Update on North American Hip Registries 2002
by Fred Lanting
Reproduced with permission.
This article is slightly more than an update on the hip registries operating in the U.S. (and Canada, to a great extent). I hope to not only bring you the current status of each as we turn the corner into 2003, but also stress again the importance of lobbying for an open registry or at least more sharing of data, to make progress in reducing incidence of HD in segments of breeds (sometimes called strains, but more accurately breeding lines). I have been working in the field of canine orthopedic disorders since 1966, and am convinced that the best course a breeder can take is multi-faceted. If you are not a breeder, you can look for suppliers who:
1. Select and offer the very best dogs (companion, working dog, or foundation stock).
2. Use the most accurate and advanced diagnostic techniques available and economically feasible.
3. Base breeding decisions partly on progeny results; one tool in that category is BV or ZW (Breeding Value or Zuchtwert).
4. Favor open registries; these are those in which the “failures” as well as the dogs with better hips are identified publicly. If no open registries are available, get all the information you can.
We might as well consider these items in the order summarized above. Whether you intend to breed dogs or not, number 1 is very important. You and/or your puppy customers certainly would not purposely select defective dogs, but in effect, not selecting against a problem can be thought of as selecting for it. Think of the analogy in training. If you do not train for correct behavior, you are actually “training” incorrect behavior. Picking a dog to share your life, home, and time could be a ten-year or longer investment. Besides the features of temperament, size, coat, general health, and so many more, you owe it to yourself and the dog to choose an animal that has good odds of having serviceable hips and other joints. Back in dogdom’s dark ages, longevity of ancestors, ability of parents and the individual to work long hours without pain or perform certain utilitarian functions were all that owners could use. In the 1950s and `60s, realization that hip dysplasia could often be detected with radiography, and that it was an identifiable genetic disorder, led to the establishment of many hip detection and registration schemes around the world. In the U.S. (and serving much of Canada’s needs), the Orthopedic Foundation for Animals was established at the U. of PA, with Wayne Riser at the helm. Breeders as of that time had a standardized means of listing the potentially valuable breeding animals that had no evidence of severe or moderate hip dysplasia. This was a definite advance over the performance tests, giving more information on this specific portion of a dog’s phenotype. Dogs that were considered “normal for age and breed” were given a certification number, and as time went on, people could fairly safely assume that a dog without this certification were probably dysplastic. The certificate thus became a valuable commodity. It marked dogs as more valuable than similar dogs without it. Unfortunately, the inertia that came with great numbers of dogs in the OFA registry may have contributed toward an unwillingness to consider technological improvements. After nearly 40 years of service to breeders, this stagnation and protection of the old method had left breeders on a plateau without offering any ladder to the next level of progress. It was time to examine new paradigms.
That much-needed route to the next pinnacle also came out of the U. of PA (called “Penn”). By the early 1990s, research had already established an improved diagnostic or predictive technique that promises great benefits to those who want to produce or buy sounder dogs. As Solomon said, there is nothing truly new under the sun, but there can be advances and better combinations or arrangements of data or genes or methods than what has been seen before. The better method, given the acronym PennHIP® for (University of) Pennsylvania Hip Improvement Program, was not entirely new, but was based on the concept suggested by earlier experiments in puppy palpation, “wedge” radiography, and other positions utilizing stress to push femurs apart and demonstrate joint laxity that was hidden in the older views. It is a more highly refined approach, standardized for accuracy and repeatability, and is more quantitative than the almost entirely subjective OFA or hip-extended approaches. While the older position with the dog’s legs stretched out as if resembling those of a bipedal human lying supine on the table is best for identifying mineralization (“calcium deposits” and arthritis) in the hip joint, it allows too much covert laxity to be a reliable indicator of things to come. Since in many or perhaps most cases a loose hip will develop degenerative joint disease (DJD), it is wise to detect as much laxity as possible and compare it with numerical, measurable standards of excellence and risk. The looser the joint, the higher that risk of the dog’s eventually getting DJD, regardless of breed. Website articles that treat the differences between PennHIP and older methods in more detail include those - http://siriusdog.com/sphider/search.php?query=lanting&search=1
for the fastest way to articles on SiriusDog and http://www.pennhip.org/
is the current location of PennHIP. One of the important advantages of the PennHIP stress-radiography method is that it allows accurate and much earlier prediction of an individual dog’s later hip status; it is a vastly improved estimate of risk for developing DJD. And the scientific data is more than sufficient to be a convincing case for breeders to use PennHIP. As I have said in another place, those who quote old information and say that “School is still out on the PennHIP method” simply have been skipping classes in the past several years.
