What Do I Need To Know About Health
Testing To Choose a Breeder?You don't need a degree in genetics, or even a college course, to understand the basics of
health testing in Labradoodles or Goldendoodles. A good Labradoodle breeder or
Goldendoodle breeder will have a pretty good handle on the genetics involved with the health
of these hybrids though!
Every aspect of your Labradoodle's or Goldendoodle's physical being began as contributions
from it's parent's bodies, carried in their genetic code. There are certain health conditions in
Goldens, Poodles and Labradors which can be passed from parent to puppy in the genetic
material and hence are found in Goldendoodles and Labradoodles, These are called heritable
(that is, "able to be inherited") disorders. There are 2 disorders, Von Willebrand's Disease ( a
bleeding disorder), and prcd-PR (an eye disorder)in which we actually know what gene is
responsible. In the case of these diseases, a laboratory test can determine if, or how many
copies, of the gene are present. A dog having two copies of the gene for either disorder
would evrntually be affected by the disease and would not be bred. A dog with one copy is a
carrier, and a breeder would take care to breed that dog only to a dog that is NOT a carrier.
Carriers remain perfectly free of these disorders, the only concern is them passing it to a
puppy that receives a second copy from the other parent. A dog is only affected by the
disease if they have 2 copies.
In all other instances we cannot look for a gene to tell us of the presence of a certain disease.
We have to look for evidence of the disease itself. In the case of heritable eye diseases in
Poodles, Labradoodles, and Goldendoodles, for example, an exam is conducted by a veterinary
opthamologist every year to determine if a disease is developing. Dogs that show symptoms
of a heritable eye disease are eliminated from the breeding program. Other examples of
heritable diseases tested for by some Doodle breeders include thyroid disease, some forms of
heart disease, Addison's disease, sebaceous adenitis, hip dysplasia and diabetes.
The heritable disease found in Labradoodles and Goldendoodles that most people seem
familiar with is Hip Dysplasia (HD). This disease is a sort of Degenerative Joint Disease (DJD)
, with symptoms similar to arthritis in humans. In dogs though, the heritable form of the
disease is not a disease of old age, but can develop while the dog is still quite young and is
obvious on X-rays as the hip joint has abnormal features. As with most things, the hip
architecture can range from great to horrible, with some hips in between. Two schemes are
commonly available in the US for evaluating hips.
OFA screening relies on veterinarians reading an x-ray and assigning a rank: 'Excellent', 'Good',
'Fair' 'Borderline' or 'Dysplastic'. This rank is based on the shape of the hip socket and ball
joint. Labradoodle breeders who base decisions about breeding on OFA generally agree that
'Excellent' and 'Good' rankings are fine to breed, and also agree that 'Borderline' or 'Dysplastic '
are not acceptable for breeding. As with all other decisions where there are gray areas, some
breeders will breed a dog with a 'Fair' rank, and others will not. Some will breed a 'Fair' under
some cicumstances and not others. This is really a judgement call and not all breeders agree.
There is a registry (www.offa.org) that collects and reports hip assessments to assist in
recording and tracking these rankings. OFA will not certify a dogs hips until the age of 2 years.
However, some breeders are using a specialized x-ray technique called PennHIP testing, which
can be done as young as 4 months of age. This test results in a score for each hip, ranging
from .1 to .9, and reflects how tight the hip joint is, and the average score varies by dog
breed. Tighter hips, that is lower scores, are less likely to develop DJD and are desirable in any
breeding dog. In my opinion, any score under .4 is clearly breedable. Anything over .65 is
clearly not breedable. In between .4 and .65 is a gray area. Breeders who utilize this method
track the average scores for their breed, and try to breed only dogs with average or
better-than-average scores. For example, the average hip score for Standard Poodles is
currently .5. If a Poodle were to score .42, in the middle zone, it would be considered
breedable by most because it is better than average. However .42 would NOT be considered
breedable by most Borzoi breeders because that breed average is .19!
So some breeders do OFA testing, some do PennHIP testing, and some do both. My personal
opinion is that there is value in doing both tests, as they do look at somewhat different
features of hip health. It can assist in choosing mates for a dog if you know the details of the
hips. If a dog has great hip conformation (OFA 'Good' or 'Excellent') but the hips are a little
lax, maybe in the .5-.6 range, one might consider an OFA 'Fair' mate if the hips are really
tight, possibly in the .3 range.
Mini-Labradoodles are at risk for slightly different problems as they are bred from Miniature
Poodles instead of Standard Poodles. For example, the incidence of hip dysplasia is so low in
the Minis that some breeders choose not to test for it. So breeders may test for some or all of
these diseases. Some breeders do not test at all. If testing for heritable diseases is important
to you it should be among the questions you ask of prospective breeders.
Another way breeders try to eliminate HD and other heritable diseases from their breeding
lines is to examine their dog's pedigrees carefully. Looking at hip assessments and other
health records of relatives (grandparents, siblings, half-siblings, cousins, etc) and choosing
breeding stock with the healthiest background possible is all part of the picture.
One of the difficulties in trying to eliminate heritable disorders in dogs is that most of the
genes that cause the disorders are what are termed 'recessive'. This means they are hidden, or
masked, by other genes. A parent that does NOT show the disease, but is carrying the gene,
can pass that gene carrying the disease to a pup. If BOTH parents happen to be carriers and
pass the genes to a pup, the pup can have TWO defective genes and will show the disease.
This is similar to 2 brown-eyed parents having a blue eyed child. Blue is recessive, but if both
parents are blue carriers, they can have a blue -eyed child. Some heritable diseases are
passed in this manner, via a single recessive gene. Complicating this picture in the case of HD
is the fact that hip dysplasia appears to be controlled by several genes, so predicting it's
inheritance is even more difficult. It IS possible to have 2 parents with good hip scores, or
good hip x-rays, produce a puppy with hip dysplasia.
In addition to testing members of a breeding pair, breeders will gather testing information on
relatives of their breeding pair. The scores of parents, grandparents, siblings, siblings of
parents, and even puppies produced from previous litters will all be examined. In some cases
it is better to breed a dog with slightly below average hips, if the test results for all relatives
are excellent, than to breed a dog with good hips who has HD in it's pedigree. So interpreting
test results is no easy task! This is true for the other heritable diseases passed as recessive
traits as well.
But Doodle breeders who test their breeding stock do the best they can. They use their dogs
test results to help make the best pairings possible in their breeding decisions. The hope is to
reduce the number of Doodle pups born with hip dysplasia by removing dogs from the
breeding population that have clearly substandard hips, and by following the offspring of dogs
with hip scores in the middle ranges to see if their pups remain healthy. We do the same for
all diseases that are known or suspected to be heritable in Labradoodles and Goldendoodles.
Please look here for more information about Labradoodles and Goldendoodles.
|
