title: Estimates of genetic parameters of distal limb fracture and superficial digital flexor tendon injury in UK Thoroughbred racehorses.
abstract: A retrospective cohort study of distal limb fracture and superficial digital flexor tendon (SDFT) injury in Thoroughbred racehorses was conducted using health records generated by the British Horseracing Authority (BHA) between 2000 and 2010. After excluding records of horses that had both flat and jump racing starts, repeated records were reduced to a single binary record per horse (n = 66,507, 2982 sires), and the heritability of each condition was estimated using residual maximum likelihood (REML) with animal logistic regression models. Similarly, the heritability of each condition was estimated for the flat racing and jump racing populations separately. Bivariate mixed models were used to generate estimates of genetic correlations between SDFT injury and distal limb fracture. The heritability of distal limb fracture ranged from 0.21 to 0.37. The heritability of SDFT injury ranged from 0.31 to 0.34. SDFT injury and distal limb fracture were positively genetically correlated. These findings suggest that reductions in the risk of the conditions studied could be attempted using targeted breeding strategies.
authors.affiliation: School of Veterinary Medicine, University of Glasgow, 464 Bearsden Road, Glasgow G61 1QH, UK. Electronic address: c.walls.1@research.gla.ac.uk.
authors.forename: Claire E
authors.initials: CE
authors.lastname: Welsh
authors.affiliation: Centre for Preventive Medicine, Animal Health Trust, Newmarket CB8 7UU, UK.
authors.forename: Thomas W
authors.initials: TW
authors.lastname: Lewis
authors.affiliation: Centre for Preventive Medicine, Animal Health Trust, Newmarket CB8 7UU, UK.
authors.forename: Sarah C
authors.initials: SC
authors.lastname: Blott
authors.affiliation: School of Veterinary Medicine, University of Glasgow, 464 Bearsden Road, Glasgow G61 1QH, UK.
authors.forename: Dominic J
authors.initials: DJ
authors.lastname: Mellor
authors.affiliation: Equine Science and Welfare Department, British Horseracing Authority, London, WC1V 6LS, UK.
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Stirk
authors.affiliation: School of Veterinary Medicine, University of Glasgow, 464 Bearsden Road, Glasgow G61 1QH, UK.
authors.forename: Timothy D H
authors.initials: TD
authors.lastname: Parkin
mesh_terms: D000818:Animals; D050723:Fractures, Bone / Q000209:etiology / Q000235:genetics / Q000662:veterinary*; D006736:Horses / Q000235:genetics* / Q000293:injuries*; D012189:Retrospective Studies; D013177:Sports; D013708:Tendon Injuries / Q000209:etiology / Q000235:genetics / Q000662:veterinary*; D006113:United Kingdom
keywords: Fracture; Heritability; Tendon; Thoroughbred