PRRS: A continual problem for pork producers
By Jennifer Carrico
Porcine reproductive and respiratory syndrome has been a challenge for producers for over 30 years and is one of the most costly diseases that producers face, costing the industry over $600 million per year.
Veterinarian Cameron Schmitt, of the Pipestone Vet Clinic in Independence, Iowa, said good biosecurity can help prevent of spreading the virus.
“When producers are keeping gilts back as replacements in the herd, isolation and quarantine space is critical,” he told pork producers at the Iowa Pork Congress. “Gilts should be tested pre- and post-placement in the herd.”
Schmitt suggests the all in/all out flow at wean to finish sites, as they tend to circulate PRRS and other diseases at a higher rate once the animals are infected.
Semen is also a risk, and he suggests knowing that the boars and other pigs at the source site are PRRS free is a good biosecurity practice.
“Between groups in a the different barns, producers should disinfect and have some down time before filling the barns again. This includes spraying all materials and equipment,” he said.
Trucks and trailers used for transportation can be an infection site as well. He said those vehicles should be cleaned out and inspected especially if disease is found in pigs that have been transported to the facilities.
PRRS is also found in the air and can spread via air and aerosols. Schmitt said the viral quantities found in the air were significantly higher in 2011 than they had been in previous yeas.
“It’s been hypothesized that the strains that are out there now are more virulent and more readily shed,” he said. “We’ve found that vaccinating for PRRS with a modified live vaccine will significantly reduce the aerosol shedding of the virus.
“If a known wean to finish site breaks with PRRS and a vaccinated group is infected one week prior, it will significantly reduce their shedding of the virus,” he added.
Non-vaccinated pigs will shed the virus a lot longer than vaccinated pigs will. He said if the pigs can’t be moved, they should be vaccinated after a group breaks with PRRS.
Schmitt said filter farms in between hog farms can help with some of the spread of the virus.
When bringing in new animals, it’s very important to isolate them. Aerosol challenges happen more than we realize and virus floats through the air and can spread the disease.
Pigs can also shed the PRRS virus through their feces for seven days. Pig manure in a slurry at 40 degrees will spread the virus for 14 days, but when the temperature is 50 to 60 degrees, it will only spread for five days.
“The virus also continues to live when spread on the ground if during the time frame where it is alive in the feces,” he said. “This also causes the virus to spread in the air.”
He suggested the use of serum to get pigs to a negative status more quickly, usually in six to nine weeks. If serum is used and another outbreak occurs, he said it’s not as severe.
Schmitt said the PRRS outbreak in the upper Midwest usually happens about the same time each year—in mid-October.
“As an industry we need to work together to prevent he spread of PRRS. We need to utilize scientific knowledge and use research to find out even more about the disease,” he said. “We need to determine if cutting corners when the hog market is low and input costs are high is the cause of some of our problems.”
Jennifer Carrico can be reached by phone at 515-833-2120, or by email at firstname.lastname@example.org.