Health Conditions in the Pyrenean Mastiff

Did you know? Common conditions that affect giant breeds and have been seen in Pyrenean Mastiffs. Please note some have been seen more commonly than others but these are just some notable conditions.

Hip Dysplasia

Hip Dysplasia is a complicated condition, when we tested breeding dogs we test for phenotype of the hips (what we can visually see). However, hip dysplasia is polygenetic and we currently have no means to test genetically for it. When breeders test for hips they are utilizing the phenotype to try and improve the gene pool or hope that the phenotype breeds true, once you have multiple generations with good hips you start raising the chances of good hips in future generations. However only ever breeding good hips in a rare breed such as the PM would limit the gene pool drastically so some breeders aim to "breed up" in hopes of improving offspring. This is when they may breed a Mild dog to a Good or Excellent dog for example. Most dogs with mild hip dysplasia do not have symptoms and even some moderate dogs do not exhibit symptoms until old age when arthritis kicks in. Hip dysplasia also has environmental factors that come into play such as being overweight while growing, high impact activities before growth plates close and more. Here is a great article about hip dysplasia: https://www.pyreneanmastiffassociation.org/post/hip-dysplasia

Club Requirement: OFA Hips – a hip radiograph to rule out conditions which can occur in any giant breed that is performed at 2 years of age or older.

We use to allow OFA preliminary xrays and breeding between 18 months and 2 years old. The reason we allowed this previously was because of studies that indicated if a female was bred during this period it was more ideal for larger litter sizes. However, we have seen no indication of this being true in the last few years and have decided to eliminate this from our guidance and set the minimum age for breeding to be 2 years old with OFA hip certification. OFA Preliminary xrays are no longer valid for breeding purposes.

Lets break down our Code of Ethics regarding hips!

Hips must be graded by OFA at no earlier than 2 years of age for hip dysplasia. The results must be publicly displayed in the OFA database. The results of these x-rays shall be made known to the owner of stud and owner of the bitch prior to breeding. It should also be made known to all buyers of pups. If the animal is not free of dysplasia, the implications of that fact shall be made clear to all buyers. Members must be aware that it is inadvisable and genetically risky to breed an animal which is not totally free of hip dysplasia.

*You can find publicly displayed results here via the OFA advanced search option and search by breed (see photo of what OFA public results look like): https://ofa.org/advanced-search/

*You may also find public results via our pedigree database by searching a dog. Most US dogs with public results in OFA will also have a link to their OFA profile in the database (See Picture of pedigree database section of profile): https://pyreneanmastiff.pedigreedatabaseonline.com/

Dogs with Severe hips must not be bred or dogs with Moderate hips born after 1/1/2022 must not be bred and will be a violation of this guidance. If a dog has Moderate, Mild or Borderline hips, it must only be bred to a dog free of dysplasia (Fair, Good, Excellent).

* In a rare breed we cannot unfortunately limit breeding to only Fair, Good, Excellent as it can bottle neck our gene pool pulling many dogs from breeding. In an effort to gradually improve hips we have set a timeline of when Moderate hips can no longer be bred and limit failing scores of breeding dogs to Mild. What is Mild? Mild hips are hips that may have subluxation or not the most ideal coverage of the femoral head but they do not have any indications of degeneration. Moderate hips will have degenerative changes and subluxation and severe hips will have extensive degeneration and subluxation. You can read more about Hip Dysplasia here: https://ofa.org/diseases/hip-dysplasia/

*If a breeder says they have done OFA hips and their results are NOT public it means three possible things, hip scores were failing (mild, moderate, severe), they were preliminary xrays or they were not submitted to OFA for scoring. OFA will not publicly post preliminary xrays of a dog prior to 1 year of age and will only release prelims done after 1 year of age or failing scores if a specific field is marked on the submission form indicating this can be public or the breeder contacts OFA requesting they be public.

Hips are a particularly difficult health test because there are also environmental factors that can impact hips. Hips for breeding dogs are evaluated via phenotype (what we can actively see). There are to many genetic markers that are not yet discovered to identify predisposition for hip dysplasia. While breeding two Excellent rated dogs could still produce a puppy with hip dysplasia the probability is much lower than breeding two dogs with hip dysplasia. We have included a statistics chart from OFA with data gathered showing the percentage of offspring with Hip Dysplasia pending the parent's ratings. This is incredibly important to understand.

Now lets get to some statistics!

