Dynamic livestock modelling for on-farm decision support

The study described in this thesis focuses on the development and use of models that simulate herd dynamics in livestock. The models can be used to calculate the herd-specific technical and economic consequences of various management strategies. The thesis is composed of four parts. (1) Existing models from the literature simulating herd dynamics were described and discussed, including their possible role in on-farm decision support. (2) A modelling approach was developed to support decisions with respect to production, reproduction and replacement in swine herds. In this, probabilistic modelling using probability distributions was used to simulate herd dynamics and to evaluate various management strategies. (3) The approach developed for swine herds was modified and transformed to model similar decisions in dairy herds. Special attention was paid to the calving pattern of the herd. The model can be used to evaluate strategies in order to change a herd's calving pattern. Additionally, a method was worked out to determine the optimum herd calving pattern, which was based on the developed model and linear programming. (4) The possible path leading from the developed prototypes towards a successful implementation in the field as part of an integrated decision support system was discussed.