Feral pig threat

With the threat of an exotic disease entering Australia, state and federal agencies have identified feral pigs as one of the greatest potential contributors to both the initial spread and subsequent hosting of such diseases.

To focus R&D efforts on the feral pig, an Action Agenda was held in June 2003 to consolidate the current research and knowledge regarding feral pigs, with the aim of developing improved management and methods of control. An outcome from the forum was a partnership between ACTA, the Pest Animal Control (PAC) CRC, state and territory agencies and other researchers to develop a manufactured feral pig bait that will provide a cost-effective, simple and reliable control method for this species.

Current control strategies for feral pigs include shooting, trapping and broad-scale, integrated baiting campaigns incorporating 1080 poison or yellow phosphorus (CSSP) using field-manufactured grain, meat, fruit or vegetable baits.

According to Michelle Smith, ACTA's R&D Manager, the development of a new bait will be a difficult task, as feral pigs are omnivorous and opportunistic, and generally prefer the most seasonally available, local food.

The challenge is to develop a bait that utilises the pigs' keen sense of smell and foraging habits, and is attractive and palatable at all times of the year, regardless of the availability of alternative food sources.

Existing baiting methods are time- consuming, with difficulties including access to poisons in remote areas, delivering a lethal dose of toxin to the pig and risks to non-target animals from a baiting campaign requiring large quantities of highly-dosed toxic baits.

The focus of the research and development for this new feral pig bait is on providing an attractive and palatable matrix into which is incorporated a toxin delivery system specifically designed to be accessed by pigs, potentially reducing the risks of non-target primary poisoning.

Research on the feeding behaviour and general ecology of feral pigs has indicated that factors such as the size and strength of their jaws can be exploited when developing a toxin delivery system that ensures the poison is delivered in a way that reduces uptake by non-target species.

Michelle explained that pen trials have already been conducted by the PAC CRC, ACTA and the Queensland Department of Natural Resources and Mines (DNRM) at the Department's Inglewood research station in southern Queensland.

These initial trials involved testing seven of ACTA's prototype bait matrices against standard controls - fresh meat and grain - the 2 bait types commonly used for pig control in NSW and Qld.

From these initial seven prototypes (which differed in substrate and attractants), the three most promising matrices were selected for subsequent paddock trials.

At the conclusion of the paddock trials (during which the prototype baits performed equally as well as the currently-used meat and grain bait substrates), two prototypes were selected for broadacre aerial trials against fresh kangaroo meat baits at Cunnamulla, south-west Queensland.

The Cunnamulla part of the trial conveniently fitted in with one of the most intensive and ambitious genetic studies of feral pigs ever conducted. The genetic trial involved an aerial survey of over 5,000 square kilometres to establish feral pig numbers prior to a population sampling exercise to identify genetic linkages between the pigs.

Michelle explained that the genetic study allowed non-toxic baits to be fed to pigs that were then culled and analysed for genetic information and bait uptake.

We trialled the prototype manufactured baits against traditional fresh (kangaroo) meat baits using different biomarkers (dyes or antibiotics).

The baits were aerially dropped and after a five day period pigs were shot from a helicopter within both baited and non- baited sites.

Michelle said that the shot pigs were sampled to determine their genetics, and also to test for the presence of biomarkers in their blood, tissue and bone, which would indicate whether or not the pig had consumed a bait.

Although we are currently analysing the data, it appears that both prototype manufactured bait matrices were readily consumed by pigs.

This feral pig bait development project has advanced quickly due to the support and assistance from a variety of agencies. ACTA would like to acknowledge the support of the PAC CRC and Meat & Livestock Australia (MLA), as well as the research effort of Dr Steven Lapidge and Dr Brendan Cowled of PAC CRC, along with researchers from the Qld DNRME (Toowoomba, Inglewood and Cunnamulla) and local council officers for facilitating this work.

Animal Control Technologies

Putting pressure on pigs