title: Efficacy of a commercial live attenuated Lawsonia intracellularis vaccine in a large scale field trial in Korea.
abstract: OBJECTIVE
  Porcine proliferative enteropathy (PPE) is known as one of the most important risk factors causing economic losses in swine industry worldwide. This study was conducted to evaluate the efficacy of a commercial oral attenuated Lawsonia intracellularis vaccine (Enterisol Ileitis) against PPE under a commercial pig farm condition in Korea.
  
  
  METHODS
  Thirty two-day-old 672 piglets were randomly allocated into vaccinated and control groups. All piglets in the vaccinated group were inoculated with a commercial attenuated L. intracellularis vaccine as following the manufacturer's instruction. Body weights of all pigs in both groups were measured on the vaccination day and 6, 14, and 20 weeks post vaccination and an average daily weight gain (ADWG) was calculated. Health status was observed biweekly during the whole trial.
  
  
  RESULTS
  The vaccinated group showed significantly higher body weight (p<0.05) and ADWG (p<0.05) than those of the control group. The vaccinated group had significantly reduced impairments in activity, growth, defecation frequency, and stool hardness (p<0.05). Additional health benefits and improved weight gain by the vaccination produced a 4.2:1 return of investment, and the higher gross margin was $4.80 per pig.
  
  
  CONCLUSIONS
  Our finding suggests that the L. intracellularis vaccine program has effects on the substantial health and economic benefits in the Korean swine industry.
authors.affiliation: Department of Infectious Diseases, College of Veterinary Medicine, Konkuk University, Seoul, Korea. ; Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, USA.
authors.forename: Sangshin
authors.initials: S
authors.lastname: Park
authors.forename: Joong-Bok
authors.initials: JB
authors.lastname: Lee
authors.forename: Kyung-Jin
authors.initials: KJ
authors.lastname: Kim
authors.forename: Yu-Sik
authors.initials: YS
authors.lastname: Oh
authors.forename: Man-Ok
authors.initials: MO
authors.lastname: Kim
authors.forename: Yu-Ri
authors.initials: YR
authors.lastname: Oh
authors.forename: Min-A
authors.initials: MA
authors.lastname: Hwang
authors.forename: Jung-Ah
authors.initials: JA
authors.lastname: Lee
authors.forename: Sang-Won
authors.initials: SW
authors.lastname: Lee
keywords: Ileitis; Intestinal diseases; Lawsonia intracellularis; Swine; Vaccines