PED elimination in a one-site farm using a novel approach

Owing to inexperience with Porcine Epidemic Diarrhea (PED) but building on experience with Transmissible Gastro-Enteritis (TGE), North American producers utilized various methods of whole-herd exposure and sanitation to eliminate PED virus from sow herds. Compared to continuous farrow flows, elimination was easier in group-mating systems due to the inherent break in piglet ages/flow. Age-segregated flows with movement at weaning to off-site nurseries were easier than one-site farrow-finish flows due to lower viral exposure coming from sero-converting nurseries. This paper examines one elimination process on a farrow-finish site which reduced viral pressure by creating an artificial break in piglet production, achieving uniform whole-herd immunity, applying aggressive sanitation, and enforcing strict control of people and pig movement.

Acute PED appeared in a one-site farrow-finish 850 sow herd in an area of low swine density. The herd was considered "highhealth," remaining PRRS/Myco negative for years. Anticipating the course of events, swift action was taken. All sows due to farrow in the next four weeks were sold and moved off-site in a matter of days. Healthy older piglets were weaned; susceptible younger piglets were humanely euthanized. Fostering between litters ceased. The entire production herd, including all replacement females was inoculated using dilute piglet diarrhea in oral/nasal spray. Emphasis on sanitation increased utilizing cold water, high pressure washing and disinfection with Synergize and bleach. Pathogen circulation within the facility was prevented by strict all-in/all-out pig movements and segregation of people and equipment.

Clinical signs spread throughout the entire population, providing uniform whole-herd immunity. Light-weight pigs and those particularly stunted were removed from the site. Evidence of disease persisted 3-4 weeks at which time farrowing sows were able to provide lactogenic immunity. Following a testing protocol patterned by AASV, the facility was PED negative within seven months.

Prompt aggressive action was pivotal to the successful elimination. Removing late-term pregnant sows reduced the susceptible piglet population at a critical period and reduced the level of PED exposure in all farrowing rooms; thus reducing pressure on the sanitation process to prevent contamination between farrowing groups. Targeted exposure processes reduced the virus exposure level in gestation while providing uniform immunity. Strict adherence to “no fostering” prevented viral movement between litters. Altogether, the balance of exposure versus immunity tipped in favor of successful PED elimination.

Disclosure of Interest: J. Geiger Conflict with: PIC employee, J. W. Lyons Conflict with: PIC employee, J. P. Cano Conflict with: PIC employee, G. Shepherd: None Declared.