The estimated 5 million feral hogs currently laying waste to the American Countryside may have finally met their match in sodium nitrate, a chemical compound used to presereve bacon.
The hybrid descendants of escaped domestic pigs and imported Eurasian boars, feral hogs cost the U.S. approximately $1.5 billion a year in damages. These massive, shaggy animals breed like rabbits, spreading from 17 states to 39 in the last 2 decades. So far, efforts to control the feral hog population through traditional hunting and trapping programs have failed.
Now, the U.S. Department of Agriculture has initiated a $20 million program to explore new methods of feral hog control.
Sodium nitrite is far more toxic to pigs than people and is currently used to kill feral hogs in Australia and New Zealand. USDA scientists believe it may also be the best solution for the U.S., but they're not ready to ask for federal approval just yet.
Vance Taylor of Brooksville, Mississippi, has seen up to 50 hogs in a field at once. He estimates the animals cost him 40 to 60 acres of corn and soybeans a year.
"It looks like a bulldozer has been through your field," he said.
Male feral hogs average 130 to 150 pounds but some can swell up to 250. They will eat anything: peanuts, potatoes, piles of just-harvested almonds. Feral hogs not only compete with turkey and deer for acorns, they will also eat their babies.
The damage isn't limited to their eating habits. Feral hog feces were among likely sources of E. coli that tainted fresh California spinach in 2006, killing three people and sickening 200.
To break even, at least 70 percent of an area's feral hogs must be killed each year, said Fred Cunningham, a USDA biologist. An estimated 2 million feral hogs are currently running rampant through Texas alone.
"The problem will never, ever end until they find a way to poison them," said Cy Brown of Carencro, Louisiana, a weekend hunter-for-hire who estimates he has shot 300 to 400 feral hogs a year for farmers.
The latest USDA program includes $1.5 million for the research center headquartered in Fort Collins CO, where scientists have made sodium nitrite studies a top priority.
Sodium nitrite, used as a salt to preserve meat, can keep red blood cells from grabbing oxygen in live animals. Unlike people, pigs make very low levels of an enzyme that counteracts the chemical. Feral hogs that eat a large enough dose of sodium nitrite show symptoms similar to carbon dioxide poisoning.
So far, baits haven't hit the 90 percent kill rate on test pigs needed for EPA consideration. Once it does, approval could take up to five years.
One problem is creating baits in which feral hogs will eat a lethal dose. Sodium nitrite tastes nasty and breaks down quickly in the presence of air or water, making it easier for pigs to smell and avoid, said Fred Vercauteren, project leader in Fort Collins.
Microencapsulating the compound masks its smell and keeps it stable longer.
"We'll work on that throughout the summer," Vercauteren said, of the potential feral hog poison.