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The
Testing Mantra - What is testing really about?
In the world of purebred dogs the
word "testing" has almost become a mantra. I test, I test, I test. The problem
is testing has become synonymous with healthy dogs and unfortunately this is
not the case.
Testing is merely a tool in the breeder's arsenal, along with
dog shows, pedigrees, vaccinations and other health checks, correct diets, etc.
to help them find ways to breed better and healthier dogs. By merely doing the
tests however, it does not mean the dogs' offspring will necessarily be healthy
and not develop a genetic defect.
To start with, let me say
that if your sole interest in having a dog is to have a companion with the
likelihood of no genetic health problems a purebred dog or even a mixed breed
is not for you. Go to the humane society and ask for a mutt or Heinz 57 with
little resemblance to any breed. Because of something called hybrid vigor this
will give you the best chance of having a dog that is unlikely to develop a
genetic defect, though it may still possibly have health problems. If, however,
you are interested in having a purebred dog with the characteristics and
temperament you like then be prepared for the chance that your dog may develop
a disease to which the breed is predisposed.
There are many articles
in dog magazines and on the Internet that lay the blame for genetic defects on
the careless breeding by dog breeders. Well there is really more to the story
than that.
First which breeders are we talking about? In the US alone
nearly 75% of the purebred population is supplied by the puppy mills and
backyard breeders. These are breeders who do not care or understand about
breeding healthy dogs, they really don't even care if the dog particularly
looks like the breed it is supposed to represent. There is little concern about
breeding the "right" dog to the "right" bitch, half the time they probably
aren't even sure who the father was, could have been a father or brother, may
not even be the right breed. The mothers are not checked for health prior to
being bred, nor are they properly nourished while pregnant or nursing. Forget
proper animal husbandry procedures. As for testing please don't make me laugh,
it would cut into the profit.
Then there are the
comparatively small percentage of purebred dog breeders who breed dogs for show
purposes. They, unfortunately, seem to get lumped with most of the blame for
the state of the genetic health of the purebreds. How often do you see the
comments that show dog breeders don't care about the genetic health of the dogs
they are breeding? This is absolutely not true. We do care, but we also care
about many other factors that make up the whole dog. Each breed is set a
guideline (Standard) within which the breeder must breed so that the dogs we
produce best represent the breed. Those guidelines generally cover everything
from the look of the dog, the structure, the movement, the temperament and so
on. By showing our dogs this allows us to make sure that we are accomplishing
our goals. After all if you wanted to buy a Cavalier King Charles Spaniel you
would not be happy if it looked and acted like a Beagle.
One reads many articles by both veterinarians and what might
best be described as armchair breeders which seem to infer that it is really
simple to fix the genetic problems in purebred dogs. Oh would this be true.
There are approximately 300 known genetic diseases in dogs,
though not all in each breed. Many of the purebred breeds have on average the
predisposition to 20 or more genetic defects particular to each breed. Some of
the genetic defects will be just minor problems, while others are more severe
and life threatening. This does not mean that all of the dogs in that breed
will carry the gene for each and every one of those defects, just that the
possibility is there. On top of this there are many other diseases which a dog
could develop that may not be genetically linked to the breed.
If one has even a basic understanding of genetics one starts to
realize just how difficult the task becomes in producing dogs free of any of
the known genetic defects to which they may be prone. The majority of the
genetic defects are carried by recessive or hidden genes. Dogs can carry a
recessive gene for a disease and yet never be affected. It gets more difficult
as many of the defects are referred to as polygenic which is where more than
one gene is required to cause the defect. Then there are the conditions which
are multifactorial in nature as well. A dog may carry a gene for a certain
condition but because of factors unknown it may or may not express itself in
that dog. Mitral Valve Disease is one such disease. It is estimated that the
large majority of Cavalier King Charles Spaniels carry the gene/s for MVD but
as yet it is totally unknown and may never be known what exactly the conditions
are that lead to the disease expressing itself in some dogs and at an early age
and not in others.
