The effectiveness of following the CM/SM MRI breeding protocol (Rushbridge, 2011)
* If both parents have CM/SM offspring are 92% likely to be affected
* If one parent has CM/Sm offspring are 77% likely to be affected
* In contrast if both parents are Clear of CM/SM offspring are 70% likely will be clear. The rate goes up to 87% if grandparents are also clear.
Statistical results of following the CM/SM MRI breeding protocol (Rushbridge, 2010)
* Offspring without SM only occurred when there was at least one clear parent.
* There were a higher number of SM clear offspring if both parents were MRI clear.
* 100% of offspring were SM affected if both parents were SM affected.
Syringomyelia (SM) is an extremely serious and prevelant condition in the Cavalier in the US and worldwide. It is estimated that 90% of all Cavaliers have Chairi-Like Malformation (CM) and of those about 50% are affected with SM to varying degrees. (Rusbridge 2011)
Here is a short video documentary about CM / SM that you should view if you are seriously thinking about buying a Cavalier.
The only accurate way of diagnosing and clearing dogs for breeding is through the use of MRI scanning. The cost range for an MRI is $750 to $2,50. Thus one of the main reason why breeders are reluctant to scan.
Excuses from breeders range from "I have never seen it in my lines" to "I refuse to have my dogs put under anesthesia" yet they do so for teeth cleaning and emergency C-sections. Here is Part Two of the video that will demonstrate what is going on in the UK and less is being done here in the US.
August 15 The Cavalier Petition in the UK passed and now there are over 22,000 signatures to require all Cavalier to be MRI scanned and to be in the heart protocol to be registered with the kennel club. Nothing in the US is being done.
Very quickly - Understanding CM / SM
Image is from Linda Baird LynWood Cavaliers This is LynWood Seven Wonders of World. MRI report NO CM/SM
CHIARI-LIKE MALFORMATION (CM) also known as Caudal Occipital Malformation Syndrom (COMS) is a condition characterized by the disparity in size between the brain (too big) and the skull (too small) such that the cerebellum and brain stem are herniated into or via the foramen magnum. (Rushbridge and others 2006)
Cavalier Matters in the UK has a great image and description: This condition is so painful it has been described as trying to shove a brain the size of a 10 foot into a size 6 shoe!
Image is from Cavalier Matters
CM/ COMS is the malformation of the back skull. CM is a flattening of the back skull. The X-ray images are from Laura Lang of RoyCroft Cavaliers.
CM on top
CM below.
One can easily see the domed affect and flattening of the the back skull and the lower has more room. Even though the two images are not to scale, you can easily see the difference. Laura Lang has devoted much time and effort analyzing head shapes of the cavaliers to MRI scans. Much can be seen on her website depicting how the head shapes of Cavaliers have drastically changed over the last 30-50 years to a more baby face with a domed head (top). The older style Cavalier has more a sporting head with a longer nose and no a pronounced stop between the eyes.
The image above is from RoyCroft Cavaliers. Laura Lang
Similarly, the image above was published by Clare Rushbridge and Penny Knowler. 'The Conformational Indicators Study' by Thomas Mitchell Bristol University is now ongoing for Cavaliers and Brussels Griffons. Click the image below for a 20 second YouTube video to see how the longer skull and shorter are transformed.
SYRINGOMYELIA (SM) is characterized by fluid filled cavities syrinix within the spinal cord and occurs secondary to obstruction of cerebrospinal fluid especially if that obstruction is at the foramen magnum. The most common predisposing cause in the Cavalier is the Chiari-like malformation (CM) (Rushbridge and others 2006)
Cerebrospinal fluid (CSF) is a clear colorless liquid flows from the brain through foramen magnum to the spinal cord and is pumped as the heart pumps blood. The fluid freely flows and is a vital function.
When the Cavalier has CM and the back half of the skull is indented or too small to accommodate the brain's cerebellum, it will herniate through the foramen magnum and thus obstructing the flow of Cerebrospinal fluid (CSF).
When the hole is obstructed, pressure increases like a jet causing a phenomenon called Venturi Effect. When a fluid flows through a constricted section of pipe / spinal cord it causes a higher pressure. With lower pressure on the outside of the spine the fluid pushes outward and creates cavities in the spinal cord called syrinx.
