title: Estimation of heritabilities, genetic correlations, and breeding values of four traits that collectively define hip dysplasia in dogs.
abstract: OBJECTIVE-To estimate heritabilities and genetic correlations among 4 traits of hip joints (distraction index [DI], dorsolateral subluxation [DLS] score, Norberg angle [NA], and extended-hip joint radiograph [EHR] score) and to derive the breeding values for these traits in dogs. ANIMALS-2,716 dogs of 17 breeds (1,551 dogs in which at least 1 hip joint trait was measured). PROCEDURES-The NA was measured, and an EHR score was assigned. Hip joint radiographs were obtained from some dogs to allow calculation of the DI and DLS score. Heritabilities, genetic correlations, and breeding values among the DI, DLS score, NA, and EHR score were calculated by use of a set of multiple-trait, derivative-free, restricted maximum likelihood computer programs. RESULTS-Among 2,716 dogs, 1,411 (52%) had an estimated inbreeding coefficient of 0%; the remaining dogs had a mean inbreeding coefficient of 6.21%. Estimated heritabilities were 0.61, 0.54, 0.73, and 0.76 for the DI, DLS score, NA, and EHR score, respectively. The EHR score was highly genetically correlated with the NA (r = -0.89) and was moderately genetically correlated with the DI (r = 0.69) and DLS score (r = -0.70). The NA was moderately genetically correlated with the DI (r = -0.69) and DLS score (r = 0.58). Genetic correlation between the DI and DLS score was high (r = -0.91). CONCLUSIONS AND CLINICAL RELEVANCE-Establishment of a selection index that makes use of breeding values jointly estimated from the DI, DLS score, NA, and EHR score should enhance breeding programs to reduce the incidence of hip dysplasia in dogs.
authors.affiliation: Institute for Genomic Diversity, College of Veterinary Medicine, Cornell University, Ithaca, NY 14850, USA.
authors.forename: Zhiwu
authors.initials: Z
authors.lastname: Zhang
authors.forename: Lan
authors.initials: L
authors.lastname: Zhu
authors.forename: Jody
authors.initials: J
authors.lastname: Sandler
authors.forename: Steven S
authors.initials: SS
authors.lastname: Friedenberg
authors.forename: Jill
authors.initials: J
authors.lastname: Egelhoff
authors.forename: Alma J
authors.initials: AJ
authors.lastname: Williams
authors.forename: Nathan L
authors.initials: NL
authors.lastname: Dykes
authors.forename: William
authors.initials: W
authors.lastname: Hornbuckle
authors.forename: Ursula
authors.initials: U
authors.lastname: Krotscheck
authors.forename: N Sydney
authors.initials: NS
authors.lastname: Moise
authors.forename: George
authors.initials: G
authors.lastname: Lust
authors.forename: Rory J
authors.initials: RJ
authors.lastname: Todhunter