A preliminary investigation of hoof circumferential changes of riding school horses with an increase in workload

Reasons for performing study: Hoof conformation responds to mechanical demands; the impact of these are not well documented, especially for horses in a non-competitive but high workload environment. Objectives: To investigate changes in circumferential hoof variables of riding school horses. Study design: Observational, cohort study. Methods: Repeated hoof base (HB) and coronet band (CB) measures were collected via tape measure at three 5 week intervals (DC1-3), from September, from 32 shod (all, n=17; shod front only, n=12) and unshod (n=3) riding school horses. Shod forefeet were sub-grouped into toe-clips (n=16) and side-clips (n=9). Workload increased from low to medium-high intensity across the study. Wilcoxon’s matched-pairs determined circumferential differences between left-right hooves for each DC (p<0.05); Kruskal-wallis analyses with post-hoc and Bonferroni adjustment (P≤0.02) examined differences between DC. Results: Right forelimb was significantly larger than left at DC3 for CB (p≤0.05) and for HB and CB in the hind-limb (DC1 p≤0.05; DC2 p≤0.05; DC3 p≤0.001). CB differed significantly between DC1 (389.8mm) and DC2 (392.1mm) (p≤0.02). All variables, except asymmetry, differed between forelimb subgroups; CB asymmetry at DC1 was significantly lower (p≤0.02) for horses with toe-clips compared to side-clips. Mean hind CB in shod feet increased significantly (p≤0.02) between DC1-DC2. Routine management meant some horses had hind shoes removed between DC2-DC3; these demonstrated right CB increase at DC3; reflecting by a significant increase (p≤0.02) in mean CB between DC1-DC3. Conclusions: CB decrease has been associated with increased workload in racehorses [1]; for riding school horses, significant changes in hoof circumference were related to CB increase. Significant differences between values for shod and unshod hooves indicate variation in foot conformation associated with the use of shoes. Ethical Animal Research: Ethical approval for the study was granted by the UWE (Hartpury) Ethics Committee. Sources of funding: This study was funded by Hartpury College. Competing interests: None declared. [1] Decurnex, V., Anderson, G.A., Davies, H.M.S. (2009), Influence of different exercise regimes on the proximal hoof circumference in young Thoroughbred horses. Equine Vet J 41, 233-236