Because each purebred dog, no matter what his size or shape, shares over 99% of his genome with all other domestic dogs, it should come as no surprise that different breeds share many of the same diseases and genetic problems.
In fact, scientists now agree that the dog, who also shares over 94% of his genes (and over 400 diseases) with man, actually provides a "super-model" for human disease research. (Luckily, most of this research now involves no more than painlessly collecting DNA from saliva. )
These "research dogs" dogs who are contributing so much to the future eradication of human disease, it should be noted, are invariably purebred "show" dogs belonging to responsible breeders.
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This genetic similarity means that much of the health screening responsible breeders do prior to breeding is for diseases and conditions common to many breeds, and there are tests for many of them which can tell a breeder if the dog is affected, or in some cases a "carrier" of a specific disorder.
Where genetic tests are not yet available, "phenotypic" screening use specific veterinary protocols to determine if an individual dog is clear of (or affected with) a particular disease.
In general, ethics and good animal husbandry practice dictate that affected dogs not be used for breeding. There are exceptions to this rule, however.
When a problem is so prevalent in a particular breed by the time it is discovered that removal of all affected animals would significantly reduce genetic diversity (which can lead to other problems) a different choice must be made.
In this situation, responsible breeders may undertake a program of testing ALL breeding animals for the problem, only breeding affected animals to unaffected ones, and then testing and selecting the unaffected offspring for breeding in the next generation. When a problem is both widespread and where genetic testing is impossible, this is the ONLY responsible course of action, and it will eventually result in overall improvement within a breed.
As they become available, genetic tests (where DNA collected from a simple cheek swab can reveal whether or not a dog is carrying copies of the causative gene for a specific disease) are used by responsible breeders prior to breeding. Some breeds' CHIC requirements include gene tests for breed-specific genetic disorders.
When gene tests are available, breeders screen breeding dogs and can avoid producing affected pups altogether.
Quality "affected" or "carrier" dogs may be bred to non-carriers, and no affected pups will result. By subsequently gene-testing the resulting pups and placing the majority of carriers in non-breeding homes, problems can be quickly eliminated from a breed without sacrificing overall quality or health.
These "carrier" pups, it should be noted, are likely going to be far healthier overall, and a far better choice for the pet owner, than those purchased from breeders who do not bother to test at all .
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Unfortunately, many of these tests, and the acronyms breeders generally use for them,
are a total mystery to the conscientious puppy buyer.
This lack of understanding can be disastrous. For example, many commercial and backyard breeders advertise that their dogs have been "health-checked" prior to breeding; this often turns out to mean only that they've had a routine health exam by their vet. The breeder actually has no idea if they suffer from hip or elbow dysplasia, eye disease, or any one of a number of problems that are not revealed by a routine vet exam, much less if they are carrying any deleterious genes!
What the puppy buyer really needs to know is:
Which health tests are important,
what do they involve,
and with whom should they be registered?
Wecome to Health Screening 101.
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Screening for Eye Disorders
("CERF")
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Many breeds (and their resulting hybrids) are prone to heritable disorders of the eye, including cataracts, glaucoma, pigmentary keratitis, retinal dysplasia and various forms of progressive retinal degeneration loosely categorized as"PRA".
Even if one "just wants a pet", these problems can lead to blindness in a dog, and may not be surgically repairable. (PRA is one.) When they ARE repairable (as with some forms of cataracts), surgery can cost thousands of dollars out of the owner's pocket. Glaucoma can lead to loss of the eye itself.
In some breeds, genetic tests are available and responsible breeders gene test the parents before breeding so no affected puppies will be produced. Where gene tests are not yet available, nearly all heritable eye disorders can be screened for during a CERF exam, so that a breeder will know if a dog is affected with a heritable eye disorder BEFORE it produces puppies.
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An inexpensive and painless examination of the eyes performed by a diplomate of the American College of Veterinary Ophthalmologists, a CERF exam can detect ocular problems long before they are obvious.
After the exam, the ophtho provides a form that must be sent by the owner, along with an initial fee of $12, to the Canine Eye Registry Foundation (CERF) to register the exam; dogs who've passed the exam are certified free of heritable eye disease at that point and are assigned a CERF number.
In breeds where ocular disorders are present at birth, puppies are often examined and the results registered by the breeder prior to sale.
In breeds where eye problems develop later in life, breeding dogs are usually screened annually.
Because CERF does not register failed exams, if a dog does not have a current CERF # on file with CERF or listed on his CHIC certificate, there is no way to tell whether the dog failed an exam or was simply not tested.
A list of ACVO-approved canine ophthalmologists and upcoming CERF Clinics around the country may be obtained by simply clicking HERE. The cost of an exam usually ranges from $30- $60.
