I had this problem with Chanel! It is a different breed more powerful but same idea! So we would go for a walk and she would see another dog an go nuts! She was friendly with family's pets,friends pets! As she was ready to start barking I would say NO very firm and tug her collar(easy with bully) and make her sit! Right when she sat I would giver her a treat and if she walke past a dog with no sound she would get a treat! Positive and Firm! The dog whisperer really helped me! I never had that problem with Brutus as he followed her lead and she is perfect now! It takes a lot of time and paitence!
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