Simulation of the dynamics of nitrogen metabolism in sheep.

1. The results of isotope tracer studies of the dynamics of nitrogen metabolism in mature sheep were used to construct a seven-pool mathematical model. 2. The model was extended to a nine-pool model, which incorporates lags describing the time taken for the passage of digesta through the gut of sheep. 3. Simulation studies using these models satisfactorily predicted results of independent experiments. 4. The dynamics of N metabolism in sheep appear to be best approximately by first-order kinetics; that is, many of the important N transport processes are substantially linear or concentration-dependent.