Ossification of the cartilages in the front feet of young Norwegian coldblooded horses.
Authors: Holm A W, Bjørnstad G, Ruohoniemi M
Journal: Equine veterinary journal
Summary
# Editorial Summary Premature ossification of the collateral sesamoidean cartilages (ungulate cartilages) in young horses can compromise foot biomechanics and potentially predispose to lameness, yet little was known about its prevalence and hereditary factors in cold-blooded breeds. Holm and colleagues radiographed the front feet of 392 Norwegian coldblooded horses aged approximately 2 years old, examining dorsopalmar views for ossification patterns at the cartilage base and separate ossification centres across 45 different paternal lines. Whilst minimal to mild ossification at the cartilage base was common, significant ossification (extending above the navicular bone or presenting as separate centres) occurred in 11.5% of the cohort overall, with notable sex differences: females showed substantially greater prevalence of both significant ossification and multiple separate centres compared to males, and lateral cartilages ossified more readily than medial ones. Most strikingly, offspring of one frequently used stallion demonstrated significant ossification in 46.3% of individuals—more than thirteen times the rate seen in progeny of four other popular sires (3.5%)—indicating a strong hereditary component to this trait in the breed. These findings have clear implications for breeding selection in coldblooded stock, as sires demonstrating high incidence of early cartilage ossification in their offspring should be identified and potentially avoided to reduce the risk of developmental orthopaedic disease in young horses destined for heavy work.
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Practical Takeaways
- •When evaluating young Norwegian coldblooded horses for soundness, expect mild cartilage ossification at the base as a normal finding, but investigate further if ossification extends above the navicular bone or shows separate centres
- •Breeding decisions should consider sire selection, as there is substantial genetic variation in predisposition to significant cartilage ossification in this breed
- •Female Norwegian coldblooded horses are at higher risk for cartilage ossification than males and may warrant closer monitoring during early development
Key Findings
- •Significant ossification of cartilages occurred in 11.5% of 2-year-old Norwegian coldblooded horses evaluated radiographically
- •Lateral cartilages showed more ossification than medial cartilages, and females had significantly more ossification and separate centres than males
- •Offspring of one frequently used stallion showed 46.3% prevalence of significant ossification compared to 3.5% in offspring of other popular stallions and 9.6% in offspring of less frequently used stallions
- •Results indicate ossification of cartilages has a hereditary background in Norwegian coldblooded horses