title: Efficacy of oral administration of a modified-live Salmonella Dublin vaccine in calves.
abstract: OBJECTIVE
  To determine the efficacy a modified-live Salmonella Dublin vaccine administered PO in an extralabel manner in the prevention of diseases associated with Salmonella Dublin infection.
  
  
  METHODS
  Randomized clinical trial.
  
  
  METHODS
  288 preweaned Holstein dairy calves on a commercial dairy farm.
  
  
  METHODS
  Calves were orally administered either 2 mL of a commercially available, modified-live Salmonella Dublin vaccine (n = 140) or a placebo (148) at 3 and 10 days of age. Signs of diarrhea and depression were recorded daily. Weight gain between 3 days of age and time of weaning was measured. Fecal samples from clinically depressed or diarrheic calves and fresh tissues samples from calves that died were submitted for bacterial culture of Salmonella organisms.
  
  
  RESULTS
  Salmonella organisms were isolated from samples of 1.4% (2/140) and 3.4% (5/148) of calves receiving the vaccine and placebo, respectively. Additionally, 57.1% (80/140) and 60.1 % (89/148) of the vaccinated and control calves, respectively, had at least 1 day with an abnormal fecal score. Calves receiving the vaccine and placebo were not significantly different in terms of overall morbidity rate, Salmonella-specific morbidity rate, or average daily gain. Adverse reactions related to administration of the vaccine were not seen. The attenuated vaccine strain was not isolated from any fecal or tissue samples.
  
  
  CONCLUSIONS
  This method of vaccination was safe in young Holstein calves, although it was not effective in reducing the incidence of disease or improving weight gain on this farm. However, the power of this study was limited by a low incidence of clinical salmonellosis.
authors.affiliation: Center for Comparative Epidemiology, College of Veterinary Medicine, Michigan State University, East Lansing, MI 48824, USA. ghabing@gmail.com
authors.forename: Greg G
authors.initials: GG
authors.lastname: Habing
authors.forename: Louis M
authors.initials: LM
authors.lastname: Neuder
authors.forename: William
authors.initials: W
authors.lastname: Raphael
authors.forename: Hilary
authors.initials: H
authors.lastname: Piper-Youngs
authors.forename: John B
authors.initials: JB
authors.lastname: Kaneene
mesh_terms: D000284:Administration, Oral; D000818:Animals; D001428:Bacterial Vaccines / Q000302:isolation & purification*; D002417:Cattle; D002418:Cattle Diseases / Q000517:prevention & control*; D005260:Female; D008297:Male; D012481:Salmonella Infections, Animal / Q000517:prevention & control*; D022562:Salmonella Vaccines / Q000008:administration & dosage / Q000276:immunology*
chemical_list: D001428:Bacterial Vaccines; D022562:Salmonella Vaccines