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Hip dysplasia has been seen in Vizslas in Australia –
the reported incidence has been low, but it is not non-existent.
There is no place for complacency, nor is there place for satisfaction –
very few of our dogs have actually been hip scored, thus our knowledge of
its incidence may not be a true reflection of its prevalence, especially
given people do not usually advertise adverse results.
What is hip dysplasia?
Canine hip dysplasia (CHD) is the abnormal development of the hip
(coxofemoral) joint. CHD has a polygenic (many genes involved) mode
of inheritance, and the expression, or extent to which we see CHD in an
animal is influenced by environmental factors such as nutrition and exercise.
The rate at which CHD develops varies between
dogs, as does the severity of the disease.
Can we test for hip
dysplasia?
There is no DNA, or genetic test for CHD. The physical status of the hip joint is assessed on x-rays (radiographs).
In Australia dogs may be hip scored once they are 12 months of age.
The dog’s hips are positioned whilst the dog is under anaesthesia, and
x-rays are taken. The degree of malformation of nine different parts of the
hips is graded on a scale from 0 (best) to 6 (worst) for all except one
feature, which is graded 0 to 5. These numbers are added together to
generate a 'hip score'. The maximum score for each hip is 53, giving
a total maximum score of 106. The lower the score the better the
hips. Unless the submitted x-rays are not of
appropriate standard, a dog is not scored again.
Can we prevent hip
dysplasia?
By using dogs with good hips for breeding, the breeder will reduce the
chance of producing a dog with poor hips. The hip score for a
prospective sire and dam are not the only scores which should be
considered - hip scores of relatives should all be considered. For
further information about hip dysplasia and it's control, the Orthopedic Foundation for Animals in the
USA (OFA) would be
a place one could start reading.
Hip Scoring in Australia. In Australia, the
hip score results are not published in the Kennel Club
journals, as they are in Britain and New Zealand, or online as they are by
the OFA in the USA. The owner of the
dog receives papers which show the evaluation of the hips.
The majority of Vizslas in Australia haven’t been hip scored, and not
all who have been scored are necessarily entered into the AVA scheme, so
we do not really know how representative the breed average score is for
our Vizslas. Only dogs that are permanently identified (eg
microchip) are included in the AVA/ANKC scheme. Hopefully with increased awareness by breeders and owners, more dogs will be scored in the
future, thus adding to our knowledge of our dogs, and reducing our chances
of producing dogs with dysplastic hips.
In March 2006, 185 Australian Vizslas had been scored,
representing approximately 3.5% of the total registered population over one year of age
[1]. The breed average score is
11.97 (total of scores for right and left hips). The best score = 0, the worst = 81
[2]. The previous breed average of 12.34 in 2003 was based on 150
submissions [3].
In the United Kingdom where a similar scoring scheme to
that in Australia is in operation, to improve hip scores (lower the
score), it is advised; “Breeds where lameness from canine hip dysplasia
occurs only occasionally still require to take steps to eliminate the
problem and for them it is important to breed only from animals whose
scores are specifically well below BMS [Breed Mean Score – or breed
average score], since to use those at BMS can be predicted to
perpetuate the problems.” [4] (my emphasis). This relies on
having a sufficient number of dogs scored across the breed, so that the
average score is a true reflection of the breed.
Many breeds where hip scoring is not mandatory or not
commonly performed, rely on dogs at public stud being hip scored, whilst
far fewer bitches are scored. Recent studies of the heritability of
hip dysplasia in flat-coated retrievers and in Gordon Setters show it is
equally, if not more important in these breeds for the dam to be hip
scored [5, 6]. A study of Labradors found hip scores would be
improved if both parents had scores of zero [7] – that is, to reduce the
occurrence of hip dysplasia, the selection pressure needs to be increased.
Every
breeder in Australia is bound by the Code of Ethics and by the Code of
Practice for Hereditary Diseases. The Hereditary Diseases code
requires breeders test for all problems that have been declared a
hereditary disease in their breed. No disease has been
‘declared’ a problem in Hungarian Vizslas in Australia. However,
we do not need a problem to be ‘declared’ before we can work towards
decreasing its’ incidence – by breeding from dogs with good hips (and
whose relatives also have good hips), the breeder will reduce the chance
of producing a dog with poor hips.
With increased awareness by breeders and owners, more dogs
may be hip scored in the future, thereby adding to our knowledge of our
dogs, and increasing our future chances of producing fewer dogs with poor
hips.
**Update** - The Australian Vizsla Health Test Registry
is a website where breeders and owners of both smooth and wirehaired
Hungarian Vizslas may share health test information (hip results from AVA/ANKC
or PennHIP schemes, elbow scores, eye certification or other health test
results). To participate or to view the submitted results, see the website
for further details.
1. Based on Hungarian Vizsla registrations
published in canine association publications in Australia, 1973-2005
2. AVA/ANKC hip score data, to March,
2006
3. AVA/ANKC hip score data to 31 March,
2003
4. Lawson, DD. Hip dysplasia and
its control in Great Britain in: Morgan JP, Wind A, Davidson AP.
Hereditary bone and joint diseases in the dog: hip dysplasia, elbow
dysplasia. Schlütersche, Hannover 2000 p272-275
5. Wood JLN, Lakhani KH, Dennis
R. Heritability and epidemiology of canine hip-dysplasia score in
flat-coated retrievers and Newfoundlands in the United Kingdom. Prev
Vet Med 2000; 46: 75-86
6. Wood JLN, Lakhani KH, Dennis
R. Heritability of canine hip-dysplasia score and its components in
Gordon Setters. Prev Vet Med 2000; 46: 87-97
7. Wood JLN, Lakhani KH, Rogers
K. Heritability and epidemiology of canine hip-dysplasia score and
its components in Labrador retrievers in the United Kingdom. Prev
Vet Med 2002; 55: 95-108
Adapted from: "Hereditary Disease in the
Vizsla" in: Vizslas Down Under 1999-2001.
Note: the above information is not intended as a
substitute for veterinary advice.
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