Health Screening for Labrador Diseases

In this article we are going to let you know what health screening for Labrador diseases your new puppy’s parents should have had. We’ll look at the most popular health tests for Labradors, why they are important, and what evidence you need to see to know that your puppy is safe.

Health screening for Labrador diseases is important. It enables us to know whether mating two adult Labradors will result in puppies less likely to suffer from inherited diseases. Ones which could give them a life of discomfort, and their owner a whole lot of stress and heartache. Not to mention putting them seriously out of pocket in the process.

Within the Labrador gene pool, lurks a range of unpleasant inherited diseases. Understanding these diseases and learning to detect and prevent them,  is an important part of improving Labrador health on a national basis.

What Is Health Screening For Labrador Diseases?

Health screening for Labrador diseases involves testing dogs.

To see whether they carry the genes which could cause them or their future offspring to suffer from an inherited disease.

A good deal of research has gone into these Labrador diseases.

As a result there are now a number of screening tests available to Labrador Breeders.

In most cases these screening tests are applied to the parents that are about to be bred from, rather than the puppies that are being sold.

The most commonly applied screening tests offered by the BVA are Labrador hip scores and eye tests.

All responsible breeders now test their breeding stock for these two conditions.

There are also a range of further tests now available to breeders.

And many responsible breeders are testing for these additional Labrador diseases too.

Are All Pedigree Labradors Health Tested?

You could be forgiven for assuming that a pedigree Labrador must have undergone some form of health screening, or come from health tested parents.

Sadly, there are still many Labrador puppies available for sale in the UK whose parents do not have even the most basic health clearances.

Puppies bred from unscreened parents can at the time of writing, still be legitimately registered with the Kennel Club.

A genuine pedigree does not offer you any health guarantees.

Have My Puppy’s Parents Been Health Screened?

It is up to you, the buyer, to determine whether or not the parents of your puppy have been screened.

But this isn’t enough. You also need to know that the results of the screening meet your requirements.

Being informed that your potential puppy’s parents have been hip scored is not sufficient.

You must check that this score was better than the average result.

You should only view a litter of Labrador puppies if both the parents have good hip scores and clear eye tests.

You should ask in advance for hip and eye test certificates of both parents to be available for your scrutiny when you visit the puppies.

Or better still, for copies to be emailed to you in advance of your journey.

If certificates are not forthcoming, you should walk away.

Remember, it’s easier and less embarrassing to decide against a puppy from a certain litter before you meet in person.

Labrador Eye Problems

Labradors are susceptible to a serious eye disease that causes blindness,  sometimes at a young age.

A ‘clear’ BVA eye test certificate means that the dog has been examined by a vet specialising in this field.

And pronounced free from disease at the time of the examination.

It does NOT mean that the dog does not have the inherited condition,  just that he or she displays no sign  of it at this time.

These basic eye tests should be carried out on an annual basis.

You should check that both parents have a ‘clear’ eye certificate, and that the eye examination took place within the last twelve months.

Labrador Hip Scores

Hip dysplasia is a crippling disease of the hip joints.

The BVA hip certificate means that the dog’s hips have been x rayed and that the xrays have been examined and assessed by vets who specialise in this field.

After examination, each hip is allocated a score.

The lower the score, the better the hips.  A perfect hip has a score of zero.   But this is fairly unusual.

The score is expressed by two numbers – one for each hip.

You will often  see these written like this    5/7   or this   5-7  or this   5:7

The final hip score is the total of the two figures added together.  In this example, 12.

What we are looking for in good breeding stock is a Labrador hip score that is better than average.

This greatly reduces the chances of the puppies inheriting severe hip problems. However, it does not guarantee your puppy will have good hips.

This is because the disease is not caused by single gene, and there are other factors influencing the development of your puppy’s hips.

What Is A Good Hip Score For A Labrador?

The average hip score for Labradors is expressed as the ‘breed mean’.

Hip scores vary from breed to breed, and from year to year.  You can find the latest data on the BVA website.

In Labradors,  the current five year mean is 12.

Most Labrador breeders should be aiming to breed from stock with a hip score that is lower than average and balanced.

This should result in gradual improvement in the breed over time.

A good hip score for a Labrador is probably anything under 6, made up of even numbers on each side.

Labrador Elbow Dysplasia

Elbow dysplasia in Labradors is similar to hip dysplasia, but affecting the elbow joints of the dog.

It occurs when abnormal growth causes a malformation or degeneration of the elbow.

This can lead to lameness, loss of range of movement and severe pain.

Fortunately you can improve the odds dramatically in your puppy’s favor by only going to a breeder who has elbow scored both the mother and stud dog.

