Abstract
Data were collected from 92 farrow-to-finish farms. The farmers from these farms were clients of 10 consulting veterinarians who were members of the Japan Association of Swine Veterinarians. Production data of the farm, porcine reproductive and respiratory syndrome virus (PRRSV) status and location were analyzed. The rate of PRRSV-positive farms was 82.6% (76/92). The post-weaning mortality of the PRRSV-negative group was significantly lower than that of the PRRSV-positive group (positive: 6.1%, negative: 3.9%: P<0.01). The average daily weight gain of the PRRSV-negative group was significantly higher than that of the PRRSV-positive group (positive: 585.1 g, negative: 638.8 g: P<0.01). Multivariate logistic regression modeling was used to examine the association between the situation in the farm (location) and PRRSV status. With regard to location, other pig farms within a 3-km radius were significantly associated (P<0.05) with PRRSV-positive status (Odds ratio (OR)=4.09, 95% Confidence interval (CI)=1.07-15.70). The Kanto region was significantly associated (P<0.01) with PRRSV-positive status (OR=41.8, 95% CI=4.80-363.0) compared with the northern area. Our findings suggest that PRRSV significantly worsens productivity in the farm. In particular, the area and presence of other pig farms are associated with PRRSV status. Regional collaboration is an important strategy to control or eliminate PRRSV.
