This aim of this project will be to investigate heavy metal, nitrogen, and phosphorous balances through pig and poultry production systems, in order to develop a predictive system for estimating manure metal and nutrient concentrations based on feed inputs. Balance studies for metals (zinc, copper, nickel, cadmium, lead and chromium) and nutrients (nitrogen and phosphorous) will be undertaken in order to determine metal concentration factors and feed dry matter conversion rates and to develop a predictive system for estimating excreta metal concentrations from knowledge of feed metal inputs. Finishing pigs will be fed solid weaner and starter diets and liquid grower and finisher diets at ADAS Terrington in order to evaluate the effects of contrasting feed metal/nutrient inputs and diet digestibilities on metal/nutrient concentration factors. Metal/nutrient balance studies will also be conducted on turkeys and laying hens at ADAS Gleadthorpe, which receive commercially available feeds, as well as on broilers fed on diets with a wide range of metal inputs. Effects of manure (turkey litter, layer manure and broiler litter) storage on dry matter metal and nutrient concentrations will also be studied.