The use of Breed Value (progeny and sibling results being made part of a dog’s likely genetic picture) has not been practiced much in this country. It is an old, established, and critical feature of dairy cattle breeding, but in the U.S., only two groups are known to utilize its very helpful advantages. One is the breeding program at The Seeing Eye, Inc.®, the famous school for guide dogs for the blind in Morristown NJ. The geneticist there, Dr. Eldin Leighton, uses PennHIP for diagnosis/prediction and BV data on relatives (mostly siblings, ancestors, and progeny) to make great strides in reducing HD incidence far below that possible in any other breeding program. The other is the community of fanciers devoted to the imported German Shepherd Dog. In Germany, the SV (parent breed club for all GSDs worldwide) has adopted a very similar data analysis system called Zuchtwert (breed worthiness). Through a very complicated formula, the numbers and values of acceptable and unacceptable hip ratings of siblings and progeny are calculated. Stud dogs and brood bitches with low ZW numbers are more desirable as breeding partners and the parents of a pup you’d want to buy. The average hip quality of the GSD in Germany is fast-normal, meaning “nearly normal”, and the ZW number of 95 correlates to that status in a statistical way. That is to say, a dog with 95 might not have fast-normal hips itself, but on average, there is a correlation across the breed population. A dog whose hip radiographs are superior will get a lower ZW number than he was born with, which was the average of his parents’ numbers. Furthermore, if he has previous siblings and half-sibs who have been radiographed, their results can also move his number one way or the other. His sire or dam may produce better or worse hips with a different parent, and that will also affect his official number. For the non-statistician, it is enough to look for families and individuals with low numbers, as the higher the number, the more HD that particular dog has produced or is likely to produce. You, as a buyer or breeder, should give preference to dogs with low ZW numbers.
The fourth major tool in a successful fight against proliferation or prevalence of hip dysplasia, or almost any disease for that matter, is specific knowledge. This time, knowledge in the form of open and honest information on the hip status of the dog you are interested in breeding to or getting a pup out of. On this side of the oceans, we recently had one truly open hip registry, the GDC, which stands for Institute for Genetic Disease Control. This organization failed to make the impact it deserved because breeders did not avail themselves of the benefits that would apply if they practiced more participation, more sharing of information. Without sufficient numbers of dogs in the database, the GDC could do very little to give what could be a better look into the genotypes of the potential breeding animals. The shrinking of the GDC organization and its lack of substantial and significant database caused them to merge into OFA in 2002. If dog owners change sufficiently, the GDC can revive, even as a part of the OFA. At present, it must act in a more limited manner. One obstacle to the open registry concept is the complacence and apathy of the typical American dog fancier. Such a stereotype owner even took a long time to accept OFA or an equivalent registry of dogs that could be identified as “normal” or “acceptable for breeding”. I’ve been in this field from the first days of OFA, and can remember when it was not taken for granted, as it is today. To change horses in mid-stream is not something most would want to attempt, or have the gumption to do, even though it is easier than you would think. The other obstacle has been the OFA’s intransigence to such matters of progress. They had the opportunity to persuade their almost-captive clientele to switch to an open registry, one in which inquirers could get the readings on potential studs, dams, or near-relatives of their own potential breeding stock, but the managers gave the feeble excuse that it might discourage owners from having dogs radiographed and entered into the database. They have refused to adopt the progressive ideas of GDC as they have refused to advance into the superior stress-radiographic technique developed at Penn. It is largely a matter of inertia and politics. OFA leaders are at personal odds with those at Penn, and resented the possible threat of competition from GDC. If cooperation were the word of the day instead, there would not have been the need for competing organizations. But the person carrying old, heavy baggage is going to be passed up by others sprinting for the best seats on the train.
