Modeling livestock systems. I. A descriptive formalism
We attempted to categorize synthetic models of livestock production and assemble a set of descriptors for structural elements, level of resolution, operational objectives and algorithm for these models. These descriptors are suggested to be necessary and sufficient elements of the published documentation of operational model objective(s), the model algorithm and model domain of models of livestock systems. We suggest that the publication of models of livestock production require documentation of this information. Using the proposed set of descriptors, published models of livestock systems can be described systematically, allowing the evaluation of suitability to task to become more transparent and stringent. Nutrient supply level driven simulation models seem to be the model design archetype with least methodological restrictions. Their suitability to task is defined by the extent of qualitative and quantitative understanding of the relevant biology upon which they are based.