Genetic relationship between Neck and Limb defects in Pura Raza Española Horses.
Authors: Ripollés-Lobo M, Perdomo-González D I, Dos Santos R, Sánchez-Guerrero M J, Azor P, Valera M
Journal: Journal of equine veterinary science
Summary
# Editorial Summary: Genetic Links Between Neck and Limb Conformation in PRE Horses Neck and limb conformational defects independently compromise movement and performance in Pura Raza Española horses, yet their underlying genetic relationships have remained unexplored until now. Ripollés-Lobo and colleagues analysed 56,644 PRE horses assessed between 2012 and 2023, using both binary and ordinal scoring systems to quantify two neck defects (cresty and ewe neck) alongside twelve limb defects across forelimbs and hindlimbs, whilst controlling for age, sex, genetic origin, stud management, and inbreeding coefficients. Moderate genetic correlations were identified between neck and limb morphology, with splay-footed rear limbs appearing in 72–80% of horses displaying neck defects; notably, genetic correlations ranged from −0.22 to 0.51 across the various trait combinations, indicating both antagonistic and complementary genetic influences. The findings suggest these defects share common genetic architecture rather than arising independently, which has important consequences for selective breeding programmes—breeders cannot assume that selecting against neck defects will leave limb conformation unaffected, nor vice versa. These results advocate for integrated, multi-trait selection strategies that simultaneously evaluate both anatomical regions to minimise the compound inheritance of conformational weakness in sport and breeding horses.
Read the full abstract on PubMed
Practical Takeaways
- •Breeders selecting for neck conformation should monitor and select against associated limb defects, particularly splay-footed rear limb which shows high co-occurrence with neck defects
- •Veterinarians evaluating PRE horses with neck defects should perform thorough limb conformation assessment, as genetic correlations suggest these traits are linked at the breeding level
- •Selection programs must adopt integrated approaches rather than focusing on individual traits, as improvements in neck conformation alone may inadvertently propagate limb defects through shared genetic pathways
Key Findings
- •Splay-footed rear limb was the most frequent limb defect co-occurring with neck defects (80.15% in cresty neck, 72.45% in ewe neck)
- •Moderate genetic correlations exist between neck and limb defects, ranging from -0.22 to 0.44 using two-class scoring and -0.25 to 0.51 using multi-class scoring
- •Strongest positive genetic correlation found between cresty neck and divergent hock (0.44) and between cresty neck and splay-footed forelimb (0.51 in approach B)
- •Study of 56,644 PRE horses (2012-2023) supports integrated selection strategies addressing both neck and limb morphology simultaneously