Mechanistic Equations to Represent Digestion and Fermentation
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Current mathematical models use different forms of equations to represent feed degradation and microbial fermentation in the rumen. For example, the Cornell Net Carbohydrate and Protein System (CNCPS; Sniffen et al., 1992) assumes that feed digestion rate is first order with respect to substrate, but the models of Baldwin et al. (1987) and Dijkstra et al. (1992) assume Michaelis-Menten kinetics. A model proposed by Kohn and Boston (2000) suggests an alternative form of equations that incorporates the Second Law of Thermodynamics to represent fermentation processes in the rumen. The purpose of this paper is to explore the differences among these approaches, including the form of the equations, the theoretical basis and assumptions, and the behavior. This analysis will identify a number of important research questions to pursue.
KeywordsMethane Production Volatile Fatty Acid Concentration ofES Mechanistic Equation Propionate Production
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