Researchers are working to find early markers for pigs who continue to perform well when challenged with diseases
By Jackie Clark
Researchers have been collaborating for five years and are getting close to finding markers for disease resilience in pigs that have the potential to be commercialized.
“Disease resilience is defined as continued productivity in the face of challenge,” Dr. John Harding told Farms.com. He’s a professor in the department of large animal clinical sciences at the Western College of Veterinary Medicine at the University of Saskatchewan. “The resilient animal is the one that continues to grow or perform when faced with a disease challenge.”
Harding is in charge of herd health in the unique experimental model, which involves “managing the level of disease that’s in that barn so we can test our hypothesis,” he explained. “We’ve created what we call a natural disease-challenge model.”
The researchers source high-health pigs from PigGen Canada, a non-profit with membership from Canadian swine breeding companies. PigGen is a research consortium that supports work to improve the swine genetics industry. The scientists receive new high-health barrows from the PigGen member organizations every three weeks “and then we introduce conventional animals from local Quebec farms that have a number of diseases,” Harding said.
“We put the high-health barrows into this high-exposure unit, and test their performance. And those that are most resilient perform very well, and those that are less resilient get sick, need treatment, potentially die, or survive and just don’t perform very well,” he explained.
“We have various performance outcomes” including average daily gain, daily feed intake, treatment required, and carcass quality, he added. “From a producer’s point of view, resilience is a pig that continues to be a full-value pig and makes it to market.”
This experiment works on the assumption that the pigs are exposed to the same amount of challenge within the herd.
“The goal is to find that genetic marker, that you could then select for in a high-health (breeding program), that predicts performance if that animal gets sick,” Harding said. To do so, “whatever trait you’re measuring as an outcome has to be heritable … and it has to be genetically correlated, meaning that we can select in a high-health unit and it relates to that performance or that phenotype in a challenged environment.”
Using those two criteria, the researchers are working to find something measurable at three to five weeks of age that would predict performance in a disease-challenged environment later in life. “Then, you can go around and test these animals at weaning or shortly after, find this genetic marker, and bring that into your selection program,” Harding explained. The scientists have found some promising traits.
The first is consistent appetite and feed consumption.
“Animals that continue to eat the same amount every single day are more resilient” than animals with variable daily feed intake, Harding said.
The second is an immunological marker that scientists can test for using high immune response technology testing.
“We’re getting closer and closer all the time,” Harding added. “The followup project that we have now on the way is to really nail down those couple technologies that we think we could take out into the commercial industry.”
The PigGen collaboration would play an important role in commercialization.
“If we do find a test we’re going to commercialize, it’s important that we get it out into industry as quickly as possible, so that’s when PigGen comes in,” Harding explained. “They would then take (the technology) internally and each individually would discuss how they’re going to implement that into their breeding program.”
Eventually those disease-resilient genetics would make their way into commercial herds, and improve herd health in Canada.
This research has been ongoing since 2015 and involves a lot of pigs, but scientists are closer than ever to having definitive answers, Harding said.
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