Hoof renewal time from birth of Thoroughbred foals

A circumferential ring in the hoof horn of foals occurs at birth and grows down to the distal border as the fetal hoof is replaced. Horn growth and complete hoof capsule renewal have not been measured in Thoroughbred foals but the determination of time of hoof renewal may allow accurate predictions of healing time to be made in cases of hoof lesions. The objective of this study was to measure the time taken for the fetal hoof of newborn foals to grow to the distal border and be replaced by hoof grown since birth. The age of the foal in days on the day that routine hoof trimming removed the hoof ring of the front hooves was recorded. The mean age at which the fetal hoof was removed was 145 ± 15 days (95% CI, 141.8–147.2), range 120–165 days. Thoroughbred foals replaced the fetal hoof in approximately half the time taken for mature horses (270–365 days).