed from the dog if she wanted to, which she was slightly aghast at and said to me "Knowing the dog has the condition and then still breeding from it, how can you sell pups knowing that." The lady had also had two other Cavaliers scanned at the time and are clear and she bought them from a breeder who does no testing, she took a chance and the breeder she got the clear tested dogs from is the breeder I got Jessica and Toby from, so I hope she's not used up all that breeders luck and Toby and Jessica are clear when I have them MRI scanned. Like most I also find it very hard to find breeders doing all health tests and then you have to understand the health tests. With Jessica and Toby I saw their very active Cavalier parents who moved well and did not look delicate as some Cavaliers can, they should be robust little dogs and if not and sensitive to be handled this can be an indicator of problems, so I took a chance on the rubust look of the parents.
So if you go on a forum, as I have seen, when a person asks about getting a Cavapoo and you are told to find  not touch cross breeds but find a Cavalier breeder doing the health tests for SM and the heart problem Mitrial Valve Degeneration (MVD) and they will be able to gaurantee a puppy without this health problem. They is talking through their arse and equally the cross breeder who tells you that the health problems in each breed are not in each breed, so when you cross they don't get the health problems. They also are talking out of their arse. There are a few specific health problems to some breeds like Brachycephalic Obstruction Airway Syndrome (BOAS) is seen in brachycephalic breeds, the name is sort of self explanatory or Collie eye anomaly (CEA) which is mostly recorded in collie /herding breeds and has been recorded in a retriever breed but on the whole all the health conditions we know of in dogs have been seen in most breeds and if they have not been recorded in a breed it does not mean it has not had it, just its not been recorded yet.
 I think its funny when you hear a breeder saying that their chosen breed, " has few inherited health problems recorded." The key is the word recorded and until recent history not much recording of health issues had been happening and when you research a breed, when a breeder makes such a remark on their website as above and you find that the research that has been done by the Kennel Club recently gives a figure of over 50% of the dogs having a on going health issue by the age of four and they also say on their website, " the average lifespan is 12 to 14 years old", but the research says, "just over eight years is the average lifespan for the breed" and lymphoma (cancer) is the biggest recorded killer and on their website they only mention a eye condition, cancer is more common in pure breeds compared with cross, mixed and mongrels, it makes you realise when looking at breeds you need to do your own research, as most breeders are either not giving full disclosure or being economical with the true picture of their breed.  
As I said at the start, "dog breeding is a roll of the dice", but its how you roll the dice, with breeding from small gene pools when you roll the dice the chance of breeding dogs that look much like their parents is high but the downside is you heighten the risk also of inherited disorders but breed dogs of similar size and temperament but from open gene pools or gene pools that have not been bred together for a while your rolling of the dice means your dogs will not look so much like book ends but the greater genetic variation means a statistcally lesser chance of an inherited disorder or it being expressed to the extreme. Breeding is a numbers game and you have to do your research and decide which game you want to roll your dice, either roll them in the closed off gene pool or the open gene pool, statistics in general favour the more genetic variation and this is where research comes in because if you cross two breeds that have an high occurance of the same health problems then the statistics are not going to be lowered for the occurance in the offspring but picking two breeds that one has a high occurance for a disorder and the other has occurances of this health disorder but at what would be considered a normal rate for the genral dog population, you will  statistacally lower the chance of the occurance of the  health disorder, so cross or mix breeding is not a cure all but a way by more genetic variation to statistically lower the occurance of health disorders. Cross breeding produces unhealthy dogs but it is generally excepted by genetic science it is at a lower rate than pure breeding. A lot of the ideology for inbreeding stems from the myth that wild wolves are very inbred and adapted to high levels of inbreeding, so its natural to think you can transfer this ideology to dogs but there is nothing to back this theory and the only place we know that wolves are very inbreed is on the Isle Royale, Michigan, USA and this very interesting post on the website Border-Wars  http://www.border-wars.com/2013/06/misconceptions-about-inbred-wolves.html rather dispels the myth that wolves are adapt to  high levels of inbreeding.
So do we record Belle's scan as a negative or not ?
If every breeder followed the CM/SM protocol we might see a very slow improvement but will it ever be note worthy without looking to change the skull shape, as the presence of CM is  thought to be the main factor in dogs that develop SM and with all Cavaliers being scanned so far showing evidence of CM, I think its changing the skull shape that will be of the most benefit in the long run. This is not going to happen over night and will take more than a first cross to undo and just two breeds. So I'm going to cautiously say, "so far crossing with the Poodle brings more positive changes than negatives", the fact that the back of the skull has in Belle not shown no notable change and this is only from the scanning of one of the cross breed dogs we have bred (a bit of a disappointment and we will hope with Treacle who is our next cross breed to scan and has been kept back because of a more lenghtened skull that some improvement can be seen sometimes with a first cross at the back of the skull) has to be countered with the fact that we see a vast cranial facial improvement with this cross from the cranial facial features of the Cavalier, I'm not talking from an aesthetic point, as beauty is in the eye of the beholder but from a health point for the dog.
Health testing has its place and is one of the tools in the breeders box but lets not fool ourselves that it is the saviour of the pure dog breeding world, in lots of breeds it will reduce breeding stock further and in time other health problems will spring up from creating an even smaller gene pool and some breeds are at such low numbers that it is excepted that in the breed that dogs with onset of heart conditions and other health conditions can still be bred from because taking dogs out with onset of heart condition or other conditions out would reduce the breed to even more dangerously low numbers, so the gene pool is already low enough that unhealthy dogs are excepted to be bred from. When you get to this stage and you could cite whether breeding from Cavaliers with CM is ethical, dog breeding really needs to take a long hard look at ourselves in unyeilding day light.

The painting above is what was known as the Marlborough Spaniel and was bred by the Duke of Marlborough and in the late 1700's into the 1800's these spaniels where the smallest of the working  spaniel types at the time and where very sought after as flushing dogs for heavy undergrowth and noted for bringing up hares for lurchers and are the forefathers of the Blenheim Spaniel to then come under the title of King Charles Spaniel and is why the chestnut brown and white colour is called Blenheim. Look at the head shape, its not brachycephalic. By the early 1900's the painting below shows what selective breeding had done for this type of dog, brachycephalic with no face and the ears have become longer and the coat much more profuse. In 1942 the King Charles breed was seperated and we see the emergence of the Cavalier King Charles Spaniel and its hope was to get back to the origins of this spaniel and have a small sporting spaniel like the original types of the Duke of Marlborough, with a closed off gene pool with only five stud founders it is amazing that this breed is still here and for me one of the ways forward for this type has to be the careful use of cross/mix breeding. I would like to have dogs that are in type, harking back to the Marlborough Spaniel. Henry I think is already half way there and its whether we can safely reduce his size to get a small robust sporting type spaniel, reducing coat and ears but keeping the personage of the Cavalier.
Next blog is the cephalic index as a follow on from the MRI scan results on this blog, as thought people might lose the will to live if this blog post is much longer.