Conclusions:The relocation of the cows from the CMS to the VMS did not affect negatively their behavior The fact that cows initiated their lactation in the CMS could have reduced the cow?s natural reactiveness to the new milking process itself which could be arguably as equal or more stressful than the change of milking system once the cows are already in lactation The behavioral classification in one system (in this case, CMS) allowed to predict the behavior in the other system ( since the differences between categories were maintained The milking reactivity as a measure of temperament appears as a promising powerful tool to identify cows that could adapt more easily to both milking systems However all these topics warrant more research.