A little trick that works for my dogs with chasing the cats and biting is:

You fill a soda can or and can that is metal with pennies and seal it shut. Then everytime shes chasing the cat or biting you shake it really hard or throw it on the floor so it make a horrible load noise. It usually surprises the dog and stops them form what there doing. And they wont do it again b/c they'll start to associate that action with the bad sound.

It worked for my dogs and maybe it will work for yours.

Good luck!