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COCCI FAQs

Frequently asked questions about cocci vaccination

Q. ARE POST-VACCINAL REACTIONS A CONCERN WITH COCCIDIOSIS VACCINATION?

A. Post-vaccinal reaction with Coccivac vaccines have not been a problem since the development of spray cabinet technology, which replaces application of the vaccine by other routes such as spraying it on feed or into the eyes.

Uniform coverage is important. If some birds are missed by initial vaccination, then other, unexposed birds receive an uncontrolled shedding dose of oocysts, which can result in insufficient protection for some birds or strong post-vaccinal reactions for others.

In the past, it was necessary to administer amprolium after vaccination to prevent excessive oocyst shedding and post-vaccinal reactions that might occur as a result of uneven coverage. In addition, birds that did not receive a full dose of the vaccine were exposed to sporulated oocysts from the litter and didn’t always achieve their full weight or performance.

The spray cabinet has changed all that by providing more uniform vaccine coverage, which has led to better protection. With the spray cabinet, 100 chicks at a time are placed in a box and misted with vaccine solution. It is believed that after spraying, the chicks preen and ingest the vaccine orally, which results in more uniform administration throughout a flock.

With uniform application, complete protection is achieved within 28 days and there is no need to use amprolium after vaccination. Studies have shown that weight gain and feed conversion in birds vaccinated against coccidiosis via spray cabinet administration is comparable to that among birds receiving conventional, in-feed ionophores.

Q. ARE BROILER CHICKS VACCINATED FOR COCCIDIOSIS MORE SUSCEPTIBLE TO COLONIZATION OF SALMONELLA ENTERITIDIS?

A. No. A recent study in Brazil by Instituto de Biociências – UNESP with 120 broiler chicks showed that vaccination with Coccivac-B has no bearing on the colonization or longevity of Salmonella enteritidis (Se) in the gut.

The birds were divided into six groups: Group 1 received the probiotic ACM (anaerobic cecal microflora) by spraying after vaccination against coccidiosis and challenge with Se; Group 2 received ACM by intra-esophageal inoculation after vaccination against coccidiosis and challenge with Se; Group 3 received ACM in drinking water after vaccination against coccidiosis and challenge with Se; Group 4 was not treated with ACM but vaccinated against coccidiosis and challenged with Se; Group 5 was not treated with ACM or vaccinated, but challenged with Se; and Group 6 was not treated or vaccinated and not challenged (negative control). The colonization of the digestive tract, the presence of Se in feces, and body weight were determined 2, 7 and 12 days after challenge.

Se count in feces and cecal colonization were reduced in the ACMtreated groups (1-3), mainly those receiving ACM by spraying and intraesophageal inoculation. This indicate that the actions of ACM against cecal colonization and fecal excretion of Se are not affected by the use of a vaccine against coccidiosis in broiler chicks. Furthermore, it suggests that ACM and coccidosis vaccine can be used together without reducing the effectiveness of ACM.

An increase in cecal colonization and fecal excretion of Se was observed in the groups not receiving ACM, regardless of whether they received coccidiosis vaccine.

Source: CocciForum Issue No.3, Schering-Plough Animal Health.