Before you breed from your dog, it is important to know about the health conditions which affect your chosen breed and the variety of breed-specific testing and screening schemes available to you.
Knowing the health status of your breeding stock and any stud dogs used enables you to make sound breeding decisions and demonstrates that you are doing everything you can to produce healthy puppies and reduce the risk of passing along genetic conditions to future generations.
We all understand the importance of keeping our dogs physically and mentally healthy; routine vaccinations, regular exercise, feeding a good diet, maintaining a good weight, checking their teeth, gums, nails, ears etc., but there are also genetic factors to take into consideration which vary from breed to breed and which can have a devastating impact, not only on individuals but on an entire breed if ignored.
Research into known inherited conditions in dogs has been taking place for many years and there is now extensive information available to dog breeders as well as a whole host of testing and screening schemes established to support responsible breeding programmes and with a view to eradicating inherited conditions from the gene pool.
At the forefront of championing dog health, the Kennel Club have been maintaining a register of pedigree dogs since the late 1800s and work in conjunction with Breed Clubs to provide information about known inherited conditions and collate data to monitor emerging conditions across breeds in order that they can be addressed before they have a detrimental effect on a breed population. The Kennel Club funds research and the development of testing and screening schemes to help improve dog health, albeit with an emphasis on pedigree breeds.
At Tailwise we understand the vitally important role that responsible breeders play in ensuring the health of all dogs and are keen to do all we can to provide them with support and drive down the numbers of irresponsible breeders flooding the puppy market with sickly puppies that are destined to either die young or suffer from life long debilitating, painful and costly conditions.
So, what are these available testing and screening schemes?
The quantity and nature of information available can be quite overwhelming, so we will attempt to keep it straightforward and have grouped the available schemes according to how they are conducted.
Many breeds suffer from joint issues and there are schemes available that offer screening that can determine to what extent, if at all, your dog is impacted.
Hip dysplasia is a complex inherited condition whereby the hip joint on one or both sides does not develop properly. Over time the joint undergoes wear and tear and can deteriorate causing pain, stiffness, lameness and in serious cases, loss of function.
The mode by which hip dysplasia is inherited is not fully understood and there are thought to be a number of contributing factors, partly genetic and partly environmental (diet, exercise, whelping complications etc.). As such, predicting whether a puppy will develop hip dysplasia from one or other of its parents is not an exact science, but guidance advises not to breed from any dog whose hip score is above the breed median. For breeds predisposed to hip dysplasia, it is irresponsible to breed from an ungraded dog.
To have your dog hip scored, you need to take it to your vet for x-rays. These will then be sent to a specialist scrutineer who will give each hip a grade from 0-53. 0 being radiographically normal and 53 being severely affected. The total score across both hips will be a maximum of 106. The breed median varies across breeds, but you can find a complete list here.
You can choose to have your vet submit the x-rays on your behalf or you can submit them yourself. The cost varies depending upon how much your vet charges for the x-rays and which scheme you use. A well established and recognised scheme in the UK is the BVA/KC Hip Dysplasia Scheme run by the British Veterinary Association, the cost for which, as of April 2022, is £70. Joint Hip and Elbow submissions are £127.50. (This is in addition to the cost for x-raying, which is paid to your vet).
Elbow dysplasia is another complex inherited condition which develops due to the same combination of factors as hip dysplasia and manifests in the same manner. Screening operates in the same way, utilising x-rays taken by your vet which are then assessed by expert scrutineers.
Grading is slightly different in that each elbow is given a grade of 0-3, 0 being radiographically normal and 3 being severely affected by osteoarthritis. The highest grade is then taken as the elbow grade for the dog, so if one elbow is graded a 1 and the other a 2, the dog’s grade will be 2. It is recommended that only dogs with a grade of 0 are bred from. For breeds predisposed to elbow dysplasia, it is irresponsible to breed from an ungraded dog.
A well established and recognised scheme in the UK is the BVA/KC Elbow Dysplasia Scheme run by the British Veterinary Association, for cost for which, as of April 2022, is £70. Joint Hip and Elbow submissions are £127.50. (This is in addition to the cost for x-raying, which is paid to your vet).
