Hip dysplasia and breeding advice

 

For breeding advice, please scroll down, or click here to jump to the appropriate section.

What is hip dysplasia?

Hip dysplasia is a condition where the hip joint does not develop correctly. As the dog gets older, the joint undergoes wear and tear and the joint deteriorates, leading to a loss of function. This can cause varying degrees of pain, discomfort, stiffness and lameness.

How is hip dysplasia inherited?

Hip dysplasia is a complex inherited disorder, which is influenced by a number of different genes and by several environmental factors (e.g. diet, exercise or factors when in the womb before birth etc.). Each of the genes that help to make a dog’s hips may have different possible versions. Some versions increase the risk of hip dysplasia, while others decrease the risk.  Each dog will have a mix of these “good” and “bad” versions of genes, making it very difficult to predict to what extent a dog will be affected. The impact one version of a gene has might only be slight, but lots of genes having a small influence will have a combined additive effect. The way in which these conditions are inherited is not straight forward; hence the name complex inherited disorders. These complex diseases are usually seen across many different breeds and are also described in both cross breeds and mixed breeds.

Which breeds are affected?

Since hip dysplasia is partly inherited, dogs that share similar genes are more likely to be similar in terms of how severely they have hip dysplasia. Individuals in each breed share a significant amount of their genetic make-up and so certain breeds are more vulnerable to hip dysplasia than others. It is generally accepted that this condition is more common in larger breeds (possibly because these breeds are heavier, and this greater weight has more of an effect in producing osteoarthritis due to laxity), but can occur in any dog of any size, regardless of whether they are purebred or mixed bred.  

Is this scheme relevant to my breed?

Find out which health tests or schemes are recommended for your breed on the Kennel Club’s Breed Information Centre. These recommendations are suggested by Breed Clubs and approved by Kennel Club committees.

How do I get my dog tested for hip dysplasia?

The severity of hip dysplasia cannot be accurately determined by a vet’s physical examination. The most reliable way of determining the health of a dog’s hips is by having your dog X-rayed. Owners should make an appointment with their vet who can take the required X-ray of the dog's hips.

Why screen your dog?

Breeders are able to screen their breeding stock for hip dysplasia before the dogs are bred from. Testing all potential breeding stock, where relevant, allows breeders to better understand the kind of genes a dog may pass on to its offspring, giving them the information required to minimise the risk of producing clinically affected puppies. Making informed decisions from health test results enables breeders to adapt their breeding programmes and reduce the risk of the diseases appearing in future generations.

 

Using the BVA/KC hip dysplasia scheme

The British Veterinary Association (BVA) and Kennel Club (KC) scoring scheme has been in operation since 1984.  The scheme screens animals for faults in the hip joints and allows animals with the best hip joints to be chosen for breeding.  A dog’s X-rays are scored by a panel of experts who are part of the hip dysplasia scheme. Your vet can organise this for you and will send the X-rays off to be scored and then relay your dog’s results to you.

 

When taking your dog for its X-ray, owners should remember that:

  • The dog must be at least one year old, but there is no upper age limit
  • The dog must be permanently and uniquely identified by way of a microchip or tattoo
  • The dog’s KC registration certificate and any related transfer certificates must be available so that the appropriate details can be printed on the radiographs
  • Microchip/tattoo numbers must also be printed on the radiographs
  • The owner should sign the declaration (first part) of the certificate, to verify the details are correct and grant permission for the use of the results in data collection and research

What are the scores my dog may receive?

Each hip joint is assessed by BVA/KC scrutineers who assign points based on nine aspects of each hip joint. The degree to which a dog is affected by hip dysplasia is represented by a score given to each hip.  This score ranges from zero to 106 (zero to 53 for each hip), with a score of zero representing the least degree of hip dysplasia and 53 representing the most. 

Are the BVA/KC results published?

