Review of genetic aspects of radiological alterations in the navicular bone of the horse.
Authors: Diesterbeck, Distl
Journal: DTW. Deutsche tierarztliche Wochenschrift
Summary
Radiological changes in the navicular bone affect between 15% and 88% of warmblood horses, with heritability estimates ranging from h² = 0.09 to h² = 0.40, indicating that genetic selection can meaningfully reduce disease prevalence. Diesterbeck and Distl's review synthesised evidence on the genetic architecture of podotrochlosis, including genome-wide association data from Hanoverian horses that identified quantitative trait loci (QTL) on equine chromosomes 2, 3, 4, 10, and 26, with genome-wide significance on ECA2 and ECA10. Crucially, radiological navicular changes appear to develop largely independently of other orthopaedic conditions genetically, yet show negative genetic correlation with athletic performance traits—meaning horses with radiologically normal navicular bones tend to perform better in competition. Simultaneous selection for improved breeding values for both navicular bone health and sport performance is achievable and can reduce disease incidence whilst maintaining competitive ability. These findings provide breeders and veterinarians with evidence-based markers to identify at-risk bloodlines earlier and make informed selection decisions that improve limb soundness across populations.
Read the full abstract on PubMed
Practical Takeaways
- •Genetic screening and marker-assisted selection can help reduce prevalence of radiological navicular changes in breeding populations
- •Performance and navicular health are not genetically opposed—horses can be selected for both sound limbs and competitive ability simultaneously
- •Early radiographic screening of young horses combined with genomic testing offers practical tools to identify at-risk individuals before clinical lameness develops
Key Findings
- •Radiological alterations in navicular bone occur in warmblood populations at frequencies between 14.9% and 87.6%
- •Heritability estimates for navicular disease range from h² = 0.09 to h² = 0.40, indicating genetic factors play an important role
- •Significant QTL for navicular pathology were identified on equine chromosomes 2, 3, 4, 10, and 26, with genome-wide significance on ECA2 and ECA10
- •Simultaneous selection for both reduced radiological changes and improved performance traits can achieve genetic improvement in both navicular health and competition success