The effect of maternal immunization with purified gametocyte antigens of Eimeria maxima on the growth performance of progeny broiler chickens raised under commercial conditions on farms in Brazil, Thailand, Israel and South Africa.

Commercial broiler breeder hens (Ross and Cobb breeds) were vaccinated twice with purified gametocyte antigens (PGA) at 15 and 20 weeks of age. Eggs were collected from groups of vaccinated and unvaccinated hens, incubated to hatching and broiler birds raised under normal commercial conditions for each country. Control flocks were either immunized with a commercial live vaccine or raised on feed containing anticoccidial chemoprophylactic drugs. There was no significant difference between the performance of control and vaccinated birds with respect to age at slaughter, mortality, Feed Conversion Rate (FCR), final body weight or European (EU) Performance Index (one-way ANOVA).*These farms were from large integrations, and the results are from several chicken houses run over a period of 2–3 years.**The results from Israel are the summary from several different farms run over a period of 5 years.