Egg Industry Presentations

Vaccination to Reduce Salmonella Infection

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Dr. Charles L. Hofacre, Professor, College of Veterinary Medicine, University of Georgia, presented data on vaccination against Salmonella infection at a special luncheon program organized by BioChek USA during the IPPE.

Although the focus of the presentation related to broiler breeders, the conclusions are applicable to pullets reared for table-egg production.

Dr. Hofacre amplified the conclusion of a WHO-FAO meeting in Rome in May 2009 in which it was accepted that vaccination is a key component of suppressing Salmonella infection in livestock.

A field study conducted by the University of Georgia involving 49 poultry farms from which 7,400 samples were collected, showed conclusively that vaccination significantly reduced vertical transmission.

A second trial covering 12 breeder flocks and 58 broiler flocks half of which were vaccinated and the other half served as controls evaluated the epidemiology of Salmonella infection in breeders and broilers by sampling the environment and intestinal contents.

The study clearly demonstrated that there was a direct correlation between the ELISA SE assay to determine circulating antibody and the plate agglutination test using Salmonella Pullorum antigen which has identical components to SE.  The appropriate slide head “Salmonella quality for commercial layers” demonstrates that many flocks were effectively vaccinated but Flocks 12 and 13 were unprotected and Flocks 3 and 11 were only partly immunized.

Dr. Hofacre considers that 95% of a sample derived from a flock should demonstrate solid immunity which would denote effective vaccination.  Flocks with low levels of antibody response should be revaccinated prior to transfer. 

Parallel studies conducted by field veterinarians affiliated with Zoetis Global Poultry (previously Pfizer Animal Health) confirmed the effect of vaccination procedures and training of operators administering inactivated emulsion SE vaccine to replacement pullets on antibody levels.                               

The slide set is reproduced with the permission of Dr. Hofacre and BioCheck USA. Specific questions relating to the slide set can be directed to Dr. Hofacre. <>

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