More about CMSM in cavaliers and the BVA/KC results:

More Cavalier breeders should be scanning for SM/CM, says expert. Campaigner calls KC ‘disingenuous’

Created: 13/09/2013

AN EXPERT on syringomyelia (SM) and the chiari-like malformation (CM) says she is surprised that so few Cavalier owners in the UK have had their dogs scanned.

Breeders can only be sure they are using SM-clear dogs at stud if there is an official scanning scheme in place, said veterinary neurologist Clare Rusbridge, who was speaking after latest figures revealed that the number of KC-registered Cavaliers had plummeted over recent years.

"Especially as at a meeting in July 2008 at the Animal Health Trust (AHT) representatives of the UK Cavalier club requested an official scheme for this disabling condition,” she said.

"However, it is still early days and it can take time for such testing to become established practice.”

Ms Rusbridge said she was delighted that there had been ‘such an excellent uptake’ among other toy breeds such as Chihuahuas, and that the scheme identified dogs clear of SM.

"We are also delighted that other European countries have been using the scheme,” she said.

Ms Rusbridge was responding to the KC’s statement that it was premature to draw conclusions from recent British Veterinary Association (BVA) test results which showed that all Cavaliers scanned for the chiari malformation (CM) were in the highest band. While it hoped the results would eventually provide ‘useful insights’, the KC said, it was too early to draw conclusions about the breadth or scope of the conditions at this very early stage, it said

The test was a useful diagnostic tool for vets, the club said, so it was likely that the first owners to use it may have had concerns about their dog’s health already, and this would give an initial bias to the results.

The dogs being graded two – the highest grade – by the BVA means that the ‘cerebellum is impacted into, or herniated through, the opening at the rear of the skull’, and the 64 Cavaliers tested were all grade two. Also tested were 22 Longcoat Chihuahuas, 11 Smooth Chihuahuas, two Affenpinschers, eight Griffons Bruxellois, three Papillons and six Pomeranians. One Affenpinscher was graded on the highest grade, seven Griffons, 21 Longcoat Chihuahuas, ten Smooth Chihuahuas, one Pomeranian and all three Papillons.

The test results printed in the Breed Records Supplement were for dogs who had their results registered with the KC between May last year and June 2013. And records show that since 2008 when the programme Pedigree Dogs Exposed was screened and the problems and extent of CM and SM revealed, the number of Cavaliers registered has tumbled from 11,226 that year to 8,884 the following year down to 5,970 in 2012 and 2,705 so far this year.

Ms Rusbridge said it was important to remember that the BVA scheme graded four parameters: 1) the presence of chiari-like malformation, 2) the presence of syringomyelia/central canal dilatation, 3) the size of the syrinx if SM is present, and 4) the age of the dog.

The CM was considered ubiquitous in Cavaliers, she said, so the results were to be expected.

"For the Cavalier breed the main purpose of screening is to reduce the prevalence of clinical SM, therefore the most important results for the Cavalier breed is the SM status and because the incidence of SM increases with age, the age of the dog at the time of scanning,” she said.

"Some breeders profess to be concerned about publication of results but breeders want to use an SM-clear sire and how can they do so safely without an official scheme? Unfortunately many breeders have relied on and still rely on results of MRI scans that are not good enough quality. It takes considerable experience to accurately interpret CM and SM.

"In addition, the official scheme feeds into an estimated breeding value (EBV) scheme via the KC’s Mate Select scheme. In a robust EBV scheme the likelihood of SM in offspring can be predicted before the dogs are mated.

"Having a scheme which can predict disease in a puppy is pivotal, especially in a disease like SM where some dogs can be asymptomatic and not affected until older.”

Campaigner Margaret Carter, former Cavalier club health representative, who appeared on Pedigree Dogs Exposed, told DOG WORLD she thought it disingenuous of the KC to say it was premature to draw conclusions from the 64 dogs scanned.

"The BVA/KC/CM/SM scheme is one that the KC has put its name to,” she said. "On the new KC website is written, ‘The collection of scientific data is of the highest importance, helping to identify the prevalence of canine and breed specific health conditions’. I was therefore disappointed and somewhat insulted, as an early user of this scheme, to see it implied that I and the other owners had used it to obtain a cheap diagnosis for dogs we had concerns about.

"Perhaps the KC health information manager is not aware that the low-cost schemes were specifically set up for non-symptomatic breeding Cavaliers?

"The health-conscious owners who have used this scheme did so because we believe that information on the incidence of CM/SM should be openly shared with other breeders, puppy buyers and health researchers.”

The published results showed not only that Cavaliers had ‘a big problem’ with SM but also that those scanned were all graded in the highest band for CM, Mrs Carter said.

"This is a condition that can produce severe pain by itself and is believed to be the reason why Cavaliers are so predisposed to develop SM,” she said. "It is a little disingenuous of the KC to suggest to suggest it is premature to draw conclusions on the scheme’s results as the prevalence of CM/SM in Cavaliers has been well documented for over a decade. There have been many other studies from all over the world that show that CM/SM in the breed is a growing problem.

"Instead of playing down these worrying results the KC should get behind the BVA in this and actively encourage breeders to use this scheme to screen breeding dogs and provide health research data.”

After much debate and amid concern on the part of Cavalier breeders it was agreed in 2011 that the scan results should be published for the first time by the KC in the spring of 2012. The aim was to reduce, and hopefully eliminate, the incidence of inherited CM and SM. To take part in the scheme, owners will need to have their dog MRI scanned at a veterinary practice. The scans will then be reviewed by two scrutineers from a BVA-appointed panel of expert neurologists and radiologists and graded for severity for both CM and SM.

The results will be sent to owners via the veterinary practice which performed the MRI scan. Results of KC- registered dogs will be sent to the KC for publication on its health test results finder online, and to the AHT for inclusion in the EBVs.

Attempts have been made to put Cavalier EBVs in place since 2007, but the subject of SM in the breed has been the cause of much unrest. Some breeders are not keen to have the results of scans recorded on their dogs’ registration documents and want them only to show the date of the scan. But the results of other breeds’ BVA/KC health schemes are made available on the KC’s health test finder and in the Breed Records Supplement.