I had a horse get killed running down a road. (She was loaned out, I was a teenager, it was the first horse I bought all by myself, a friend asked to borrow her, I said ok, if she herself rode the horse and let the friend ride her horse, but she didn't, and my horse was green broke, and the friend fell off, no one ever covered the replacement cost, didn't get another horse for quite a while...)

An ankle Road ID would probably fit on a horse's pastern...

My Road ID has name, allergies, organ donor, BF's number, sister (MD's) number, city, health insurance company, blood type (though I am told this doesn't matter, they type, of course, before giving blood) and I am not sure if I put my SS# on it or not.