ArchiMod: a metamodel of farming systems functioning to address future livestock challenges

Livestock farming systems (LFS) are facing different challenging issues, questioning our viewpoint: rather than technical objects to be optimized, LFS are components of the agro-ecosystem (AES). This change in our viewpoint involves: (1) integrating dynamical, multidimensional and multifunctional aspects; (2) facilitating collaboration among disciplines; and (3) developing and re-using computer models. In this work, we developed ArchiMod, a metamodel describing structure and functioning of any LFS based on a set of concepts, used in a protocol of description and a graphical language. The graphical language represents the biophysical functioning of an AES, seen as made of entities (non-living components) and biomasses of living organisms, in a given life stage of a given species, interacting by way of processes within 4 contexts of interactions. The concept of context for processes enables progressively organizing the diversity of processes, each of them corresponding to a defined level of organization, where a given type of processes occurs. The Organism Stage context describes input and output flows at the interface of a living organism with its external environment (e.g. feed intake). The Species pathway context describes transitions between organism stages within each species life cycle (e.g. non-lactating to lactating for dairy female). The Environmental Interactions context describes biotic (e.g. pollen dispersal by insects) and abiotic (e.g. N leaching) processes within a physical environment. Finally, the Management operation context describes processes driven by the farmer (e.g. drying-off). Key principles of ArchiMod are: (1) each process is a building block used to describe the whole system dynamics; (2) the system’s functioning is described by defining the contextualization of all elementary processes; (3) it gives a graphical display of the whole set of components to be defined in a mathematical and/or computer model; (4) it provides the rules to articulate elementary models, independent of the mathematical formalism chose to describe processes. ArchiMod was tested on contrasted LFS with various species (fish, rabbit, goat, sheep, cattle, chicken and pig).