These stats are based on the primary countries with the most puppies produced.

Finland (over the last 10 years):

A/Good/Excellent - 89 dogs

B/Fair - 64 dogs

C/Mild - 77 dogs

D/Moderate - 39 dogs

E/Severe - 22 dogs

Spain:

A/Good/Excellent - 31 dogs

B/Fair - 21 dogs

C/Mild - 15 dogs

D/Moderate - 13 dogs

E/Severe - 2 dogs

United States/Canada:

A/Excellent - 10 dogs

A/Good- 31 dogs

B/Fair - 13 dogs

C/Mild - 8 dogs

D/Moderate - 12 dogs

E/Severe - 7 dogs

See last photo for percentages of dogs tested. For ease the OFA scores were grouped in the chart for Good/Excellent and FCI ratings were used in the chart for comparison purposes.

When it comes to giant breeds hips and joints are essential even more so because our breed is a working breed. It is important for breeders to know what they are breeding to aim to stack the deck in favor of improving offspring's chances for healthy hips. While not fool proof it is essential and since efforts have been made to actively improve hips you can see over 50% of Pyrenean Mastiffs xrayed and scored have passing hips. However, it would be wonderful to see this percentage even higher and we can only do so by practicing ethical and responsible breeding.

Elbow Dysplasia

Elbow dysplasia is very similar to hip dysplasia but affects the elbows. There are several things that can happen to elbows that are classed as dysplasia. Here is a great article on the topic. https://www.akc.org/expert-advice/health/elbow-dysplasia-dogs/

Club Requirement - OFA Elbows – an elbow radiograph at 2 years of age or older to rule out conditions which can occur in any giant breed.

Like hips we use to allow OFA preliminary xrays and breeding between 18 months and 2 years old. This is no longer the case and PMAA has set the minimum age of breeding to be 2 years of age with OFA hip and elbow certification.

Lets break down our Code of Ethics regarding elbows!

Elbows must be graded by OFA at no earlier than 2 years of age for elbow dysplasia. The results must be publicly displayed in the OFA database.

*You can find publicly displayed results here via the OFA advanced search option and search by breed (see photo of what OFA public results look like): https://ofa.org/advanced-search/

Dogs who are Grade 2 or Grade 3 elbows may not be bred. If a dog has Grade 1, they can only be bred to normal elbows.

In a rare breed we have to consider a small breeding pool of dogs and try to give some wiggle room for breeding purposes. Luckily elbows are one our breed is doing overall really well with an average of over 90% of dogs having normal elbows. See the chart attached for the stats in the 3 main countries with the highest number of puppies born on average. Elbows are like hips where we can only evaluate phenotype (what we can see). There are to many genetic markers that are not yet discovered to identify predisposition to elbow dysplasia. Environment can also be a factor and this is why impact activities while young are important to avoid. You can read more about elbow dysplasia: https://ofa.org/diseases/elbow-dysplasia/

With the numbers and what they are currently it is important that we keep working to manage and improve. Elbows overall in the population are looking great based on what is reported and continued best practices in breeding will help us maintain such a great rate of normal elbows. It is important to note though that some elbow issues go unreported.

Heart Disease

Heart Disease is something giant breeds can be prone to so it is important to maintain regular checkups for your dog. Here are some good links on the topic: https://weu-az-web-cdnep.azureedge.net/mediacontainer/medialibraries/yorkshirevets/documents/heart-disease-in-large-dogs.pdf

https://www.eastvalleyanimal.com/causes-risk-factors-heart-disease-in-dogs/

This next topic of health is something that has caused a bit of controversy or misinformation in the US since it was announced so let's break it down.

Next we are going to discuss Heart Testing and why PMAA opted to add OFA hearts to our health testing requirements.

The requirement: OFA Heart – auscultation (Basic Cardiac) by a General Practitioner or by a Board-Certified Veterinary Cardiologist at 2 years of age or older to rule out conditions which can affect the heart. Results must be submitted to OFA, this cost is $15 per dog or $10 each dog if 5 or more dogs results are submitted together.

Abnormal results should be followed up by an Echocardiogram.

The Finnish Kennel club has records showing 46 dogs born between 1990-2025 dying of heart disease with the average age of death being 6 years and 10 months. This is 6.25% of reported deaths during this time period.

From the same data set 23 of those dogs were born in the last 15 years with the average age of death being 5 years and 10 months which is 6.61% of reported deaths in FKC.

