Can knowledge originating from developmental physiology, nutritional immunology, or nutritional endocrinology in other species (humans, rodents, or other farm animals) have implications for ruminant nutrition? Would this new knowledge help break through the current paradigms of nutrition and production in ruminants and create a new one? Could unremitting issues (e.g., ketosis, acidosis) be reinterpreted within this new paradigm to help derive efficient new concepts? These questions were the fundamental subjects debated during the symposium “The rumen and beyond: Nutritional physiology of the modern dairy cow,” held during the 2015 American Dairy Science Association-American Society of Animal Science Joint Annual Meeting in Orlando, Florida.