They're not bad doggies. They are not used to being around the cat, so they are just following their instincts. My 2 shepherds are the same way. Cats are just not their friends and are looked upon as things that are threatening the household. This is a socializing problem.

Have your dogs been through obedience training? If not, go. Try to get a trainer that has diversions to assist in the proper correction. My opinion, Pet Smart is not training.

Do not let them inside with the cat under any circumstance. You will end up missing a pet.