I didnt read all the comments so I don't know if this was said
I have your answer right here, I have a purebred german sheperd and she is to strong to fight with. She will stalk that cat down then......BAM blood everywhere.....
What you need to do is pick the strongest kitty and let your dog go up to it and touch it, sniff it, lick it she is aloud to do what she wants with it execpt:
Hold it down
If she does any of these shock her
Now keep doing that but there is another that gets in the way with my dog
My dog is learnning to leave the cats alone because of the method above but she still can't take her mind off them, she will sit in the middle of the yard and stare at cats, I cannot get her to sit or anything as she does not listen
DO NOT SHOCK HER FOR THIS please don't shock them because that is the wrong attention, when she bites a cat shock her because your mad but when she just wont focus....
This will sound harsh but give her a boot, I know you probley think that's harsh but im dead serious when your mad because she is biting a cat but when you are annoyed Boots her, not to to hard and right on the back of the bumm because it will not hurt as they think it will.
I don't ever hit my dog but when it comes to not focusing our dog trainer recomended this