Let's have a look at what T'Pol tells us about domesticated Sehlats:
ARCHER: How long before it starts to lose interest in us?
T'POL: Days, at least. They're very persistent creatures. When I was a child, I had one as a pet.
ARCHER: You had one of those?
T'POL: Domesticated. They were smaller, slightly.
ARCHER: How slightly?
T'POL: You have Porthos.
ARCHER: Porthos doesn't try and eat me when I'm late with his dinner.
T'POL: Vulcan children are never late with their sehlat's dinner.
ARCHER: I can believe that.
So we have domesticated Sehlats, who are smaller than their wild cousins. I would consider the two variants the same as Wolves and Dogs. Domestication doesn't happen over a generation. An animal can be tamed, but that's not the same as domestication. Many humans have dogs, yet dogs are still predators and therefore somewhat dangerous, but not so if their master knows, what he/she is doing. I think the same goes for the pet sehlats. They are sehlats, but the wild component and several predatory insincts have been bred out, just as it happened, when wolves became dogs.