Horse shoes are tough to get an accrete date on.
They have been made the same way for eons.
The best guestamate is to date them by other relics found in the area.
Keep hunting there's more relics to be found...
If you could provide us with some dimensions, maybe take a pic next to a ruler.
Upon first glance, it looks to be a factory-made pony horseshoe dating after 1860.
I enlarged your pics for a closer look at their construction, it may be an early racehorse shoe if it's a standard size shoe.
I detected an old racehorse farm for years here in Ontario prior to it being built on, I found a few of these in aluminum and iron.