In Canada, there is also the OVC, Ontario Veterinary College, that has maintained a database and diagnostic method similar to OFA’s. Certification is available at age 18 months (vs. OFA’s 24-month minimum and the 12-month minimum required by the SV and other countries), and the reports are slightly different. But the technique is the same, that is, the hip-extended view. Many Canadians in many breeds are also switching to, or supplementing their knowledge with, PennHIP. Penn’s early accuracy (around 4-6 months basically the same as throughout life in most cases) is a great advantage, and their demonstration of passive laxity gives far more information and predictive value. The procedure adds another position, one that mimics the posture of a dog standing or walking with hip joints in a neutral-natural mode. Much more like that which entails a true approximation of functional laxity (the actual looseness in a real-life situation).
I contend that the wisest breeders and shoppers will use all the tools they can to improve their breeds and lines. The ultimate would be to use PennHIP for early risk prediction and a numerical comparison value, selection of stock with lower ZW-BV numbers if available, and submission of radiographs to an open registry (GDC if they still operate that service for hips). Breed clubs can do much to improve genetic health by peer pressure through awards and codes of ethics. Unfortunately, if they are affiliated with AKC, they are not allowed to put restrictions on which dogs are allowed to breed, as that monolith is in the business of appropriating not only breeds and breed clubs, but controlling all registration decisions as well. And their lax practice has always been to register anything as long as the money and the form are sent in, and there is no complaint about it. They subtly yet inadvertently encourage breeding of the worst animals, and thus perpetuate genetic diseases. In other countries, it is the breed club that is the sole and responsible guardian of the breed. Here, we must rely on salesmanship, peer pressure, and “P.R.” to mold attitudes and encourage compliance with common-sense practices such as those that would improve hip quality.
What about the update on progress mentioned at the outset? The GDC was floundering, and now that it has merged with the larger, richer, better-known OFA, it is unlikely to convert the giant that it married. OFA shows no signs of progress in reaching new levels of excellence in hip joint quality. Nor do they supply us with print information, but direct us to their inadequate but large website. It does little good, when the hip-extended method is ambivalent in value or accuracy, to list only dogs that have “passed” their low or imprecise standards — what of the other relatives that do not pass?
What of progress at U-Penn? This is the only one of the three that is moving at “fast-forward”, and much has been published in the professional (veterinary) literature that supports the value of the PennHIP technique. Among the latest are two articles that appeared early in 2002, including in JAVMA, the largest and possibly most prestigious and demanding of the vet journals. One is on risk factors for DJD and its confirmed relationship to DI. Distraction Index is Penn’s numerical (quantitative) description of how much laxity can be revealed when a small but significant force is applied to separate the ball from the socket so that a picture can be taken while the hip is in this loosest state. Remember, OFA’s premise is also that “tighter is better”, although Penn has the only well-known method of determining true tightness. Another article deals with the significance of a radiographic line of extra density, thickening, or mineral deposits on the shoulder of the femur, first studied by Dr. Joe Morgan at U-Cal.-Davis and popularly known as “Morgan’s line”, but in the new paper referred to as “caudolateral curvilinear osteophyte”. I predict this mouthful will not replace the common moniker. Whatever it’s called, it may be a help to vets who still rely only on the hip-extended, subjective view.
