Evaluation using hoof wall strain gauges of a therapeutic shoe and a hoof cast with a heel wedge as potential supportive therapy for horses with laminitis.

This study evaluated the use of a hoof cast with heel wedge and a therapeutic shoe with an unsupported toe as potential treatments for horses with laminitis. Researchers used strain gauges on the hoof wall to see how effectively these treatments redistributed load from the dorsal hoof wall.

Methodology

• The scientists conducted an in vitro biomechanical study involving 20 forelimb specimens.
• Rosette strain gauges were placed on the dorsal and lateral hoof wall of normal shaped hooves. These gauges help measure the strain or deformation of an object, in this case, the horse’s hoof.
• The limbs were subjected to vertical loading using a tensile testing machine. This machine applied a sinusoidally cycling load up to 3000 N during a period of 15 seconds.
• The study evaluated mean values of principal strain and direction at 2500 N load under three different experimental conditions: unshod, with a therapeutic shoe with unsupported toe, and with a hoof cast with heel elevation. The data were analyzed using ANOVA for statistical significance.

Results

• Under normal circumstances, vertical limb loading in an unshod hoof produced a biaxial compression of the dorsal wall with high longitudinal compression (measured as epsilon2 = -1515 microm/m).
• The application of the therapeutic shoe resulted in a 23% decrease in principal strain at the dorsal wall, while the use of the hoof cast resulted in a 59% decrease.
• The lateral hoof wall’s principal strain remained unchanged when the therapeutic shoe was applied, but it increased by 34% when the cast was applied.

Conclusion

• Based on the strain measurements, both the therapeutic shoe and the hoof cast effectively unloaded the dorsal hoof wall. However, the cast was slightly more effective than the shoe.
• The hoof cast with the wedge substantially unloaded the dorsal wall but increased the load on the quarter. This indicates that it could be the most useful in cases of acute laminitis when the palmar structures can still bear load.
• In contrast, the therapeutic shoe facilitated rehabilitation and regrowth of the dorsal wall without adding extra load on the quarter wall. This means it could be ideal for longer-term treatment and recovery from the condition.