Reduced shedding and clinical signs of Salmonella Typhimurium in nursery pigs vaccinated with a Salmonella Choleraesuis vaccine

Methods: Three studies were conducted using 3to 4-week-old crossbred pigs. The studies differed in the number of times the vaccine was administered (twice in Study One, once in Studies Two and Three), the severity of the challenge (1 × 1010 in Studies One and Two, 1 × 106 in Study Three), and the principle variables recorded during the study (clinical disease in Studies One and Two, shedding and isolation of the challenge organism in feces and tissues in Studies One and Three). In each study, pigs in a VACC-CHAL group were vaccinated orally (individually in Study One or with a water proportioner in Studies Two and Three) at 3 weeks of age and challenged 3 weeks later with virulent Salmonella Typhimurium. CHAL pigs were challenged but not vaccinated, and Control pigs were neither vaccinated nor challenged. Pigs were weighed and their temperatures were taken; they were scored for clinical signs of disease and for fecal consistency; and fecal, serum, and necropsy samples were taken for culture and ELISA.