Oakum is a traditional hoof packing material used by farriers to protect, support, and maintain the health of a horse's hoof. It consists of loosely twisted, oil-treated jute or hemp fibers. When applied under a pad, it helps fill the sole cavity and prevents other packing materials from seeping out.

Uses and Benefits in Farriery
Hoof Packing Support: Farriers separate and "feather out" strands of oakum to form a pad-like covering over other packing materials that don't set up on their own.
Antiseptic Dressing: It is frequently coated with Pine Tar or Venice Turpentine to act as a therapeutic dressing for the hoof.
Moisture Barrier: Many modern varieties, such as Nupak Oakum, are treated with Bentonite, a clay that expands when wet to provide a tighter seal against moisture.
Protection: It provides a physical cushion for the sole and frog, though farriers must be careful not to apply too much pressure on horses with thin soles or navicular issues.