Feral swine numbers are not declining and are possibly increasing in Louisiana.
Louisiana Wildlife and Fisheries Commissioners heard the troubling news at their monthly meeting on Thursday, Nov. 7, by Veterinarian Dr. Rusty Berry.
Rough estimates number the feral swine at more than 900,000 in Louisiana with the outlawed quadruped in all 64 parishes. The pigs are not only a Louisiana problem. The World Health Organization recognized feral swine as the number one invasive species in the world.
“As a veterinarian who has lived in Louisiana for 65 years and has seen feral swine since a kid, I want you to consider that 900,000 plus number is most likely very low,” Berry warned commissioners.
Economic damage in 2022 was $91 million, according to LSU AgCenter. The amount was obtained by landowners and farmers.
“We are not talking about the damage they are doing to the wildlife, and the diseases they are spreading to other animals,” Berry said. “None of that is included in the dollar figure on damage.”
Along with economic damage, feral swines carry brucellosis. Brucellosis spreads to humans through contact with infected animals or contaminated animal products. This can include direct contact, eating or drinking contaminated animal products, inhaling airborne agents, or contact with blood, placenta, fetuses and uterine secretions.
In humans, brucellosis can cause flu-like symptoms, including fever, headache, fatigue, sweats, back pain, weakness, joint pain and weight loss. Symptoms can appear 5–60 days after exposure. In severe cases, the central nervous system and heart lining may be affected.
LDWF does not recommend consuming feral swine due to the concern of brucellosis transmission. However, if feral swine are consumed, officials highly recommend the use of proper PPE such as gloves and eye protection when handling or dressing pigs and thoroughly cooking the meat.
Rapid reproductive rate
Complicating control efforts is the feral swine’s rapid reproductive rate. A sow can have two litters of about six piglets yearly, outpacing the number of hogs that can be removed from the landscape through hunting and trapping.
“If you don’t remove 70 to 75 percent of these animals from your landscape, you are at a steady state,” Berry said. “So if you have 100 pigs on your property, if don’t remove 75 of them you are going to have more than a 100 the next year. If you remove 75, you are going to continue to have 100 pigs on your property.”
In 2023 and 2024, according to LDWF records, 75,000 hog hunters harvested nearly 500,000 through trapping, aerial and traditional shooting.
But Berry cautioned, “Removing a half million pigs every year will not decrease the population.”
Trapping and hunting are not going to eradicate the feral swine, according to Berry. What it will create is a “trap shy” and “bait shy” feral swine due to the animal’s intelligence.
“You are always having to develop new trapping methods,” Berry said. “Trapping efforts are also very time consuming and expensive.
“The aerial gunning and other efforts will decrease the population for a temporary time to allow a crop to get to a certain level. That’s their goal. They are not eradicating these pigs. They are decreasing them enough to allow the agriculture to go up.”
Is toxin the answer?
Berry in his address to commissioners said a toxin would be a more affordable answer to feral swine control.
“We desperately need a toxin,” Berry said.
The veterinarian said research, particularly from LSU AgCenter, needs to continue that specifically targets the pigs with no or minimum collateral damage to other species such as black bears and birds.
In 2023, a patent was issued for a bait developed by scientists with the LSU AgCenter and LSU Department of Chemistry.
The bait uses sodium nitrite, which is lethal to feral swine. The bait has minimal impact on the environment and non-target species. With a consistency similar to gummy bears, it is shaped into golf ball-sized spheres, tastes fishy and even glows under blacklight.
The patent was issued Aug. 8, 2023 to LSU with the inventors listed as Glen Gentry, an animal scientist and director of the LSU AgCenter Bob R. Jones-Idlewild Research Station in Clinton; John Pojman, an LSU chemistry professor; and Baylen Thompson, a former graduate student who worked under Pojman.
The bait offers a more effective control method with the bonus of being humane, Gentry said. Within three hours of consuming the bait, hogs become sleepy and die.
Sodium nitrite is an ideal toxicant, he said, because it is deadly to swine and eventually breaks down into compounds that do not harm other species or pose environmental concerns.
“With sodium nitrite the pigs basically just go to sleep,” Berry said.
There are new toxins under development at LSU, but according to Berry, obtaining FDA approval could cost $500,000.
LWF Commissioners passed a resolution in 2022 urging the EPA to approve the new toxin. When commissioners asked their legal counsel if he had heard from the government organization, he advised that the EPA did not have an application from LSU for a new toxin.
“$500,000 considering $91 million worth of damage is pretty simple math in my mind,” said Commission Chair Brandon DeCuir. “I think we can figure out where to come up with $500,000.”
