Canine hip dysplasia: study of heritability in 401 litters of German Shepherd dogs
Hedhammar, A.; Olsson, S.E.; Andersson, S.A.; Persson, L.; Pettersson, L.; Olausson, A.; Sundgren, P.E.
Journal of the American Veterinary Medical Association 174(9): 1012-1016
1979
ISSN/ISBN: 0003-1488 PMID: 570968 Document Number: 151781
Heritability of hip dysplasia was estimated to be about 0.4 to 0.5 when based on the radiographic evaluations of the hip joints of 2404 German Shepherd dogs born at the Armed Forces Dog Training Centre in Sweden. The material included all dogs in 401 litters born at the centre from 1965 to 1973 that reached the age of 15 months. Frequency of hip dysplasia in the offspring was influenced by the hip joint status of sire and dam, as well as by that of their parents and littermates. Even matings between sires with normal hip joints and dams with only slight dysplasia resulted in an increased frequency of hip dysplasia in the offspring. Frequency of hip dysplasia in the progeny of sires with normal hip joints varied greatly. Since 1973, selection of the breeding stock has been based on hip joint status (phenotype) of the breeding animals and of their relatives as well as on what had become known about frequency of hip dysplasia in the litters already born (progeny testing). In this way, frequency of hip dysplasia in 347 dogs born at the Centre during 1975 was lowered to 28%. This figure should be compared with the figure of 50%, which represents the frequency of hip dysplasia in the kennel up to 1970, when selection was not as strict as could be expected in a well-controlled kennel.