The critical control points for coccidiosis vaccination; effective way of preventing coccidiosis is vaccination at the hatchery. This only works out well if critical points are taken into account, both at the hatchery as well as in a later stage at the farm.
Vaccination against coccidiosis in poultry is used mainly in broiler, turkey and layer breeder flocks; commercial layer flocks reared on the floor; antibiotic free broiler operations and some commercial turkey grower operations. Vaccinating with a coccidiosis vaccine in conventional broiler operations is increasing rapidly, mainly in a rotational programme with anticoccidials, aiming at restoring the sensitivity of the anticoccidials. Whatever the reason for vaccinating with a coccidiosis vaccine, attention to some critical factors will determine the level of success of establishing immunity against coccidiosis.
The Eimeria parasites given during the vaccination, infects the intestinal cells and continues its life cycle inside the gut. Un sporulated oocysts are excreted after 5-7 days, time depending on the species; the oocysts then sporulate outside the bird, given suitable environmental conditions exists, and after re-ingestion of these sporulated oocysts, infection and another cycle starts. Immunity development is dependent on successful excretion of oocysts and then re-ingestion of these sporulated, shed oocysts. Depending on the species, 2-3 infection – excretion – re-ingestion – re-infection – excretion cycles are needed to acquire a protective immunity.
The vaccination process and the subsequent development of immunity, irrespective of the application method, can thus be divided in two distinct areas:Vaccine application – ensuring uptake of the vaccine . Post vaccination management include ; ensuring suitable environmental conditions for sporulation exists and recycling of the sporulated oocysts takes place.
The necessary procedures to actually check the vaccine uptake by the birds must be implemented. Adding a suitable dye to the vaccine makes this possible by randomly checking boxes/crates of chicks/poults and see if they actually did ingest the vaccine by counting the number of chicks/poults in the box/crate with a dye colored tongue .
. Recycling of oocysts and monitoring
Oocyst shedding can be measured by sending faecal samples to a lab that is capable of doing an Oocyst Per Gram (OPG) count. Faecal material (NOT bedding) is collected at specific intervals post vaccination: Chickens at days 7/14/21/28 post vaccination
Turkeys at days 6/13/20/27 post vaccination. The first count should be positive. This is a very good indicator of the effectiveness of the vaccine application done in the hatchery as well as an indicator that the vaccine that was used was still infective. The second count should show a significant increase. This is used as an indicator that the shed oocysts sporulated and re-ingestion of these shed oocysts have taken place.
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