A Huge Step Forward For Breeders
Four years ago, I first heard about a new approach to identifying the processes leading to faulty hip joint development in dogs. Having bred giant breeds, St Bernard’s for many years, one of the most import aspects of my breeding is to breed structurally sound dogs, placing a clear focus on environment and diet. Many breeders will recognise that, try as we might to advise some new puppy owners with the requirements of your breed, it is inevitable that some will always “know best”. This ‘know best’ stance often results in the puppy developing problems of one form or another.
One of the major problems that is recognised by those of us involved in the St Bernard breed is acquired through over exercising resulting in joint trauma. When this happens, it is always claimed to be the ‘breeders’ fault’, (many of us across the breeds have heard that before,) for breeding a dog with a genetic condition, followed by demands for a replacement puppy, their money back or threatened with social media, to name a few scenarios. An all too familiar story these days.
I met up with a friend, Pam Mckenzie-Hewitt (now MacLellan) a fellow breeder. Pam filled me in on the research project she and her now husband, Gordon (a consultant Orthopaedic surgeon) had begun the previous year. They were studying hip development in puppies from one to eight weeks of age as a starting point. At this stage they had not been able to screen many St Bernard’s, so I offered my next litter to be scanned as part of the Project. Gordon advised me hip ultrasound scanning has been practiced in human infants since the early 1980s. Pam had prevailed upon Gordon to see if the same” human” technology could be used for the benefit of dogs.
Previous researchers in Brazil and Germany had tried the method, but had been unable to identify the hips that subsequently developed problems from the six week scans and their investigations therefore did not lead to any firm conclusions. Between the two studies almost 600 pups had been scanned in 17 breeds without finding any abnormal hips. The assumption therefore, was that there could be a genetic disorder causing faulty hips that arose after birth. This is clearly not the same as in humans, because in babies almost all possibly genetic dysplastic hips are abnormal at birth. Just as in dogs, there are both gender and racial differences in the incidence of human hip dysplasia. How was it that in almost 600 puppies of differing breeds no cases of hip dysplasia were identified? This earlier research was not continued, possibly due to lack of research funding, but Pam, Gordon and the growing Pupscan team, who I must say are quite an impressive group of academics, are determined to find answers.
Since those early days, the Pupscan Team has grown to include Vets, both general and Specialists, academic experts in Nutrition, Genetics and Radiology, to name a few with most carrying the title of Prof. A major step forward came when Pupscan joined forces with Bodo Backmo, a researcher in the Swedish Kennel Club; he has led a team analysing the results from 40 years of hip “Scoring” and has demonstrated no statistically significant benefit in any breed. As the Scandinavian breeders have a much higher percentage of all dogs scored than in the United Kingdom, this finding is of great importance and casts doubt on the merits of all the different scoring systems used around the world where pre-selection makes statistical validation impossible.
My concern is that if hip scoring is valid as a health test then why is it not repeatable and robust? I know of many colleague breeders who have appealed scores only to be told ‘you are not guaranteed to get the same score if you appeal.’ Why not? Let’s face it, if a score is so relied upon to eliminate dogs from the gene pool, then surely the scoring system must be proven to be reliable and repeatable. Yet it claims only to be an opinion (it says so on the sheet)!
In my humble opinion I question why after 54 years of scoring is it not under scrutiny as a valid test. Yes, I know lots and lot of papers have been published relating to hip scoring, but they are based on a test that falls at the first hurdle (small sample with pre-selection) in my opinion. The dog-breeders “bible” on genetics, the wonderfully readable “Control of Canine Genetic Diseases” by the late Professor George Padgett of Michigan State University (1998) is very clear. You need only to get to page three to see some of the questions that need to be answered before assuming a fault is predominantly genetic! In bold type he wrote “MAKE SURE THE DIAGNOSIS IS ACCURATE”. Breeders like me have been disappointed that this guiding principle has been overlooked by hip dysplasia researchers all over the world in numerous Peer-Reviewed academic papers.
What about X-Rays?
The Pupscan team have, through their Breeder network, had the good fortune to have been sent X-Rays of faulty hips of dogs from Norway to Australia and many countries in between. Some had been X-Rayed for “scoring” and others for symptoms. As the Team reviewed the X-Rays (though not all because of poor image quality,) they were almost always able to start answering Professor Padgett’s questions about diagnosis.
My understanding is that there is still a question mark over the possible genetics of Perthes disease. However, the contribution of trauma and infection, both bacterial and viral, in causing damage to the femoral head blood flow is probably as significant in dogs as in humans. Again, why would it not be? We share so many genes and so many biological processes.
By far the commonest cause of problem hips in dogs has been trauma. Try as we might, we cannot wrap pups up in cotton wool and most hip trauma has occurred before skeletal maturity. Things are further complicated because different breeds mature at different rates. It could be thought that a much higher risk in giant breeds and overweight pups is anticipated, but actually ALL breeds are at risk (as it is proportionate to size and weight) if not looked after correctly. I am sure we can all agree on that point.
Pupscan certainly prompts the thinking process. One interesting point they raised is that if dogs are to be used for breeding then why are the gonads not shielded when x-rayed to reduce the risk of radiation-induced genetic abnormalities (as in all humans)? Many pictures are often taken to achieve a “Standard” view x-ray. Think about it, if it can affect humans and other species, why neglect to protect your dogs ‘valuable assets’? Our dogs are precious and deserve protection.