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Immediately prior to the CERF exam, each owner fills out the dog's information (including registration # and date of birth) on a CERF exam form provided at the clinic. Once a dog is examined, the ophthomologist provides the owner a signed copy of the exam form. In order to register your dog's "normal" results and obtain a CERF #, you must fill out the back of the form, make a copy for your records, and send the form to CERF with the recording fee. If you do not send it in, your dog's CERF results will NOT show up on the CERF or OFA websites.
Because CERF maintains a reciprocity agreement with OFA, CEF #s on all dogs with matching names and registration numbers are automatically transferred into OFA's database and will show up there as long as the dog has other health-screening registered with OFA.
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Screening for Heart Abnormalitites
("Cardiac Clearances")
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Like disorders of the eye, cardiac abnormalities are common to many breeds, and dogs should be screened prior to breeding. Many breeds' CHIC requirements require cardiac certification to screen for congenital defects; those breeds where heart problems are not congential but occur later in life often require an annual cardiac exam.
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In most cases congenital cardiac abnormalities result in an audible heart murmur, which can be detected through ascultation with a stethscope.
Dogs over the age of one can be certified free of congenital cardiac disease by OFA via ascultation alone if no murmur is detected, although it should be noted that some Parent Clubs require an echocardiogram for a CHIC #.
If a murmur is detected, an echocardiogram with Doppler will be required to ascertain if it is "innocent" or a symptom of a congentital structural defect prior to certification by OFA.
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| An echocardiogram (or ultrasound of the heart) is a painless diagnostic procedure, and, unlike x-rays, no radiation is involved.
Instead, it uses sound waves that penetrate internal organs to create an image. A hand-held probe is rubbed on the skin over the area of the heart, and the image produced is transferred to a computer screen in real time.
An echocardiogram is the most useful test for evaluating a heart murmur in a dog; with it a veterinarian can literally "look inside" the heart chambers and visualize the valves. This test can rule out or confirm a diagnosis of heart disease in the case of an "innocent" murmur, and in other cases determine the severity of the abnormality.
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An application for the OFA Cardiac database may be downloaded by clicking HERE.
The form is filled out online by the owner, printed out, and brought along with the dog to the cardiac exam.
After the exam, the form will be signed and mailed to OFA by the vet. If the dog's exam form reflects normal results, an OFA Cardiac # will be assigned, and a certificate will be mailed to the owner.
Many of the Health Clinics listed on the CERF website offer cardiac exams as well. Typically, an ascultation exam at a a clinic runs around $40, while an echo cardiogram with Doppler is $200-$250.
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Screening for Orthopedic Problems
("OFA")
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Hip Dysplasia, Elbow Dysplasia, and Patellar Luxation
These three orthopedic disorders affect a huge number of breeds and as a result, many Parent Clubs require screening for one or more of them as part of their CHIC requirements.
As all three can result in the need for expensive orthopedic surgery (running into several thousand dollars) to alleviate pain in affected animals, it is prudent for puppy buyers to make sure that even a puppy intended as "just a pet" come from parents (and ideally grandparents) who've been screened prior to breeding, especially in those breeds where the incidence is high.
ALL of these orthopedic disorders, it should be noted, can be screened for by a clinical vet, who then submits the results to OFA for evaluation.
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The best-known is hip dysplasia, which means badly formed hips. Poor conformation of the hip joint can lead to degenerative arthritis, which may require expensive orthopedic surgery to alleviate pain.
A hip x-ray to screen for HD is painless for the dog, and can generally be done by a competent clinical vet for around $100- 150. There is NO WAY to tell if a dog has hip dysplasia without one.
Any owner may download and fill out an application for OFA evaluation HERE ; the vet signs it and sends it to OFA with the xray. Contrary to popular belief, OFA will also evaluate hybrids, which in spite of their "hybrid vigor" are indeed succeptable to HD.
Another misconception is that hip dysplasia is only occurs in large breeds. NOT TRUE. Hip dysplasia is found in breeds of all sizes and shapes.
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How can a puppy buyer figure out the
incidence of hip dysplasia
in a particular breed?
Easy. Simply click HERE to view the OFA statistics on all breeds with more than 100 x-rays submitted to OFA over the years.
If a breed doesn't show up on the list, it doesn't mean there is no hip dysplasia in that breed; it simply means that less than 100 x-rays had been submitted for evaluation by the end of 2009.
These statistics do not include the names of affected dogs; they reflect the numbers of dysplastic dogs diagnosed in the breed by OFA over the years.
Now, when looking at percentages, it often helps to think of them in understandable terms.
- In Bulldogs, for instance, the number of dysplastic dogs is 73.2 pecent- that's pretty close to 3 out of every 4 Bulldogs submitted!
