Post date: Sep 26, 2012 4:42:19 PM
This is an update on the Dachshund Breed Council's current approach to tackling back disease in the breed.
Background:
Representatives of The Breed Council's Health and Welfare Sub-committee met with the Kennel Club in August 2010 to discuss the latest research into IVDD and the X-ray screening approach being implemented in Denmark. We discussed the factors to be considered in deciding whether or not an X-ray screening programme of this type would be of value in the UK. These factors include:
the reliability of the evidence (it may take some years to be certain that the Danish programme is making a significant difference)
how easy/difficult it would be to persuade breeders that the screening programme would make a difference (the Danish are very specific about which dogs should/should not be bred from, based on their X-ray scores)
the risks to dogs being screened (they require some degree of anaesthesia)
the technical difficulty of the screening process (it requires accurate and specific positions of the dog's spine – this may mean it should only be carried out by “approved” vets in controlled conditions)
the cost of any screening (estimated to be between £100 and £200 per dog)
On balance, it was felt that it would not be viable to establish a UK X-ray screening programme at present. Other options were discussed:
Avoid breeding from dogs until they are older than the typical age at which IVDD occurs
This is impractical as most Dachshunds are bred from at a relatively early age
Adopt an approach based on Estimated Breeding Values (EBV)
There is insufficient clinical data to enable this to be done
Investigate the possibility of a DNA screening programme
Some work had already been started on this in the USA at UC Davis and also Texas A&M
It was agreed that a DNA screening approach would be worth investigating further since there have been significant advances in the technology over recent years. It was also agreed that, if we were to start a research programme, this could have a positive effect in raising the profile of IVDD and the importance of reducing its incidence. The KC would be able to include information on any research programme on Registration and Transfer documents, to raise awareness further.
DNA Research Programme:
During 2011 we began the first stages of a research programme, in conjunction with the Animal Health Trust (AHT). Our first task was to recruit Dachshunds over the age of 12 that had never suffered from a back problem, however minor. We advertised on our Facebook page and in our Newsletter for dogs and requested a small donation (£10) to cover the AHT's costs. These samples will be used as “Controls” for the genetic research. We have recently (Aug. 2012) asked breeders for further samples from dogs over the age of 10 with no history of back disease, to add to our control sample set.
The next stage was to decide the criteria for “Affected” dogs and we are now collecting swab samples from dogs in the 4-7 age range who have had surgery as a result of a herniated disc. These are from dogs undergoing surgery at the AHT's clinic and Dr. Clare Rusbridge's clinic.
The original project proposal by the AHT was to conduct a Whole Genome Scan (WGS) on the Control and Affected samples. However, an interesting piece of research was published during 2011 which might enable the AHT to narrow the search. [Genome-Wide Association Study in Dachshund: Identification of a Major Locus Affecting Intervertebral Disc Calcification – Morgensen et al: Journal of Heredity 2011]. This study suggests that a major locus on chromosome 12 contains genetic variations affecting the development of intervertebral disc calcification in the Dachshund. Earlier Danish research had suggested a correlation between calcifications and herniations, although some counter research in 2010 disputed this link. However, our research is looking for a genetic marker that can be a predictor of IVDD and we are not exclusively relying on identifying a gene test related to calcification.
We expect the project to cost somewhere between £10k and £20k, so there will inevitably be a period of fund-raising and we hope the UK Breed Clubs will make donations in the same way as they have supported our Lafora Screening Programme.
At the moment, we don't have peer-reviewed evidence from the Danish programme that X-ray screening is reducing the prevalence, or severity, of back problems. For that reason, we feel we are still best off pursuing the DNA route.
With regard to X-raying in the UK, there is no UK expert who can "score" the X-rays. Doing the X-ray screening "informally" may give a result indicating numbers of calcifications, but it is doubtful how much use could be made of that.
The Breed Council is determined to do everything possible to reduce the problem of IVDD in our UK Dachshund population and we are working on this with the UK's leading experts at the Animal Health Trust. There will be no "quick fixes" and we will continue to monitor the published scientific papers to ensure we adopt the best evidence to help us.