We aim to continue an ongoing study to increase knowledge of cattle locomotion on different floors, how they work in practice and what the long term consequences are for welfare and for farmers´ economy. For that purpose advanced biomechanical methods will be used to assess dairy cows´ manoeuvrability and slipping experimentally. The best adaptable and informative variables from the locomotion laboratory will then be used to evaluate possible flooring solutions to reduce slipperiness in practice on dairy farms. By epidemiological methods and data from Swedish milk recording scheme, the long term effects of different flooring improvements on welfare, health, fertility and longevity will be assessed retrospectively. Finally, the farmers´ decision making and economy of improved flooring solutions will be evaluated as base for the judgement of which is the optimal flooring solutions for new as well as for renovated barns with both animal welfare and farmers´ economy in mind.