I had cats before I got my yorkies. My cats were still young and in the beginning, Couver got along great with them. He would even wrestle and play with them. My female absolutely adores the cats and will kiss them like crazy every time she sees them. She even does this on command now
Couver, however has decided that he is the dominant one in the family and started chasing the cats about a year ago. The cats are pretty quick, but he has come back with mouthfuls of cat hair a few times. I always discipline him for it, but it hasn't really stopped. He can be in the same room with them, but all of a sudden he will run full force toward them and chase them away. I'm hoping we can correct this, but for now I just put him in a room by himself after he does it and hopefully he will figure out that it's not an acceptable behavior.