I’m not sure how I ended up with four hoof trimmers, the closest I’ve ever been to a horse was petting one on the nose a few times. They are really cool, though, I think. Very comfortable geometry for a carving knife, which is how I’ll use them.
The Frost knife is still made, and is really cheap without being from China.
The metal one is interesting. No manufacturer or model on it. It’s a hollow handle with a quick-release mechanism for the blade. I know that hoof knives come right-handed and left-handed, maybe this one came with two blades and you swapped them out as needed. Though, if this blade were really sharp, there doesn’t seem to be anywhere good to hold onto it to give it the yank required to remove it from the handle. Not without slicing your hand, anyway.