Cavalier Matters in the UK has a great image and description: When the heart beats, the brain expands and pushes the CSF fluid through the hole in the back of the skull down the spine. If the hole is obstructed this causes the CSF to be forced down the spine under pressure (like putting your thumb over a hose pipe). These pressures on the spinal cord lead to fluid accumulation which creates fluid filled cavities (syrinix) destroying the spinal cord. There is NO cure! A huge percentage of these beautiful Cavaliers are affected.
Image is from Cavalier Matters
Below you can see the * which are the syrinx and the arrow is pointing to the herniation. This particular dog has hydrocephalus.
The arrows below are showing the syrinx and how it is bulging outward causing pressure in the spinal column and nervous system.
Magnetic Reesonance Imaging (MRI) Scanning is currently the only way to diagnose CM / SM and assist breeders in making educated breeding decisions. The MRI scan will also diagnose other brain and spinal diseases including Hydromyelia, Hydrocephalus, Intervertebral Disc Disease (IVDD) and Primary Secretory Otitis Media (PSOM) which can also be found in the Cavalier.
MRI scanning in the US and Canada is a costly adventure for Cavalier breeders. Scanning ranges from $750 - $2,000 per dog.
Some Basic Canine NeuroAnatomy and MRI information from Canada that is very helpful and Understanding Canine Chiari Malformation and Syringomyelia.
Currently there is NO database available for North American Breeders. There is NO breeding guidelines or protocols. Most breeders in the US and Canada that are scanning use the detailed reports by the Veterinarian Neurologist to make decisions on breeding. Basically affected dogs are taken out of the breeding program and dogs with good scans are bred to excellent scans.
The British Veterinary Association BVA and the UK Kennel Club KC issued in March 2012 a set of CM/SM breeding guidelines and breeding protocol. Their scheme is to reduce or eliminate the incidence of inherited CM and SM in the Cavalier. It requires a MRI examination of the brain and upper neck.
Sara Blott PhD derived an Estimated Breeding Values (EBVs) for all measured (scanned) dogs as well as dogs in their pedigree. There are over 3,000 cavaliers that have been entered into this database in the last year for CKCSC only in Europe. The BVA says " Yes, it allows buyers to verify that the parents of their new puppy have been MRI scanned and at what age. Potential buyers can therefore gain reassurance that they are buying from breeders who are performing the recommended tests to control CM/SM and are using the suggested breeding protocols. Breeders using the scheme will be demonstrating the highest standards of testing for CM/SM and are doing their best to promote good health and welfare in the dogs they breed"
Unfortunately there has not been all good will with the new scheme and the BVA program. First none of the previously scanned dogs were allowed into the program. Dogs all had to be rescanned and then re-graded. The UK breeders are given a specific grades where most US breeders are given specifics on a diagnosis report and digital copies of the scans.
The grading scheme is an essential tool for the EBV for statistical purposes, however the breeders need clear and concise information and facts on specifics for breeding. CM/SM is multi-factorial and not due to just one single malformation. It was little improvement over the old scheme shown below.
This is the old CM/SM Protocol: The best Grade a Cavalier could receive was a Grade A. However, Grade A included dogs that were completely clear to those that exhibited a 2mm syrinx and herniation.
In my honest opinion, this was one of the worst protocols that could have occurred due to the fact the breeder was given NO information, just a grade. Therefore Two dogs with a Grade A with syrinx and or herniation could be bred together and would produce CM/SM… well they themselves were affected but asymptomatic. The breeder had no idea what range the dog was.
Had the Grade C been for CLEAR and had NO age requirement, breeders would have seen a dramatic improvement. To further add insult for the breeders they were not given details of other issues such as kinking, herniation, hydromyelia, ventricular dilation, central canal dilation and even the appearance of PSOM in the ear.
The US Breeders are given a full Evaluation sheet that cover all the findings in detail. This allows us more tools to make better evaluations and breeding decisions.
In comparison, there are hands down many more breeders in the UK that are MRI scanning their dogs to just a very few in the US.
This is a new video produced in the UK by Cavalier Owners and Reputable Breeders petitioning to make MRI scanning mandatory in the UK for any puppies to be registered by the Kennel Club.