Where does testing come
into the equation? Testing allows the breeder to have a snapshot of the dog's
health for a specific condition at a particular point in time. At this stage
with the average genetic defect no definitive test such as DNA testing has been
developed for the majority of diseases, largely because the genes for the
particular diseases have yet to be identified. With some exceptions such as hip
dysplasia where an x-ray can be done once at 2 years of age to grade the hip
joint, many tests such as eyes and hearts should be done on an annual basis as
some diseases can become clinical at any age. For example a dog may be clear of
a heart murmur at 2 years of age but have developed one a couple of months
later. Current testing of many defects does not tell a breeder if a dog is
going to be clear of a genetic defect for its lifetime just that it is
currently healthy. And at present it does not (and may never) tell a breeder
that, though their dog is clinically clear of a genetic defect, that it does
not carry the gene for that particular defect.
So what is the point of
testing? It allows breeders to make reasonable assumptions based on the overall
results of the testing in their dogs. For example should a dog prove, through
testing, to be clinically affected by a certain genetic defect for which the
breed is predisposed, a breeder based upon the knowledge of that disease and
its mode of inheritance, can attempt to analyse how that dog came to be
affected and make decisions with respect to other related dogs in their
breeding programs. The easy answer would be to remove all related dogs from
their breeding program because they could potentially be carriers of that
disease, but what if those dogs are clear of most or all of the other 20 or so
genetic defects that could affect the breed? What if those dogs are very good
representatives of their breed and have the correct termperaments? What if they
are dogs that are producing dogs that are overall healthy and long lived? It
would be a bit like throwing the baby out with the bath water. Instead breeders
have to make judgment calls and it becomes a matter of balance, breeding for an
overall healthy, sound dog of correct breed type and temperament. They may
choose to continue to breed the dogs who may potentially be carriers of a
genetic defect but avoid doubling on it by breeding to dogs who have not
produced the similar defect.
Testing could become the double edged
sword in the world of purebred dogs. Some breeders feel the need to use the
testing mantra as a way to "beat" up on other breeders and ultimately sell more
puppies. They will claim that they do more testing, better testing or that
their competition really doesn't test and is lying. Does this make the dogs
that they are selling any healthier than their competition? No! Even if they do
one or two more tests for the genetic defects that a breed is predisposed to,
they are still only testing for a handful of diseases. Also some breeders
become so engrossed with trying to test and breed out, from their dogs, that
small handful of diseases that they completely forget the ENTIRE dog. Other
unanticipated problems start to creep into their lines, so while they may have
developed a dog that doesn't have the one particular disease that they have
been concentrating on, it could have a myriad of other health and temperament
problems.
When talking to a breeder about their dogs, while it is
valuable to know the results of the testing that they have done on their dogs,
you should go beyond the certificates and delve into the breeder's particular
understanding of the genetic conditions that they are testing for, what it is,
what do they know about the mode of inheritance, what the breeder does (other
than the testing) to try to eliminate the defect from their dogs. Do they
follow the guidelines or protocols set down by the specialists? Beyond those
specific defects that they have been testing for, how do they ensure that the
dogs they are producing are going to be free of other possible diseases? How
long are their dogs living? What is the quality of life of their dogs? What do
they do to make sure that their dogs are good specimens of the breed? What are
they doing to ensure that the dogs they are producing are of good temperament?
Have they ever produced dogs with health problems and what were they? It is no
crime for a breeder to have produced some dogs that may have had health
problems, they are after all living creatures and nothing in life is certain,
it is however a crime not to admit it.
Yes, testing is helpful but it
is not the whole story to breeding healthier, long-lived dogs of correct breed
type and temperament. Breeders must learn to use all the tools at their
disposal and start to be more open about problems that their dogs may have
produced for the long term health of the purebred dog world.
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All articles and information
on this site is copyrighted by Rhiannon Cavalier King Charles Spaniels and
Creature Comforts Inn. Redistribution on any other website is only
permitted via a link to this site.
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