Have a three year old Australian cattledog.We got her when she was about 4 months old from people who rescued her from her previous owners,who kept her tied up.As we lived on a farm,she had plenty of excercise and regretfully,I did not then feel the need to socialize her with other dogs.We have now moved to Canada andd are no longer on a farm.Therefor I started to take her on walks with a lead,which is escalating into a major problem.If I have her off the leash,she is not very friendly toward other dogs,but definately seems to tolerate them better than when on her leash.On the lead,she becomes very aggressive toward other dogs and almost impossible for me to control.As soon as she sees another dog,she starts barking aggressively,pulling at the lead and lunges at the other dog.She does not respond to any commands an gets so agitated and excited that she nips at me and even once attacked my other dog(poodle-terrier cross).I then enrolled her in dog-obedience-classes,where she did very well in terms of obedience,but poor with socialising.Even the trainer could not control her if another dog came to close.If she gets into that excited state,it seems that nothing can get through to her.She gets plenty of excercise,as I take her for long runs twice a day off the lead.I think that I am a big part of the problem,as I now also become very tence whenever I see a dog approach,knowing how my dog responds.I feel that I am ttansferring my own anxiety to her and do not know how to break this cycle.I am even weary of socialising her off her leash,as it seems that her dog aggression is escalating,and I am terrified that she might bite somebody"s dog.At home I am doing the alpha-dog training and it is going very well,although I believe that we could still do better.She is a lovely dog and wonderful towards children and strangers,although she seems less friendly towards unknown males.Hopefully that will get better the more we work on my dominance.Please help.....