There have been round/oblong corrective shoes for hooves.
More round than oblong usually though.
Yours may have been crushed for some reason. Or failed (cracked) during smith hammering on it to fit a foot.
It does appear it was specifically made for a hoof. That said , I have an old logging chain (for connecting booms) that has a round eye on one end , and an oval one on the other.
It was recovered with the oval ring through the round ring.
Your shoe would be light duty if substituted for the oval link on my chain.
But who knows who improvised what on your site?
An off the wall idea would be that the shoe was made oval , then repurposed and hardened as a strike a light. To use with a piece of flint to start tinder for fires.
Here's one credited as a Hudson Bay type.