Genetic analyses of the radiographic appearance of the distal sesamoid bones in Hanoverian Warmblood horses.

This study is about determining if there are inherited genetic connections between certain visual features of the distal sesamoid bones in Hanoverian Warmblood horses, as seen in radiographs, and other limb changes.

Objective and Methods of the Research

• The analysis seeks to investigate the existence of additive genetic correlations between certain features of the distal sesamoid bones, also known as navicular bones (NBs), as seen in radiographs or between the radiographic appearance of these bones and other types of changes in the limbs of Hanoverian Warmblood horses.
• The study evaluated 5,157 horses and recorded traits like the appearance of the canales sesamoidales (CSs) and the structure and form of the forelimb NBs.
• The study also looked at the prevalence of bone fragments in specific joints as well as deforming joint diseases. They analyzed these traits using multivariate linear models.

Key Findings

• The observations demonstrated that the heritability estimates for various aspects of the navicular bones ranged from 10% to 34%.
• Additive genetic correlations among these different traits were found to be high, often close to one.
• Dramatic radiographic changes in the NBs, such as alterations in CSs and the structure and contour, were linked with less distinct radiographic changes.
• Negative genetic correlations were found between a small number of short and conical CSs at the center of the bottom border of the NB and bone fragments and joint diseases; and between most types of radiographic findings of the NBs and bone fragments in the tarsal joints.

Conclusions and Implications

• This suggests that genetic bases for different types of RNB were not identical highlighting the need for more research to examine the correlations observed between normal distal sesamoid bones and the findings of short and conical CSs versus deformed CSs and structural and contour changes.
• This kind of distinction that takes into account genetic justification between normal and pathological navicular bone changes could improve the efficiency of selecting against navicular bones with radiographically evident alterations, benefitting the horse breeding and health sector.