Technical Abstract: The USDA-Agricultural Research Service (ARS) received a program increase in FY2002 to establish the Forage-Animal Production Research Unit (FAPRU) in Lexington, KY. The unit came into physical existence in March of 2003 with the hiring of the Research Leader. The mission of FAPRU is to improve productivity, competiveness and sustainability of forage-based enterprises through improved understanding of the fundamental biological processes that occur at the animal-plant interface. Region of focus is the transition zone between the subtropics of the southeast and the temperate region of the northeast. Livestock production within this zone is heavily dependent on forage systems for sustainability and future competitiveness in agriculture. The unit will accomplish its mission through the use of multidisciplinary-interinstitutional teams that will work to identify, evaluate, and manipulate genetic and physiological factors for the enhancement of animal health and performance and to improve forage plant persistence and production. Examples of research objectives include: 1) Identify factors affecting forage plant persistence and performance, 2) Identify factors affecting health and performance of grazing animals, and 3) Enhance the competitiveness, profitability, and environmental sustainability of forage-based enterprises. These objectives will be accomplished through collaboration with its partners at the University of Kentucky and other entities within and outside USDA-ARS.