It's a Farrier's Formula copy cat:

http://www.deltahoofcare.com/html/hoofpower.html

If your horse's diet has adequate protein and well balanced minerals,
all you need to add is biotin.

It's very interesting that the successful hoof (and coat) supplements
all target the most common trace mineral deficiencies (zinc, copper,
iodine to some extent) rather than using a kitchen sink to
supplementing across the board. This is why they are often successful
even in horses on heavily supplemented grains or "multi" type
supplements. It's all about balance.

Eleanor