Lab/German Shepherd Mix Is Fed Pedigree Large Breed Dry Food

I have a Lab/German Shepherd mix. Her name is Madison and she is 3.5 years old. I feed her Pedigree Large Breed Dry Food. I have used the same brand ever since she was a puppy. I decided to use this brand becuase the puppy trainer recommended it. It was not recommended by my vet? I purchase the dog food from Walmart. I purchase it there because it has the best price and the largest size bag for convenience.