We had a shephard that was allergic to Dairy. She could not have the smallest bite of it or the diareha would flare. We got her onto a lamb and rice formula. At the time (16 years ago) Purina was one of the first to come out with the Lamb and Rice formula, then we changed her to Sensible Choice.
Which actually she liked.
What you have to do is get her onto a better food than Beneful. From what I've read around here, its not a good food? I've never tried it, my dogs now are on Innova and so far they love it. Your gonna have to do trial an error to see what exactly she is allergic to. I would get some samples of dog food that doen't have beef or wheat in it or is known not to cause allergies and see how it works on her. Go to either a feed store, Local pet store, or the food threads here and just read.
Just keep a box of white rice around just in case she does get the runs from the food. Cook some up and add with Chicken and that will help bind her.
Good luck!!!
