While it takes nearly a year for an adult horse to grow out a length of hoof, a young foal can replace his hoof wall in half that time, according to new research from England.
Simon Curtis, a farrier working toward his master’s degree at the University of Central Lancashire, tracked hoof-horn growth in 45 newborn Thoroughbreds by charting the downward progress of the “foal hoof crease,” a visible growth ring that delineates hoof present at birth with hoof grown since. “All hoof wall eventually grows down to the bearing border and loses attachment by wear, breaking or rasping,” explains Curtis. “The foal hoof crease is obvious in all foals between 1 and 4 months of age.”
The foals in the study were trimmed by the same farrier every three weeks. At each visit, the farrier would note the distance from the coronary band that the foal crease had moved until it had grown out entirely. The data revealed the foals replaced their entire hoof wall in about 145 days, compared to the 270- to 365-day replacement period documented in mature horses.
Such rapid hoof growth means problems can crop up quickly, says Curtis, but also provides an opportunity for effective intervention. “With such dynamic growth any change to hoof shape is rapid and may become permanent without immediate corrective trimming,” he says. “Most of the conformational problems seen in mature horses can be traced back to their early life. This is the time for correction."
Although this study focused on Thoroughbreds, Curtis says he’d expect the results to hold true for other breeds: “The only other published study on the hoof growth rate of newborn foals was carried out using six American Quarter Horse foals. Although this is a very small number of subjects, the results were very similar to ours. Growth rates may vary among different breeds and under different environments, but we believe that our study on hoof renewal in Thoroughbred foals is representative of other breeds.”
The underlying cause for such rapid hoof growth is still unknown, although Curtis says he’s working on finding the reason: “Why foals replace their hooves in half the time of their mothers is an interesting question. We believe that our project will give an answer to this and other questions at a future date.”
Reference: “Hoof renewal time from birth of Thoroughbred foals,” Veterinary Journal, April 2014
This article first appeared in EQUUS issue #443.