I have tried my level best in calming my dog down and I have lately been on my last nerves because of my rough collie. She is 4 years old, she has recently started behaving in this awful manner, and I can’t understand what she is trying to retaliate against. She has suddenly become very dominating towards the other dogs. She had a lab friend and the other day she pounced upon him trying to show him whose boss. Then she even climbed over a female spitz that she knew for about two years and appeared to attack her. I have had to pull her away both times. Explain to me the cause of this and what must be done. She was quite gentle before this.