Heritabilities of health traits in Swiss Warmblood horses.
Authors: Lauper M, Gerber V, Ramseyer A, Burger D, Lüth A, Koch C, Dolf G
Journal: Equine veterinary journal
Summary
# Editorial Summary: Heritabilities of Health Traits in Swiss Warmblood Horses Equine sarcoid disease shows meaningful heritability (0.21) in Swiss Warmblood horses, suggesting that genetic selection could meaningfully reduce its prevalence in breeding programmes, whereas four other commonly assessed health traits—brittle hoof horn (0.04), marked growth ring formation (0.03), prognathism (0.06) and increased talocrural joint filling indicative of osteochondrosis (0.08)—demonstrate very low heritabilities that limit the effectiveness of selection pressure alone. This retrospective analysis drew on comprehensive clinical examinations of 3,715 Swiss Warmbloods from 2005 to 2013, integrated into a pedigree database of over 217,000 horses, with heritability estimates derived using sophisticated animal model methodology. The notably low prevalences of these conditions (2.4–13.0%) and the substantial variation introduced by different examiners raises a critical practical concern: inconsistent assessment protocols may have masked true genetic effects for some traits and inflated estimates for others. For practitioners and breeders, these findings suggest that whilst genetic selection for sarcoid resistance is viable, improvements in hoof quality and joint health should prioritise environmental and management factors alongside any selective breeding approach, and that establishing standardised clinical examination criteria across breed society evaluations would strengthen future genetic assessments and the reliability of breeding recommendations.
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Practical Takeaways
- •Sarcoid disease has a genetic component worth considering in breeding decisions, but environmental/management factors likely play major roles in other health traits studied
- •The low heritabilities for hoof quality and joint issues mean breeding selection alone won't substantially reduce these problems—farriery, nutrition, and management are critical intervention points
- •Inconsistency between examiners at field inspections is significant; standardized evaluation protocols should be implemented to improve reliability of trait assessment and genetic estimates
Key Findings
- •Equine sarcoid disease showed moderate heritability of 0.21 ± 0.07, making it the most heritable trait examined
- •Hoof horn quality defects (brittle/friable horn and growth ring formation) showed low heritability estimates of 0.04 ± 0.02 and 0.03 ± 0.01 respectively
- •Prognathism and increased talocrural joint filling showed low heritabilities of 0.06 ± 0.03 and 0.08 ± 0.04
- •Examiner variance was considerable across all traits, suggesting standardized protocols could improve assessment reliability