Not a farmer/rancher but I think it is some kind of a band expander for placing castration bands on certain animals.

Not a farmer/rancher but I think it is some kind of a band expander for placing castration bands on certain animals.
Your thinking of an elasticator. Everyone I've been around have 4 fingers and open the ring to a square. The tool shown would open a ring to a 1/2 moon making the process harder. It is also to big to get a ring on I believe. And yes I have a couple of elasticator tools and use them to neuter lambs and calves.
If you need to see the process;
lg
no neat sig line