I have two female Great Pyrs and they have gotten in to fights few times. The first one started when the young female wanted to be the boss and it ended very badly ... both dogs in to vet and stitches. Contacted a dog trainer for advice but that was not useful and got my dogs in to another fight - mistake was made by me carrying out the advice from dog trainer. I wanted to bring the young female down from her high heels so I got tips from TM breeder. She told me to muzzle the younger one ... then she can not start the fight and it did wok for me. Both bitches are very dominant but they live outside 24/7 and it is peace now. After that incident they have gotten in to a fight once but that was totally my fault - I gave wrong signal. We learn from our mistakes! The fights have been serious and I have needed help to break them loose. I thought next time if they get in to fight I will use these small fire crackers to break them up because I know they are scared of them.