A horse is a heavy and by nature nervous creature. It also has iron shoes. If I was a horse, which I'm not, I'd know exactly what to do if someone tried to rub a straight razor against my more private parts. So I strongly recommend against it. What I do recommend is that you look up Scrupleworks as recommended above. There are also very good strops that are cheaper than horse hide strops, but horse shell will always be expensive.
