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DNA Testing for von Willebrand Disease (vWD) in the Dobermann as part of an overall breeding strategy
The most important thing to emphasise when discussing a breeding strategy is that breeders are producing Dobermann dogs. As such, the most important criteria for selecting particular dogs for breeding should be their potential for producing puppies with the correct type and good temperament. Obviously, the potential health of any puppies must also be considered, and that is where tests like the DNA test for vWD come into play.
The DNA testing scheme for vWD will allow owners to determine the genetics of each dog with respect to this condition before they are mated. This simple DNA/vWD test will tell whether a dog is genetically clear of the mutation that causes the disease, a carrier of the mutant gene or genetically affected, having two copies of the mutant gene responsible for vWD. Obviously, a genetically clear dog will be clinically clear and cannot pass on the mutant gene to its offspring. A carrier dog will also be clinically clear of vWD, but will pass the mutant gene onto approximately half of its offspring. A genetically affected dog will also be clinically affected; in addition it will pass a mutant gene onto each of its offspring.
It is therefore vital that all potential breeding stock are DNA tested for vWD before they are used in a mating programme so that breeders can avoid genetically incompatible pairings that might produce clinically affected offspring. The availability of the DNA/vWD test broadens the scope that breeders have in terms of breeding from affected and carrier dogs.
· Dogs affected with vWD and shown to be so by DNA testing.From a genetic point of view, such dogs could certainly be mated, but only to a dog that is DNA tested clear. If such a mating was to take place, then all of the offspring will be carriers. One of these progeny, when old enough, could also be mated, but again only to a dog that is DNA tested clear of vWD. In this second generation approximately half of the offspring will be clear and half will be carriers, so the entire litter could be DNA tested to discover which are clear and which are carriers. An affected dog should not be mated to another affected dog nor to a carrier dog.
There is of course, the added complication that genetically affected dogs are also clinically affected and so a decision to mate such a dog would also require a consultation with a veterinary surgeon to discuss the potential risks that pregnancy might bring to an affected bitch, in particular. Obviously, if the affected animal were a male, this would be a far less important consideration.
· Breeding from Carrier dogsCarriers can certainly be used for breeding, but again a carrier should only be mated to a DNA/vWD tested clear dog. A litter produced from such a mating will contain both carrier and clear puppies, so the entire litter could be DNA/vWD tested to identify those puppies that are genetically clear and those that are carriers. The responsibility should also lie with the breeder to inform new owners of the puppies as to the vWD status of the pups. If the litter is not tested then any pups from this type of mating should be tested before breeding in the future. A carrier should not be mated to another carrier or an affected dog.
To re-emphasise the point made in the introductory paragraph, dog breeding is about producing dogs of the correct type and temperament first and foremost. So, when selecting potential mates for your carrier or affected dogs, make your selection on the basis that the mating might produce a quality litter, then check to see if they are DNA/vWD tested to be suitable.A Suggested Breeding Strategy for the Dobermann Breed using DNA testing for vWD.
1. Aim to test as many potential breeding stock as possible before they are bred from.
2. If affected or carrier Dobermanns are to be mated, then ensure that they are mated to a genetically clear dog. If an affected dog is mated to a clear, there is no need to DNA/vWD test the litter because all will be carriers of vWD. However, if a carrier is mated to a clear, then the litter could be tested to identify the carrier and clear offspring.
3. Breeders should only breed from dogs that are likely to produce puppies of the correct breed type and temperament and breeders should certainly be encouraged to breed from carriers that have breed qualities and to continue this until they produce a clear puppy that also has the qualities that the breed desires.
4. Such a scheme will allow the removal of the mutant gene from the breed gene pool without the necessity to remove large numbers of dogs from the breeding programme.
5. Ultimately, the breed will get to the situation where DNA/vWD tested clear dogs are bred to DNA/vWD tested clear dogs. Under such circumstances, the KC registration system has the facility to recognise this and the puppies from such a mating are registered automatically as hereditarily clear (clear by birth). However, this designation depends on the correct dog being tested, the correct parents being registered and there are no errors in the actual DNA/vWD testing.
Although in the vast majority of circumstances all of these criteria will be correct, errors might creep in, which might certainly allow a carrier to go undetected and bred from. For this reason, it would be highly desirable for the breed to recommend that ALL potential breeding stock are vWD/DNA tested before mated. This will allow a continued monitoring of the state of the breed. The hereditarily clear status would then be confined to those offspring that don’t go onto to become parents in their own right.
Your vet may offer to have your dog tested for vWD - Please DO NOT ACCEPT as this test will be a von Willbrands Factor Antigen Test by Elisa which gives variable results and can be unreliable. The ONLY way to be sure of the status of your dog is by DNA testing.
The DNA kits for testing for vWD are NOT available from your vet but only from
Dr. Jeff Sampson
The Kennel Club
1-5 Clarges Street
Picadilly
London W1J 8AB
Tel: 020 7518 1068 -Fax: 020 7518 1028
Email: jsampson@the-kennel-club.org.ukThe following Dobermanns have been DNA tested for von Willebrand’s Disease (vWD) under the Dobermann Breed Council / Kennel Club vWD Scheme (or have sent copies of Certificates in to scheme). . Dogs affected by vWD have two copies of the mutant von Willebrand’s gene - carrier dogs have one mutant von Willebrand’s gene and one normal copy of this gene. Genetically clear Dobermanns have two normal copies of the von Willebrand’s gene.
Dogs tested under the Dobermann Breed Council / Kennel Club scheme are listed in the PDF files linked to below:
vWD Clears
vWD Carriers
vWD AffectedsYou will need a copy of Adobe's "Acrobat Reader" to read these files, if you do not yet have this, download your free copy from the following link