Enquiry finds 322 inherited disorders

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DISTURBING evidence about inherited problems in pedigree dogs has been forwarded to the Kennel Club/Dogs Trust-funded enquiry.
A report commissioned by Dogs Trust has concluded that the UK’s 50 most popular breeds – according to KC registrations – have 322 inherited disorders.
Written by four epidemiologists from the Royal Veterinary College, the report, entitled ‘A preliminary investigation into inherited defects in pedigree dogs’, commissioned after the broadcasting of Pedigree Dogs Exposed, was presented recently to the Universities Federation for Animal Welfare at Bristol University.
It has been sent as evidence to Professor Patrick Bateson, who is chairing the KC/Dogs Trust’s independent enquiry. His findings are due in January.
The contents of the epidemiologists’ report – revealed here exclusively – follows last week’s statement from the Association Parliamentary Group for Animal Welfare (APGAW), which is holding its own enquiry into ‘the breeding and showing industry’.
A spokesman for APGAW told DOG WORLD that its review – the contents of which are still not known – had concluded that purebred dogs were suffering from ‘serious welfare problems’ which needed to be addressed urgently by the Government. APGAW’s findings will be revealed next month.
The two enquiries have been running in tandem and were both prompted by Passionate Productions’ documentary.
Dogs Trust’s veterinary director Chris Laurence told DW that the KC’s reworking of breed Standards may have been done with the best motives but that they could make the situation worse. Getting rid of one problem could produce another, he said, and that a patient and methodical approach based on scientific data was needed.
“A lot of it comes down to how breeding is controlled,” he said. “And at the moment, legislation doesn’t consider inherited disease at all.”
The report has shown, say its authors, that each of the 50 most popular breeds in the UK have at least one aspect of their physical conformation predisposing it to a heritable defect.

Implications

Conformational features form a large proportion of these problems, the report reads, from musculoskeletal diseases such as hip and elbow dysplasia to brachycephalic airway obstruction syndrome, eyelid defects, excessive skin folds and predisposition to gastric dilatation-volvulus in barrel-chested breeds – ‘these defects affect all body systems across the variety of breeds’.
“The association of some of these conditions with official breed Standards and the high maintenance implications of some breed features, such as prolific coat or pendulous ears, makes conformational extremes an important area for consideration when discussing the problems of the purebred dog breeding industry,” it says. Also highlighted by this report are the diverse and often severe genetic conditions suffered by the 50 breeds.
Inbreeding, population bottlenecks, the use of strictly-closed stud books and breeding toward features genetically linked to deleterious conditions such as the link between spot size and deafness in Dalmatians, have all contributed to the current situation.”
Breeding to a Standard has meant that breeds’ traditional purposes were lost when breed clubs began concentrating on aesthetics and looks as opposed to the original purpose, the report said.
“By selecting for looks as opposed to purpose or health.... has led to many breeds being predisposed to health problems. In nature, selection would be for health and vigour and those dogs predisposed to health problems would not survive or be able to compete with the healthy dogs. Therefore, the ongoing generations would also be healthier. However, many traits that breeders and dog owners regard as desirable are sometimes a fault predisposing a dog to disease problems.
“In addition, some conditions can be treated with relatively routine or simple procedures such as adnexal surgery in Shar-Pei puppies and this may reduce the incentive for breeders to address the cause or prevalence of the disorder.”
The report uses the Dalmatian as an example, saying that a link has been found between colouration and deafness. Dalmatians who have patches are less likely to suffer deafness, but the Standard says patches are unacceptable.
The Pug is mentioned, saying screw or curly tails are predisposed to spina bifida and hemivertebrae.
A good example where breed Standards have been changed to try to improve the health of dogs is that of the Pekingese, the report says. The Standard now states that dogs must have a defined muzzle. The Standard has been fixed for three years, and so, if by selecting for certain traits it predisposes the breed to ‘other, previously unknown or low incidence problems’ this can be detected and addressed early on before further changes to the Standard are made.
Another good example of the KC, the British Veterinary Association (BVA) and breed clubs working together to improve health is the Cavalier, the report reads. The goal is to develop a screening strategy to reduce the occurrence of a skull malformation which predisposes dogs to syringomyelia.
The report mentions the KC review of all the Standards, and that breed clubs must now adopt its code of ethics which forbids culling of healthy puppies.
“The KC is also looking into ways of increasing the gene pool in order to decrease the incidence of inherited diseases,” it says. “By adjusting some of the breed Standards and through the KC, BVA, vets, breed clubs and breeders working closely together, perhaps faster improvements in health could be achieved.”
A major finding of the report is a lack of prevalence data reported in scientific literature. This is needed to understand the scale of disorders such as how many dogs are likely to be suffering from each.

