Effect of simultaneous or delayed competitive exclusion treatment on the spread of Salmonella in chicks

Exposure of newly hatched chicks in the hatchery to salmonellae results in the establishment of seeder chicks with fecal shedding and the transmission of salmonellae to other contact chicks in the broiler house during growout. This study investigated the protective effect of treatment with a characterized competitive exclusion culture, CF3 on the transmission of Salmonellae from seeder to contact chicks when CF3 treatment occurred simultaneously with seeder challenge or when treatment was delayed until 24 hr after challenge. Delayed treatment failed to prevent the establishment of seeder chicks, but did significantly (P less than or equal to.005) reduce the spread of Salmonellae from seeder to nonchallenged contact chicks. Simultaneous Salmonellae challenge and CF3 treatment significantly (P less than or equal to.005) decreased the establishment of seeders and was highly effective in preventing the spread of Salmonellae from seeder to contact chicks. The results demonstrated that treatment on the day of hatch can significantly help reduce seeder establishment and the spread of Salmonellae from seeder to highly susceptible contact chicks.