Will 'outdoor pigs' give parasites new lease on life?

Tuesday, August 4, 2009

Organic standards that span North American borders came into effect in June and are accompanied by poor pork prices. There are already reports of a renaissance in "outdoor pigs" as pork producers explore new avenues of profitability.

Andrew Peregrine wonders what that is going to bring to his laboratory at the Ontario Veterinary College in Guelph. Peregrine, a clinical pathologist, says he "does a very tiny bit of teaching about parasites." Pig parasites "literally disappeared" when nearly all pigs were moved indoors 20-30 years ago. Vets still see the pig roundworm indoors, along with whipworm, but both are more often seen outdoors.

Peregrine sees pig lungworm "very rarely" now that most pigs are kept indoors. It needs earthworms to complete its parasitic growth cycle. When it strikes it has a major impact on growth rates.

Red stomach worm "disappeared as soon as we put pigs indoors." There are also nodular worms in pigs, which cause nodes in the intestine that render it unusable as sausage skin. The most common worm is oesophagostomum detatum and Peregrine says: "Honestly, I've never seen it in 11 years here."

Organic producers face a double challenge, Peregrine says. They can't use traditional worming treatments and they will be required to put pigs outdoors where they are exposed to more parasite species. He cites one organic producer who kept pigs indoors, and began having pig deaths within a year from roundworm.

The worse parasite disease is trichinella, largely eradicated by putting pigs inside. It is the only zoonotic disease of the bunch and "can potentially kill people," Peregrine says. Pigs are typically infected by eating rodents. They also get it from eating infected meat in uncooked garbage and it is spread when pigs chew tails of infected pen mates.

Trichinella "doesn't make pigs sick," according to Peregrine, but rather "people who eat the pork."

Larry Lenhardt of Lindsay, a long-time organic promoter, describes parasites as "a management issue" for organic producers and says it can be resolved. But just don't be surprised if younger veterinarians seem unfamiliar with symptoms. "You wouldn't believe how difficult it is to find pig parasite cases to teach students," Peregrine says.