Hoof kinetic patterns differ between sound and laminitic horses.

Abstract

No kinetic data on hoof loading in laminitic horses are available, despite their importance for optimising supportive shoeing therapies. To quantify the load distribution pattern in laminitic and sound horses. Controlled observational study. Fifty-four sound and laminitic horses were assigned to three groups: control group (sound horses), group 1 (G1) horses with acute laminitis, evaluated immediately after acute clinical signs subsided, and group 2 (G2) horses that had been free of acute laminitis signs for 6-12weeks. Measurements on both forelimbs in barefoot condition were performed during walk using the Hoof™ System. Kinetic parameters were recorded and compared between hoof regions and groups using covariance analyses and t tests (P<.05). Peak loading in the toe region occurred during midstance phase in control group, but during break-over in laminitic horses. This is reflected by the time to peak vertical force in the toe, which was significantly shorter in the control group compared to laminitic horses (G1 and G2) (76%±6% vs 89%±9 [P=.002], 86%±7 [P=.001] of stance duration respectively). The relative vertical force in the toe in the control group (46%±7%) was significantly higher compared to laminitic horses (G1: 29%±9% [P=.001]; G2: 32%±10% [P=.003]). The main shift of the load occurred between toe and middle hoof regions in laminitic horses as compared with the control group. No significant differences were found between G1 and G2. Measurements were not obtained in horses with acute laminitis on admission, to avoid risk of further damage to the lamellae. Supportive therapy in laminitis should focus on supporting both caudal and middle hoof areas to decrease the peak pressure in these regions, and ease break-over during which the maximal loading of the toe occurs.