Not really new, but an update of sorts for newcomers to the discussions on hip quality analysis, is the fact that PennHIP radiographs can only be submitted by trained and certified vets and their certified/trained technicians. Trained by Synbiotics/Penn, that is, in such symposia-connected sessions as their seminars held in connection with national and regional veterinary conferences. Vets who withhold radiographs because, there is obvious HD or DJD, or any other excuse, are dropped from participation. This protects the integrity of the database and prevents the type of bias found in OFA, where mostly the good hip pictures are sent in, and the bad-hip dogs hide in the shadows. Vets who would allow their non-certified assistants to do the radiography without their personal action in holding the distractor or manipulating the dog’s legs will also face expulsion, as has happened twice that I know of. Semi-annual breed prevalence and statistical profile updates are made available to participating veterinarians and the Synbiotics or Penn websites. Penn has made a small move in the direction of an open registry, leaving the decision up to the breeder/owner to decide whether to check off the box indicating willingness to share information. That is a small box, and since an office worker often fills out the form down to just before the owner’s signature, it is not checked as often as it should be. Make sure you see and check-mark it when you have your dog evaluated by a PennHIP practitioner, so others interested in breeding to your dog or its parents can contact you. If you want to find out about the DI of a dog or close relatives, you can network with the owners who allow their names and addresses to be made available. PennHIP is still a closed registry, so they will not reveal the DI of dogs, but they advise that when you contact the owner-participants, you ask for a photocopy of the official PennHIP report. If not, you could be fooled by disreputable owners. For example, a dog with considerable DJD may have its joints so “frozen” by calcium deposits that much laxity cannot be demonstrated. You also must see the part of the report that mentions the absence or presence of remodeling or DJD or evidence of HD. Just to say that a dog is in the 80th percentile or whatever, in regard to comparative laxity is not enough. You need all the information on the report. An owner can get his breed’s listing by phoning Synbiotics at 800-228-4305, and using the phone prompt for “Technical Services”, then asking for “Breeders wishing to share information”. This may also be available on their website.
What is the latest in certain breeds? I am listing here only those breeds for whose magazines or websites I have previously written articles. The others will be found on Synbiotics’ website. I’ll start with my own favorite breed, the GSD, although the Golden has one-third more dogs in the database and the Lab has nearly 80% more. The GSD has a mean DI of about 0.43 which means that you should prefer breeding partners that are not higher, and especially look for ones closest to the 0.3 threshold, below which there is no DJD development. The Shiloh Shepherd, basically a strain of GSD selected for larger size among other characteristics, also has a mean of 0.43 but the King Shepherd, a small splinter or dissident group from the Shiloh club’s original registry, has 0.5 as their mean DI. This could mean that the breeders and owners of King Shepherds are more lax than their dog’s hips! For those not familiar with DI, let me suggest that you could think of a number such as 0.50 as representing a joint in which distraction allows the ball to be moved about 50% out of the socket. For a Corgi, Catahoula, Neapolitan Mastiff, or Newfie, this amount may not be as serious, but for a GSD it is definitely a situation to be avoided. There are breed differences as to relationship between laxity (DI) and later DJD.
Airedale Terriers: 0.58, but this is one of those breeds in which the DJD isn’t as bad at that level as it would be, on average, in the GSD.
American Bulldog: 0.57 (The “English” Bulldog’s is 0.71)
American Pit Bull Terrier and American Staffordshire Terrier (basically the same breed with different registries): 0.59 to 0.61
Australian Shepherd: 0.49
Australian Cattle Dog: 0.56
Boxer: 0.49 (As elegant as we have made our American Boxers, they cannot escape the influence of their distant Bulldog heritage.)
Canaan Dog: 0.48, which may surprise some who believe that the rigors of feral life eliminate much HD; in fact, more depends on a combination of breed/group/family phenotype in those “wild” breeds that actually do not compete that much for food and breeding. But the truly wild dogs that rely on very demanding environments that weed out the weak, and allow only the strongest to do the breeding in the pack, are famously low in HD incidence. The wolf in its many varieties, the Dingo, and even such wolf-domestic dog blends are examples. The Lupine breed, which is mostly Northern Gray Wolf or Timberwolf, and the American Tundra Dog which is another wolf blend, do not have statistically high enough numbers submitted to PennHIP yet, but so far are quite low in DI and I predict will continue to be so.