The names and results of Kennel Club registered dogs will be sent to the Kennel Club for recording on their database and will be made available:

  • In the next available Breed Records Supplement
  • On any new registration certificate issued for the dog and
  • On the registration certificates of any future progeny of the dog
  • On the Health Test Results Finder in the Kennel Club's online health resource, Mate Select

What are the costs involved?

In addition to the charges levied by the vet for anaesthetic and X-raying, the cost of having one dog graded under the scheme is currently £60.00 (inc VAT). If an owner submits 5 or more dogs at the same time, the cost falls to £52.50 (inc VAT) per dog. There is a reduced fee when radiographs are submitted simultaneously to the BVA/KC Hip and Elbow Dysplasia Schemes. The charge for joint Hip and Elbow submissions is currently £108.00 (inc VAT) per dog.

Number of dogs

Charge ex VAT per dog

(inc VAT)

1-4 dogs

£50

£60

5 or more dogs (same owner)

£43.75

£52.50

Re-scoring under appeal

£90

£108

Copy of certificate

£30

£36

Joint Hip & Elbow

£90

£108

Who reviews the X-rays?

There is a panel of BVA-appointed radiologists and orthopaedic specialists who will review the X-ray. The X-rays are assessed by two scrutineers who will agree the grading.

Where can I get more information on the BVA/KC scheme?

Free, detailed leaflets can be download here, or are available from either: Health & Breeder Services Department, The Kennel Club, Clarges St, Piccadilly, London W1J 8AB or the Canine Health Schemes Department, BVA, 7 Mansfield Street, London W1G 9NQ.

For further information on the schemes please visit the BVA website.

Using BVA/KC hips scores to produce Estimated Breeding Values (EBVs).

Data from the BVA/KC Hip Dysplasia Scheme is used to calculate an estimated inheritance ‘risk factor’ for each dog (EBV). EBVs help breeders of Kennel Club registered pedigree dogs to continue to make sensible and informed health choices for breeding, based on robust data.

Complex inherited disorders, such as hip dysplasia, are influenced by both genetic and environmental factors.  EBVs essentially strip away the environmental influences to estimate the genetic component of these conditions, enabling breeders to better understand the genes a dog may pass on to its offspring. If used as part of breeding decisions, EBVs can help reduce the risk of puppies inheriting hip dysplasia more effectively than by the sire and dam’s individual hip scores alone.

EBVs link all available pedigree information with data collected through the BVA/KC testing schemes. The information on relatives (who share genetics) influences the genetic risk of an individual. Therefore, the more breeders that make use of these schemes, and the more dogs that are scored, the more accurate the EBV will be. By continuing to hip score, breeders are securing the future for countless other dogs by providing the information needed to continue Estimated Breeding Values. For a full list of breeds that currently have an EBV for hip dysplasia, please click here.  As more breeders continue to hip score their dogs using the BVA/KC schemes, it is hoped that more breeds will be added in the near future.

What do EBV values and figures mean?

The Kennel Club’s EBV resource provides the hip score, the EBV as a number, the confidence as a percentage, and a graphical representation of the EBV and confidence. 

EBV scores

The breed average is always set to zero. Dogs with a higher than average risk of passing on genes associated with hip dysplasia will have an EBV higher than zero. Dogs with a lower than average risk of developing hip dysplasia will have an EBV lower than zero (i.e. a negative number, e.g. -10).  The further a dog's EBV is from the average, the higher or lower its genetic risk. A dog's EBV can change during its lifetime, either upward or downward, as more data becomes available, either about the dog itself or its relatives. At birth, a puppy’s EBV will be the average of its parents’ EBVs.  For example, a sire with an EBV of -5 and a dam with an EBV of +5 will produce a litter or puppies with an EBV of zero.

Confidence

The confidence is an indication of how much scoring information has been used to calculate the EBV. The more scoring information available from the dog itself and/or its relatives, the more confident we are that the EBV is close to the actual genetic risk. The confidence of the EBV can increase if more relatives are, or the dog itself is scored.

