Archive for September 2009

Soundness in Pedigree Dogs

September 30, 2009
Animal Care College – caring for people caring for animals
The key components of soundness which I have stated on many occasions goes back to the Judging Diploma Course which I wrote (with a great deal of advice from Les Crawley, Pamela Cross Stern, Peter Larkin and Wendy Boorer) back in 1980.  Not that the concept was new: I wrote about the book Conformation and Soundness in Animals published in the 1960s by the Veterinary Surgeon RH Smythe recently but I think my phraseology summarising those ideas, was concise and has stood the test of time.  It is that in any species subject to selective breeding, any departure in conformation or characteristics from the ‘norm’ is acceptable so long as the animal can eat, move, breathe, mate (and whelp and suckle so far as females are concerned) naturally and effectively.   Once you have to restrict exercise, mash food, have generalised and persistent back or joint problems to give just three examples, then the exaggeration selectively bred for has exceeded what is tolerable.
Wendy Boorer used to use the example of a breed of pigeon which had such a distorted beak that it could no longer release its chicks from the egg and I know a few years ago a food company produced a specially shaped kibble which allowed very short-faced cats to pick it up easily.  This is not a criticism of the food company (they were only responding to customer demand) but is a criticism of the breeders who felt that such short-faced cats were acceptable.
Now apply the same arguments to dogs and you can see where I am coming from.
I think none of these criteria need any further explanation but in recent years I have come to the conclusion that we should add a further requirement: that a healthy dog will have a length of life within the longevity spread of the ‘bell’ curve for the species as a whole.  Let me explain for those, like me, who have forgotten all that stuff about graphs and statistics they learned at school.  A bell curve is a graph which looks just as it says – roughly the shape of the sort of bell used in church steeples or in a hand bell.  The graph expresses two factors being measured.  They can be anything but in this instance it is ‘age’ with the length of the curve (the X axis) showing the length of life in years and the height (the Y axis) showing the number that die at any given time.  In statistics it is usual for the very first and the very last readings to be omitted so this would eliminate still born puppies and those dying within a few days of birth and the exceptionally old.  What is left in this instance is an indication of the population longevity of a given species. At the beginning of the curve few die young and at the end, few become very old so the height of the curve is low at the beginning and tails right off at the end when all are dead.  The high point is when the maximum number of animals die.  There are what are called ‘normal’ curves for, say, intelligence and these look very much the correct ‘bell’ shape but those showing longevity are distorted, for the highest point will be well over half way along the X axis.  In humans that highest point is gradually moving further along as, in most populations at least, stay healthier so more of us die at an older age.  In dogs, the same applies, the curve rises until between nine and twelve it is at its highest and then drops away again as by, say, fourteen, most dogs have died and fewer and fewer live longer lives.   If we draw a graph showing the longevity of breeds we have a very different story.  Those closest to the ‘norm’ would fit neatly on the curve for dogs as whole but for some the rise and fall of the line would start earlier and fall away sooner. What we would see is the curve for breeds much larger than the ‘norm’, although approximately the same shape, is ‘shifted’ markedly towards shorter life spans.  I have not carried out any research into the specific breeds listed in the Kennels Club’s ‘fourteen highlighted breeds’ about which they have expressed particular concerns, but I suspect that they would all, whatever their size, show that ‘shift to the left’ described above.  (If breeders in those breeds can show that this is not the case, please contact me direct at mail@davidcavill.co.uk so that I can bring it the attention of readers).
However, extremes of type which affect general health and welfare (which are the result of breeders choosing certain characteristics) are dissimilar to genetic health and many people make the mistake of confusing one with the other although there are some generalised genetic conditions which are the result of extreme characteristics.  Entropion is one example and the breathing difficulties which some breeds’ exhibit is another.  However, these are not the same as, say, Progressive Retinal Atrophy, Mitral Valve Diseas or Syringomyelia which develop unseen.  These and many other conditions may certainly be the result of selective breeding but they are involuntary on the part of the breeder and for a wide variety of reasons difficult to eradicate.  However with understanding, knowledge and commitment they can be reduced and eventually eliminated.  This may require considerable investment in research, expense on the part of the breeder to run the various tests required and the involvement of other, allied breeds (cf Dalmatians) but it can be done.
Conditions directly and voluntarily caused by selective breeding such as entropion are much easier to deal with and this is why the KC is forcing changes in the Standards.  Chows have successfully greatly reduced entropion simply by focusing on breeding dogs with larger, less deeply set and therefore healthier eyes.  Breeding for a longer muzzle can eliminate breathing difficulties: if the dog’s mouth cavity has enough room for its tongue and its nasal cavity enough room for air flow then there is no need for it to ‘snuffel’.  The difference does not need to be great – Shih Tzu have relatively short muzzles but I have come across few with breathing problems.   As far as longevity is concerned, breeders can increase it simply by breeding smaller (or less extreme) dogs – none of this is rocket science once one’s head has been raised from the sand.
David Cavill
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