Comparison of techniques for controlling the spread of PRRSV in a large swine herd

Gonzalo Bruna, DVM,MS; Salvador Cabeza de Vaca (deceased February 1997), DVM,MS; HanSoo Joo, DVM,PhD; Carlos Pijoan, DVM,PhD

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Objective: To evaluate medicated offsite weaning (MOW),partialdepopulation (PD), and the use of a modified live virus vaccine (MLV) aspossible techniques to control porcine reproductive and respiratory syndromevirus (PRRSV).

Methods: Four groups of 30 pigs from a PRRSV-infected farm wereincluded in the study. Serum antibody responses to PRRSV (IFA), Mycoplasmahyopneumoniae (Tween-ELISA), and Actinobacillus pleuropneumoniae(BAHIA) were examined and bacteriology was performed at days 21, 35, 60,90, 120, and 150 in all groups. We also measured average daily gain (ADG),mortality, and incidence of cough from 10 days of age to slaughter. PigMON®data were collected at slaughter.

Results: MOW was the only technique able to maintain PRRSV-negativeanimals. PD and MLV resulted in a decrease in PRRSV seroprevalence. Eventhough PD was unable to eradicate PRRSV, performance was improved afterthis procedure was initiated. Differences in performance were not seen betweenthe PD and MLV groups.

Implications: Medicated offsite weaning may be able to stop thespread of PRRSV. Partial depopulation will reduce the decreased growth performanceassociated with PRRSV. Modified-live virus vaccine did not improve performancecompared to partial depopulation in herds infected with PRRSV.

Keywords: PRRSV, MEW, depopulation, vaccine

RIS citationCite as: Bruna G, de Vaca S, Joo HS, et al. Comparison of techniques for controlling the spread of PRRSV in a large swine herd. J Swine Health Prod 1997;5(2):59-65.

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