I have two rescue dogs a pitbull and a lab and both hated cats. It took a while--but I used crates and baby gates to keep them apart. I would let the dog have run of the house and then put him away. Then the cat would have run of the house and then when it got calmer--the baby gates created safe areas for the cat to be out and escape if necessary. It took about 3 months for each dog--but now they all get along.