Effect of hoof orientation and ballast on acceleration and vibration in the hoof and distal forelimb following simulated impacts ex vivo.

The researchers sought to understand the effects of different hoof-strike conditions and specimen mass on the impact loading of the distal limb in horses. Their findings indicate that the way a horse’s hoof strikes the ground significantly impacts how much potential damage could occur to their leg tissues, but adding weight does not affect these results.

Research Objective and Methodology

• The aim of this research was to add to the baseline data on the impact loading of the distal limb to help in understanding the potential role of impact in injury and joint disease in horses.
• The researchers tested three different hoof-strike conditions— toe first, flat, and heel first, and two specimen masses— with and without an added weight of about 2% body mass.
• The study used eight cadaver limbs in a controlled experimental setting in which the hoof was struck by a velocity controlled pendulum machine.
• Data from triaxial accelerometers attached to different parts of the limb (hoof, first phalanx, and third metacarpal) was collected to quantify variables like peak impact acceleration, frequencies following impact, and energy distribution.
• The research team used repeated-measures ANOVA for statistical testing of the effects of the two conditions— hoof-strike and mass— on various variables.

Results

• The results showed that the energy reaching the third metacarpal was just 6-31% of that initially generated at the hoof.
• A heel-first strike produced the highest accelerations and frequencies among all strike conditions.
• Interestingly, altering the mass of the limb, i.e., adding weight, had no significant effect on the impact, regardless of the strike condition.

Conclusions

• The study concludes that significant accelerations occur upon the impact of the hoof with the ground and these are attenuated by the distal structures of the equine limb.
• However, this impact still carries considerable energy that potentially could damage tissue, depending largely on the hoof-strike condition, and not on the weight.
• The findings suggest that impact loading on the hoof might be contributing to bone injury and joint disease in the distal limb of horses.