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 result s in the establishment of seeder chicks with fecal shedding and the tr ansmission of salmonellae to other contact chicks in the broiler house during growout. This study investigated the protective effect of trea tment with a characterized competitive exclusion culture, CF3 on the t ransmission of Salmonellae from seeder to contact chicks when CF3 trea tment occurred simultaneously with seeder challenge or when treatment was delayed until 24 hr after challenge. Delayed treatment failed to p revent the establishment of seeder chicks, but did significantly (P le ss than or equal to.005) reduce the spread of Salmonellae from seeder to nonchallenged contact chicks. Simultaneous Salmonellae challenge an d CF3 treatment significantly (P less than or equal to.005) decreased the establishment of seeders and was highly effective in preventing th e spread of Salmonellae from seeder to contact chicks. The results dem onstrated that treatment on the day of hatch can significantly help re duce seeder establishment and the spread of Salmonellae from seeder to highly susceptible contact chicks.