The financial contribution made by Government to the agricultural industry results in the views of the general public on farming practices being of major importance. Environmental issues remain high upon the public agenda and have recently been re-emphasised by two Government publications “People Prosperity and Partnership” and Biodiversity: The UK Steering Group Report”. It remains important therefore that the design of any animal production system should take account of environmental effects and seek to achieve an acceptable balance between financial returns and environmental costs. The development of such a strategy requires information on: - the main environmental characteristics which are influenced by animal production - the extent to which environmental impact might be modified by change in fanning practice - the probable changes in farming systems over the foreseeable future which are likely to influence the environment. Assessments of these factors will require information at both detailed and systems level. These issues are discussed using information from a number of systems trials.