The Use of WinSAAM for Modeling Complex Ruminal Metabolism

In this chapter we describe how a complex non-linear mathematical model concerning bovine rumen metabolism can be easily translated into constructs and terminology that are employed in WinSAAM software for mathematical modeling. After implementing this model, we have used it to make predictions concerning effects of diets based on sugarcane with or without urea supplementation on processes that occur in the bovine rumen. The model predictions were compared with previous simulations confirmed the ability of the model to make predictions in agreement with previously published predictions. Despite being non-linear model, we show that with WinSAAM, the “steady state” concentrations of all the state variables can be readily predicted. Indeed the model predicts that after a major dietary perturbation, steady state conditions are regained in approximately six days. Simulations were also conducted to compare the effects of different levels of nitrogen supplementation on microbial growth efficiency and on the extent of “energy splilling” i.e. the use of energy by microbes for purposes other than growth of maintenance. As well as the above studies, we describe how to employ WinSAAM to simulate the impact of intermittent feeding schedules on rumen fermentation patterns.