Please note that not only is it cheaper to conduct both hip scoring and elbow grading at the same time, but it requires your dog to only have to undergo anaesthetic/sedation once, so plan ahead. To undergo screening for both conditions, your dog must be at least 1 year of age and be microchipped.
Due to the complex nature of both Hip and Elbow Dysplasia, interpreting results is not clear cut. Utilising data from the BVA/KC Hip and Elbow Dysplasia Schemes, the Kennel Club have developed Estimated Breeding Values (EBV’s) for a number of the most commonly affected breeds. EBV’s predict whther a dog is more or less likely to have, and pass on, genes related to a particular problem. They take into consideration not only your dog’s hip score and elbow grade, but also those of its relatives, giving a better indication of the genetic influence on inheritance. Where available, EBV’s should always be taken into consideration as part of a responsible breeding programme.
Most DNA tests are easy to conduct, require you to take a simple swab from inside your dog's mouth - usually from their cheek - and then send the sample to your chosen laboratory for analysis. Only a small number of DNA tests require a qualified person to take a blood sample from your dog.
A large number of breeds are predisposed to specific inherited eye conditions, many of which can be definitively diagnosed via DNA test. That said, it is important to conduct routine clinical eye examinations throughout the life of your dog in the same way that we get our eyes tested. As humans, we don’t necessarily go to an optician on a regular basis unless we have an ongoing issue or require corrective lenses, but we are able to recognise when we are experiencing something abnormal and can seek advice at that point. Dogs are not able to let us know when there is an issue, and without routine checkups, abnormalities may go unidentified and untreated.
It is recommended that dogs of all breeds undergo a clinical eye examination at least 3 times during their normal lifespan; the first around 1 year of age, and pre-breeding. The second at around 3-4 years of age and the last at around 7-8 years of age. Clinical eye examinations can give an early indication of a number of different health issues, not just eye-related, for example, raised blood pressure, anaemia, diabetes and lymphoma.
The Hereditary Eye Disease Scheme is run by the BVA in conjunction with the Kennel Club and the International Sheep Dog Society and is open to all breeds. You can book an appointment directly with a BVA appointed Ophthalmology Specialist near you.
As of April 2022, a routine eye examination for one dog starts at £60. The BVA offer discounts for additional dogs and group bookings and dogs over 8 years cost just £32. Litter Screening is also available for breeds known to have congenital (present from birth) inherited eye conditions, such as Collie breeds. After the examination, the panellist will provide you with an eye certificate showing your dog’s result and if your dog is KC registered, the result will automatically be published on the KC website Health Test Results Finder.
Glaucoma is an inherited condition whereby reduced drainage of the fluid (aqueous humour) that is produced within the eye results in a buildup of intraocular pressure within the eye causing pain and even blindness. Glaucoma is divided into two types: Primary Open Angle Glaucoma (POAG) and Primary Angle Closure Glaucoma/Primary Closed Angle Glaucoma (PACG/PCAG).
Gonioscopy is the technique used to determine if a dog has, or is at risk of, PACG/PCAG, by assessing the development of the drainage angle (the angle between the iris and the cornea). Defective development of the drainage angle is known as Pectinate Ligament Abnormality (PLA) or is sometimes referred to as goniodysgenesis (gonio = angle, dysgenesis = defective development).
Gonioscopy is carried out by specialist ophthalmologists (eye panellists) as part of the BVA/KC/ISDS Eye Scheme and you can book an appointment with them directly, but the technique requires specialised equipment, so make sure you specify that you want a Gonioscopy appointment to ensure your chosen panellist can perform this. The panellist will examine your dog, usually using local anaesthetic eye drops, and will then issue a certificate detailing your dog’s grade.
Dogs can undergo gonioscopy from 6 months of age, but their grade can change with age, so ideally gonioscopy should be performed at approximately 1 year of age, 3-4 years and then 7-8 years.
Grade classifications are:
It is recommended that only dogs with a grade 0 or 1 are used for breeding. Breed-specific advice should be sought for dogs with grade 2 and those with grade 3 should not be used as part of any breeding programme.
As of April 2022, the cost for Gonioscopy is £60 per dog, or £54 if done in conjunction with a clinical Eye Examination (details above). On occasion, dogs require sedation to conduct the examination, which would be charged separately.
