Stones General question re: stone prevention

If this shouldn't go here I apologize and of course, feel free to move it.

So I was watching a vet show, animal ER, and they did a stone removal surgery. It was kinda cool to see it since Colonel has had it done once. What surprised me was that they said he would be getting a supplement for the rest of his life that helps prevent stones. Now I know it's TV but I was bummed that they didn't say what it was as I've never really heard of one. Any idea what they would be talking about? I was just curious.