Protective effects of vaccines against experimental salmonellosis in racing pigeons

Five inactivated and one attenuated vaccine produced for the prevention of salmonellosis in pigeons were compared in an experimental challenge model. The birds were vaccinated according to the recommendations of the manufacturers and they were infected by gavage with a Salmonella typhimurium (var copenhagen) pigeon strain. The challenged control animals showed severe weight loss, excessive water intake over a prolonged period, and excreted large numbers of salmonellae. None of the vaccines fully protected the pigeons, and only an inactivated oil adjuvant vaccine was able to reduce the severity of the clinical signs significantly. Mortality was low and tended to increase with the severity of the clinical signs. These results do not justify the preventive use of salmonella vaccination in pigeons. Nevertheless, the oil adjuvant vaccine may help in the effective cleaning of lofts after an outbreak of salmonellosis.