I nvited R eview : Matching forage systems with cow size and environment for sustainable cow-calf production in the southern region of the United States 1 1This review article is based on a presentation by the authors in the symposium “Management Strategies for Intensive, Sustainable Cow-Calf Production Systems in the Southeastern United States” at the meeting of the American Society of Animal Science Southern Section, February 9, 2016, San Antonio, Texas.