Hoof ridges...hmm... I was looking at my own ponies feet and can see the rings of growth from over the past 6 months and was intrigued to learn a bit more. So I found great visual information from the Progressive Horse, run by Ross Barker, who provides holistic hoof and horse care in the North of England. Do have a look round their website and get out looking at your horses' feet!
THE PROGRESSIVE HORSE