This reference is for researchers interested in the state-of-the-art in theoretical methodology, modelling and practical application of systems concepts in livestock farming systems. The referred papers were presented at the 3rd Symposium on Livestock Farming Systems held in Aberdeen, Scotland in 1994. The topics are grouped in seven sections: current approaches in livestock farming systems; pressures on livestock systems; livestock farming analysis - cattle; livestock farming systems analysis - sheep, goats and small ruminants; environmental issues; modelling livestock farming systems; decision support systems.