Health Testing

Health Testing

All canines are susceptible to carry genetic disease traits and passing them onto their offspring with results varying from fatal to minimal.  Many years ago, there was no proactive way to test dogs for various disease traits prior to breeding them.  Scientists have worked tirelessly to isolate and identify specific genes that cause various diseases and created methods to test for the genes.  There are numerous reasons for dogs to have genetic testing prior to being considered as breeding stock.  According to a 2016 APPA study (http://fortune.com/2016/08/26/pet-industry/ ), people have spent over $38 billion on food and veterinary care in only one year.  These increased feeding and healthcare costs as well as the broken hearts that families experience due to results of untested breeding pairs are two of the many reasons that genetic testing is required to be a member of the Guild.  There are several companies that offer genetic testing, and many have Labrador Retriever specific panels.

Labrador Retrievers are known to carry 7 main diseases.  To be a member of the Guild, one must pledge to test their stock for at least the 7 main diseases as well as perform certifications for hip dysplasia (through OFA or PennHip) and elbow dysplasia (OFA).  There are other recommended tests such as CERF, which tests the heritable eye disease, and a cardiac evaluation.  To do improvements with testing doesn’t mean only breeding dogs clear of all genetic diseases, but breeding dogs in light of their health and the genetic diseases they carry to avoid producing affected puppies in conjunction a long-term goal to eliminate as many diseases as possible.  This is one of the main reasons for the Guild; to help educate potential breeders not only on the importance of genetic testing, but the ramifications of it as well.  One may think that only dogs that are clear of all heritable diseases should be bred.  In doing that, a sizable portion of the gene pool would be eliminated, and positive character traits could be lost indefinitely.  Being a carrier of a specific disease in and of itself should not necessarily be a disqualifier as breeding stock.  However, through proper mentoring and education, the whole picture of the dog (the benefits and drawbacks) can be assessed to determine whether or not the dog should be used in a breeding program.

First, these recommendations are not all-inclusive or exhaustive and are meant as a general guideline.  Second, most of the gene abnormalities that will be described requires two copies of the abnormal gene to produce an affected offspring.  It is of the utmost importance to learn which genes are dominant and only require one copy to produce an affected, or symptomatic, puppy  and will aid in understanding the consequences of breeding carriers, clear, and affected dogs.

• Hip dysplasia (HD) – Screening by the Orthopedic Foundation for Animals (OFA), PennHIP or Ontario Veterinary College (OVC) is recommended for all Labrador Retrievers used for breeding.  There is still more research being conducted to determine the weight that environment versus genetics bears on the formation of hips.  Since genetics has been shown to be a component of the hip condition of offspring, the importance of this test should not be overlooked.  Preliminary testing can be accomplished with OFA as early as 4 months old, however finalized certifications must be submitted after the dog is 2 years old.

Expense for this test – Fees for x-rays vary, however they are approximately $150-400 for x-rays plus fee to send to OFA.

• Elbow Dysplasia (ED) – a general term that is used to describe a developmental degenerative disease of the elbow joint. There are in fact three different etiologies that can create a diagnosis of ED.  Therefore, elbow dysplasia screening by OFA is recommended for all Labrador Retrievers used for breeding.

Expense for this test – Like hip dysplasia x-rays, the price varies.  One can expect an approximate cost $150-400 for x-rays plus fee to send to OFA

• Progressive Retinal Atrophy (PRA) – refers to retinal diseases that cause blindness. Some breeds have blindness by abnormal development of the retina and this is called dysplasia. Other breeds have a slowly progressive degeneration or death of the retinal tissue and this is degeneration. It is a long recognized, hereditary, blinding disorder. It is inherited as a simple autosomal recessive in most breeds.

• Centronuclear Myopathy (CNM) – More and more veterinarians are encountering Labrador Retrievers, especially field bred Labradors, with an inherited health condition that weakens the muscles, making it difficult for a dog to walk. CNM, or hereditary myopathy, begins in puppies and climaxes at about 1 year old. This disease is similar to Muscular Dystrophy in human children, however it is 100% preventable in dogs with proper health testing and should be accomplished prior to being bred.

