It's hard to imagine how those would be used without actually hurting the horse. A horse needs flexibility in its pastern as they lift the foot and then strike the ground. That contraption would seem to act more like a splint, preventing the necessary flexion in the pastern and ankle.
11 posted on 08/09/2018 4:45:50 AM PDT by Avalon Memories
( Proud Deplorable. Proud born-in-the-USA American Dreamer.)