A preliminary study into the correlation of stiffness of the laminar junction of the equine hoof with the length density of its secondary lamellae.

This research explores the relationship between the mechanical behaviour and microscopic structure of the laminar junction in horse hooves, specifically whether the stiffness of the laminar junction is related to the length density of its secondary lamellae. The findings indicate that higher length density of the laminar junction basement membrane is associated with higher resistance to stress, potentially offering a simple tool for identifying initial signs of laminitis.

Research Methods

• 25 samples of the laminar junction from different parts (front, quarter, and heel) of 3 horse hooves were collected.
• The samples were subjected to uniaxial tensile tests till rupture to measure parameters including Young’s modulus of elasticity, ultimate stress and strain.
• The specimens neighboring those used in the biomechanical analysis were processed histologically to study the length density of the laminar junction basement membrane using stereological grids.

Results

• The median length density of the laminar junction basement membrane was found to be 0.024/µm.
• The Young’s modulus of elasticity was found to be 0.15 MPa in the small deformation region and 7.58 MPa in the linear region.
• The ultimate stress was 1.67 MPa, and the ultimate strain was 0.50.
• In the region of small deformations, the Young’s modulus of elasticity has a moderate correlation with the length density of the laminar junction basement membrane.

Conclusions

• The laminar junction, like many other soft biological tissues, exhibits nonlinear mechanical behavior.
• Within the range of small deformations equivalent to physiological loading, a higher length density of the laminar junction basement membrane is associated with a higher resistance of the junction to high stresses transmitted from the distal phalanx to the hoof wall.
• Quantification of the condition of the laminar junction apparatus in terms of the length density of profiles of secondary dermal lamellae could be a useful tool for comparing the susceptibility of the various parts of the laminar junction to the onset of laminitis.