Financial evaluation of vaccination and testing alternatives for control of parvovirus-induced reproductive failure in swine

The preferable testing and vaccination strategy for control of porcine parvovirus (PPV) during a 6-month period was investigated using decision-tree analysis and computer simulations of a 300-sow farrow-to-finish herd. The initial decision alternative was serological testing of 30 females to estimate herd PPV prevalence against not testing any females. On the basis of serological test results, herds were classified into 1 of 3 PPV-risk categories: low (≥ 80% seropositive females), moderate (40 to <80% seropositive females), or high (<40% seropositive females). Vaccinating all females, only gilts, or not vaccinating was the second decision alternative. It was found that for initial model assumptions (test sensitivity and specificity = 0.95; test cost = $5/female; vaccination cost = $0.30/dose; vaccination efficacy = 0.95; and foregone gross margin = $10.85/pig), vaccination of all females (with or without serological testing) was preferable, but that the financially preferable option was to omit serological testing. The most profitable vaccination option varied with foregone gross margin, vaccination cost, and efficacy. For herds in which all sows were known to be immune, vaccinating only gilts was financially preferable, and serological testing was not warranted. Variation in expected financial losses was less in vaccination options than with non-vaccination. For most herds in the USA, serological screening for PPV before selection of a vaccination programme is unlikely to be cost-effective, because vaccination is inexpensive ($0.30/dose) and effective (95%). At current profit margins ($10.85/pig), vaccination of all females has the least-risk and is the preferred option.