Potassium balance in dairy cows, model update 2021

This updated model is derived from MODEL1710230000 here on Biomodels. In the current version we changed 2 parameter values and the rate equation Keku. Parameter p46, carbohydrate fraction in diet, was changed from 0.08 to 0.3, and parameter p53, basic potassium excretion with urine in the rate KeKu, was changed from 0.01 to 0.25 g/h. The linear dependency of the rate KeKu on Kecf was replaced by a threshold-dependent stimulation. In the corresponding publication we used this model to perform experiments on hypokalemia in cows.