• Copper Toxicosis – Copper Toxicosis is an inherited dominant metabolic disease which could cause chronic liver failure.  An important aspect of this disease is that since it is dominant, it only takes one copy of the abnormal gene to cause a dog, or its offspring, to be affected.
• Degenerative Myelopathy (DM) – DM is an inherited neurological disorder which typically presents in adult Labradors (approximately 9 years old).  This disease has been compared to Lou Gehrig’s Disease with its symptoms and usually progresses until the dog is unable to walk.
• Exercise Intolerance and Collapse (EIC) – EIC is an inherited neuromuscular disorder which causes an apparently healthy dog to exhibit symptoms such as wobbly hind legs, full body weakness, confusion, and even in some cases, death.  Dogs are typically diagnosed prior to two years but with proper health testing, EIC affected abnormalities can be completely eradicated.

• Hereditary Nasal Parakeratosis (HNPK) – HNPK is a hereditary condition that causes a dog’s nose to become rough, dry, crusty, and crack.  This disease can be painful and is easy to treat, but it also avoidable with proper testing.
• Retinal dysplasia/oculoskeletal dysplasia (RD/OSD) – Is a dominant disease that requires only one copy of the gene for dogs to be affected, or symptomatic, as well as produce affected, or symptomatic puppies.  A dog, or offspring, with only one copy of the gene may experience mild eye abnormalities such as retinal folds which could cause the dog to fail a CERF evaluation.  While two copies of the gene causes dwarfism and eye abnormalities, since only one copy may cause symptoms, it is extremely important to test any dog that may possibly be used for breeding purposes.

• Skeletal Dysplasia 2 (SD2) – SD2 is a musculoskeletal disease which may cause dwarfism when present in a dog with two copies of the genes.

Other Recommended Testing

• The CERF Exam – A CERF test is a distinctive eye screening exam that is carried out by board certified by the American College of Veterinary Ophthalmologists (AVCO).  These are recommended from age 1 to at least age 9 for all breeding stock.

• Auscultation – A Cardiologist Veterinarian listens to the heart to detect abnormalities such as cardiac arrhythmias, heart murmurs, and extra heart sounds.  Abnormalities could be an indication of early heart diseases.  they also listen to the lungs to discover if there are normal or abnormal, such as wheezing or crackling, lung sounds.
• Echocardiogram – Echocardiography is an ultrasonic examination of the heart used to investigate a potential congenital or acquired heart disease. The Cardiologist Veterinarian must be able to perform two-dimensional, pulsed-wave Doppler, and continuous wave Doppler examinations of the heart.

Expense for this test – Approx. $100-$500 plus the fee to send to OFA

How to know if genetic testing has been accomplished before breeding ?

Ask what genetic tests/clearances have been done on the sire and dam of a litter of puppies then ask to see proof of any testing the breeder has claimed to have done.   Ask to see the OFA certificates or OVC documents to prove the dogs have been x-rayed free of Hip Dysplasia AND Elbow Dysplasia. Most breeders will have an OFA certificate for their cardiac clearances too. For eye testing, the breeder should have either an OFA certificate or a copy of their ACVO eye exam findings.

If any breeder cannot provide you with PROOF that these genetic tests have been done, buy at your own risk! Some breeders claim that their dogs have never had health issues and neither have the pups they’ve produced but as previously stated, some diseases may take as many as 9 years or more to show symptoms.  As with all genetic discussions, it must be understood that nothing is guaranteed.  As equally important to understand is results of testing are only as good as those collecting the specimens and the methods of running the tests.  If an individual makes a mistake, such as mixing up swabs, then the results the laboratories produce will not be accurate.  Also, if a laboratory only runs the tests one time, instead of in duplicate, then there is a chance that a false result can be justifiably produced.  When choosing where to accomplish genetic testing, or what laboratories to accept testing from when purchasing a puppy, it is important to learn how each laboratory runs their tests and reports their results.

At this time, there are two companies that are known to test in duplicate and have breed specific testing; PawPrint Genetics and Embark.  The following links may be used to be linked directly to their respective websites and panels:

https://www.pawprintgenetics.com/products/breeds/76/

http://try.embarkvet.com/breeders/