Making the most of health schemes by Steve Dean
Last week AVV suggested that not every person breeding dogs understands how to get the best out of health schemes such as hip scoring. The same is true for the whole range of health tests, be they official British Veterinary Association/Kennel Club organised schemes or breed club initiatives. In particular it is the limitations of any health scheme that are most frequently ignored or misunderstood. Health testing is not an endpoint but a starting position.
For example, an eye test under the BVA/KC scheme will detect inherited conditions associated with the internal structure of the eyeball but does not include similar conditions of the eyelids, the cornea, tear production or the tear duct (collectively called the adnexa). Such adnexal problems may be recorded on the eye report but they do not contribute to the pass or fail status of the eye test. Eye tests therefore contribute to breeding dogs free of inherited eye conditions but do not do as much for adnexal problems.
Furthermore certain inherited diseases may not manifest themselves at the outset (eg late onset cataract, glaucoma) and therefore a clear eye test at an early age does not always signify the dog is free from an inherited condition for life. If AVV is correct and some breeders do not understand this (or choose to ignore the facts) then what is the hope the puppy buyer will do sufficient research to fully understand the parents’ test results. This is particularly pertinent with genetic testing where a carrier of a recessive gene is very likely to be a healthy dog and yet this result may well be regarded negatively by a puppy buyer.
The good news is that clinically based health schemes and genetic tests are usually linked to good advice and thus guidance is available if either dog breeder or new owner wish to research the subject. However with some breed schemes this is not always true, especially for the puppy buyer. The whole issue becomes even more confusing when conformational exaggeration is considered to be associated with certain clinical conditions. In these cases the assessment of health status becomes very subjective and objective sensible data is often hard to come by.
There are two ways of being objective where exaggerated conformation is concerned. For individual dogs the clinical signs of a problem can be observed and suitable action can be taken. For breeds as a whole, the incidence of a specific problem can be the subject of a health survey and advice provided on how to reduce the incidence or eliminate the problem. However none of this is necessarily easy.
Currently, the subjective assessments (ie personal opinions) are based on historical information and perception. This works up to a point but offers no ongoing assessment of improvement across a breed nor does it isolate the source of the problem so it can be tackled (as we would expect with a health screen or genetic test). It is perhaps not surprising that frustration, disagreement and annoyance follows.
Some examples may help to reveal the point more effectively. Breeds with flat faces or very short muzzles have been linked with breathing difficulties. However, not all dogs with very short muzzles have difficulty breathing. Making sure that evaluation is based on an ability to breathe rather than shortness of muzzle will ultimately select for short-muzzled dogs that can live normal lives.
Heavy wrinkling of skin is associated with skin inflammation and infection. However, concentrating any effort to improve health by selecting dogs with healthy skin removes the personal bias against any given amount of skin wrinkling, as dogs with healthy skin will inevitably have skin wrinkles that are acceptable. The same applies to skin folds on the head where the effect on the eyes must also be taken into account.
Skin folds suggest a certain loss of skin elasticity. When taken to extremes the effect on the eyelids can be dramatic. The lower lid may be dragged downwards away from the eye or the upper lid may roll over placing eyelashes and coat hair in contact with the eye. In both cases an amount of inflammation or damage may be done and it is these that represent markers of excess.
The eye must be moist and well washed in tears to remain operational and as anybody who has had grit in their eyes will know, severe discomfort invariably accompanies the ingress of foreign material or infection. The normal function of tears associated with the wiping action of the eyelids removes accidental ingress of material but this is not the case where the foreign material is formed of hair or eyelashes or the eyelids make such poor contact with the globe of the eye that clearance of foreign material is slow or inefficient.
The last example is conformation of the back or topline. Interestingly excessively curved (perhaps roached) backs are criticised in some breeds and accepted in others. Long, straight backs are the subject of comment in others. In fact it is difficult to predict how the conformation of a dog might affect the function of the spine. However it is well known that spinal instability invariably affects the ability of the dog to control its hindquarters. Thus the objective view is to consider dogs that can move well without signs of ‘looseness’ in hind action, otherwise known in veterinary terminology as ataxia.
From the health point of view if breeders, exhibitors and judges stick to observing the obvious effects of defective conformation this is surely as far as they can go in delivering good health in the show ring. Of course they are still able to judge excessive conformation as a matter of opinion (and preference) but this is rightly the preserve of the judge (and exhibitor).
Assessing the health of a breed may require clinical health assessments or genetic testing depending upon the perceived problem in the breed. However, the first step surely has to be the breed survey to understand the health issues within a breed and thus assess the relative seriousness and sensible action to deal with a problem. On going surveys are necessary to measure progress and will permit modification of opinions on the health status of any given breed. One of the main advantages of the pedigree dog is its known parentage. It is high time we put this advantage to good effect and, by example, set the KC registered pedigree dog apart from the dogs bred by those who care little about health or welfare.
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