Please note that Gonioscopy cannot identify dogs with, or at risk of, POAG. A DNA test is available for this condition (see DNA tests for Autosomal-recessive conditions below).
The Respiratory Grading Function Test is run by the Kennel Club in conjunction with the University of Cambridge and assesses the breathing ability of brachycephalic (flat-faced) breeds.
Brachycephalic Obstructive Airway Syndrome (BOAS) is a condition whereby excessive soft tissue in the nose and throat obstructs the airway making it difficult for affected dogs to breathe well or normally. It is a progressive disorder that can affect a dog’s ability not only to breathe normally but to eat, sleep and exercise.
Dogs can be assessed from 1 year of age and they should be reassessed every 2 years whilst being used for breeding.
Grade classifications are:
For breeds that can be affected by BOAS, you should only breed from dogs that have been assessed. Grades 0 and 1 can be used for breeding, as can a grade 2 as long as mated with a grade 0 or 1. Dogs of grade 3 should not be used for breeding.
You can book an appointment directly with a vet trained in BOAS assessment. Costs may vary depending upon the assessor, so make enquiries when booking.
Chiari-like malformation (CM) is a mismatch in brain size - that being too large - and skull size - that being too small - which can cause part of the brain to protrude from the back of the skull and can block the flow of cerebrospinal fluid around the spinal cord.
Syringomyelia (SM) is where this blockage causes fluid-filled pockets called syrinxes to develop within the spinal cord. Some dogs with mild CM/SM can appear normal and exhibit no obvious symptoms, but other dogs experience intense pain, increased sensitivity to touch, and may demonstrate an unwillingness to exercise, incoordination, ‘air-scratching’ and excessive paw licking.
This is another complex inherited disorder; the exact mode of inheritance is unclear, and genetic and environmental factors play a part, but it is shown to be inherited in the Cavalier King Charles Spaniel and the Griffon Bruxellois. It is suspected to be inherited within the King Charles Spaniel and has been reported in a small number of other breeds.
In order to screen your dog for this condition, you need a referral from your vet to either a veterinary centre with MRI scanning facilities or to a neurologist. The MRI image is then sent to the BVA where it is graded by a panel of neurologists and radiologists.
Both CM and SM are graded from 0-2. In the case of CM, 0 being no malformation and 2 being impacted or herniated and in the case of SM, 0 being no syrinxes and 2 being the presence of syrinxes.
Breeding advice is complex, but you should seek advice once your dogs’ grade is received. Dogs exhibiting clinical signs of CM/SM should not be bred from.
As of April 2022, the cost of grading is £100.
Some breeds are predisposed to congenital deafness. This is another complex condition and one that is thought to be controlled by many different genes, but there are some breed-specific characteristics that mean that puppies of certain breeds are more likely to be born deaf than others.
Those breeds that have a mostly white coat are considered more at risk, linking the condition to the ‘extreme piebald’ gene. There is also evidence that links the merle coat colour with congenital deafness.
Dogs of breeds that are considered at higher risk for deafness should be BAER tested before being bred from, although the ideal age to get this test carried out is between 5 ½ and 6 ½ weeks old, as puppies of this age will sleep following periods of activity, giving the specialist the perfect opportunity to conduct the test. This is also a good age as responsible breeders will want to have a litter tested before the puppies go to their new homes, as the training of deaf or partially deaf dogs can be difficult, especially if the owner is not aware that there is a hearing problem.
Some deaf dogs will exhibit unpredictable behaviour due to being startled by movement or sounds that a dog of normal hearing would be aware of. They are also more at risk to everyday dangers such as traffic.
The BAER test will determine if a dog is:
Unfortunately, offering definitive breeding advice is not yet possible due to the varying factors involved in inheritance, but scientists would suggest that only bilaterally normal individuals should be bred from.
You can book an appointment for individual or litter screening directly with a registered Test Centre near you. You need to take a copy of the BAER Test Report Form with you.
As of April 2022, individual screening costs £116.14 plus the cost of a certificate should you want one. Litter screening costs £68.89 for the first puppy and then £31.92 for each additional puppy in the litter. Again, certificates are at an additional cost.
