Porcine reproductive and respiratory syndrome (PRRS) caused an estimated $1.2 billion per year in lost production in the US pork industry from 2016 to 2020, an 80% increase from a decade earlier, according to a new analysis by an Iowa State University expert.
The viral disease has been present in US swine herds since the mid-1980s and remains a growing threat, said Derald Holtkamp, professor of veterinary diagnostic and production animal medicine.
“After 40 years of experience fighting this virus, veterinarians and producers are still losing the battle against PRRS,” said Holtkamp, who led the new research and a 2012 study that estimated the virus caused $664 million in annual losses from 2006 to 2010.
Data crucial for producers
The sharp increase in economic damage caused by PRRS isn’t driven by changes in market prices, production cost or the size of the US pig inventory. Those factors only account for about $108 million of the $536 million increase in annual losses, Holtkamp said. The other $428 million is attributed to the portion of herds affected by PRRS and the differences in productivity between affected and unaffected herds.
The new estimate relies on weekly herd disease status data gathered by a swine health reporting program at the University of Minnesota and productivity data collected from pork producers by Iowa State postdoctoral researcher and study co-author Henry Osemeke. Holtkamp presented the study earlier this summer at the International Pig Veterinary Society Congress in Leipzig, Germany.
The increase was larger than Holtkamp expected, but pork industry veterinarians who have seen the data aren’t surprised. “Without fail they say, ‘Nope, that seems right,’” he said.
Holtkamp has a master’s degree in economics, a rare background for a veterinarian. Cost of disease studies are crucial for allocating research funding and informing industry decision-making, he said.
“It’s foundational data for big producers, who plug these numbers into their formulas,” he said.
Improved biosecurity needed
PRRS is the most economically damaging illness for swine producers, causing respiratory distress in pigs of all ages and reproductive problems in breeding stock. Controlling the disease is a continuous challenge in part because the RNA virus that causes PRRS evolves frequently and vaccines have limited effectiveness.
“I’ve been doing this for going on 30 years now, and more than half a dozen times in my career we’ve thought we had things figured out and were on top of it,” Holtkamp said. “But this virus always finds a way. It outsmarts us every time.”
A disproportionate amount of the production loss increase came in herds of growing pigs, as opposed to breeding herds. In the 2006-10 study, growing herds accounted for 55% of lost production. In the new study, 68% of the estimated losses come from growing herds. Holtkamp attributed that to new virus variants and changes in sow immunization methods.
Heightened biosecurity is essential to reversing the mounting impact of PRRS because industry consolidation and growth makes facilities more interconnected, increasing exposure, said Holtkamp, a swine disease expert who often conducts outbreak investigations. Enhanced sanitation of livestock trailers and at facility entrances are common improvements, but every operation is different. Producers should devote resources to identifying their largest biosecurity gaps and most effective prevention measures, he said.
“It can be complicated, but it’s worth it to spend that time to find those risks. You don’t know if you don’t take the time to look,” he said.
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