Testimonial of a Veterinarian

"Farm A is a 3000-sow farrow-to-wean farm located in southern Minnesota in a very swine-dense area. The farm was PRRS-positive, but stable, as of September 1, 2005. Beginning the week of September 24, Farm A developed clinical signs for PRRS including abortions, off-feed animals, early farrowings, and increased stillborns. This continued into mid-October.

Diagnostics and sequencing on piglet and sow inventory confirmed that a new and different strain of PRRS virus had entered this farm.

On October 16, 2005, the decision was made to inject the entire herd with a new autogenous killed PRRS subunit vaccine, produced using Selectigen-MJPRRS technology.

Much to our surprise, within 14 days of vaccination abortions and other clinical signs within the herd had ended. The pigs farrowed from the vaccinated sows began to be born normal and healthy. Weaned pigs from the vaccinated sows were PCR-tested weekly beginning November 1 and continuing through the end of the year, with all groups testing PCR-negative.

Conclusions and Observations: Using MJPRRS vaccine stopped the clinical outbreak in the 3000-sow herd infected with a new heterogeneous PRRS strain within about two weeks of vaccination. The vaccination did not have negative effects upon the sow herd.

Using MJPRRS vaccine shortened the time to produce PCR-negative pigs farrowed from positivevaccinated sows down to about three weeks.

The economic impact was further reduced by being able to wean PCR-negative pigs off vaccinated sows in about three weeks, stopping the spread of the virus into the nursery-grower system.

Farm B is a 350-acre sow farrow-to-finish unit located near Truman, Minnesota. The unit was PRRSpositive but stable through the end of November 2005. Beginning the week of December 4, 2005, the unit started to have abortions, sows off-feed, early farrowings, and increased pre-farrowing mortality.

Diagnostics of sows and piglets confirmed active PRRS. The sequencing of the virus later established an 11% difference from the strains that the farm had experienced previously.

The total inventory of sows and gilts were given a shot of MJPRRS, a new autogenous killed PRRS vaccine. A booster shot was given to the sow herd three weeks after the initial vaccination.

Abortions and clinical signs within the sow herd ended within 14 days of the vaccination. The weaning of healthy baby pigs started about 10 days later. The pigs tested PRRS-negative at weaning time.

Conclusions and Observations:
The new vaccine stopped the clinical outbreak in this herd challenged by a heterogeneous PRRS virus in about two weeks.

The new vaccine shortened the normal time it takes to produce PCR-negative pigs in a chronic outbreak of the virus.

Maternal antibodies from the vaccinated sows extended the time of seroconversion in the weaned pigs to a weight of about 45-50 pounds. At the time of conversion, the pigs in the grower didn’t experience the normal clinical signs or elevated death loss associated with PRRS in the past.

The economic impact of the chronic break was greatly reduced due to the small number of abortions and the large number of baby pigs born PCR-negative within a short period of time."

Brian Roggow, D.V.M.
Fairmont Vet Clinic
Fairmont, Minnesota