We present the MERISE method for the design of an information system, detailing data modelling. An exploratory research program on peri-partum pathology in intensive dairy herds is used as an example. The information system is divided into thematic subsystems called 'fields', which are represented by a global conceptual scheme. For each field, a detailed conceptual model is then determined through precise modelling guidelines. This division facilitates the validation of models by the partners of the project, and makes it possible to re-use the fields in other research programs