This is just the reported cause of deaths, many causes of deaths go unreported so this number may be much higher.

From OFA we have 24 dogs who have had Basic Cardiac testing either by General Practitioner or Cardiologist.

1 of those dogs had an abnormal Basic Cardiac and was followed up with Advanced Cardiac (Echocardiogram) by a Cardiologist who deemed the heart normal.

There have been known cases of heart disease related deaths in North America but we do not have detailed record data on this as of now, we hope this improves as people realize the importance of reporting this data.

Based on the data that we know of from the FKC database we do see some inheritance as we have seen sibling cases of heart disease related deaths and or aunt/uncle niece/nephew correlations.

From an owner submitted study held by the Finnish Kennel Club for the Pyrenean Mastiff we also saw a case out of Spain where a father died of Heart disease and so did 2 of his offspring.

This plus knowing that Giant and Large breed dogs are more predisposed to heart disease compared to smaller breeds with things such as Dilated cardiomyopathy it was decided to attempt to stay ahead of heart disease in the Pyrenean Mastiff.

PMAA has a similar reporting method that is open year round and not for a limited time, we do encourage owners and breeders to report health conditions and cause of death to help further data collection.

https://www.pyreneanmastiffassociation.org/pyreneanmastif...

The Finnish Kennel Club has set Echocardiograms to recommended for breeding dogs based on data that has been gathered.

CMPE does not have a rule specific to cardiac testing but if breeders do an additional health test (which can be cardiac, DNA, etc) on the parents of their litters the litters are rated with 1 additional point. (CMPE rates litters on a point scale based on health tests and show results of the parents with a 10 point maximum). CMPE did have a seminar regarding heart health as one of the topics and it was decided from their perspective not to require heart testing at this time.

Upon speaking to several key people in the Pyrenean Mastiff community from around the world we were encouraged to continue with heart testing, we know some breeders in North America may not like that it is a requirement. Our Health Discussion Group Club Members did revisit the topic after comments were submitted to the Board of Directors regarding heart testing and it was still deemed an essential item especially since we opted to go with the most affordable heart testing as the mandatory test.

PMAA has opted to go with a phase plan starting with the most cost-efficient minimum requirements that also allow easy accessibility by breeders. Breeders are more than welcome and even encouraged if they choose to only use a Cardiologist for evaluations or to perform Advanced Cardiac (Echocardiograms) for their heart testing requirement if they feel like doing so as long as at least Basic Cardiac is done after the age of 2.

To learn more about OFA Cardiac Testing: https://ofa.org/diseases/cardiac-disease/

Here is a list of Hierarchy to Cardiac testing in North America and PMAA's stance on each:

Basic Cardiac by General Practitioner - Required

Basic Cardiac by Cardiologist - Alternative/Encouraged

Advanced Cardiac by Cardiologist - Optional

Yearly Heart Testing (not required) - Encouraged

Degenerative Myleopathy and Genetic Testing

Next and last required health test for the Pyrenean Mastiff per PMAA.

Genetic testing and submission of results to OFA to rule out risk of Degenerative Myleopathy which can affect the spinal cord.

Degenerative Myelopathy is a condition that affects the spinal cord in middle age to older dogs. It is a autosomal recessive, if a dog has 2 copies of the gene it makes them at risk for DM. The Great Pyrenees is known to have this and as we already know the PM is a distant relative. When we began doing genetic testing in the United States we started seeing dogs popping up as carriers (not affected). To prevent producing puppies who are at risk most breeders in the US decided to begin genetic testing parents to ensure they do not raise the chances of producing at risk puppies.

https://cgd.missouri.edu/?page_id=326

https://embarkvet.com/resources/dog-breeders/is-your-dog-at-risk-for-dm-what-the-latest-genetic-research-can-tell-you-2/

Genetic testing must be done prior to breeding. The primary item for testing is Degenerative Myleopathy (DM) and the requirement is to submit the result to OFA. The available genetic tests for the Pyrenean Mastiff may change as more data is collected but the rule of thumb for any genetic test that applies is as follows: Dogs who are carriers or at risk/affected must only be bred to dogs who are clear to avoid producing at risk/affected dogs.

Please note there may be new tests that once data is reviewed do not apply to the Pyrenean Mastiff in which case the club will make an announcement about this, such as our PSA recently about Copper Toxicosis.

