Gone are the days when breeder simply looked at two adult dogs and made a decision to breed based on their temperament, ability to learn and their looks. Well, maybe not gone but we should get rid of those days. The professional breeders of today now have not only x-ray testing for hip and elbows. This goes along with the observations they make on their adults. They have genetic testing a Labrador Retriever for a wide variety of genetic diseases common to that specific breed. It is possible to test a Lab’s genetic health using a dna test prior to breeding.
A good breeder will take precautions available to them in order to screen their breeding stock. This is so these most common diseases are not passed on to their puppies by their parents. After all, if you were buying a quality puppy and hoping it to last for 10-15 years and there were testing methods available, wouldn’t you want to know if the Lab you’re purchasing is clear, a carrier, or affected by the disease?
There are three ways disease genes present in a genetic test. The first is if a dog is Clear. Clear means that the dog does not carry the genes necessary for the disease to manifest. In this case it would not be possible for a dog to contract for example Exercised Induced Collapse. This is because the genetics that cause it are not present.
Genetic Testing a Labrador Retriever to Identify Disease Carriers
The second possibility is for a Lab to be a carrier of a particular disease. Dogs who are carriers don’t normally display symptoms of the particular disease. They are able to pass the gene to their puppies. When a carrier mates to another dog who is clear, 50% of their puppies are carriers. 50% will be clear. If the carrier dog mates to another carrier, then 25% of the puppies will be clear. 50% are carriers, and 25% are affected by the disease.
The third possibility is for a dog affected with a genetic disease. This means that they inherited 2 copies of the disease from their parents. They will sadly have the disease. We have been breeding long enough to not have any dogs who are affected by the genetic diseases we test for. If a breeder did test and discover their dog is affected it should be fixed and retired from breeding. It will be affected by the disease and will require Veterinary treatment.
What does this all mean? To a professional breeder, it allows us to genetically test our Labrador retrievers in order to determine if they are going to produce healthy puppies or puppies that are at risk for disease. Initially one normally thinks ok I’ll just test and breed dogs who are clear. Think about that for a minute, selecting dogs who are only clear would limit the gene pool and greatly limit the genetic diversity in the Labrador purebred line. This could pose many problems.
Responsibly Breeding Genetically Tested Labs
Instead, we responsibly breed genetically tested Labrador Retrievers who are clear to carriers or dogs who are carriers of one type of disease to carriers of different types of diseases. If for example a male carries a PRA mutation and a Female carries the mutation for Nasal Parakeratosis (HNPK), mating them results in unaffected puppies. In this example some puppies would carry PRA, some would carry NPK and some would be clear. Then, once the puppies from this litter were genetically tested we could select the clear puppies to become the breeders of the future. Thus using the carrier parents genetics to keep as much diversity as possible and selecting a clear puppy.
Finding A Puppy With Clear Genetics
In this last example only 1 puppy in the litter is clear. The number of puppies is the determining factor. As well, the problem that back yard breeders have is that they don’t want to spend the money testing all puppies especially if there are 7 or 8 of them in order to find 1 good puppy. Testing varies in price and also depends on the number of diseases tested for, but on average one could expect to pay around $300 USD per dog to have them tested. So, a litter may cost $2100 to screen and the parents would be another $300 each for a total after converting to Canadian dollars would be around $3500. Money is big reason why back yard breeders don’t genetically test a Labrador retriever.
So far you should have a sense of how the mixing of different clear, carrier, affected dogs works in regards to breeding and making healthy puppies. This is something we believe should be mandatory. This strengthens each dog breed. It ensures the Veteran has a genetically healthy puppy. Not only for service dog work, but to place a healthy puppy in your home.
It Is Not Possible To Test For Every Genetic Disease
There are a limited number of tests available for some of the most common Labrador diseases. As science progresses in the field of pet genetics, I would suspect that tests become available for more. At present, we conduct a Service Dog Panel as our genetic test. It is a health focused test and covers the most common diseases of the Labrador Retriever breed. There are other tests that can be done which can test for the coat color a Lab will pass on, but I’d like to focus on the health-related tests here.
Some Genetic Tests We Have Our Dogs Screened For
The first test in the panel is Centronuclear Myopathy (CNM). It’s a disease where muscles do not function properly resulting in muscular weakness. The symptoms vary though it is typically present in dog between 6 and 7 months of age. This is done by observing exercise intolerance, weakness, difficulty eating and awkward gait. The symptoms seem to stabilize around one year of age. Many dogs live long into old age, however they often have life-long muscle related problems.
Degenerative Myelopathy (DM) is an inherited neurological disorder that affects the white matter tissue of the spinal cord. It is similar to the human Lou Gehrig’s disease and the average onset is around 9 years old. The disease is not so much a painful disease rather the Lab will eventually lose its ability to walk.
Exercise Induced Collapse (EIC) is a disease common to Labs. This is one that hunters are more concerned with. This is an intolerance to exercise and if affected the dog will begin to walk wobbly and could collapse. They are usually alert during the 5-10 minute episode and are generally not in pain. They normally make a full recovery in 15 to 30 minutes.
Hereditary Nasal Parakeratosis (HNPK) is a disease where the nose will crack and become crusted. Though it is manageable using topicals, when the nose is cracked it is prone to infection particularly if your dog digs and noses in the dirt a lot. Also affected is the loss of pigment in the nose over time.
A Few More Genetic Tests
Progressive retinal Atrophy, progressive Rod-cone degeneration (PRA-prcd) is normally a late onset disease where the photoreceptor cells of the retina experience degeneration. Labradors with this disease will show signs of vision loss usually beginning around 5 years old. In particularly, the disease affects their ability to see in bright or dim light. This disease eventually progresses to blindness in most dogs affected.
Retinal Dysplasia/Oculoskeletal Dysplasia 1 (RD/OSD) is an inherited collagen disorder in Labrador Retrievers. Symptoms include shortening of the limbs and retinal folds. Carrier dogs of this disorder will not have affected limbs but could have mild eye abnormalities. Carriers of this disease is different than most in that carriers are mildly affected. This is a disease that we would choose not to mate a carrier even to a clear dog.
Skeletal Dysplasia 2/Dwarfism (SD2) is a musculoskeletal disease that can affect Labs. Affected dogs develop shorter legs while having a normal body length and thickness. The mutation shows incomplete penetrance meaning that not all dogs affected show signs of the disease.
Conclusion
Nobody can play God when developing a breeding program. There are reasonable measures taken such as genetically testing your Labrador retriever in order to ensure the healthiest Lab puppies are made to make the breed stronger. Genetically tested Labrador retrievers serve as service dogs, hunting retrievers, Police and Customs dogs and of course a healthy family pet. A genetically tested Labrador retriever is one you would want to invest in training, vaccinations and give your heart for a long healthy life.
