Recently, three separate models for evaluating environmental pollution have been developed at the Department of Agriculture, The University of Reading. Dynamic models of nitrogen and phosphorus utilisation and of methane emissions from dairy cows have been constructed. This proposal is presented to permit development of a user-friendly decision support system (DSS) that integrates the dynamic models of methane emission and N & P pollution. The DSS would be run using readily available feed composition data and would evaluate the pollution potential of various feed rations used on farm. The UK is signatory to various international treaties governing the levels of methane (e.g UN Framework convention) and nitrogen (EC Drinking water directive, Gothenburg protocol) emissions to the environment. Manipulation of feed has proved to be an effective way of reducing these emissions. Instead of using three separate models to evaluate nutritional strategies, the development of DSS allows simultaneous evaluation of potential risks and mitigating dietary manipulations. Its user-friendly nature will maximise its uptake by research scientists, consultants and farmers. The outputs will be transparent to the user and provide estimates of cost of diets and its associated benefit or detriment to the environment. Objective 1. To develop the integrated model coded in Visual Fortran a. Develop a framework of integrating the three models b. Reconcile the coding of the three models c. Run the model with data from previous experiments and compare the results with the experiments, the literature, and the outputs of the individual models. Run a sensitivity analysis. 2. Develop a user friendly interface in Visual Basic a. Coding of input and output interfaces b. Addition of other functions including cost-effectiveness indices and calculation of emissions on farm or national levels 3. To run the DSS using farm data and evaluate its predictions 4. The ultimate objective is to evaluate diets and give the user information on cost of diet and environmental impact. The information will be given in spreadsheet with tables and figures showing pollution indices against pollutant for each diet; and if multiple diets are used, a summary of cost of diets against individual nutrient pollution and/or combined emissions (cost benefit index).