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Southern Minnesota veterinarian Tom Wetzell had several herds participate in MAGIC™, which stands for Monitoring Assignment for Global Insight of Circovirus. MAGIC is a diagnostic protocol to root out porcine circovirus type 2 and its coinfections.

Death loss was a shocking 25 to 30 percent in one herd, a northern Iowa wean-to-finish operation turning out 30,000 pigs per year.

Diagnostic workups to identify the deadly pathogens have led to strategies to control them and happily, that has had a major impact on the farm’s mortality figure.

“Early indications are a drop in mortality down to 5 to 7 percent,” said Wetzell, of South Central Veterinary Associates, Wells, Minn.

The case is one of many in the 2006 MAGIC study to not only have PCVAD (porcine circovirus associated disease), but PRRS as well. In fact, PRRS was identified as a cofactor to PCVAD in 78 percent of the herds tested.

After PRRS was diagnosed, Wetzell went to the sow-farm source, which then worked hard to stabilize the virus at that level. “We also made some pig flow changes,” he said, which he feels contributed to the lowered mortality.

“One of the sites is supposed to have three different age groups – pigs come in every eight to nine weeks. But pigs that weren’t growing as well were always being held back, so there really were four, even five different age groups. That practice has since been stopped and poor-performing pigs are culled immediately, so it’s back to three age groups.”

PRRS was affecting pigs two to three weeks after arrival, all the way through the nursery period, Wetzell added. Porcine circovirus type 2 hit later, in pigs 9 to 10 weeks of age, and lasted about two months.

Were there any other cofactors? “Salmonella. It was surprising. I know in the MAGIC study, salmonella was the second most common cofactor. This farm also had salmonella.”

Part of the MAGIC program was to vaccinate pigs with Boehringer Ingelheim’s Ingelvac® CircoFLEX™. Wetzell’s client used the vaccine on half the pigs and “The differences were pretty dramatic,” he said.

Intervention was not used for the salmonella, but Wetzell noted that it seems to have quieted down now that PRRS and PCVAD are under control.

“The take-home message may be that once we control the primary viral agent, secondary bacterial infections don’t show as many clinical signs,” said the Minnesota practitioner.

A second herd in southern Minnesota had a different scenario. Mortality was much lower – 7 to 9 percent in a 15,000-head wean-to- finish operation. Still, death loss was 3 to 4 percent higher than normal, which is why they were concerned and why they did MAGIC, Wetzell said. “We found PCVAD in that set of pigs.”

PRRS, too, was a cofactor. In this herd, every pig now receives Ingelvac PRRS ATP vaccine at weaning. The PRRS vaccine and Ingelvac CircoFLEX are given at the same time upon arrival to the nursery from the sow farm.

And again, vaccination reduced mortality. The vaccinated group ran 2.5 percent mortality and non-vaccinated pigs about 7 percent. But there was an added benefit with lights and cull pigs.

“The percentage of lights and culls from nonvaccinated pigs was 2.5 percent,” Wetzell pointed out. “The percentage from vaccinated pigs was 0.5 percent; so there was a 2 percent improvement in the number of good pigs sold to market, in addition to the difference in mortality.”

The circovirus vaccine is not inexpensive, but producers want it in the worst way, he continued. “It’s so effective. But first confirm the diagnosis; that’s important before using vaccine. Make sure you have PCVAD in the herd before vaccinating the pig.”

This issue brings up another point. “It was surprising how many times we did not see good lesions when posting pigs, yet the lab confirmed at three weeks pre-peak mortality, high levels of circovirus.

“The MAGIC program really clarified for me as a practitioner what tissues we need to send and the need for a complete set of tissues from all organ systems when looking for PCVAD. My take-home message was even if you do not see gross lesions, it’s important to take those sets of tissues.”