Health MattersThe importance of health testing breeding stock
With any living creature, be it a human being or a dog, there is never any guarantee that it will be born 100% healthy or that it will stay that way throughout its life. However, we do know that with dogs, as with humans, some conditions are hereditary or there is a hereditary pre-disposition to some diseases. With pedigree dogs the gene pool is relatively small (meaning there is less choice when choosing dogs to breed from) and we need to take care that we are not knowingly going to produce a specific condition or health problem. Newfoundland dogs are known to suffer from specific health conditions, these include:
These conditions have been researched for many years by Veterinary establishments and Scientists and as a result Health Tests have been devised to help reduce the risk of a Newfoundland having any of these conditions.
Some conditions such as Hip Dysplasia are 'multi-factorial'. That means that as well having a genetic component (inherited the condition from its parents/grandparents) other factors can affect the development of hips and lead to Hip Dysplasia, for example diet, exercise and environment.
To try and reduce the risk of puppies being born or developing any of the above conditions, the SNC Better Breeders Scheme makes Health Testing of both parents mandatory!
In the UK (there are comparable schemes in other countries although the scoring results are expressed in a different way), Hip Scoring, to identify whether Newfoundlands have Hip Dysplasia and the degree to which they are affected, is carried out by the British Veterinary Association (BVA). The same scheme is used by all pedigree breed dogs. The dog is x-rayed by the vet at a minimum of 12 months old (when the hip joint is fully formed). The dog’s microchip number is recorded on the x-ray to ensure there is no confusion regarding which dog is being scored. The x-rays are then sent to the BVA where they are assessed by a specialist panel of vets who look at a number of components of the hip and reach a score for each hip socket and a total score (a combination of both hips). The maximum score for each hip is 53, making the maximum total score 106. The lower the score the better, the higher the score the more severely the dog is affected with hip dysplasia.
A Newfoundland who had a hip score expressed as 0/0, total 0 (meaning each hip had been scored as 0) has no Hip Dysplasia, a Newfoundland who has a hip score of 53/53, total 106 (meaning each hip has scored 53) has the most severe Hip Dysplasia possible.
Hip scores are not necessarily even on both sides, for example a Newfoundland may score 6/11, total 17 (meaning one hip scored at 6 and the other hip scored at 11). Or a Newfoundland may even have a score such as 6/31, total 37 (meaning one hip scored at 6 and the other scored at 31). This is unusual but would be interpreted as the dog having one good hip and one not so good hip. Interpreting the very high scores and very low scores is easy, it is the middle scores that are more complex! The BVA produces an 'median' hip score for each breed on a regular basis. Currently the median score for Newfoundands is 11 and breeders should be aiming to breed to reduce the incidence of Hip Dysplasia in their puppies. (Note the BVA provides information regarding the median Hip Score and a rolling average over a 5 year period).
SNC Better Breeders Scheme does not currently specify the maximum score that can be used for breeding, however the BVA web site provides information regarding interpreting results including results from dogs scored abroad - there is a link to that web site on this page.
Both parents must be hip scored and the lower the hip score the better.
Hip Scoring reduces the risk of your puppy having Hip Dysplasia but does not guarantee it!
In the UK (there are comparable schemes in other countries although the scoring results are expressed in a different way), Elbow Scoring, to identify whether Newfoundlands have Elbow Dysplasia and the degree to which they are affected, is carried out by the British Veterinary Association (BVA). The same scheme is used by all pedigree breed dogs.
The dog is x-rayed by the vet at a minimum of 12 months old (when the elbow joint is fully formed). The dog's microchip number is recorded on the x-ray to ensure there is no confusion regarding which dog is being scored. The x-rays are then sent to the BVA where they are assessed by a specialist panel of vets who look at a number of components.
Each elbow is then scored and a final score is given. Each elbow is scored as either 0 (0 is the best score and means there is no Elbow Dysplasia), 1, 2 or 3. 3 is the worst possible score and means the dog is severely affected. Unlike Hip Scoring, the two elbow scores are not combined. Only the worst score on either side counts towards the final score. For example a Newfoundland who scored 1 on the left side and 3 on the right side would have a final score of 3. A Newfoundland who had a score of 3 in both elbows would also have a final score of 3. A Newfoundland who had an elbow score expressed as 0/0, total 0 (meaning each elbow had been scored as 0) has no Elbow Dysplasia.
Elbow scoring has not been used to assess Elbows for as long as Hip Scoring, therefore although both parents of the puppy must be scored, it is possible that the grandparents have not been scored at all.
A grade is given for each elbow and the overall grade is determined by the higher of the two individual grades. The grades are:
- 0 = Radiographically normal
- 1 = Mild osteoarthritis
- 2 = Moderate osteoarthritis or a primary lesion with no osteoarthritis
- 3 = Severe osteoarthritis or primary lesion with osteoarthritis
The BVA recommends only breeding from dogs with an elbow grade of 0.
Elbow Scoring reduces the risk of your puppy having Elbow Dysplasia but does not guarantee it!
Sub Aortic Stenosis
SAS is a disease of a heart valve. In Newfoundlands, sub-aortic stenosis is characterised by a ring of scar tissue below the aortic valve, this scar tissue obstructs blood flow to the heart. The left ventricle must therefore pump harder to overcome the obstruction and the muscle wall becomes thicker. If the obstruction is very severe, the muscle becomes so thick that the blood vessels which supply it with oxygen cannot keep up with demand. This lack of oxygen in the heart muscle causes an irregular heart rhythm, which may cause fainting or sudden death.
If you have a puppy with severe SAS, more often than not, you will see no signs at all in your puppy. But as time goes by and the puppy's heart muscles thicken, problems in the electrical system of the heart can cause fainting or unexpected sudden death. Sadly some owners do not even know their dog has the disease until it has died.
