Page 488 - WSAVA2017
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An Urban Experience
WSVA7-0309
DSAVA: HEALTHY BREEDING
HANDLING AN INCREASED RISK OF INHERITED DISORDERS IN PEDIGREE DOGS: PAST, PRESENT AND FUTURE
A. Hedhammar1
1Swedish University of Agricultural Sciences, Department of Clincal Sciences, Uppsala, Sweden
HANDLING AN INCREASED RISK OF INHERITED DISORDERS IN PEDIGREE DOGS
PAST, PRESENT AND FUTURE
Åke Hedhammar DVM, PhD, Dipl. ECVIM- CA
Department of Clinical Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
Ake.hedhammar@slu.se
Although various types of dogs defined as breeds have been recognized for much longer, it is less than 150 years since national kennel clubs were established and stud books instituted to regulate breeding of Pedigree dogs (PGD). An increased international trade in dogs
of various breeds started and geographical barriers
were replaced by regulatory barriers between different populations of dogs. Selection for size, shape and variations in temperament has created breeds of dogs for an overwhelming wide range of functions. (1)
During the past century the burden of “unhealth” in humans as well companion animals in western societies have changed from infections and malnutrition to congenital, developmental and degenerative disorders. These entities are to great but variable extent influenced by inheritance.
Inherited disorders do occur in all populations of mammals including man as well as dogs. To greater extent in isolated and inbred populations but are documented in mixed bred dogs as well as in so named Pure bred dogs. Some of them accumulated to much greater extent in certain breeds but others of about the same prevalence (2)
Even if some inherited disorders are much more common in pedigree dogs the advantage is that by known pedigree we can follow the segregation and have possibilities for more sophisticated measures to select against them
There are mainly two problems that are overrepresented in PDGD. Related to conformation (3) and related
to small closed populations (4). To counteract these problems screening potential breeding stock for desired as well as undesired features has been practiced since long time.
PHENOTYPIC SCREENING
One method that has been practiced since long in animal breeding is to screen for advantageous phenotypes at various gathering as shows and trials. In the past also screening for disadvantageous phenotypes as inherited disorders have been instituted.
Ideally such a screening procedure should be easy and inexpensive to perform and thereby widely used in the selection of breeding stock.
Phenotypic screenings for diseases are based on the possibility to evaluate and indicate “affected as well as “none affected” individuals and thereby depicture the population.
More structured screening programs for specific entities as hip dysplasia and inherited ocular disorders can be dated back to the mid-19th.
Most phenotypic screening programs are based on
an ability to predict at an early age if a dog is going to develop an inherited disorder. Hip dysplasia is a typical example, where a standardized radiological procedure was proven to indicate if a dog would develop clinical signs by a deviation from normality regarding laxity and form of the hip. The origin of hip screening is a study from the Kennel of Swedish Armed Forces in which early screening for hip status predicted clinical signs of Hip Dysplasia (5)
In the late 1960’s the British Veterinary Association (BVA), in conjunction with the Kennel Club (KC), started a scheme to assist dog breeders in the eradication of the inherited eye disease, progressive retinal atrophy (PRA). Later the International Sheepdog Society also became involved because of their concerns about inherited eye diseases in Border collies.
INTERNATIONAL HARMONIZATION
Unfortunately screening programs for hip dysplasia as well as hereditary eye diseases despite similar function have evolved somewhat differently in UK, the rest of Europe and in US.
Both WSAVA and FCI have actively sought to harmonies national certificates and to implement international certificates for exchange of results from screening of hip, elbow and eye examinations. [6]
After screening programs for Hips and hereditary eye defects instituted in the mid 19th century a number of number of phenotypic screening programs have evolved on i.e. heart disease and patellar luxation.
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 42ND WORLD SMALL ANIMAL VETERINARY ASSOCIATION CONGRESS AND FECAVA 23RD EUROCONGRESS
  

































































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