Aumüller Mikado Sticks for Cats

So I can't really talk about hours of play and chewing fun. My cat chews through these sticks in 2 minutes. On top of that, he tries to swallow the broken-off, splintered pieces. I've already taken several large pieces out of his mouth, and he's already swallowed the smaller ones. My vet strongly advises against them. I threw the remaining 7 sticks in the bin. I'm far too worried about my pet.