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Progress in hip joint phenotype of dogs in the
United States between the 1970's and early 1990's
has been shown through results of a retrospective
study using the OFA data base. This improvement was
evident as an increase in the percentage of dogs
classified as having excellent hip joint phenotype
and a decrease in the percentage of dogs classified
as having hip dysplasia (HD). The increase in
percentage of dogs classified as having excellent
hip joint phenotype was greater for German Shepherd
dogs, Golden Retrievers, Labrador Retrievers, and
Rottweiler's than for all dog breeds combined. In
addition, the submission screening rate for these
four breeds was higher than the screening rate for
all dogs. Within these four breeds, the improvement
was greatest for Rottweiler's, which also had the
highest screening rate.
Overall, low screening rates for breeds found in
this study offer some insight into the problems
involved with reducing the incidence of HD. The
typical dog breeder is involved in breeding dogs for
about five years. Thus, informed, experienced
breeders are continually replaced with uninformed,
inexperienced breeders who may not be as aware of
the problems associated with HD or of the importance
of participating in a screening program. In
addition, many breeders choose which dogs they breed
on the basis of the hip phenotype of individual dogs
without knowledge of the phenotype of related dogs
or previous offspring. It can be very difficult to
get hip information on siblings and previous
offspring due to the overall low number of dogs
radio graphed in a given litter (most dogs in a
litter end up in pet homes). This is the slowest
method of reducing the incidence of an undesirable
trait or increasing the incidence of a desirable
trait. The use of preliminary radiographs as early
as 4 months of age can be used by breeders to add
valuable information on the hip status of dogs they
choose to use in a breeding program.
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Hip dysplasia appears to be perpetuated by
breeder imposed breeding practices, but when
breeders and their breed clubs recognize HD as a
problem and establish reduction of HD as a priority,
improvement of the hip status can be accomplished
without jeopardizing other desirable traits.
Prospective buyers should check pedigrees and/or
verify health issues with the breeder. If suitable
documentation is not available, assume the worst
until proven otherwise.
Do not ignore the dog with a fair hip evaluation.
The dog is still within normal limits. For example;
a dog with fair hips but with a strong hip
background and over 75% of its brothers and sisters
being normal is a good breeding prospect. A dog with
excellent hips, but with a weak family background
and less than 75% of its brothers and sisters being
normal is a poor breeding prospect.
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