EFFECT OF GENETICS, VACCINE DOSAGE, AND POSTVACCINATION SAMPLING INTERVAL ON EARLY ANTIBODY-RESPONSE TO SALMONELLA-ENTERITIDIS VACCINE IN BROILER BREEDER CHICKS

Broiler breeder chicks of two different genetic Lines were evaluated f or early antibody response to Salmonella enteritidis (SE) vaccine. Ant ibody responses to three dosages of SE vaccine administered at 22 d of age were measured at 3, 6, and 10 d postvaccination. Within each line , antibody levels at 10 d postvaccination were significantly higher th an at either 3 or 6 d postvaccination. At all vaccine dosages, there w as a significant antibody-response difference between the genetic line s at 6 and 10 d postvaccination. The vaccine dosage significantly affe cted antibody levels in one of the two genetic Lines. These results de monstrate a genetic component of early antibody response to SE vaccine in broiler breeder chicks.