Changes in Hoof Shape During a Seven-Week Period When Horses Were Shod Versus Barefoot.

This crossover study tested the hypothesis that hoof shape would differ after a seven-week period of horses (n = 11) wearing shoes versus barefoot. An ANOVA appropriate to a crossover design was used to assess the differences in the change in hoof shape over the seven-week period and significance was set at p < 0.05. Results are displayed as the mean difference for horses when shod versus barefoot ± the SEM for the left (L) and right (R) front hooves. Proximal hoof circumference (PHC) decreased when horses were shod and barefoot, but this decrease was greater when horses were shod (L -0.65 ± 0.16 cm; p = 0.0026; R -0.78 ± 0.13 cm; p = 0.0002). Hoof angle increased slightly when horses were barefoot and decreased when they were shod (L -1.70 ± 0.31°; p = 0.0004; R -1.84 ± 0.54°; p = 0.0079). Sole length decreased more when horses were barefoot, but this was only significant for the right fore (R 5.07 ± 1.06 mm; p = 0.0010). Solar circumference increased when horses were barefoot but decreased when shod (L -1.19 ± 0.41 cm; p = 0.0182; R -1.50 ± 0.31 cm; p = 0.0010). This is the first study to show a significantly lower PHC when horses were shod compared to barefoot. The study suggests that shod horses may benefit from a shorter shoeing interval to help mitigate the changes in hoof angle.