Your puppy will most likely have one of two reactions to a cat. If your puppy’s interaction with a cat causes the cat to run, which in turn will cause your puppy to chase him (puppy’s love to chase), you must put a stop to it immediately. To do this is very simple. Pick your puppy up and put him in time out. Continue this each time he begins to chase the cat. He will learn in a very short time that chasing a cat isn’t proper behavior. The other reaction is the cat could interact pleasantly with your puppy. The two will play and set boundaries for each other. If this occurs it is very important for you not to get involved unless one of the animals are in danger.