Elbow scores are rated differently to hip scores, being given a rating of 0 to 3. Where 0 is a perfect elbow and 3 is one that is very affected.

The range of scores is small, which means that there is not a lot of scope to clearly separate the range of potential problems.

For this reason we recommend that you only choose a Labrador puppy if their parents’ elbow scores are 0.

Health Screening Labs

There are some additional tests now available to Labrador breeders,  and these have been developed by independent organisations.

These tests are for:

• Prcd form of GPRA run by Optigen in America and under license at some other laboratories
• CNM (Autosomal Recessive Centronuclear Myopathy) done by the Animal Health Trust
• EIC Exercise Induced Collapse that is run by the University of Minnesota in America
• Macular Corneal Dystrophy (MCD) a progressive hereditary visual disease

What Is Optigen Testing?

The Optigen test is becoming popular, and many breeders are now testing their stock.

This test is a ‘once only’ test and tells us whether the dog carries the gene which causes this type of blindness.

This means that if you purchase a puppy from two parents that are Optigen ‘Clear’, he can never develop or pass to his progeny, this type of inherited progressive blindness.

These tests are relatively recent developments and the more breeders that support them,  the better our chances of eradicating these unpleasant diseases.

My Labrador Is A Carrier

Sometimes, one parent of a litter of puppies, will be a ‘carrier’ for a particular disease, rather than ‘clear’.

This is not normally a problem provided that the other parent is ‘clear’ for the disease in question.

If you have been told that your Labrador puppy is a carrier for a nasty disease you might be concerned.

So let’s look at what this actually means for your puppy, and the potential implications upon breeding from him in the future.

Imagine you have picked out your beautiful labrador puppy and horror of horrors your breeder responsibly tells you that this puppy could be a carrier for a serious inherited disease.

What should you do?    Is it safer to back out and look for another puppy?

Or should you go ahead and purchase a puppy that carries a serious disease?

Should I Buy A Puppy Who Is A Carrier?

In most circumstances where the mechanism of inheritance is clear cut, it is perfectly safe for you to purchase a puppy that is, or might be, a carrier for a known disease.

Every aspect of how your dog is constructed at birth right down to the tiniest detail (and much of how he will develop as he grows) is planned out and coded into a set of instructions packaged inside a ‘gene’.

Labrador Genetics

Genes come in pairs, one from each parent,  and each pair works together to determine one  aspect of your dog, coat colour for example, ear length.

And then of course the millions of less obvious features that go to make your dog what he is, and which in some cases, may make your dog prone to illness.

Dominant Genes In Labradors

Some genes are ‘dominant’,  this means that they have the power to over-ride or ‘switch off’  their partner gene.

The gene for black coat for example, is dominant.  So even  if it gets paired with a gene for  a chocolate coat,  the labrador will still be black.

The black gene ‘over-rides’ the brown one.

Check out this link for more about labrador coat colour inheritance.

Recessive Genes In Labradors

The gene which has been over-ridden is called the ‘recessive’ gene.

A dog needs two such recessive genes in any given pair, in order for the instructions in the recessive gene to be ‘acted on’.

Thus the chocolate Labrador always has two chocolate genes.

Obviously this is an oversimplification of genetics! But it is helpful to understand.

Because there  are many diseases that we now test for in pedigree dogs,  and some of these diseases are autosomal recessive in nature.

This means that the ‘faulty’ genes with instructions for the disease cannot be activated unless they are in a pair.

If  the faulty gene is paired with a normal gene,  it will be switched off and lie hidden there inside the dog.

Without causing any problems.

There are genetic tests now which can determine whether a dog is clear, normal or a carrier, for a number of diseases.

Health Screened Clear Dogs

Each puppy inherits two genes for an aspect of it’s development with potential to cause a certain  disease and each of these genes can either be normal, or faulty.

Only if both genes are faulty will the puppy develop the  disease.

The pup gets one gene from each of his parents to make up the pair of genes.

If the puppy inherits two normal genes he will be in the  ‘clear’ (or unaffected).  He will never get the disease nor can he ever pass it on to his puppies.

But let’s look at what happens if the puppy inherits a faulty gene.

Will My Puppy Get Ill If He’s A Carrier?

Happily, because  the normal gene in each pair usually has the power to  ‘switch off’ or override its faulty partner the dog only needs one of the pair of genes to be normal in order to stay perfectly free form this condition.

So if the puppy gets one faulty gene from his Mum and one normal gene from his Dad (or vice versa) he will still be healthy.

He is called a ‘carrier’ because he has the potential to carry the disease on to the next generation.

If he is mated he will pass a faulty gene on to about half of his puppies.

Provided that each of these Labrador puppies inherits a normal gene from its other parent, they too will be healthy.