For many years Embark was the required testing company for the Pyrenean Mastiff, PMAA opted to remove this requirement allowing other testing companies because Embark stopped updating test results of past tested dogs when new tests became available. They began charging $99 for a rerun of dog who was already tested. To help make things more affordable for breeders it was opted to allow other testing companies and to specify which genetic test item was most important. While it is encouraged for breeders to do broad panel testing like Embark it is not a requirement. Because some companies do not have public results it was decided to have breeders submit their DM test results to OFA to ensure public results of DM testing.

Dogs with DM carrier status have been identified with certain lines and pedigrees within the Pyrenean Mastiff. Reputable breeders will work to gradually remove DM carriers from their lines but to do so it is essential to know if a dog is a carrier or has two markers and is considered at risk. Luckily DM is not wide spread in the population which is why it is imperative to test to prevent it from spreading unknowingly.

You can read more about Degenerative Myleopathy here: https://www.vet.cornell.edu/.../degenerative-myelopathy

Persistent Pupillary Membrane - Iris to Iris and most common form of PPM found in the Pyrenean Mastiff, does not affect vision

Persistent Pupillary Membrane - Iris to Iris , a little more dramatic effect, the strands of membrane can cross over the pupil and vary from one strand to many. May or may not affect vision

Persistent Pupillary Membrane - Iris to Cornea, this does affect vision

Entropian eye lids, eyelid top or bottom roll inward.

A dog with Ectropian eyelid that required surgery to correct due to impact of vision.

Eye Conditions

Now that we have covered the primary items of health testing as recommended by PMAA we will move on to other health things that can impact the breed.

Next up we have Eye Conditions that have been found in the breed.

PMAA Encourages breeders to complete the OFA Companion Animal Eye Registry but does NOT require this. Many of the eye conditions that affect the Pyrenean Mastiff do not impact vision but there are some eye conditions that can or causes unknown that may affect vision. This is why PMAA is encouraging eye testing for further data gathering on eye conditions that may affect the breed.

OFA recommends yearly eye exams but at this time it is not a request of PMAA and is a breeder option if they choose to do yearly eye exams.

To learn more about CAER Eye Exams and diseases of the eyes: https://ofa.org/diseases/eye-disease/

From our AKC Health Statement

Additionally, the PMAA encourages breeders to conduct the following optional tests prior to breeding to ensure that offspring are unaffected by these conditions:

• OFA Companion Animal Eye Registry after 1 year of age to gather information related to eye conditions that may be affecting the breed.

From the PMAA Code of Ethics:

It is recommended but not required to do the OFA Companion Animal Eye registry to gather information related to eye conditions that may be affecting the breed.

Now moving on to eye conditions!

Persistent Pupillary Membrane.

Persistent pupillary membrane (PPM) is an eye condition that occurs when strands of tissue remain in the eye after birth. PPM can affect vision, but in many cases it doesn't cause problems. PPM is an inherited conditions and puppies from parents with it are likely to also have it.

The pupilary membrane is a fetal structure which covers the pupil prior to birth. Sometimes all or part of it fails to go away, or “persists.” This can occur in one or both eyes. The PPM is made up of iris tissue but sometimes parts of it will attach to the cornea, the clear covering over the front of the eye, or the lens. Most dogs with PPM have functional vision but occasionally there will be moderate to severe vision loss in the affected eye, particularly with corneal or lens attachment.

When PPM is iris to iris (what we have found in PMs) it does not impact vision and you may see the strand like structures or almost a starburst like effect over the iris portion of the eye, sometimes it may cross over the pupil connecting the iris to the other side of the iris.

This becomes a problem when PPM is Iris to cornea or iris to lens, when this happens vision is impacted.

A great write up by the Australian Shepherd Health & Genetics Institute on PPM.

https://www.ashgi.org/eyes-ppm

Like the Australian Shepherd the condition appears to be fairly common in the Pyrenean Mastiff though severe forms have not been noted as of now.

Entropian

Entropion is a condition where the eyelid rolls inward, causing the eyelashes and hairs to rub against the cornea (the clear outer layer of the eye). This can lead to irritation, pain, inflammation, and even vision loss if left untreated. This often needs corrective surgery for the comfort of the dog.

With Entropian often times when you do the OFA eye exam with the ophthalmologist if it is minor they will note it and OFA will clear eyes as Normal. More severe forms will be noted in OFA with a "Breeder Option" Code. Meaning it is up to the breeder to decide if it is breed-able in some breeds it is deemed a complete fail.

