Although vaccines may be a good option for broiler breeders and layers, where there’s an extended grow out for immunity development and where one desires to have long-term, lifetime protection of immunity in the birds, they are not an ideal option for control of coccidiosis in broilers for several reasons.
1. Vaccine administration in a hatchery does not provide uniform exposure to the vaccine.
Some birds get too many oocysts resulting in coccidiosis, since all coccidiosis vaccines contain live oocysts. Others may receive few if any oocysts preventing an antigenic exposure to initiate immunity development.
2. Another potential problem results from the fact that protective immunity is only obtained through repeated injection of oocysts from the litter.
While administering vaccines, broilers are not protected from clinical coccidiosis using anticoccidial medication. This of course results in a loss of efficiency due to a reduction in intestinal integrity and it serves as a precursor to necrotic enteritis resulting in even greater losses.
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