This is how diseases can sometimes skip generation after generation.

If your breeder has had a litter of puppies blood tested for a particular disease then you may be informed that your puppy is a carrier.

With autosommal recessive conditions,  if the puppy gets two faulty genes we know that he will definitely develop the disease at some point because there is no normal gene to switch it off.

We call these puppies ‘affected’.

Obviously we all want to avoid affected puppies being born, and most of us would want to avoid purchasing an affected puppy.

Benefits Of Health Screening For Labradors

A responsible breeder tests his dogs and female dogs for autosommal recessive diseases which are evident in the breed,  and only ever mates a ‘carrier’ with a dog that is ‘clear’.

Remember that the clear dog has no faulty gene and gives a healthy normal gene to every single pup so none of the pups can ever get sick from this disease even when the other parent is a carrier.

It is important to know that if you buy a puppy from untested parents and both happen to be carriers,  a quarter of all their puppies will be ‘affected’ puppies.

Worse still if one parent is a carrier and one is affected,  half the puppies will be affected.

This is why buying from health screened stock is so important.

Should You Mate From Labrador Disease Carriers?

“But why is the breeder using carriers at all”  you say.  Why not have a policy of only mating ‘clear’ dogs to other ‘clear’ dogs

To understand the benefits of breeding from carriers,  we need to look at the whole dog and at the range of different health issues that affect each breed.

Maintaining a good sized ‘gene pool’ in each breed is crucial to health.

The smaller the gene pool,  the greater the chance of more diseases appearing.  It is important that we do not eliminate perfectly healthy dogs from this gene pool for no good reason.

With the development of so many available tests,  breeding from carriers is not only possible,  it is actually a  good thing.

Because it helps to keep that large and healthy gene pool.

One of the beauties of widespread testing is that it allows us to breed from carriers because we can ensure that they are always mated to a clear dog.

The more people that test,  the more clear dogs that will be available, and the bigger our gene pool will be.

With so many diseases to test for  nowadays that to attempt to restrict our breeding stock to dogs that are ‘clear’ for a whole range of different conditions, would reduce the gene pool dramatically and harmfully.

Does It matter If Your Puppy Is A Carrier?

I hope I have shown that there is nothing wrong at all in a breeder offering for sale puppies that may be carriers for a disease inherited in this straightforward way.

To find out if this is a case of straightforward inheritance of the sort described here you should get the details from your breeder and check with your vet.

It is important that the disease in question is not one that can affect carriers.

However,  in most cases is absolutely no need to avoid a puppy who is genetically a carrier unless perhaps you are intending to found your own breeding line.

Even then you should not discount a carrier if all else is right.

You will obviously need to be careful when choosing a mate, but as more and more dogs are health tested,  this is becoming easier.

As tests are developed for ever more diseases, finding a puppy that is ‘clear’ for all of them would be a difficult and unnecessary challenge.

To sum up: carriers of an autosomal recessive disease of the type described hear do not get sick.  At least not from the disease that they are carrying!

Carrier puppies are not necessarily substandard,  and the breeder is perfectly within their rights to sell a puppy knowing that it is, or might be, a carrier of this type.

She is also doing the responsible thing by providing her puppy buyers with this information.

Remember, if you buy a carrier puppy her faulty gene will have been switched off by the normal one and just sits there doing nothing throughout the dog’s lifetime.

All you need to do is keep in mind that your dog could pass the faulty gene on,  so if you ever mate your ‘carrier’,  you must mate her to a ‘clear dog’  to ensure none of her puppies get sick.

Why Don’t All Labrador Breeders Health Test?

Genetic testing is not cheap.

Breeders who don’t health test will tell you things like, “the parents are both healthy, so I didn’t need to”.

Or “none of the dogs in their line were affected so I didn’t need to”.

But these statements are misguided, as two healthy dogs can be carriers for an inherited disease and therefore produce puppies who are born to suffer.

You would never know without the health tests.

Don’t put your puppy’s future on blind faith, make sure you have evidence that the breeder has done everything you can to protect him.

As long as there is no obligation on breeders to test their stock, there will be breeders who do not bother.

It is therefore up to the public to put pressure on breeders to carry out these tests by refusing to purchase puppies from untested parents.

You can help encourage breeders to carry out these tests by enquiring about them whenever  you contact those offering puppies for sale, and by choosing puppies whose parents have been tested.

More Help and Information

You can find out more about Labrador health screening in the following articles:

• Hip dysplasia: improving the odds
• Labrador Hip Score FAQ
• The fight against PRA blindness in Labradors
• Labrador Health

More information on Labradors

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References and Resources

• British Veterinary Association