Economic gain

The report states that of the 7.54 million dogs in the UK an estimated 65 per cent are purebred. A total of 270,707 dogs were registered in 2007 so there are substantially more non-registered than registered pedigree dogs.
Although less extreme conformation is expected in non-registered dogs, the report states, practices such as inbreeding and closed-stud systems probably occur to a greater extent in puppy farms, where the focus is on economic gain rather than the health and well-being of the dogs.
The extent to which these breeders are contributing to the level of inherited disorders in British dogs is unknown. It adds that crossbreeds are also affected by some inherited conditions .
In summary, the report says that 322 inherited disorders were found in the 50 most popular breeds according to the number of KC registrations in 2007. Of these disorders, 84 were either directly or indirectly associated with conformation.
“At present there are a total of three clinical health screens and 18 DNA tests available in the UK for these heritable disorders,” the report says. “Most of the disorders have little, if any, prevalence information available either for all dogs, all pedigree dogs, or at the breed level.
“This is the first report to pool all the available information on inherited disorders in pedigree dogs and to create a generic severity index for inter-disorder comparisons.
“As such, we can conclude that there is a general paucity of information either on the prevalence or the severity of difference disorders. Further research is required to enable accurate, probabilistic models of overall welfare impact of different disorders on the breeds that they affect.”
Mr Laurence, who is president of Bath CA, told DW that the report was commissioned because the charity wanted to know the facts.
“And it aimed to put some science into the whole thing rather than going on people’s impressions of it being just like it was portrayed in the programme,” he said.
“It was done as a one-off to review what was already known about inherited defects in dogs and their welfare consequences.
“Our intention to do this was determined well before the jointly-funded enquiry was under way. The report’s findings underline what we thought was going on, that there were probably welfare consequences caused by breeding practices.
“Many of the problems are exacerbated by breed Standards and how they are interpreted and welfare issues come from those.”
He cited deafness in Dalmatians.
“The report raises this and says it is caused by distribution of markings. It is known that the whiter the dog the more likely it is to have inherited deafness. But patches in Dalmatians are banned by the breed Standard so Standards can contribute to inherited defects in the Dalmatian because of the way they are written...
“We are trying to ascertain the frequency of these because without that data we may get a false impression. For example, how common is inherited deafness in the Dalmatian? Is it a big problem or of lower priority?
“We know there are instances of upper respiratory problem in dogs with short noses but we have very little idea of how common that is.
“Now the review has been done there needs to be a surveillance mechanism established. We will try to look at the breed Standards and try to get the breeding world to accept that changes are necessary and get judges to judge to a welfare standard rather than just individual dogs’ welfare, for example the Dalmatians and deafness.”
Mr Laurence stressed that the enquiry was independent, that it was funded by Dogs Trust and the Kennel Club but that they had no influence on any findings.
“We are trying very hard to let him get on with it and form his own conclusions,” he said.
“The whole point of doing it was to try to review the scientific aspect to the subject and see if it points us in a direction.
“I agree with APGAW that there are welfare issues in dogs relating to the shape of the dog and the way it is bred. And it is not restricted to KC-registered pedigree dogs.
“The KC has a reasonable point when it said that so-called pedigree dogs bred in puppy farms are probably genetically far worse than the ones from the KC system. Puppy farmers do not screen dogs at all.”
Dogs Trust will now wait for Professor Bateson to conclude his enquiry.
“And we will put money into our budget to do further work if it needs to be done,” he said. “Surveillance is needed as we don’t know the extent of any problem and by trying to address one problem we might exacerbate another. Sheep can suffer from scrapie, which is similar to BSE, so DNA studies were carried out to see if sheep being bred are carrying the gene. If they do, breeding is stopped.

Best motives

“But that reduces the gene pool, so although it may have got rid of scrapie it may have created other inheritable problems.
“This is just what we don’t want in dogs. It is more about instances of the problem, where they occur, the underlying gene issues and how to control that with breeding programmes.
“All I know is that there is a chance of making it worse. My concerns about the new Standards is that although they have the best motives they might make the situation worse rather than better. We won’t know for future generations and then it’s much more difficult to undo it.
“I said to APGAW that leaping in the dark now is probably the wrong thing to do. We need to be patient and have a more methodical and controlled approach based on science. You might be able to breed out the shape of German Shepherds’ back ends and hocks touching each other as they move but by doing that one might exclude genes that you do want.
“A lot of it comes down to how breeding is controlled and at the moment legislation doesn’t consider inherited disease at all. The Breeding and Sale of Dogs Act contains nothing about it. If you tighten up on pedigree dogs and controlled the bottom end of the market, the puppy farmers, it would improve the situation in a lot of ways.
“Whatever is done has to be done with science and – if it’s the answer – legislation, and doing it any other way is likely to cause a worse mess.”