Head Study - Syringomyelia Conformational Indicators of Disease by Thomas Mitchell and Claire Rushbridge. The video takes an average 5 year old Cavalier head shape that is clear of CM/SM and compared it to the average head shape of affected Cavalier.
How the Cavalier has changed over the last 50 years from the sporting dog to a more 'Toy' or 'Baby Doll' head.
"The high prevalence of Chiari-like Malformation in the breed and the confirmation that brain morphology is directly influenced by head phenotype (Hussein 2012) suggests that CM in the Cavalier is likely to be the inadvertent consequence of misguided breeder selection to emphasize certain cranial features deemed to be desirable." (Jacues Penderis 2012)
This report needless to say, was not well received by the Cavalier world but did highlight what many breeders were finding when MRI scanning different head styles. It does bring back to the subject of the Cavalier of yesteryear. It is not to say that they were all clear either since MRI imaging was not available.
Where the Cavaliers from 50 years ago had a much longer maxillary nose, slight stop and elongated skull. More easily seen in profile than head on shots. Below is English CH Homerbrent Carnival by the late Molly Coaker. Molly did her first MRI scan in 1994 when CM/SM was being researched.
This is a great drawing of how the skull has started to change due to selective breeding. The nose has become shorter and the dome of the skull has become higher and more dome shaped. Many have a very pronounced brow and a deep stop.
One can visualize the difference in a traditional head and a modern head even in young puppies. My personal opinion is that it is a combination of the head shape and a gene that actually tells the brain to stop growing. We have seen smaller heads.. yet not rounded but are MRI scanning clear.
Below are more traditional style heads of just 20 years ago on some puppies that have a more traditional head with longer skulls. They have more of a spaniel style head. I have tried to show paintings vs actual photos unless it is dogs that I personally own.
The more modern cavalier has a shorter nose, steep stop and a rounded head with more dome above the eye. Giving a more toy dog and doll face appearance.
The breeders and public are looking for more 'doll like baby' appearance seem above in contrast to the older traditional spaniel below.
This is a stunning comparison. This was from a LynWood litter that was outcrossed to a different line. The puppy on the right is a very traditional style head and the puppy on the left is a more modern with a shorter muzzle, indented stop between the eyes and a round dome head. Very baby like. The blenheim to the left has a longer muzzle, slight stop and flat long skull. Both will have X-rays at 6 months, 1 year and MRI scanned at 2.
There is much discussion and controversy surrounding the head shape vs CM/SM. MRI scanning and testing will determine the final outcome and ultimately possibly a DNA marker. However until then, we can only scan and look to breed using the reports as a tool for making decisions.
The most important point is not to breed an affected dog. MRI scanning is the only accurate way to determine if a dog is clear.
LynWood Cavaliers started from the Homerbrent lines by Molly Coaker and we continue today to breed the same healthy 'sporty type' that Molly was known for. She was one of the first breeders to have her Cavaliers MRI scanned in the 1990s
Here is a wonderful tribute to Molly by Norma Ingles.
Mrs K M Coaker (Molly) and the Homerbrent Cavaliers
The death of Molly Coaker, at the age of 73, on 7 November 2010, was a blow, not only to the Cavalier world, but to the world of dogs as a whole. Her ability as a breeder and exhibitor would be considered exceptional in any breed and in this tribute, on behalf of Cavalier lovers across the Globe, we acknowledge and celebrate, all that she did for Cavaliers.
By the time we became regular attendees at Championship Shows in 1974, Molly Coaker and the Homerbrents were already established in the show ring, having made up 2 champions in 1972 and 1973. For some that would be the culmination of a life’s efforts as a breeder. However, for Molly her star was merely rising and she would go on to be the most successful breeder and exhibitor in the breed’s history.
