Grazing is a full-time job for horses. Given their druthers, they’ll graze for 14 hours or more every day, with their broad, flat teeth and sideways chewing motions making short work of the tough, stemmy grasses and weeds that they favor. Like all true herbivores, horses get most of their daily energy requirements from eating plant fibers.

Of all the studies conducted on the correlation between nutrition and the hoof, the role of biotin, a water-soluble vitamin within the B group, has been a central focus time and again.