Effects of Heel Nails on the Hoof

At the University of California, Davis, researchers used cadaver limbs loaded in a hydraulic press to determine the effects of being barefoot and three different nailing patterns (two toe nails; two toe and two quarter nails; and two toe, two quarter and two heel nails) on hoof wall surface strains, deformation and expansion under loads that simulated full weight bearing at the walk, trot and canter.

Nine limbs transected across the middle of the radius of nine horses were used, and the shoeing treatment utilized a Queen’s Plate XT. Rosette surface strain gauges (six) and markers (14) were attached to the hoof and lower limb to measure the magnitude and direction of surface strains as well as movement of the limb and hoof wall.

As expected, fetlock extension increased significantly with increased loading but did not vary by treatment. Hoof expansion approximately doubled at the trot compared with the walk and at the canter compared with the trot. The heel area showed the largest hoof wall expansion, which increased with increasing loads, and expansion in the quarters was great proximally compared with distal measurements. More palmar-placed nails (quarter and heel nails compared with toe nails) decreased expansion of the heels, and heel nails (compared with toe nails) changed hoof wall deformation during loading. The authors suggest in the live horse this could change hoof conformation over time resulting in underrun heels and increased risk of injury.

— Dahl VE et al. Animals 2023:13:1872