In vitro strength of the suspensory apparatus in training and resting horses.

The research studies the strength of the horse’s suspensory apparatus, discovering that active training appears to strengthen this system, evidenced by the fact that under force, less active horses would experience failure in the suspensory ligament while more active horses will see failure in the sesamoid bones.

Research Methodology

• The study used 48 limbs from 12 freshly euthanized horses. This allowed the researchers to directly study the effect of pressure on the horse’s suspensory apparatus.
• Out of the 12, six horses were noted to be actively training or racing before euthanasia and the other six were either pasture exercised or stalled.
• The research method involved determining the point of failure in the suspensory apparatus of each limb. This means identifying where the system failed when progressively more pressure was added.

Active Training and Racing Horses’ Findings

• The suspensory apparatus in these horses usually failed at the proximal sesamoid bones – failing in 20 out of 24 legs. The specific types of failures observed were 17 apical fractures, 2 basilar fractures, and 1 midbody fracture.
• An average force of 1338 kg, within a range of 1082 to 1673 kg, was required to cause failure within the suspensory apparatus.

Pasture Exercised or Stalled Horses Findings

• The study found that the suspensory apparatus most often fails at the suspensory ligament. It happened acutely in 10 horses (42%) or insidiously (gradually becoming apparent) in 12 horses (50%).
• For these horses, the average force required to cause failure was 1100 kg, falling within a range of 918 to 1241 kg, significantly less than the force in the first group of horses.

Conclusion

• The results of the study indicate that active training appears to fortify the suspensory apparatus in horses, shifting the weakest point from the suspensory ligament to the sesamoid bones.
• Furthermore, the study supports the notion that horses in active training or racing possess a stronger suspensory apparatus — capable of withstanding larger forces before failure — than horses in less strenuous activities.