With modern technologies, vast amount of data are produced in experimental science. These data typically arise from the complex interplay of multiple biological mechanisms. In order to better understand and analyze the underlying dynamical biological interactions, we apply a holistic systems biology approach where we integrate the experimental data into predictive mathematical models. We interdisciplinarily develop models on the base of ordinary differential equations (ODEs) together with mathematicians, bioinformaticians and veterinarians. These dynamic, mechanistic ODE models are developed iteratively by fitting parameters to field data and refining modeled processes with mechanistic knowledge according to the application.
For dairy cows two mechanistic ODE models have been developed in our group, so far. One model for the bovine estrous cycle, BovCycle, and one model for potassium balance. In both models, ODEs describe the dynamical feedback mechanisms and alterations of the most relevant involved substances. With such models, simulations can be conducted predicting the behaviour of the system over time. The aim of this research is to understand and visualize the network of processes in individuals and to make predictions for mechanistic relations under varying conditions.
Prospectively, the models can be adapted for versatile applications in science and in production on farms. Integrated into larger models and software for herd or farm management, our research can contribute to a sustainable production of food and a predictive veterinary practice, including early warning for disease, and identification of new targets for diagnosis and treatment.
Potassium Balance Model
The model of potassium balance in dairy cows is the basis for computer simulations of potassium intake, distribution in the organism, and excretion. The model has been developed and validated with experimental data from the Clinic for Ruminants of the Freie Universität Berlin. Our aim is to use this model to study mechanisms of potassium and its disorders as hypokalaemia. Such potassium disorders are diagnosed with increasing frequency in cows with displaced abomasum and other metabolic disorders.
Currently we are working on improvement of the mechanisms and more functionalities. For more information contact Julia Plöntzke or Mascha Berg.
BovCycle
With the model BovCycle, the growth and decay of follicles and the corpus luteum and the key hormones along the hypothalamic-pituitary-gonadal axis can be simulated. The BovCycle has been used for various application and within this its mechanism have been validated and advanced.
In Stötzel et al. 2012 a single Prostaglandin F2α (PGF2α) administration to the BovCycle was simulated. Model equations and parameters were determined in such a way that experimental progesterone measurement values after administration of PGF2α were reproduced by the simulation, and an estrus synchronization effect could be obtained.
Follicular wave patterns have been explored with the BovCycle with different mechanistic approaches in de Boer et al. 2011 and Stötzel et al. 2015 by Fourier Analysis.
Metabolism and Fertility
In a master thesis, the interaction of Glucose, Insulin and IGF- 1 with the estrous cycle model have been explored.
Currently this topic is worked out in a PhD thesis by Mohamed Omari.