- In a Toy breed like Cavaliers, where over 5,000 dogs have been submitted, the rate is 12.1%, which doesn't sound too bad until you realize that pretty close to 1 out of every 8 Cavaliers submitted was diagnosed with hip dysplasia...unless you're feeling lucky, buying from a breeder who doesn't bother to x-ray hips would be pretty dicey in that breed.
- In breeds like the Coton, where the hip dysplasia rate is "only" 9 % , it's good to remember that 9% is perilously close to 1 out of every 10 Cotons.
- And in a breed like the Irish Wolfhound, where incidence is considered low -- "only" 5.3% of the 1,500 dogs evaluated were diagnosed with hip dysplasia over the years -- the dysplasia rate is really over 1 in of every 20 Wolfhounds. If you happen to buy that 20th puppy (who is most likely to come from a line that has not had generations of screening behind it), the overall incidence in the breed doesn't really doesn't matter, does it?
When a breeder tells you they do not screen for hip dysplasia
because "the incidence in my breed is low",
the only logical response is "No thanks to YOU."
Dogs whose hip x-rays have been certified by OFA will also receive a hip rating of Excellent, Good, or Fair in addition to an OFA number. It is important for the novice to understand that these ratings do not reflect the degree of hip dysplasia, but rather an evaluation of the conformation of a "normal" (i.e. non-dysplastic) hip.
Any dog granted an OFA # has been certified free of hip dysplasia.
Some breeds' CHIC requirements accept evaluations from registries other than OFA, which may have different screening and evaluation protocols.
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| Elbow dysplasia is a term used to describe 3 separate inherited diseases in the elbow, which may occur independently or together.
These are ununited anconeal process (UAP), osteochondrosis (OCD), and fragmented medial coroniod of the ulna (FCP), each of which can lead to painful degenerative joint disease.
Unlike hip dysplasia, certification here requires two radiographs, with the dog placed on both its right and left side so each elbow may be x-rayed separately.
Because the degenerative changes in the joint may be critical to diagnosis, a dog cannot be certified by OFA as "normal" until it is at least two years of age.
A form for submission of elbow x-rays to OFA may be downloaded and filled out by clicking HERE..
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Unlike the first two, screening for patellar luxation does not require a radiograph, but is diagnosed by a simple and painless physical examination while the dog is standing on the exam table.
The patella, or kneecap, is part of the stifle joint (knee). In patellar luxation, the kneecap luxates, or pops out of place, either in a medial or lateral position. Bilateral involvement is most common, but unilateral is not uncommon. Puppies can be affected by the time they are 8 weeks of age, or it may not show up until the dog is mature.
Patellar luxation is considered to be an inherited condition, and occurs in giant breeds (such as Great Danes and Irish Wolfhounds ) as well as the tiniest ones. Severe cases invariably require orthopedic surgery.
Can can download and fill out an application for OFA patellar certification for your vet to sign after examining the dog by clicking HERE.
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Screening for Congenital Deafness
("BAER testing")
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| In spite of its "Frankenstein" appearance, BAER testing is a simple and painless test used to diagnose congential cochlear nerve deafness in puppies as young as 5 weeks.
Because unilaterally deaf puppies seem to hear normally, BAER testing is the ONLY method by which breeders can identify these pups so they may be placed in pet homes rather than inadvertently bred.
Although the mode of inheritance is polygenic, congenital deafness is more common in primarily white and parti-colored dogs, and many breeds of these colors require BAER as part of their CHIC program.
BAER testing runs from $30 per pup and up, with BAER clinics the least expensive. You can download the application for OFA BAER certification by clicking HERE.
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BAER testing results can be registered with OFA by submitting an application which can be downloaded by simply clicking HERE. The application can be filled out online (unless you have a Boston Terrier, only the first page of the application is required), filled out online, printed out and sent to OFA along with a signed copy of the BAER test results and the required recording fee.
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Screening for Thyroid Disease
("Thyroid Panel")
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| Autoimmune thyroiditis is the most common cause of primary hypothyroidism in dogs.
The disease has variable onset, but tends to clinically manifest itself at 2 to 5 years of age.
Dogs may be clinically normal for years, only to become hypothyroid at a later date.Screening for thyroid disease involves a simple blood draw by a clinical vet, which is then sent to one of several OFA-approved labs for evaluation.
The application form for lab submission can be downloaded HERE, filled out online, printed and taken to the vet when the blood is drawn.
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There are many other tests now available for genetic diseases specific to particular breeds. Information on these can be obtained by checking the CHIC requirements for that breed.
In the final analysis, the question is not why breeders who really wish to "breed for improvement"
would choose to screen their breeding stock for the problems in their respective breeds
and register them with the CHIC program, but rather:
WHY ON EARTH WOULDN'T THEY????
And why would any intelligent person even want to buy a puppy from those who
won't invest the time, or money... or simply can't be bothered?
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