Our attention was drawn to the Homerbrents, not by seeing her dogs, but by a partcular dog in Scotland, where we lived until 1979, that had a Homerbrent sire. This was Prince Robert of The Grange (by Ch Homerbrent Minstrel), a small tricolour dog with an enchanting head and expression, owned by Brian Arnott. The first championship show we entered was in August 1974 and it was quite an adventure for us, as it involved a long drive from Scotland then into the Peak District to the Northern Club’s show at the Pavilion Gardens in Buxton. A beautiful venue and a warm summer’s day, topped by the fact that Molly was there with an impressive team, including the minor puppy Andy Capp, the blenheim Highlander, Champion Minstrel, Samantha and the bitch CC winner that day under Amy Nugent, the beautiful Captivation. A wonderful day was spent at the ringside soaking up Cavaliers. I recall another young couple on the other side of the ring, taking it all in, Brian Rix and Kevan Berry (Ricksbury)
The Homerbrent Cavaliers were to dominate the show ring for more than quarter of a century. In this tribute, there is a lot of what some might consider statistical data. However, this is necessary to illustrate the extent of the success of Molly as a breeder and exhibitor and the far-reaching influence her dogs have had in shaping the breed as we know it today.
Listed below are the Champions shown by Molly, with regular assistance from the teenage Anne in the earlier years. Reading the names and the years they were made up will, no doubt, provoke memories of the dogs, the times, the occasions and, of course, Molly showing each of them in her unflustered and understated way.Ch Homerbrent Lindy Lou 1972
Ch Homerbrent Minstrel 1973
Ch Homerbrent Captivation 1974
Ch Homerbrent Samantha 1974
Ch Homerbrent Andy Capp 1976
Ch Heidi of Homerbrent 1977
Ch Homerbrent Samson 1977
Ch Homaranne Caption 1978
Ch High Head Dolly Dimple 1979
Ch Ronnoc Rhum of Sancem 1981
Ch Homerbrent Pegasus 1982
Ch Homerbrent Bewitched 1982
Ch Homaranne Carson 1984
Ch Homerbrent Romeo 1984
Ch Homerbrent Cover Girl 1984
Ch Homerbrent Carnival 1985
Ch Homerbrent Pentilly 1986
Ch Caroline of Homerbrent 1988
Ch Homerbrent Festival 1988
Ch Homerbrent Jaspar 1992
Ch Pageant of Homerbrent 1991
Ch Easter Gala of Homerbrent 1992
Ch Homerbrent Tradition 1993
Ch Homerbrent Illusion 1997
Ch Homerbrent Isadora 1998
Ch Homerbrent Expression 1999In addition there were others bred by Molly:
Lil and Roy Steven’s Ch Homerbrent Attraction of Milkeyn 1985
Pauline Thrupp’s Ch Homerbrent Emerald 1986
Heather Wheeler’s Ch Homerbrent High Day 1991
as well as others, including two of ours, that carried the Homerbrent affix
Ch Craigowl Storm of Homerbrent 1985
Ch Devon Lass of Homerbrent at Ricksbury 1985
Ch Craigowl Hopscotch of Homerbrent 1991
A number were multi CC winners, like Caption and Pentilly who each had 13, Captivation, Samantha and Jaspar with 10 each. However, there were no record chasers. Instead, there always seemed to be yet another Homerbrent coming behind or like the proverbial buses, a number would come along at the same time.
The success of the Homerbrent show dogs inevitably led to their being in demand as Stud Dogs and in the 16 years from 1978 to 1993 Homerbrent/Homaranne dogs won The Cavalier Club’s Stud Dog Trophy 13 times and were 2nd twice and 4th in the other year. Commencing in 1978 and 1979 with the tricolour Homaranne Andy Capp, he ceded his position in 1980 to his half brother Homaranne Caption, who held the top spot for 7 years until 1986. In 1988 and 1990, Homerbrent Carnival was the winner, and for 1992 and 1993 the position was held by Homerbrent Jeremy of Cottismeer.
However, the record of Caption is, I think, unsurpassable. He sired 16 champions in his long and distinguished life, listed below.Ch Peatland Flora Jenson (bitch) 1980
Ch Ricksbury Only Charm (b) 1981
Ch Pinewood Snowflake (b) 1981
Ch Hurleaze Naughty But Nice (b) 1981
Ch Homerbrent Bewitched (b) 1982
Ch Crieda Rosella (b) 1983
Ch Homaranne Carson (dog) 1984
Ch Homerbrent Cover Girl (b) 1984
Ch Craigowl Cashmere (b) 1984
Ch Craigowl Storm of Homerbrent (b) 1985
Ch Devon Lass of Homerbrent at Ricksbury (b) 1985
Ch Homerbrent Attraction of Milkeyn (b) 1985
Ch Homerbrent Emerald (b) 1986
Ch Cherokee of Rossbonny at Delhaze (d) 1990
Ch Craigowl Hoodwink (d) 1990
Ch Craigowl Hopscotch of Homerbrent (d) 1991Ch Homerbrent Carnival sired 5 champions, Festival, Highday, Pageant, Telvara Kasanova (1991) and Tweedworth Carnavella (1990).
