Hi IkeE,
I just read an article that may answer your question(s).
One Foot For All Seasons
Take a look, it's really interesting too.
Other hoof articles by the same author that you may be interested in :
Pete Ramey writes about white line disease thrush navicular disease hoof balance
One of the articles is on hoof casts too.
Hope this helps.
I love getting educated! it takes the big mystery away.