A National Pork Board and Iowa State University study showed that PRRS costs the U.S. pork industry $560 million to $762 million annually.PRRS costs about $74 per litter in the breeding herd, says Jim Kliebenstein, Iowa State University agricultural economist.
“In the farrowing phase, PRRS causes lower farrowing rates, reduced litter size and open facility space since sows weren’t moving through at the normal rate,” he notes.
While reproductive problems were expected, problems in the nursery and finishers were far more severe than expected.
“About two-thirds of PRRS’ costs are incurred on growing pigs; the other one-third is felt in the breeding herd,” says Eric Neumann, DVM National Pork Board.
Nursery pigs affected by PRRS have a 10.65 percentage points higher mortality rate than unaffected pigs, according to Neumann. It was more than six times greater. Adding to the economic losses, PRRS causes nursery feed efficiency to drop by 11.69 percent. The pigs didn’t grow as fast, taking about 25 percent longer to grow from 12 pounds to 50 pounds, which creates more pig-flow problems.
“Between death loss, reduced feed efficiency and longer time spent in the nursery, PRRS costs about $6 per pig more just in the nursery than if pigs are unaffected,” says Kliebenstein.
In grow/finish, PRRS infected pigs had a 6 percentage points higher death loss than unaffected pigs. Feed efficiency was 7 percent to 8 percent worse than pigs not encountering PRRS, and average daily gain also dropped. It took PRRS-infected pigs 12 percent longer to grow from 50 pounds to 260 pounds. This all contributed to an extra $7.67 per pig in costs for PRRS-infected pigs versus unaffected grow/finish pigs.
While the average impact from PRRS is substantial, the individual farm impact can be far worse. Researchers performed case studies to identify a range of impacts.
The case studies revealed a range of $28 to $160 per litter impact of PRRS in the farrowing phase. In the nursery, it ran from $3.30 per pig to $9 per pig. In grow/finish it was 21 cents per pig to $28. Kliebenstein says one farm was hit hard in the finishing barn, which skewed the range. The next highest total was $10.
PRRS can damage an operation in intangible ways as well. “In addition to elevated medical costs and lost production, PRRS can hurt employee morale,” says Scott Dee, DVM University of Minnesota. “It’s hard to put a dollar figure on employee morale. But with PRRS, you work so hard and the virus makes all your efforts wasted.”
There is no type of operation or management style that is unaffected by PRRS, and there seems to be little difference between operation types and PRRS susceptibility.
“All you can do is follow best management practices, like having a source of PRRS-naive seedstock and boar semen, good gilt isolation and acclimatization, all-in/all-out animal flow and strict biosecurity,” says Dee. “Vaccines are an option based on the herd veterinarian’s recommendations.”
One reason PRRS has been such a problem for the pork industry is because since being discovered in the United States in the late 1980’s the virus has continually mutated and taken on multiple strains. This has caused tremendous frustration because just when a producer has eliminated PRRS, a new strain could hit.
“Often you can drive PRRS off a farm, but you fail to drive it completely out of your system,” says Neumann. “Driving it out of a region is even more difficult. Strain variation and lack of cross-protection has made it difficult to eradicate PRRS from a region.”
Still, Neumann is confident PRRS can be eradicated eventually.
NPB’s and USDA’s National Research Initiative is coordinating with the North Central 229 multi-state PRRS project. They are allocating $6 million for multi-state PRRS research, over the next several years with efforts in place to secure more funding.
“We’ve never had that much money before,” says Dee. “Hopefully this will cause scientists from different areas to work together and stimulate advances.”
“One of the objectives listed is to consider the development of regional eradication projects,” says Neumann.
As part of the coordination, there is a PRRS Initiative area on NPB’s Web site. Go to www.porkboard.org, then click on “Pork Production” and then go to “PRRS Initiative.”
The additional research money and focus provide some reason fo r optimism on a topic that has offered mostly frustration and bad news. Without question, PRRS has changed the face of U.S. pork production.
“There has never been a more devastating disease in the swine industry, and it is by far the disease with the greatest cost to the industry today,” says Dee. “It has put quite a few people out of business. It’s made others more cognizant of the disease and better managers. It’s completely changed herd-health strategies and pig flow.”