  • A dog with just its own hip score, and no relatives scored will have a confidence of about 60%
  • A dog without its own hip score, but with the score of both parents will have a confidence of around 40%
  • A dog without its own hip score, but with only one parent scored will have a confidence of around 30%

Breeding Advice

Where EBVs are available for your breed

EBVs provide a more accurate measurement of genetic risk than using a dog's hip score alone. It is therefore recommended that breeding decisions are principally made using EBVs. 

Ideally breeders should use dogs that that have an EBV which is lower than average (i.e. a minus number), and preferably with a confidence rating of at least 60%. EBVs with a confidence less than 60% can still be used, but the higher the confidence, the more accurate the EBV will be.  A dog does not need to be hip scored in order to have an EBV, but to ensure an EBV is accurate as possible, it is recommended that breeding dogs are scored under the BVA/KC scheme. This is also important in understanding an individual dog’s health risks for being at risk of developing hip dysplasia.

The lower the EBV the better, but breeders do not need to seek out dogs with the lowest risk EBV. Selecting animals with a lower risk EBV than average will still lower the risk of hip dysplasia. 

It is recommended that breeders make well balanced breeding decisions. Each puppy will have an EBV that is the average of its parents. Therefore dogs with an EBV which is higher than average can still be bred from, providing that it is mated to a dog with an EBV which is well below average (assuming that the confidence for both dogs is high); and the EBV of the resulting puppies is lower than the breed average. 

Previously, the best advice was to use dogs with hip scores below the breed average, which meant that many dogs could have been excluded from a breeding plan if their scores were a significant consideration. Excluding dogs from a breeding plan can have an impact on genetic diversity. By using EBVs, it is reasonable to use a dog with an individual BVA/KC score over the breed average, as long as the EBV indicates low genetic risk with good confidence. In such cases the hip condition of the offspring should be carefully monitored and preferably hip scored themselves. 

Where EBVs are not available for your breed

An average (or median) score is calculated for all breeds scored under the scheme and advice for breeders is to choose breeding stock with hip scores around and ideally below the breed median score, depending on the level of hip dysplasia in the breed. Each breed’s median score is available here.

It is recommended that hip scores of a dog’s family members should also be considered.

This could be done by using the Kennel Club’s Health Test Results Finder to look at parents, grandparents, siblings and progeny.

Making balanced breeding decisions

As well as considering the implications of a dog’s EBV or hip score, there are other equally important factors to consider when deciding whether two dogs should be mated together, such as temperament, genetic diversity, conformation, other available health test results, the general health of the dogs, etc. Your breeding decisions should always be well balanced and take into consideration the qualities and compatibility of both the sire and dam that you are considering.

Can the results of the scoring scheme or EBVs be used to precisely predict if future puppies will be affected?

Hip dysplasia is a condition which is inherited in a complicated way not yet fully understood by scientists. Due to the complex nature of inheritance of this condition, it is still possible that affected offspring may arise from parents which have good EBVs. It is hoped that breeding appropriately from screened dogs will reduce the risk of producing affected offspring, and using EBVs reduces this risk even further, but it must be stressed that this is not a guarantee.

Will a DNA test for hip dysplasia be developed in the near future?

It is unlikely. Hip dysplasia is a complex inherited disorder, caused by a number of different genes and also influenced by several environmental factors. Traditional DNA tests can be developed for conditions controlled by only one gene to predict whether a dog will be clear, a carrier or affected, but not for conditions controlled by more than one gene. For a disease such as hip dysplasia, even if the effects of all the genes involved were known, a DNA ‘test’ would give a genetic risk of the disease.  

What statistics are known about hip dysplasia?

Statistics on the number of dogs scored by the scheme and their results can be accessed in the Kennel Club’s Dog Health Group Annual Report.

Version suitable for printing
Tools & Services
Insurance

Related Topics

Dog HealthHealth SchemesHip Dysplasia

Copyright © The Kennel Club Limited 2016. The unauthorised reproduction of text and images is strictly prohibited.