Traction distorts the hip joint anatomy and some of you reading this will assert that traction is not applied. ‘My vet only holds the legs and only rotates and pulls the legs into extension’, I hear. Have you ever thought about whether the person performing the procedure is left or right-handed or about how strong they are? it is impossible to be sure that the same forces are applied to each leg, let alone each dog, possibly causing lasting damage to the joint. I have heard from colleagues that their dogs have been x-rayed for scoring and when returned they are lame, have frozen tail or worse still have not recovered from the sedation. Why? This is more common than you would think, not as one would expect, exceedingly rare. Some breeds do have a high-risk element.
Why have I turned to Pupscan?
I and others in my breed, have used Pupscan for over three years to screen pups for faulty hips before they leave for their new homes. We have supported Pupscan by building up their database of St Bernard’s. I am reassured to know that the pups I have bred have normal hips when they leave me to live with their new owner in a different environment and with different interactions.
This form of hip health screening is gradually being recognised by breeders and Kennel Clubs around the globe as a way forward. Not only are scans collected, but DNA data bases are being created to enable geneticists, (the ones who wear white coats and work in laboratories,) to screen for a genetic component collected from pups and young dogs with true probable issues, yes, they do exist. Pupscan has identified this factor. In other words, eliminating the acquired conditions from those that are truly suspect. This surely make sense if we hope to find out if there really is a genetic mischief at play.
Do Pupscan work with Vets?
Yes of course they do, and geneticists, radiographers, Orthopaedic specialists, nutrition specialists and many more. As mentioned earlier the Pupscan team has many significant individuals working with them towards finding a way forward. Pupscan are also supporting Vets in scanning injured pups with ultrasound to diagnose problems that cannot be shown on x-ray. Vets have therefore been able to guide puppy owners on how to manage the injury and thereby avoiding hazardous operations when non-surgical alternatives are available.
Every few weeks something new seems to emerge from the research that needs attention. Now I am excited by the challenges of excessively rapid growth or excessive weight gain by managing the diet. Legs growing too long too quickly, therefore causing the puppy to become clumsy and injury-prone, needs a planned dietary approach that is different to diets for early onset obesity in puppies. As breeders, we all recognise that all breeds are not the same and individual dogs all have personalities, some shy, some too busy. They are all unique with individual needs and responses.
Puppy contracts are so difficult to enforce these days, even though we all work hard to get it right. What does not help is when the man in a white coat comes along with the throw away comment, ‘you were sold a ‘dysplastic puppy’, or this breed is susceptible to ‘hip dysplasia’. Just remember ‘Dysplasia is a description NOT a diagnosis. So, your first question should be ‘so what is the diagnosis? No doubt you will get a blank look and the reply will be ‘Dysplasia.’ In my opinion that is not helpful, it means “Faulty development” but does not differentiate between all the various causes of the faults. Soon I hope to be able to design a Puppy Contract tailored to the sort of home the dog is going to, rather than the home in which it was bred. Urban verses Rural, it can and does make a difference.
Is the problem of Canine Hip “Dysplasia” predominantly genetic or not?
As a breeder I remain to be convinced about the genetic side of “dysplasia” and the reason I say this is simple. When I have asked the veterinary world for the gene or genes identified as the genetic cause, and the test required to screen for this, I am told there isn’t one. If I cannot screen for genes to test for hereditary ‘genetic dysplasia’, then how can a phenotype score tell me a genetic element exists? A bit like taking a photo of my parents to the doctor and asking him to tell me the problems I will develop!
Scoring does not take into account the whole of the litter. We breeders select which dogs to score but why? If we score two dogs out of a litter of ten (because we want to breed from them) then are we not doing ourselves an injustice? An example, in human families three children may be born normal, but the fourth has a genetic problem. We would need to study the whole family to work out where the abnormal genes came from and all the apparently normal children to find carriers.
I have asked, of the first 5000 puppy hips scanned before eight weeks of age by The Pupscan Project since 2015, how many have been abnormal with an un-developed hip socket (acetabulum)? Answer, four. Of 600 pups scanned in previous studies there were none. So, in over 70 breeds and 6000 + puppy hips scanned of all sizes, the incidence of congenital canine hip dysplasia (at birth) is less than one in one thousand. So predominantly genetic canine hip dysplasia must be exceedingly rare. I hear some of you saying, ‘but that is because the bones are not formed’, well no, is the short answer. It is because they are normal. The abnormal puppy hips were found at four and six weeks, and one nine days old. Pups are followed through to adulthood and screened regularly, even screening some at eight months depending upon breed.
One thing all breeders will recognise is that different breeds develop differently. Pupscan have identified that the breeds (just as we breeders have always known) would appear not to develop at the same rate. As breeders, most of us recognise that different breeds develop differently, and some breeds take longer to mature. An example of this found by the Pupscan research suggests that the Alsatian/GSD hips appear to mature much more slowly than the Rottweiler. A Rottweiler at six weeks of age is developing much more quickly than the GSD comparable. Looking at the documented research, this appears to be supported by Rottweiler and Alsatian/GSD breeders. This is seen across many breeds and it seems the groups of breeds show different maturation rates too.
Professor Padgett’s advice to MAKE SURE THE DIAGNOSIS IS ACCURATE is therefore more important than ever. Our dogs and breeding lines are too precious to be lost from our lives by failing to make a diagnosis.
Some breeds guide the blind, hear for the deaf, sniff out cancers or detect a diabetic or epileptic attack; they have been man’s best friend for over 5000 years, now it is our turn to be the dog’s best friend!
Tan Nagrecha
Breeder of Chandlimore St Bernard’s