Does she know the "leave it" command? This command works for so many things. I use it repeatedly, as in every word out of my mouth, on walks with my three. They will stop smelling the grass, lunging at dogs barking on the other side of fences, ignore people walking down the street, etc. Also being super vigilant when you are walking to see if you can spot the cats and squirrels first works great too. That way once you have seen them you can either redirect the walk or her attention from the chase and you are also prepared for the lunge itself. Hope that helps some.
