Simpler, less costly monitoring methods helping pork industry get a better read on PRRS

Newer testing methods for the porcine reproductive and respiratory syndrome (PRRS) virus are not only simpler and less costly than traditional procedures, they are also helping farms more accurately track the virus through different production segments, Daniel Linhares, DVM, PhD, told Pig Health Today.

For example, collecting processing fluids during castration and tail docking has proved to be “a very powerful and easy method” that can help determine if sows are producing PRRS-negative pigs or if a PRRS virus elimination plan is a success, he said.

In the nursery, collecting oral fluids after sows and baby pigs chew on ropes provides a “family sample” and is a useful way to evaluate the PRRS status of litters ready for weaning, he said.

Look more, find more

Both mass-collection methods require far less labor than conventional monitoring that requires an ear prick or drawing blood. Furthermore, they allow veterinarians to evaluate groups of pigs rather than individual animals.

“You’re looking at more and you find more,” said Linhares, an assistant professor at Iowa State University.

Monitoring production data daily or weekly is another way to monitor for the PRRS virus — one that complements processing- and oral-fluid sampling, he said.

Producers can also “mix and match” monitoring methods to suit their needs, and some are using all three methods to monitor for PRRS virus as well as other infectious diseases, such as porcine circovirus and porcine epidemic diarrhea virus.

Processing fluids

Processing fluids for sampling involves placing all tails and testicles removed into a bucket lined with a plastic bag then cheesecloth, secured around the top of the bucket with a large rubber band. Tissue fluids drain through the cheesecloth into the plastic bag.

After collection, a small hole is made into the bottom of the plastic bag, and the fluids are funneled into testing vials and sent to a lab, usually for testing by PCR (polymerase chain reaction), he explained.

Data from veterinary diagnostic labs indicate processing-fluid sampling now accounts for 7% of all samples submitted for PRRS virus testing, so “it’s really taken off” over the past year. “It’s cheap, it’s easy, it’s a no brainer,” the veterinarian said.

Oral fluids

Oral fluids are gathered by hanging ropes in pens where both sows and baby pigs can chew on them.

“We’ve found that it’s not consistent if you try to collect only from piglets. But if you hang the rope where the sow can see it, it’s amazing…As soon as the baby piglets see mom interacting with the rope, they all copy her behavior and chew on the rope,” he said, adding that oral-fluids testing is highly sensitive for PRRS virus detection.

Production results can be monitored daily or weekly. Using a cloud-based reporting system developed by Iowa State University, producers can enter production data into a mobile device.  If the program detects a shift in the production parameters being monitored — an increase in abortions, for instance — it sends an alert to the user.