Simulation results. Cows which shed above the cutoff value (x axis) were culled. The average number of total culled cows (blue) and the average number of MAP infected cows per day (black) for the CFU cutoff. This number converges at cutoff = 0 to approximately δN. In order to significantly reduce the frequency of sick cows, a low culling level must be used. Thus, removing only super-shedders does not significantly affect the spread of the disease.