It’s clear that the porcine reproductive and respiratory syndrome virus is a formidable opponent. For nearly three decades the virus has evolved, retreated, resurfaced and, some might say, outsmarted attempts to gain control over it.
When it’s you staring at ailing sows and pigs, counting up the losses and trying to figure out how to put out the fire, it certainly seems like there are more questions than answers. Still, much progress has been made, and more will come.
Steve Tousignant, DVM, University of Minnesota Prevention and control techniques are among the things that are clearer today. While you can encounter a PRRS break most anytime, the virus definitely favors a seasonal pattern. University of Minnesota researchers Bob Morrison, DVM, and Steve Tousignant, DVM, and PhD student, are collecting and evaluating PRRS incidence data to determine when cases surface and how long they persist. It’s no secret that the PRRS virus favors cool temperatures and damp conditions, but the researchers found that late October/early November repeatedly ushered in “PRRS season,” which runs into March.
A surprise, however, is that another blip surfaces in late June/early July. Exactly why is not yet known, but having the information is the first step.
So knowing when PRRS virus exposure is likely to occur can help you batten down the hatches, so to speak.
Where do you start?
Paul Yeske, DVM, St. Peter, Minn. With hogs being the greatest source of PRRS virus spread, it’s important to know the status of neighboring herds. While it can be touchy to approach fellow pork producers about PRRS status, some of those obstacles are receding as more regional PRRS elimination projects (now more than 20) get underway. Paul Yeske, DVM, Swine Vet Center, St. Peter, Minn., suggests talking to producers with herds up to 5 miles around your site. “Understand the PRRS status of the pigs, what is being done for virus control and the biosecurity program — if they will share that information,” he says.
The PRRS virus travels well via air (as much as 7 miles), as well as on muck and slush. “Cooler weather and lower amounts of daylight may account for virus being able to survive better in the environment, allowing for greater herd-to-herd spread,” Yeske says. With fall becoming analogous with PRRS season, now is the time to brush up on biosecurity practices.
Increasingly, veterinarians point to PADRAP — or Production Animal Disease Risk Assessment Program — site assessments as a “must do,” especially in hog-dense areas. Conducted through a veterinarian, the process evaluates your production system for risk factors associated with PRRS virus exposure; it flags concerns and provides insight into needed changes. The American Association of Swine Practitioners manages the program, and while information is confidential by site, PADRAP also provides information to an industry database to identify answers for everyone. (For more, go to http://tinyurl.com/9q9thbg.)