The testing protocols for boar studs and replacement gilts are also built around providing safeguards against introduction of the PRRS virus, says Nerem. PRRS can be transmitted very efficiently through semen, so the staff tests for PRRS at the boar stud every collection day. A random sample is sent to the South Dakota state diagnostic laboratory at Brookings, and next-day test results are provided. “The semen cannot enter the clean side of the sow farm until the test results come back negative,” he says.

The gilt-testing program is still being standardized for all sow farms. Basically, gilts are tested for PRRS on arrival, quarantined, and then retested a couple of weeks later. Gilts must test PRRS-negative before entry to the sow farm is permitted.

For most other diseases of concern, clinical signs or herd health history are relied upon to gauge disease status. “In our view, the cost-benefit ratio to testing for a lot of diseases is just not there,” Nerem asserts. “If these were multiplication herds, it would be different. But these are commercial breeding herds, so we are mainly looking at PRRS, and then keeping in close contact with the source herd upstream to make sure that health is good there as well.”

Circovirus is a major health concern. But since it is usually manifested in finishing pigs and not replacement gilts, and most U.S. herds will test positive for the virus, there would be no point in screening incoming stock, he says.

Despite intensive biosecurity efforts to keep out the PRRS virus, there are still reports of breaks. But that doesn't mean that every known effort shouldn't be made to keep the virus off farms, says Nerem.

Walkes feels “biosecurity is good insurance and it protects your investments.”

With mounting evidence that aerosol transmission of PRRS is more common than previously thought, Pipestone System installed air filtration systems on boar studs a year ago. So far, none have broken with PRRS. Nerem says after several years of expensive PRRS breaks, there has been a “huge movement within the boar stud community to get these studs filtered.”

Air filtration systems are being seriously looked at for commercial sow farms within the Pipestone System, too, he adds. None are filtered at this time.

“What we once thought was a clean trailer wasn't really clean — it was partially clean,” Nerem says. “First hand, we sampled some trailers that had been through a truck wash and found infectious PRRS virus on the trailers a day after washing. We were able to get test samples for PRRS and actually infect pigs with those samples.”

To prevent that scenario from re-occurring and provide another layer of biosecurity, the Pipestone System is planning to build a new, two-bay truck wash this summer to allow proper washing and disinfecting of trailers, Nerem remarks. It will replace the current single-bay truck wash. Sow farms in other areas contract with commercial truck washes approved by Pipestone veterinarians.

Another new feature coming soon is a trailer audit, Walkes says, to make sure trailers are cleaned and disinfected according to specifications.

“I'm not sure this is really anything new. Other systems have done it, but we have made an expectation of the level of sanitation at both the truck wash and in a trailer before it goes back to the farm. Now, we are following up to make sure that standard is being met,” Nerem reports.

Walkes will also be responsible for randomly auditing trailers, much as she does for the sow farms. “If the truck and trailer are not kept clean, then everything that you do at the sow farm (for biosecurity) is kind of useless,” she states.

To minimize the biosecurity risk of a potential disease transmission, a trailer is dedicated to each sow farm. Nerem believes this step, along with good sanitation and disinfection, will alleviate much of the risk of transportation and the need for expensive drying technology.

A system that provides good biosecurity protects animal health, animal welfare and maintains positive morale of staff, while also reducing the cost of biosecurity to the production system, Nerem suggests.

Biosecurity must be made a higher priority in order to safeguard the swine industry from PRRS and circovirus, he adds.

To achieve success against these two serious pathogens will require improved communication and disease-monitoring strategies, using regional efforts guided by computer-aided, disease-mapping technology, Nerem says.

“It will really require a higher level of cooperation than what we have done in the past, including a willingness to share information about what is happening on producers' farms as far as disease status in order to achieve the overall benefit of getting rid of certain diseases, before they become epidemics. We need to look at how we cooperate, coordinate and communicate,” he concludes.