It is possible that your Vet will identify a heart murmur in an affected puppy. However it is unlikely that they will be able to accurately identify the cause of the murmur without referral to a specialist Veterinary Cardiologist.
SAS is an inherited condition and the risk of you buying a puppy with the disease is reduced if both parents have been Heart Tested.
DCM means that the muscle of the heart is diseased. In dogs with dilated cardiomyopathy, the heart is unable to contract effectively which results in the heart being unable to pump the blood normally through the body. Dogs with dilated cardiomyopathy may not show signs of illness until they are in heart failure. Symptoms can include:
- Difficulty breathing (increased respiratory rate and increased respiratory effort)
- Pale gums
- Fainting episodes
- Lethargy/exercise intolerance
- Lack of appetite
- Weight loss
One of the most common causes of dilated cardiomyopathy is a genetic mutation. The disease may not show up until later in life which is why Heart Testing is so important.
There are other Heart Diseases that affect Newfoundlands and further information can be found on the Newfoundland Breed Club web sites.
Heart testing Newfoundlands in the UK commenced approximately 25 years ago. Initially screening was carried out by means of auscultation (A Veterinary Cardiologist listening to a dogs heart with a stethoscope) and grading any murmur they heard according to its severity. It was soon recognised that to effectively reduce the risk of puppies inheriting heart disease that Heart Testing needed to be performed by means of a Colour Flow Echo Doppler, commonly referred to as Dopplering.
Newfoundlands are taken to a specialist veterinary surgeon who has achieved advanced qualifications in Cardiology. The dog needs to be at least 12 months old before it can be tested for the purpose of obtaining a test that is valid for breeding purposes. The Cardiologist shaves a small amount of hair in 2 or 3 places on the dog’s chest and abdomen in order to ensure that the probe makes effective contact with the skin. The cardiologist, whilst the dog is fully conscious and lying on its side on a special table, is then able to view on a screen detailed pictures of the dog's heart. They take measurements such as the rate at which the blood flows through the various parts of the heart. This process take approximately 45 minutes to an hour. The cardiologist will then make an assessment of their findings and issues a Heart Test certificate that states that a dog is either Normal, Abnormal or Equivocal.
A dog that is Normal has no apparent evidence of Heart Disease and can be bred from, however it should be noted that a dog’s heart can change as it gets older. With diseases such as DCM it is possible that a dog that is normal as a youngster may still get the disease when it is much older. Because of this, some breeders will have their dogs tested again at a later date. Dogs that are Normal as youngsters and then develop DCM when they are older may possibly produce puppies that are affected by the disease. However, those puppies will in turn probably be more likely to develop the disease when they are older, whereas a dog who has evidence of DCM as a youngster is more likely to produce puppies who are affected by the disease at a young age. A dog that is tested as Normal will not go on to develop SAS, SAS is present when the dog is only young.
Normal - Newfoundlands that are tested as bring 'Normal' for SAS usually have a blood flow measurement that is 1.7m/sec or less.
Equivocal - A Newfoundland that has a blood flow measurement of over 2.0m/sec is normally classified as Abnormal, but the cardiologist will take in to account in making their assessment a range of factors in reaching their conclusion. Interpreting a dogs heart image and blood flow measurements can be tricky, the blood flow can vary from heartbeat to heartbeat. If there are no other significant abnormalities visible on the images from the echo doppler examination, but the blood flow measurement is higher than that which is classed as normal, then the dog will have a heart test result of Equivocal. In other words they fall into a grey area, they are likely to have a blood flow measurement of between 1.7m/sec and 2.0m/sec. These Newfoundlands can be bred from, but with caution. A responsible breeder would consider mating an Equivocal Dog to a Normal Dog.
Abnormal - A dog that is Abnormal has clear evidence of heart disease and may be abnormal for one type of heart disease or for several. Whatever the reason, these dogs should not be bred from.
More information regarding interpreting Heart Testing is available on the Newfoundland Breed Club's web sites.
Both parents must be heart tested by a Cardiologist with a Diploma in Cardiology using a Colour Flow Echo Doppler as the method of testing.
Non-specialist Vets without the necessary qualifications cannot effectively Heart Test a Newfoundland to assess its genetic risk of producing puppies with heart disease.
Heart testing is complex, however only Normal or Equivocal Newfoundlands should be bred from.
Any puppy you are intending to purchase should have a Vet listen to its heart BEFORE you take it home.
The testing of Newfoundlands for Cystinuria is very easy and can be done at any age, even very young puppies can be tested. A DNA sample is obtained by the owner using a Buccal Swab, a process which involves rubbing a swab (like a cotton bud) on the inside of the dog's cheek. The swab is then sent away to a specialist laboratory for DNA analysis. The laboratory tests the sample and provide written confirmation that the dog is one of the following:
Clear - this Newfoundland does not carry the gene that causes Cystinuria and therefore this dog alone could not be responsible for producing a puppy with Cystinuria.
Carrier - this Newfoundland is a carrier of the gene that causes Cystinuria. It does not suffer from the disease itself and never will. However, if mated to another Cystinuria 'Carrier', it will produce progeny who are in turn 'Carriers' and could produce a puppy that is affected with the disease. Even mated to a dog which is 'Clear', some of the progeny can inherit the gene and will be 'Carriers'.
Affected - this Newfoundland has the disease and should NOT be bred from!
Where an adult Newfoundland is to be bred from and it is known that both its parents are clear from Cystinuria, then that dog itself does not need to be tested as it is impossible for it to carry the gene that causes Cystinuria. These dogs are known as 'Cystinuria Free (or Clear) by Parentage' or 'Hereditary Clear'.
All Newfoundlands must either be tested for Cystinuria or be known to be 'Clear by Parentage' prior to being mated.