Health Testing

BVA Eye Test

The dog is examined by an eye specialist.  It is not an invasive procedure so it is one of the minimum tests that should be carried out on any dog before breeding with.  The test certificate lasts for 12 months and does need updating to ensure conditions haven’t developed since the previous test was performed.

The test, when performed on Labrador Retrievers, is looking for two conditions which the dog can be born with and three conditions they can develop later on in life.

Congenital

MRD (multifocal retinal dysplasia) Areas of the retina are not attached.  Once diagnosed the dog will always have MRD of varying degrees.   TRD (Total retinal dysplasia).
They would have to be born with it, as they are both congenital conditions.

Non Congenital

GPRA (Generalised Progressive Retinal Atrophy) sometimes known as Progressive Rod-cone Degeneration.  Appears in Labradors from 3yrs of age with the dog being completely blind by the age of approximately 6yrs.  A serious condition within Labradors.
CPRA (Central progressive retinal atrophy) Retinal Pigment Epithelial Dystrophy, not to be confused with GPRA).  An ocular manifestion of a metabolic defect.  If detected at early onset then it can be maintained with vitamin supplements.

HC (Hereditary cataract).  Heridatary cataracts are usually bi-lateral, restricted vision but the dog wouldn’t be entirely blind.  There are two types of HC, one is early forming and would be seen in a dog of roughly a year old, the other type is seen usually when the dog is 8yrs old.

A BVA eye tested dog will show as affected or unaffected.  If the dog holds a current “unaffected” eye certificate it simply means the dog does not have the conditions currently.  It CANNOT ascertain whether the dog is a carrier for the condition.

When the test is complete a certificate will be given afterwards showing if the dog was affected or unaffected by the problems being examined for. The eye certificate should be renewed every 12 months.  When checking the certificate from a breeder, you must check two elements, 1) the date, it has to be within the last year and 2) make sure the unaffected box is ticked and NOT the affected. If an up to date certificate can not be produced then this could be the dog had been retested and failed or the breeder hasn’t bothered testing again.   Having a series of unaffected certificates does not guarantee nor confirm the dog is not a carrier for any of the conditions being looked for within the test.

DNA Tests

CNM – Centronuclear Myopathy is an inherited autonomic recessive disorder and is characterized by skeletal muscle weakness and exercise intolerance.  Also known as Heridatory Myopathy of the Labrador Retriever (HMLR).

PRA .  Progressive Retinal Atrophy leads to blindness.  This DNA test will determine whether a dog carries the gene for GPRA   (Generalised Progressive Retinal Atrophy) also known as Progressive Rod-cone Degeneration.

EIC – Exercise Induced Collapse.  Dogs suffering with EIC display signs of muscle weakness, incoordination after a short period of exercise.  As the name suggests they could also collapse.  When an animal collapses they are at risk from not being able to oxygenate themselves adequately which will have detrimental outcome. If a dog suffers with this condition then it will have an impact on the level of activities the dog can partake in throughout his/her life.

HNPK – Heridatory Nasal Perakeratosis.  This painful skin condition can cause crusting, scales and or cracks on the nose.  These would need treatment with moisturiser and medication of antibiotics.

How to understand the DNA test results and how the results may impact on the puppies!

The status of both the Dam and Sire will give you a good idea whether the puppies may have the disease or not as CNM,PRA and EIC are inherited conditions.  IF both parents are CLEAR then the puppies will also be clear.  If one parent is clear and the other is a carrier then the puppies CAN NOT be affected but 50% of the litter could be carriers.  Being a carrier for a condition does not mean the puppy will suffer from the condition.

Clear dogs do not have any copies of the mutant gene, will not develop or pass on the gene to its offspring.

Carrier dogs have one copy of the mutant gene, they will not develop the condition but will pass a mutant gene on to roughly half of their offspring.

Affected Dogs have two copies of the mutant gene and will develop the disease so will pass on the mutant gene.

Status of Parents                    Percent Chances of Offspring being Clear, Carrier or Affected
Clear x Clear                              100% Clear offspring
Clear x Carrier                              50% Clear 50 % Carrier offspring NOT affected.
Carrier x Carrier                             25% Clear, 25% Affected, 50% Carrier offspring
Clear x Affected                                 100% Carrier offspring NOT affected
Affected x Affected                               100% Affected offspring

For simplicity in having a basic understanding of the needs of the parents that have had DNA tests.  At least one of the two parents must be Clear.  If both are clear that is great, if one parent is clear and the other parent is unknown then it will be impossible for the entire genetic code of the disease to pass to the puppies from the unknown result based on the CLEAR parent.  So basic rule of thumb that least one parent must be clear.  If a parent is a carrier and the other is not known, then you are risking creating puppies that are going to be affected by that condition (whatever the dna test is testing for).

BVA Hip Scoring

Hips can be scored by means of an xray which is sent for assessment to the BVA.  This can be done when a dog reaches the age of 12 months.  Currently (November 2011) The BMS (Breed Mean Score) for a Labrador is 14.    The scoring of hips can be anything from 0 to 106.  (a maximum of 53 points on each hip).  The score is then added together and must be lower than 14 to meet the breed average.

As the scores are added together it is helpful to know the individual score of the hips and if they are fairly balanced or not.  For example if a dog has a hip score of 8:8 this would put the combined score of 16 only just above the BMS and would be acceptable based on the hips being balanced BUT if a dog had a score of 0:16 (still a combined score of 16) then clearly the affected hip is going to cause problems and should be avoided when it concerns breeding.

Labradors can be susceptible to hip dysplasia (HD) which is why this is one of the minimum tests that must be completed before breeding.  If your dog develops hip dysplasia it can have it from a pup but it may not be evident until your dog is older.  To provide your dog the best possible care for this condition it is very important to keep the weight of your dog at its correct level and ensure your dog is fit.  If your dog develops HD in later life it is the muscles which will help hold the joints together.  If the dog is unfit and overweight, this will put immense strain on the bones.  Whilst Hip dysplasia is partly down to genetics  (the rest is upbringing, environment, exercise and diet).  A dog predisposed to hip dysplasia does have a chance of not getting advanced dysplasia ONLY IF the dog is raised on a quality dog food and not over exercised whist it is growing.  If a dog has a stressful time while growing up, then it is likely it will not metabolise its food correctly, leading to nutritional imbalance.

By having health checks done does not guarantee the pups will not get these conditions (other than clear results with dna tests are a guarantee) but hopefully the results can help determine the chances of developing the condition(s) which hopefully if the results are used as a tool the chances are far more reduced than in using an unchecked sire or dam with no medical history to speak of.

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