Ectropian

"Ectropion eyelid" in a dog refers to a condition where the lower eyelid rolls outward, causing a droopy appearance and exposing the delicate inner lining of the eye, often leading to irritation and discomfort due to the exposed tissue being prone to dryness and infection. This may not always require surgery to correct.

Ectropian like other conditions thus far is one with varying degrees of impact. Impact can be as simple as seasonal eye gunk from debris and pollen touching the inner lining. Chronic dry eye, repeated eye infections, etc are also a risk. Worst case depending on eye conformation the upper lid can droop so far as to cover the eye at all times due to the excess skin pulling down around the eye, this is generally a conformation issue with the tissue around he eyes in conjunction with Ectropian.

Distichiasis and Trichiasis

Distichiasis and Trichiasis are a common condition in dogs that causes extra eyelashes to grow in the wrong place on the eyelid. This has also been seen in the Pyrenean Mastiff, with OFA this is generally a breeder option item. This can of course also vary with maybe 1 or 2 eyelashes to many eye lashes involved. If it is a severe case it can cause corneal ulcers with the repetitive irritation of the eyelashes against the cornea.

Next up some random odd balls cases that have been reported:

We have seen 1 case of Lens Luxation though it is suspected trauma induced versus genetic inheritance because there are several eye test results in the lineage.

1 case of Punctate and Capsular Cataracts that is not suspected to be inherited but being monitored.

1 case of half siblings (2 dogs) having developing blindness, 1 presenting at 5 years old and one identified at 1 year of age.

Spine Conditions

There have been various spinal issues that have been reported but we do not have a lot of consistency of data as this is primarily only reported in Finland by some breeders who do spine radiographs. We have seen inheritance and distribution of these conditions with relatives.

Spine OFAs can be expensive especially and giant breed dogs as it requires more xray views. PMAA has taken the stance of making this a recommended test but not required.

Many of these are mild in the Pyrenean Mastiff and some dogs who have lower grades of it such as grade 1 do not show symptoms. We are not often seeing grades 2 or 3 but we do not have enough data to make a good assessment.

From our AKC Health Statement:

Additionally, the PMAA encourages breeders to conduct the following optional tests prior to breeding to ensure that offspring are unaffected by these conditions:

• OFA Spine radiographs at 2 years of age or older are optional to better understand potential conditions affecting the spine in the breed.

From the PMAA Code of Ethics:

It is recommended but not required to do Spine OFAs at no earlier than 2 years of age, if a dog has any spine conditions noted even if from incidental findings on hip radiographs they should only be bred to dogs who do not have the same conditions.

Conditions:

Spondylosis - Spondylosis is a degenerative condition of the spine that affects dogs. It is characterized by the formation of bone spurs (osteophytes) on the vertebrae, which can lead to pain, stiffness, and reduced mobility.

Lumbarsacral Transitional Vertebra - Lumbosacral transitional vertebrae (LTV) is a spinal abnormality in dogs that occurs when a vertebra in the lower spine is malformed. It's a common congenital, hereditary condition in many dog breeds, especially German Shepherds and Greater Swiss Mountain dogs.

Vertebral Anomalies

Vertebral anomalies in dogs are birth defects that affect the spine. They can be caused by genetic factors or disturbances during embryonic development.

Types of vertebral anomalies

Atlantoaxial subluxation: A congenital disorder that's common in young toy and miniature breeds
Block vertebra: Two or more vertebrae are fused together
Hemivertebra: Part of the vertebral body is missing, resulting in a triangular, wedge, or butterfly shape
Transitional vertebra: Has the characteristics of two types of vertebra, such as short ribs at the first lumbar vertebra

Butterfly vertebra: A congenital anomaly that originates in the embryonic period

Other Miscellaneous Health Conditions

Last of our health series! Other conditions that have been reported in the Pyrenean Mastiff. There is no known preemptive testing for these conditions as of now other than whether a dog has it or not. In the case of these conditions reporting is super important so we can develop a better understanding of inheritance.

There are other conditions which may affect the breed such as:

Addison’s Disease
Autoimmune Conditions
Allergies
Epilepsy
Cancers such as Osteosarcoma though not limited to Osteosarcoma
Gastric Dilatation and Volvulus (GDV)
Subluxation or hock instability
Idiopathic trembling of rear legs (testing of dogs with this has not identified any condition as of yet)