[The control of bovine salmonellosis under field conditions using herd-specific vaccines]

Data were collected from 39 cattle herds in Northern Bavaria with confirmed outbreaks of salmonellosis and analysed regarding the use of herd-specific Salmonella vaccines in control of this infectious disease. The inactivated vaccine was applied intranasally three times at intervals of 1 week (each dose of 5 ml; concentration of antigen about 10(10) organisms/ml, inactivated by heat at 100 degrees C). Efficacy of vaccine was evaluated by comparing bacteriological examination of fecal shedding of Salmonellae before and after vaccination. The number of Salmonella-positive fecal samples was reduced within one week p. vacc. from 25% to less than 1% of all examined fecal samples. Two thirds (65.7%) of the herds were free of infection within 3 weeks p. vacc. Best results after vaccination were obtained when each animal, including the calves, was vaccinated. Further it could be determined that smaller farms with up to 70 cattle did better than larger farms, where often only a part of the herd was immunized (82.6% and 33.3%).