We had him on a leash in the house for a long time. When the cats would come around we would keep telling him no. I would also hold the cats and let him come over and smell them. We would also let the cats bat at him if he got to close, I wouldn't stop them from protecting themselves. Brutus also has a strong prey drive and will go after cats he doesn't know, but we are at the point where we tell him no a few times and change his focus and he leaves them alone. I carry his balls with us everywhere we go because Brutus gets very focused on something and won't let it go and I can distract him and refocus his energy on his ball. Works every time, he's very simple. Try to redirect buttercup to something she loves, other than the cat.
I also posted in your other thread!!
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