Development of a biosecurity assessment tool and the assessment of biosecurity levels by this tool on Japanese commercial swine farms.

It is well known that infectious diseases such as porcine reproductive and respiratory syndrome (PRRS) and porcine epidemic diarrhea (PED) decrease herd productivity and lead to economic loss. It is believed that biosecurity practices are effective for the prevention and control of such infectious diseases. Therefore, the objective of the present study was to investigate whether or not an association between biosecurity level and herd productivity, as well as disease status exists on Japanese commercial swine farms. The present study was conducted on 141 farms. Biosecurity in each farm was assessed by a biosecurity assessment tool named BioAsseT. BioAsseT has a full score of 100 and consists of three sections (external biosecurity, internal biosecurity and diagnostic monitoring). Production data for number of pigs weaned per sow per year (PWSY) and post-weaning mortality per year (PWM) were collected for data analysis. Regarding PRRS status, the farms were categorized into two groups: unknown or unstable and stable or negative. In addition, these farms were categorized based on their PED status, either positive or negative. The total BioAsseT score was associated with herd productivity: as total score increased by 1, PWSY increased by 0.104 pigs and PWM decreased by 0.051 % (P < 0.05). Herd productivity was associated with the score of external and internal biosecurity (P < 0.05), but did not correlate with the score of diagnostic monitoring. Regarding PRRS status, farms with an unknown or unstable status had lower total score than those with stable or negative status (P < 0.05). Similarly, PED positive farms had a lower total score compared to PED negative farms (P < 0.05). In conclusion, the present study provides evidence for the association between high biosecurity levels and increased herd productivity as well as a decreased risk for novel introductions of infectious diseases such as PED.

Impact of a porcine epidemic diarrhea outbreak on swine productivity in Japan: a retrospective cohort study.

The objective was to investigate porcine epidemic diarrhea (PED) outbreak that occurred in 2014 in Japan and its effects on herd-level productivity using a data recording system (PigINFO). The study herds were selected from farrow-to-finish herds (n=99) that entered in the PigINFO system between July 2013 and March 2015. From 1 April to 30 June 2014 (PED epidemic), any herds with clinical signs of PED and feces positive for porcine epidemic diarrhea virus (PEDV) on polymerase chain reaction analysis and/or immunohistochemical staining were defined as PED-positive (n=38). They were further classified into those with long PED periods (L-PED-positive; n=28) and those with short PED periods (S-PED-positive; n=10). Herds with no clinical signs of PED were classified as PED-negative (n=61). Herd-level production data, including preweaning mortality (%; PRWM), postweaning mortality (%; POWM), pigs weaned per litter (PWL), pigs born alive per litter, litters per mated female per year and pigs marketed per sow (MP), were calculated every 3 months during study period. During the PED epidemic, L-PED-positive herds had significantly higher PRWM and POWM than PED-negative herds, and L-PED-positive and S-PED-positive herds had significantly lower PWL. During October-December 2014, L-PED-positive herds had significantly fewer MP than PED-negative herds. The PED outbreak increased mortality and consequently reduced the numbers of marketed pigs. The rapid control of an outbreak is important for reducing the financial losses arising from PED infections.

Aujeszky's disease and the effects of infection on Japanese swine herd productivity: a cross-sectional study.

Pseudorabies virus (PRV) is endemic in some regions of Japan. We investigated the effects of PRV infection status on herd productivity. Serum samples were obtained from 48 swine herds in Japan. Within each herd, three serum samples were obtained from growing pigs at four different ages, as well as from sows in low and high parity groups. Sera were tested for antibodies against wild-type PRV via competitive ELISA. Herds were classified into PRV positive and negative groups based on serological results. Herds infected with PRV exhibited postweaning mortalities (6.84%) that were significantly (P=0.0018) higher than those in unaffected herds (4.73%). Because of the reduced productivity in PRV positive herds, the current PRV eradication program must be strengthened.