LAUSR

&NA; Copper‐coated steel nails are being increasingly used during shoeing due to their proposed ability to reduce bacterial invasion, despite limited evidence for their effectiveness in this application. The aim of the present study was to determine whether copper‐coated horseshoe nails would have a beneficial effect on nail hole health compared to traditional steel nails. All horses were shod by the same farrier at 5‐ to 6‐week intervals. In phase one of the study, a cohort of 11 sport horses was shod for two shoeing cycles using copper‐coated nails in the left forefoot (LF) and steel nails in the right forefoot (RF). To eliminate bias related to the use of the same foot in all animals, a second phase of the study was carried out where a subset (n = 6) of the horses were then reshod for two shoeing cycles using a cross‐over design. In phase two, the copper‐coated nails were used in the RF and steel nails in the LF after a washout period. At the completion of each phase, the horseshoes were removed and the feet trimmed for reshoeing. Before reshoeing, a photograph was taken of the solear surface of each foot and a 10‐point pathology score scale was used to assess nail hole health. Overall, the mean ± standard error nail hole pathology score was significantly (P < .01) higher (less healthy) for the steel nails (6.1 ± 0.31), compared with the copper‐coated nails (4.4 ± 0.27). Following the cross‐over period, the mean ± standard error nail hole pathology score was found to be similar for the LF and RF for each type of nail. Consistent with phase one of the study, there was a significant difference between the pathology scores when copper‐coated nails were used in the RF, compared to the steel nails. It appears that the well‐known antimicrobial effects of copper may apply to the application of copper coating of horseshoe nails in reducing the microbial damage to the horses' hoof frequently associated with horseshoe nail insertion. HighlightsCopper‐coated horseshoe nails are used despite limited evidence for their effectiveness.Nail hole pathology score was higher for the steel nails compared with the copper‐coated nails.Antimicrobial effects of copper appear to apply to the use of copper coating of horseshoe nails.