Description of a model to simulate effects of Eimeria acervulina infection on broiler production

A simulation model for effects of Eimeria acervulina infection on technical and economic characteristics in broiler production is presented. The model describes development over time of the growth depression, feed 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. Major assumptions made were: infection with E. acervulina occurs in each flock; production is affected in each flock; compensatory growth takes place because immunity develops and cell regeneration occurs. The results show that the pattern of development of the production characteristics during a flock cycle depends on the initial contamination level. 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 revenue compared to an intermediate contamination level.