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

SIMPLE SUMMARY: This study explored changes in hoof shape related to the application of horseshoes. Past research has indicated that horse hooves change shape in response to gallop exercise, so this study sought to separate the changes due to exercise from changes due to wearing horseshoes. Amongst the most important findings were that proximal (coronary band) hoof circumference decreased more when horses were shod compared to barefoot, and hoof angle decreased when horses were shod but increased when horses were barefoot over a seven-week interval. A better understanding of the relationship between hoof shape and shoeing could help improve horse management practices. ABSTRACT: 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.