What’s the Deal with Health Tests?

Prior to year 2002 there were only 9 Norwich terriers entered in the database of the Orthopedic Foundation for Animals, or OFA as it is more commonly referred to.  As of the day of this writing, the OFA database for health screening grew to include the information about one thousand one hundred and three tests performed on Norwich terriers.  I could not resist spelling out “thousand” tests.  Whenever I feel saddened by news of some irresponsible actions on parts of some breeders I remind myself of this heartwarming statistics.  Norwich terrier breeders do deeply care about the breed.  It is in excellent hands.

With the NNTC joining CHIC database (Canine Health Information Center) we have really seen a great shift in the health testing awareness. CHIC is a joint venture between AKC and OFA that is a goldmine of information for breeders, for puppy buyers, and for the researchers.  As the database grows to include multiple generations of dogs and vertical pedigrees (siblings and half-siblings), breeders have a tool to evaluate genetic risks of their planned breedings.   The buyers have an objective source of information on both the breed statistics telling them what health issues to be prepared for in a given breed, and also on the chances of individual puppies to develop a particular inheritable disease. The probability that a puppy will develop an inherited disease is reduced when its ancestry has been tested normal. Finally, with aggregate information on multiple generations of dogs, CHIC database will also be useful for researchers, especially epidemiological studies.

But why test Norwich for eye problems, luxating patella and hip dysplasia when these are not our main health concerns? Let me explain why. Or better yet, let the facts do the talking.

The OFA and CHIC database is organized based on the birth year of the dogs.  Norwich terriers born between the years 2000 and 2002 and entered into OFA showed 15.7% of hip dysplasia among 121 dogs tested.  Just in the next couple of years that number dropped to 8.2%, based on 97 dogs tested. I know that many breeding decisions were influenced by what we could learn in OFA database. Speaking from personal experience, I was taking into consideration hip rating when one of my bitches tested “fair” and her sibling dysplastic in one hip (never bred). Was it the only consideration? Of course not, but I was glad to have OFA database as a useful tool in finding “excellent” rated stud that also suited my bitch phenotypically.  I know of a number of Norwich terrier breeders that intelligently bred away from the problem, armed with the knowledge that OFA database gave them.

Breeds like Akita, Belgian Malinois, , Bernese Mountain Dog, Brittany, English Setter, Komondor and many others dropped the rate of hip dysplasia by more than half in 20 years. That is an incredible trend, and all attributed to the knowledge that OFA provided. There were thousands of dogs tested in each of these breeds.  Akita showed 61% improvement from dogs born before 1980 as compared to dogs born in 2003-04.  Before you think that the numbers of tested dogs before 1980 were insignificant let me dispel that with the exact number: 2047 Akitas born before 1980 had been evaluated. In Golden Retrievers dysplasia dropped by 30% in 20 years based on over 50,000 (!) dogs evaluated. In Old English Sheepdogs bad hips are reduced by half, and excellent ones doubled based on roughly 6,000 evaluations. To stick to terriers, Kerry Blue doubled the number of excellent evaluations and reduced dysplasia by 67%.

Just the way the breeds with high numbers of tests performed improved their hip rating, those with dropping numbers of tests performed suffered negative consequences.  Bearded Collie is an example.  There were 9% of dysplastic Beardies based on almost 500 dogs born before 1980, then 20 years later dogs born after 2000 had less than 3% hip dysplasia.  Whether the breeders relaxed, and dropped their guard, or whatever else was their reason the numbers of dogs tested fell dramatically, and by 2003 the OFA registrations in Beardies dropped to almost half the previous numbers. The result was statistically astounding. Dysplastic numbers almost doubled in dogs born after 2003 compared to the dogs born before 2000!

Interestingly, the dogs now ranked as the worse are mostly medium and small sized breeds. The fact that hip dysplasia in smaller dogs is less debilitating is a two-edge sword.  The breeders of small dogs tend to be more nonchalant about hip dysplasia and these are the breeds with the trend upward in numbers of dysplastic hip evaluations. 50% of Bassett Hounds in the OFA database are dysplastic, and that breed is experiencing much more debilitating degree of the disease than just a few years ago.  Predictably, there were hardly any tests done on Basset Hounds before 1980. The breed that is currently ranking as the worse among AKC dogs is Bulldog (English) with 74% dysplasia based on 443 evaluations. Our sister breed Norfolk shows 33% of hip dysplasia, roughly one in three dogs!  To those who say that hip dysplasia in a small dog is not that bad, don’t bank on it!

If you go to the OFA database to view the breed statistics you will see that Norwich are rated with 13.1% abnormal results.  But, as I already mentioned, this is an aggregate number of all evaluations ever done.  Our most recent few years show the downward trend that now stands at 8.2% from 15.7% when the numbers of evaluations started to be significant. The 13.1% is a historical average, not the current number. We can be truly proud! A dog that is pain free and has full mobility is a happy dog.

When we test our dogs we might be thinking of our own breeding programs but that is much less important than the influence our aggregate testing does for the breed. Health testing is more than a pedigree mapping tool. It is an ethical obligation we have to the breed.

As we are working fervently to avail tests for the more pressing health problems for our breed let us not forget to use the tools we do have. We hope to have a genetic test for epilepsy one day, and we are working right now on a screening protocol for Upper Airway Syndrome.  Meanwhile, let us not fall victim to false logic that screening for hip dysplasia, luxating patella and inheritable eye diseases is not important.  When I hear people say that screening for hips or eyes will not help their dog with a breathing problem I ask them if they tell their doctor that screening for breast cancer will not help them with their heart problem.  Are you going to advise a friend to stop going for mammograms because they won’t help her heart?

I am very happy to know that the majority of Norwich terrier breeders who are club members understand the value of health screening. My hat is off to you!

Magda Omansky (NTCA Health Chair)

NT health test statistics at a glance: Hips- 413 dogs evaluated (13.1% abnormal results).  Cardiac – 92 dogs evaluated (0% abnormal). Patellae- 222 Norwich in the database (4.5% abnormal). Eyes- 347 dogs evaluated (2% abnormal). 29 dogs tested for other conditions (no statistics).