DESCRIPTION OF A MODEL TO SIMULATE EFFECTS OF EIMERIA-ACERVULINA INFECTION ON BROILER PRODUCTION

A simulation model for effects of Eimeria acervulina infection on tech nical and economic characteristics in broiler production is presented. The model describes development over time of the growth depression, f eed intake reduction, and decrease in feed efficiency associated with infection. The model also shows a phase of compensatory growth during which earlier negative effects are counterbalanced, at least partly. M ajor assumptions made were: infection with E. acervulina occurs in eac h flock; production is affected in each flock; compensatory growth tak es place because immunity develops and cell regeneration occurs. The r esults show that the pattern of development of the production characte ristics during a flock cycle depends on the initial contamination leve l. Both a high and low initial contamination level results in a lower average daily gain, a worse feed to gain ratio, and a reduced net reve nue compared to an intermediate contamination level.