title: Prevalence and inheritance of and selection for hip dysplasia in seven breeds of dogs in Sweden and benefit: cost analysis of a screening and control program.
abstract: OBJECTIVE
  To determine the prevalence and changes over time in the prevalence of hip dysplasia; to ascertain whether prevalence or severity of hip dysplasia was associated with sex of the dogs, age at which coxofemoral joint status was evaluated, or ancestral background; to determine the effects of selective breeding; and to conduct an economic evaluation of the hip dysplasia program operated by the Swedish Kennel Club.
  
  
  METHODS
  Analysis of radiographic evaluations of coxofemoral joint conformity.
  
  
  METHODS
  83,229 dogs from 7 breeds registered by the Swedish Kennel Club.
  
  
  METHODS
  All radiographs were scrutinized by a single radiologist (LA), and coxofemoral joint conformation was classified as normal or dysplastic, with the degree of dysplasia classified as 1,2,3, or 4.
  
  
  RESULTS
  Decreasing prevalence of hip dysplasia corresponding to selection of breeding stock and high heritabilities was found. Sex differences were documented in 3 of the breeds. This was interpreted as breed differences in the distribution of genes related to hip dysplasia. Economic analyses showed that costs of screening and registration of coxofemoral joints was less than the value of dogs estimated to have been saved from moderate, severe, or very severe hip dysplasia in 6 of the breeds.
  
  
  CONCLUSIONS
  Documented effects of age suggest that all dogs should be screened at the same age, rather than screening a few dogs at an older, more revealing age. In screening and control programs based on an open registry with access to family records, decreasing prevalence of hip dysplasia can be expected, and related to selection of breeding stock.
authors.affiliation: Department of Animal Breeding, Faculty of Agriculture, Swedish University of Agricultural Sciences, Uppsala, Sweden.
authors.forename: L
authors.initials: L
authors.lastname: Swenson
authors.forename: L
authors.initials: L
authors.lastname: Audell
authors.forename: A
authors.initials: A
authors.lastname: Hedhammar
mesh_terms: D017677:Age Distribution; D000818:Animals; D001947:Breeding; D003362:Cost-Benefit Analysis; D004285:Dogs; D005260:Female; D006619:Hip Dysplasia, Canine / Q000145:classification / Q000453:epidemiology* / Q000235:genetics* / Q000517:prevention & control; D006621:Hip Joint / Q000000981:diagnostic imaging; D008297:Male; D008403:Mass Screening / Q000191:economics / Q000662:veterinary*; D015995:Prevalence; D011859:Radiography; D012641:Selection, Genetic; D012720:Severity of Illness Index; D017678:Sex Distribution; D013548:Sweden / Q000453:epidemiology