Dutch Shepherd: 0.53 It is interesting to compare this with its close cousins the Belgian Shepherd varieties — the black Groenendal has 0.30, the mahogany Tervueren has 0.35, and the short-coated Malinois has 0.39. The Dutch Shepherd is phenotypically and probably historically an intermediate form between the GSD and the Belgian Shepherds, but with likely admixtures of Beauceron and others.
Mastiff: 0.51 More commonly, perhaps, referred to as English Mastiff or Old English Mastiff
English Shepherd: 0.62 Also known by some as “Farm Shepherd”, a breed found mostly in the U.S.
Fila Brasileiro: 0.56
Greater Swiss Mountain Dog: 0.56
Neapolitan Mastiff: 0.65
Nova Scotia Duck Tolling Retriever: 0.53
Rottweiler: 0.55 It is of importance and interest that the typical Rottie with a given DI will have less DJD than a typical GSD with the same DI. There are even greater differences between several other breeds.
Shiba: 0.52 Compare this with its descendant, the Akita which has 0.6, but also with breeds more frequently identified with HD symptoms. Even light-weight, small-dogs’ hips should be monitored and improved.
By the way, the Greyhound is listed as having a mean DI of 0.23, but it was not made clear if this included both the track and the show Greyhounds. Breeds like this and the Whippet have nearly a zero incidence of HD, although occasional examples of dysplastic individuals are seen.
In summary, big advances in the field of hip dysplasia do not come along frequently, but when they do, there is no excuse for not availing ourselves of them. The latest “great new thing” was the introduction of that measurable stress radiography technique at Penn. Since then, voluminous studies there and elsewhere have confirmed the superiority of this radiographic approach over all others in the world. I am not including such overpriced research methods as MRI, nor do I foresee any genome maps in the future that will help, partly because of the polygenic nature of HD. Those who can use the most tools will have the best chance of success. If you have friends in countries where there are no PennHIP certified vets, urge them to use the ZW system where they can, and radiograph dogs later in life to see if DJD has developed after the usual age of certification, which frequently happens. If you don’t have BV-ZW available in your breed, use PennHIP even if you have to travel. These two are the very best methods of gaining the most clues as to the genotype of dogs. Share all your results with the public, whether flattering or dismal or anywhere in between, for the sake of the breed and your fellow dog fanciers.
Copyright Fred Lanting, All rights reserved, but reprinting allowed after permission. Please read his other articles on SiriusDog.com, for example, or e-mail him at Mr.GSD@netscape.com or Mr.GSD@Juno.com for specific articles.
Editor’s Note: A well-respected and frequent GSD specialty and all-breed judge for many clubs around the world, with KC and other-country credentials, Mr. Lanting since 1966 has lectured on Gait-and-Structure, Canine Orthopedic Disorders, and other topics, and has judged in about 30 countries. He has been described by a former OFA director as the world’s leading non-veterinarian authority on hip dysplasia. He has lectured at numerous veterinary schools in the USA and abroad, and is the author of the following “must read” books for the dog owner (E-mail for curriculum vitae). “Canine HD and Other Orthopedics Disorders” : This expanded revision is a comprehensive (nearly 600-page), amply illustrated, annotated, monumental work that is suitable as a coffee-table book, a reference work for breeders and veterinarians, and a study adjunct for veterinary students. It is equally valuable for the owner of any breed. It covers every aspect of HD and other orthopedic, bone, or spinal disorders, and includes genetics, diagnostic methods, treatment options, and the role of environment. Your autographed copy will be mailed from the USA as soon as the appropriate amount is received and is processed. Pricing: US $68 in the U.S., or ask about mail overseas. Combine orders with “The Total German Shepherd Dog” by the same author ($50 plus $4 postage). 17 of the 20 chapters are suitable for owners of any breed. Order both at once direct from the author, and the postage will be waived.