The objective of this presentation is to introduce and to discuss how the Systems Science Approach can be used to optimize intervention strategies in Food Animal Systems. The presentation advocates the idea that the challenges of maintaining a safe food supply are best investigated by integrating modeling and mathematics with the biological studies which are critical to the formulation of public policy to address these challenges. Much information on the biology and epidemiology of food animal systems has been extensively characterized through single-discipline methods, but, until now, this information has not been thoroughly utilized in a fully integrated manner.
The examples are drawn from Dr. Grohn’s current research. The first case study, which will be explained in depth, uses clinical mastitis as an example to introduce the underlying concept of dynamic programming to optimize management decisions in dairy cows (also introducing the curse of dimensionality problem). In the second case study, using Johne’s disease as an example, so-called SIR (susceptible, infectious, resistant) models with different intervention strategies will be optimized. The goal of the optimization strategy depends on whether there is a relationship between Johne’s and Crohn’s disease. If there is, the optimization will be based on the eradication of infection; if not, then the optimization will be based on the cow’s performance only (i.e., economic optimization, similar to the mastitis example). The third case study will focus on food safety using Listeria monocytogenes and Salmonella Typhimurium to introduce risk assessment. The last case study, practical interventions to effectively manage antibiotic resistance in beef and dairy cattle systems, introduces meta-population modeling that includes bacterial growth in host (cow), feed, water and the environment. Each of the modeling examples points to the need to progress towards multi-scale modeling. The presentation ends with examples of multi-scale systems, from mastitis to Johne’s and bovine tuberculosis.
Based on the examples given, it is clear that reducing the consequences of food borne illnesses can only occur through an understanding of the system as a whole, including all its complexities. Therefore the goal of future research should be to merge disciplines ranging from molecular biology to applied math to social sciences in order to gain a better understanding of complex systems such as the food supply chain.
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