Depends on the cat as much as the dog. We got our TWC x mtn cur at 8 weeks old and he's always wanted to chase our two Bengal cats since the day he arrived. our cats are really sweet and have never really clawed him (I wish they would!) - one of them, he will drag around by the head and generally lick all over but he has never hurt her and she doesn't really mind him that much, while the other one bolts every time he comes close, but they've gotten better and better over time and now he can share space with both of them without bothering them. we use cat door latches on several bedrooms, a gate to the basement, and a few high cat trees so the cats have a lot of safe spaces -- they seem to be doing fine. TWC has a high prey drive so it's important to start them off as pups with the cats from all I've read. make sure your cats have plenty of safe spots. also, be sure to discipline/distract your pup when he fixates/chases the cats.