[A comprehensive form for the standardized characterization of transgenic rodents: genotype, phenotype, welfare assessment, recommendations for refinement].

When "creating" transgenic mouse strains it is not possible to predict their phenotype with certainty, particularly not with respect to welfare. The generation of models for (human) diseases deliberately implies a compromised health ranging from minor (clinically inapparent) to lethal. To ensure animal welfare requirements and apply the criteria of the 3R, a careful phenotype characterisation and welfare assessment has to be done routinely for each newly produced strain, at individual and strain level, starting by the standardised monitoring of founders and their consequent generations. A comprehensive form has been developed for a standardised characterisation of transgenic mouse strains. It is subdivided into basic and detail information. It can be kept up to date continuously in the form of a computerised database, incorporating growing knowledge and experience of the strain. Basic information mainly serves the requirements of housing and breeding facilities as well as the authorities in view of animal welfare measures, detail information mainly serves the interests of research and efficiency.