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This Article Full Text Full Text (PDF) All Versions of this Article: jas.2008-1199v1 87/6/1906    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Google Scholar Articles by van Grevenhof, E. M. Articles by van Arendonk, J. A. M. PubMed PubMed Citation Articles by van Grevenhof, E. M. Articles by van Arendonk, J. A. M.

Genetic variables of various manifestations of osteochondrosis and their correlations between and within joints in Dutch warmblood horses¹

E. M. van Grevenhof^*,2, A. Schurink^*, B. J. Ducro^*, P. R. van Weeren, J. M. F. M. van Tartwijk, P. Bijma^* and J. A. M. van Arendonk^*

^* Animal Breeding and Genomics Centre, Wageningen University, PB 338, Wageningen, the Netherlands; and Veterinary Faculty, Department of Equine Sciences, Utrecht University, 3508 TD, Utrecht, the Netherlands; and Royal Dutch Warmblood Studbook of the Netherlands, 3846 AK, Harderwijk, the Netherlands

² Corresponding author: ilse.vangrevenhof{at}wur.nl

Osteochondrosis (OC) is an important orthopedic developmental disorder in many horse populations. A review of the literature revealed widely variable heritability estimates for the disorder. We estimated the genetic variables (heritabilities and genetic correlations) of various manifestations of OC. Femoropatellar, tarsocrural, and metacarpophalangeal and metatarsophalangeal joints of 811 randomly selected yearlings from the Royal Warmblood Studbook of the Netherlands, descending from 32 representative stallions, were scored for OC at 28 predilection sites. At each site, OC was scored in 5 categories, distinguishing between flattened bone contours and fragments. At the animal level, the overall heritability of OC was 0.23, the heritability of flattened bone contours was 0.08, and the heritability of fragments was 0.22. At the joint level, heritability was greatest in the tarsocrural joints, intermediate in the metacarpophalangeal and metatarsophalangeal joints, and least in the femoropatellar joints. The heritability estimates for the contralateral joint homologs were very similar. The genetic correlation between the tarsocrural and femoropatellar joint was strong, whereas correlations between the metacarpophalangeal and metatarsophalangeal and other joints were moderate. The genetic correlation between flattened bone contours and fragments at the animal level was 0.80. Scoring OC on a 5-point categorical scale resulted in greater heritability on the observed scale than when analyzing OC as a binary trait. Our results suggest that selection against OC could best be performed by taking into account the OC status of all 4 joints, the femoropatellar, the tarsocrural, and the metacarpophalangeal and metatarsophalangeal joints, and discerning between flattened bone contours and fragments.

Key Words: genetic correlation • heritability • horse • joint • osteochondral fragment • osteochondrosis