There are a huge number of DNA tests available which are an invaluable resource to not only better understand your dog’s genetic makeup, but to protect future generations of your chosen breed and to give peace of mind that the puppies you are producing are as healthy as they can be.
Fully understanding the health status of your breeding stock before planning your breeding programme is imperative and responsible breeders should be utilising all available tools to reduce the chances of passing on known inherited conditions and producing affected puppies.
DNA tests fall into the following 4 categories:
With autosomal-recessive conditions, a dog must inherit two copies of an abnormal gene - one from its mother and one from its father - before it will be affected by that condition. The majority of available DNA tests are for autosomal-recessive conditions and, unlike the complex inherited conditions discussed above, interpretation of these results is straightforward and clear breeding guidance can be given.
A dog can be:
Clear - they have no copies of the abnormal gene, will never develop that condition and cannot pass the condition on to future generations. Clear dogs can be mated to any other without producing affected puppies, however, if bred with a carrier dog, they may produce carrier puppies and if bred with an affected dog, all puppies will be carriers.
Carrier - they carry one copy of the abnormal gene but will never develop the condition themselves. Carrier dogs should only be mated to clear dogs. Mating a carrier to a carrier runs a 25% chance of each puppy being affected. Mating a carrier to an affected dog runs a 50% chance of each puppy being affected, with the remainder being carriers. No puppies from a carrier to affected mating will be clear of the condition in question.
Affected - they carry two copies of the abnormal gene and will develop the condition in question. Affected dogs can only be mated to clear dogs to avoid producing affected puppies, however, all puppies will be carriers themselves so the use of affected dogs should be avoided unless under specific and well-considered circumstances.
An autosomal-dominant condition means that a dog only needs to inherit one copy of an abnormal gene, from either its mother or its father, before its health is affected. As such, interpretation is a little more complicated, but breeding guidance can be given.
A dog can be:
Clear - they have no copies of the abnormal gene, they are highly unlikely to develop the condition and will pass on a normal copy of the gene to their puppies.
Heterozygous affected - they have one copy of the normal gene and one copy of the abnormal gene. They are likely to be affected by the condition and could pass on a copy of the abnormal gene to their puppies.
Homozygous affected - they have two copies of the abnormal gene, are likely to be affected by the condition and will pass on a copy of the abnormal gene to their puppies.
Only clear to clear matings will produce a litter of clear puppies.
Most DNA tests look for a particular gene that is known to cause a particular condition. Where the exact gene cannot be identified, sometimes it is possible to determine where it is located in the dog’s genome and scientists can then identify a section of DNA that the gene is linked to and that it will be inherited alongside. This is known as a linked genetic marker, and can predict with a high level of confidence, the genetic status of a dog in relation to the specific condition.
Laboratories often provide an estimate of how accurate their linkage test is. The interpretation of these results is the same as for Autosomal-recessive conditions.
For some conditions, certain environmental factors, or other genetic influences can also contribute to whether a dog becomes affected. Having copies of the disease-causing genes will not necessarily be a guarantee that the condition will occur and an absence of these genes will not necessarily be a guarantee that the condition will not occur.
Risk-based tests can be less accurate than other DNA tests, but they are still sufficiently accurate to be worthwhile and, as with the linkage tests, laboratories will often provide an estimate on how accurate their test is.
A dog can be:
Only minimal risk (0) to minimal risk (0) matings offer the lowest chance of each puppy in the litter not developing the condition and these puppies will not be passed a copy of the abnormal gene variant.
Most DNA tests are easy to conduct, require you to take a simple swab from inside your dog's mouth - usually from their cheek - and then send the sample to your chosen laboratory for analysis. Only a small number of DNA tests require a qualified person to take a blood sample from your dog.
Costs vary from laboratory to laboratory and depending upon the test type and condition, but it is worth bearing in mind that there are a number of unregulated laboratories across Europe from which the validity of results is unproven. Make sure you check the credentials of your chosen laboratory or use one approved by the Kennel Club. The Kennel Club also offer some cost-effective breed-specific CombiBreed packages for breeds where multiple DNA tests are recommended.
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