U.S., Australia team up on wild hog control

*Krissa Welshans holds a bachelor's degree in animal science from Michigan State University and a master's degree in public policy from New England College. Welshans has long been involved in agriculture and has worked with numerous agricultural groups, including the Animal Agriculture Alliance.

ACCORDING to the latest estimates, Australia has more wild hogs than human beings — possibly more than 23 million.

Pennsylvania is also dealing with wild hogs, and just how many wild hogs — mostly escapees from commercial hog hunting preserves and their offspring — actually roam in the state is unknown.

Because both commonwealths need to control and perhaps eliminate feral pigs, The Pennsylvania State University is collaborating with Australia's University of New England and the Invasive Animals Cooperative Research Centre, Australia's largest integrated invasive animal research program.

The project is aimed at bringing new approaches and added support to rural communities that want to better manage the risks these creatures pose.

"In Australia, invasive animals are a high-priority issue that most rural residents are well-versed in and concerned about," said Theodore Alter, professor of agricultural, environmental and regional economics in Penn State's College of Agricultural Sciences. "They deal with a range of more than 50 species of invasive animals, such as feral cats, feral swine, wild dogs and rabbits, pest fish such as carp and some birds."

According to Alter, feral swine are an emerging threat in Pennsylvania that pose health risks to people and livestock, "but my sense is that this is not well known or well understood by the public."

Recently, 13 Australians who have been working on the problem in Australia participated in a three-week, intensive short course at Penn State. The focus was on providing support to rural communities and local government officials who are struggling with invasive animals such as wild hogs.

In addition to Penn State experts, the group spoke with representatives from the Pennsylvania Game Commission, Pennsylvania Department of Agriculture, Pennsylvania Farm Bureau, Pennsylvania Invasive Species Council, Cornell University and U.S. Department of Agriculture's Animal & Plant Health Inspection Service.

"We wanted to compare hog control in Australia and the United States, particularly Pennsylvania and New York, and we wanted to get a sense of the institutional and public policy differences between the two," Alter explained. "We were able to exchange ideas about how to work more effectively with landowners, citizens and the public in the context of these animal control issues."

The course also contrasted leadership and engagement strategies for dealing with invasive animals and looked at using technology in the fight against wild hogs.

"For example, using radio-collar technology over time would help us get a sense of what control strategies might be most effective," Alter said. "In Australia, they are using that technology to better engage landowners and help them get a clearer sense of where these animals go and what impacts they have on landholders and native wildlife."

Alter predicted that if Pennsylvania collared and tracked wild hogs in strategic locations, it would help communities better understand the nature of the issues and the potential impact of the animals.

If that were done, Alter believes wildlife scientists in the Penn State College of Agricultural Sciences could work with the Game Commission and other state agencies to implement the technology and track wild hogs.

"And we certainly would be involved in the issues associated with engaging citizens, landowners and local officials to develop control strategies and manage hog populations," he said.

Wild hogs in Australia are the descendants of domestic pigs that explorers released as a living larder for future expeditions. Over the centuries since then, the animals have found Australia to have plentiful food, a balmy climate and no natural predators.

Unlike in the U.S., specific breeds, such as the European wild boar, have not been introduced in Australia for hunting.

Now, they are wreaking havoc on the Australian economy. In the tropical state of Queensland, wild hogs are causing millions of dollars of damage to crops and are threatening the survival of endangered rainforest animals. They also attack and eat some domestic livestock, such as young lambs.

Further complicating management of the wild boars is that their meat cannot be eaten due to worm infestation and disease.

Controlling invasive animal populations in Australia is more of a community-based endeavor than in Pennsylvania, where the state takes major responsibility.

"The management of most invasive animals depends on the motivation, capacity and coordination of volunteer community groups, who are the backbone of rural sustainability," said professor Paul Martin, who is leading the community action research at the University of New England.

Questions remain about who will lead and support these groups and what skills these leaders will need in an age of the internet, an aging rural population and increasingly diverse rural land uses and communities. Martin said those were the questions the attendees attempted to answer during the short course at Penn State.


Penicillin G residues

USDA's Food Safety & Inspection Service (FSIS) recently validated its testing methodology to enable the identification of penicillin G procaine in edible animal tissues at processing. This has resulted in an increase in penicillin residue violations in cull sows.

These violations raised the concern of pork producers and veterinarians because many of the violations occurred even though the producer was following the prescribed withdrawal period.

The American Association of Swine Veterinarians (AASV), in collaboration with the National Pork Board (NPB) and the National Pork Producers Council (NPPC), has been working diligently with FSIS and the Food & Drug Administration to try to understand what is causing this increase in penicillin violations.

According to Dr. Harry Snelson, director of communications for AASV, penicillin G procaine remains an effective treatment in cull sows. It is relatively inexpensive and can be purchased over the counter. It is most often administered intramuscularly at an extra-label dosage of 33,000 IU/kg for three consecutive days.

The Food Animal Residue Avoidance Databank (FARAD) recommends at least a 15-day withdrawal period to allow the drug to clear the animal's tissues prior to processing.

Snelson said the first challenge with penicillin G is that, in swine, FDA established zero tolerance for penicillin residues in edible tissues. This means that any detectable level of penicillin G in the edible tissues of swine is a violation.

FSIS samples both muscle and kidney tissue. Because both are classified as edible tissues by FSIS, Snelson said both are eligible for testing.

NPB funded a study at USDA's Agricultural Research Service to investigate the withdrawal time needed to ensure zero tolerance for penicillin G in cull sows.

The investigator, Dr. David Smith, used a dose of 33,000 IU/kg for three days with various injection strategies.

His findings indicate that the FARAD recommendation of 15 days is adequate to prevent a violation of residue levels in muscle tissue. Unfortunately, the drug is depleted from the kidneys much more slowly.

Because of this, Smith estimated that it would require at least a 51-day withdrawal period to ensure that the kidney is free of violative residue levels.

Snelson said AASV, NPB and NPPC are engaged in ongoing conversations with FDA and FSIS regarding possible remedies for this issue.

FDA has agreed to consider establishing a threshold other than zero for swine.

Additionally, the groups have asked that FSIS consider declaring all sow kidneys inedible since cull sow kidneys are not used for human consumption in the U.S. Such a declaration would make the kidney ineligible for testing. This option is still under consideration.

For the time being, though, Snelson said at least a 51-day withdrawal period is necessary if penicillin G is used in swine that are destined for processing.

Volume:85 Issue:39

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