The biggest thing you can do to be successful is to PRE-PLAN how you will do things and what the approach will be if some type of overt aggression begins.
Pre-planning means to take enough time in the introductions to insure success. You should never force the animals to do something they are not ready for. It will take as long as it will take. Sometimes this will be a few days, sometimes weeks, sometimes months! By forcing things or by not planning how you will do the introductions, you can ruin the chances of a good working relationship between your animals. BE PATIENT!
Handling aggression should be done BEFORE it escalates into action. If you watch your animals' ears, eyes, tails, body posture and body tension, you will be able to tell serious threats from display. If you have any doubts, then separate them and take no risks.
Behavior on Introduction
Typical reactions are to chase, bark, paw or drool! Make sure you are careful and have a leash or some other form of restraint when introducing a new cat. Basic control learned in training classes, such as a "down, stay" can be an asset here.
Typical responses will be to attack, stalk, ambush, glare and make lots of horrible noises and contortions to communicate their displeasure. Some will just run off and hide.
Over the years we have successfully introduced many coonhounds to family cats. Our collective experience says that one of the keys to a successful dog-cat relationship is to initially control the environment when your pets are around one another and to insure that the dog is ALWAYS under your control, either with a dog crate, a dog leash or a remote collar.
The first step in the introduction is to get them used to each other's scent. It is important to let them investigate each other's living areas singularly. While the cat's outside or elsewhere in the house, bring the dog in to sniff around her favorite lounging spots and vice versa. This way they can explore the other's territory and scent without a direct face-off.
When you are ready for the first face to face introduction, the best way to introduce dogs and cats is to have the dog on a leash and collar so you can control the situation. Do your best to give the dog some exercise and practice a few obedience commands before entering the catís home (or bringing the cat in). Next (and this is really important) all the humans in the room need to be relaxed. If you act tense and worried, the animals will sense it and may have a more difficult time behaving calmly themselves. Remember, most dogs are not interested in biting cats at all. Theyíre usually just curious and want to meet the cat, the same way theyíre interested in meeting people and other dogs. Ideally, introduce them outside or through closed door or baby gate. Bring the leashed dog and cat on opposite sides of a closed door or baby gate, with a person on both sides.
Don't restrain your cat at all; feeling like she can't get away may frighten her. Let them sniff under the door or through the gate, but if your cat doesn't want to get too close, don't force them to. Lavish them both with praise, attention, and treats. You want them to think that good things happen when the other pet is around.
Ask the dog to sit, lie down, and perform any other commands he knows, praising and rewarding him whenever he focuses on you and not the cat. Keep practicing this step until the cat doesn't seem frightened and the dog doesn't seem overly excited. Introduce them with the dog on leash. Again, don't restrain the cat--she may panic if she feels like she can't escape this new, scary creature. Keep the dog on leash so you can stop him if he tries to give chase. Again, ask the dog to obey some commands, rewarding him for focusing on you rather than on the cat. Some cats will hiss and swipe at a curious or obnoxious dog to warn him, "Back off!"
That's actually a better response than running away, which often triggers the dog to take off after her. If the cat flees and your dog starts to chase her, grab the leash, firmly tell your dog, "No" or "Leave it," and ask him to sit. If he returns his attention to you, give him a food reward--a really tasty one--for his restraint. Once the dog and cat have met, resume normal casual activity with the dog on leash by your side. By having the animals simply coexist without focusing on one another, you send an important message: that they can simply coexist and not focus on one another!
And as far as the catís personal items, keep them in a place where your new hound canít access them. The litter box should be off limits as well as the cat food (which is much higher in fat than dog food). This can easily be done with a baby gate. And experts recommend that you elevate the gate just enough so that the kitty can get under the gate but low enough to keep a curious hound from following suit!
But to keep the peace, it's wise to separate them in different areas of the house when you go out until you're very, very sure they'll get along.
Bottom line: Many dogs and cats can coexist peacefully, but you'll keep everyone safe and make life much less stressful if you plan carefully and introduce family members slowly and carefully.
And remember, if folks tell you it canít be done...well, they might just be WRONG!