Case Study

Pike Pig Systems
113 E. Washington Street
Pittsfield, IL 62363
(217) 285-4636

February 2, 2010

In the fall of 2008 we started working with a 4-5 year old 6400-sow farm that had a history of at least two previous PRRS virus outbreaks. Each break followed up with treatment with PRRS serum therapy of both the sow herd and attached GDU. The farm was in the process of trying to eradicate the virus through redesigned animal and personnel flows as well as stricter bio-security procedures. However, after a period of time with poor quality pigs, short pig placements, disgruntled owners, disgruntled workers, and higher costs, the frustration level was at an all time high. At this time ownership changed their focus from PRRS eradication to improved numbers of good quality pigs regardless of the PRRS status of the pigs or the sow herd. Scrapping the PRRS eradication program led us to explore other PRRS management strategies.

The farm structure is a 6400 sow breed-wean farm with 2 gestation barns and common farrowing rooms. There are 2 isolation nurseries capable of handling 360 gilts which are delivered (PRRS naïve) to the farm every four weeks at 3-4 weeks of age. After an 8 week stay, the gilts are moved into the gilt grow finish facility that is attached to the sow farm. Once gilts reach 28 weeks of age and have received proper vaccination and acclimation, they are then moved into the breeding/gestation barns. Once the PRRS eradication procedures had been eliminated, the daily foot traffic and chores returned to a more normal farm routine. We also began using a new sub-unit PRRS vaccine as a 2-dose vaccination prior to replacement gilts being introduced into the breeding herd. The new PRRS sub-unit vaccine was the same product that had been given to all sows in weeks 44 and 48 of 2008. Prior to the use of the PRRS sub-unit vaccine, the herd performance was at a 10.85% live born, 4.7% still born rate, 1.9% mummy rate, 17% pre-weaning mortality and 8.7 pigs per sow weaning average.

With these changes we had targeted producing 2700 pigs per week rather than the 1900 to 2100 pigs per week we had produced over the previous nine months. Approximately 12 weeks after beginning the new vaccination program (week 4 of 2009), we started seeing an increase in the pre-weaning mortality, stillborn and mummy rate, and experienced 37 late term abortions. Keeping in mind that all these animals had already received two doses of the new sub-unit PRRS vaccine, we pulled blood out of symptomatic sows in gestation, pigs in farrowing and gilts getting ready to leave the isolation nursery (delivered naïve and sero-converted naturally) after their 8-week stay. We found all three sampled areas yielded 100 percent PRRS PCR positive results. Immediate virus sequencing was done. Samples from all 3 areas of the farm yielded the same PRRS virus. The decision then was made to come back and booster the entire population with another dose of the same, new sub-unit PRRS vaccine on week 8 of 2009.

During that time, we had planned on investigating other possibilities in regard to PRRS management control. We also started testing pigs coming out of the farrowing house 4 weeks after the sow booster of the new sub-unit PRRS vaccine was given. We found pigs to be PRRS positive coming out of farrowing every week that we tested between weeks 13 and 17, 2009. Considering that it had been 6 weeks since the booster of the new sub-unit vaccine had been given, we concluded that it was time to look at our next option. During our testing we had heard about MJ Biologics, and submitted the 3 strains of PRRS virus sequences for evaluation and characterization of viruses based on MJPRRS™ grouping technology to make sure that the virus groups of those isolated would be included in the vaccine that we used. Once we got the vaccine, we used it on the entire sow herd and all the way through isolation (10,000 doses+/-).

When the MJPRRS™ vaccine was put into the herd we were operating at a 5.5% stillborn rate and 18% mummy rate over the previous 10 weeks. The new sub-unit vaccine that we had used appeared to stop late stage abortions, but did not seem to have an effect on stillborn or mummy rates. The vaccine also appeared to have no affect on limiting PCR status for PRRS virus in pigs at weaning time. The booster (2nd vaccination) of the MJPRRS™ was given to all sows in the herd on weeks 22 of 2009. Once again all groups being weaned had samples taken from the poorest pigs in the group to do PCR analysis for PRRS virus beginning with week 18 and continuing through week 25.

The summary of information based on records and laboratory analysis appears to be very significant. By the 4th week after the first dose of MJPRRS™ vaccine, mummy rates had dropped from 19% down to 6.3% and continued to inch its way down to the present level of 1.6%. The stillborn rate also decreased from 5.5% down to 4.5%. Pigs remained PCR positive for PRRS until the 6th week (week 24 of 2009) after the initial vaccination or 2 weeks after the booster. The farm has continued the vaccination program by giving a whole herd booster of the MJPRRS™ vaccine every 13 weeks. Pigs coming out of the farrowing house remain PCR negative for PRRS from week 24 of 2009 to the present time.

At this point, the MJPRRS™ approach has resulted in a significant increase in pigs produced each week (2750-2850) as well as a major improvement in pig quality. Owners claimed that a year earlier the pigs they received averaged 70% good, 20% questionable but start-able and 10% of no value. The same owners today rate them 95% excellent pigs, 3% good pigs and 2% off pigs. Performance of the pigs in nurseries and finishers has been exceptional. Due to these results on this farm as well as others where MJPRRS™ was used, we plan to continue to use this product as our first option.

Patrick L. Graham M.S., D.V.M.
John McIntire, General Manager
David Bishop, PhD