DESCRIPTION OF A SIMULATION-MODEL FOR THE POPULATION-DYNAMICS OF EIMERIA-ACERVULINA INFECTION IN BROILERS

A simulation model for the population dynamics of Eimeria acervulina i nfection in broilers is presented. The model describes the development of the numbers of parasites in the various life-stages during the gro wing period of broilers and the empty house period between grow-outs. The model includes assumptions with respect to development of immunity to E. acervulina infection and effects of application of anticoccidia l drugs. The model consists of a set of difference equations that are solved numerically at 1 h intervals. Under constant conditions, an equ ilibrium level was reached after a few grow-outs during which infectio n always peaked around the 21st day in the growing period. Within a gr owing period, infection peaked earlier (later) than the 21st day in ca se initial numbers of sporulated oocysts were higher (lower) than the equilibrium number.