Ch Homaranne Andy Capp sired 4 Champions, Tregarron Caprice (1978), Amantra Bohemian Rhapsody (1978), Sweet Seraphim of Amantra (1980) and Talark Jamie Lad of Lymrey (1985).
Ch Homarannne Carson sired 4, Caroline, Carnival, and the Milkeyn brothers Matchmaker and Mascot (1987).
Lorraine Higgins’ Homerbrent Jeremy at Cottismeer sired 4, Toraylac Joshua (1994), Pamenda Lord Byron (1994), Pamedna Dee–Lite (1994) and former CC record-holder Spring Tide at Alansmere (1991).
The following Champions also had Homerbrent sires.
Ch Tregarron Tanya’s Kathy 1975
Ch Dill of High Head 1980
Ch Salador Crystabelle 1982
Ch Cottismeer Gem Signet 1982
Ch Lanola Sister Sledge 1983
Ch Merrylaine Made to Measure for Symra 1986
Ch Moonglow Venturer at Trirayne 1990
Ch Ronnoc Rumba 1991
Ch Fontelania Whispering to Charalier 1992
Ch Fontelania Dancing Brave 1993
A glance through the above reveals many affixes that have become household names in the World of Cavaliers, illustrating the esteem in which Molly and her cavaliers were held and how they have contributed both to the breed in general and to the success of those breeders who chose to tap in to the Homerbrent fountain. There were a number of others, ourselves included, who were fortunate to obtain Homerbrent bitches on which they have substantially based their breeding. Indeed, examine a present day pedigree and you are most likely to find the Homerbrent name somewhere.
It would be difficult to estimate how many Cavalier enthusiasts from all corners of the globe, have sat in that South Brent kitchen, enjoying the unassuming hospitality of Molly and her family, talking about Cavaliers in general and enjoying the company of some of the very special canine personalities detailed above. She seemed to have a natural affinity and skill to nurture and develop all growing things, be it dogs, children or plants! We should all be grateful that she turned her special talent to Cavaliers and feel extremely fortunate that she touched our lives.
A truly sad time for not only the Coaker family but for the whole of the Cavalier Community worldwide. There will be many, many tributes from across the globe in the weeks ahead and I am happy to display these on ChatterBox at www.cavaliers.co.uk. If anyone feels they would like to express their feelings in respect of one of the “greats” in our breed please email your message to me, ncraigowl@btinternet.comand this can be displayed. Many may not have known Molly personally but feel they would like to pay their respects as the Homerbrent affix has had such a good influence on the breed and we all owe her our gratitude for her ability to breed such beautiful dogs, sound both in mind and body. Anyone with a love of Cavaliers has reason to feel this loss. In time, her family may get comfort from these tributes and appreciate all our sentiments. The page on Chatterbox will remain open indefinitely to receive tributes.
Sometimes though, a few words of condolences doesn’t quite cover the depth of association and feelings involved, and a more detailed tribute is merited.
I am sure there are many who would like to post a longer, more personal piece about their individual involvement with Molly and the Homerbrents. Molly’s own contribution to the breed assisted so many along the way of their own journey in Cavaliers and if anyone feels they would like to post more than a line or two, please contact me as I have opened a second page on ChatterBox, solely for this purpose.
Norma Inglis
Interestingly, the dog above is Homerbrent Caption which is LynWood's Seven Bridges Road - LoveBug's Great Great Grandfather. You can see the traditional old sporting dog appearance. LoveBug pictured below has CM0 / SM0 grade and has produced excellent scanned children.
LoveBug's daughter Marilyn Monroe below that is much smaller than her mother, however still has a longer muzzle, mild stop and longer back skull. She has CM0/SM0 like both her parents.
We now wait a couple years for Norma Jean to grow up and see how she develops. We also have her litter sister Carlee that has a more modern style head. We will be scanning the two to review.
