Purina Pro Plan Specialized Beef & Rice Formula High Protein Large Breed Dry Dog Food, 47-lb bag; Help make sure your big dawg is getting the right amount of nutrients with Purina Pro Plan Specialized Beef & Rice Formula With Probiotics High Protein Large Breed Dry Dog Food. Beef is the main ingredient in this recipe, which is specially crafted for large breed dogs. It’s designed to have the paw-fect amount of protein and fat to help big pooches stay fit, which can help alleviate pressure on joints and bones. It also contains glucosamine and EPA, an omega-3 fatty acid, to support joint health. Chews wisely!