Species-Specific Visitation and Removal of Baits for Delivery of Pharmaceuticals to Feral Swine

Abstract

ABSTRACT:Within the domestic swine industry there is growing trepidation about the role feral swine (Sus scrofa) play in the maintenance and transmission of important swine diseases. Innovative disease management tools for feral swine are needed. We used field trials conducted in southern Texas from February to March 2006 to compare species-specific visitation and removal rates of fish-flavored and vegetable-flavored baits with and without commercially available raccoon (Procyon lotor) repellent (trial 1) and removal rates of baits deployed in a systematic and cluster arrangement (trial 2). During trial 1, 1) cumulative bait removal rates after four nights ranged from 93% to 98%; 2) bait removal rates by feral swine, raccoons, and collared peccaries (Pecari tajacu) did not differ by treatment; and 3) coyotes (Canis latrans) removed more fish-flavored baits without raccoon repellent and white-tailed deer removed more vegetable-flavored baits without raccoon repellent than expected. During trial 2, feral swine removed fish-flavored baits distributed in a cluster arrangement (eight baits within 5 m 2 ) at a rate greater than expected. Our observed bait removal rates illustrate bait attractiveness to feral swine. However, the diverse assemblage of omnivores in the United States compared with Australia where the baits were manufactured adds complexity to the development of a feral swine-specific baiting system for pharmaceutical delivery.

Strawberry‐Flavored Baits for Pharmaceutical Delivery to Feral Swine

“…An alternative explanation may be that some breeds of cattle find PIGOUT baits to be more palatable than do other breeds (S. J. Lapidge, Invasive Animals Cooperative Research Centre, unpublished data). For example, the Santa Cruz breed was stocked in Campbell and Long (2007) and during our trial 1, whereas the Brahman breed was stocked during our trial 2.…”

“…From an island population in Georgia, Fletcher et al (1990) concluded that oral vaccine delivery to feral swine was feasible and Kavanaugh and Linhart (2000) determined baits could be used to administer pharmaceuticals orally to feral swine. In southern Texas, USA, researchers found high removal (Campbell and Long 2007) and consumption (Campbell et al 2006) of both fish-flavored and vegetable-flavored PIGOUTt feral pig bait (Animal Control Technologies Australia P/L, Somerton, Victoria, Australia). However, removal and consumption was also great for nontarget animals (Campbell et al 2006, Campbell andLong 2007), a discovery inconsistent with findings for PIGOUT baits evaluated in Australia (Cowled et al 2006a, b).…”

“…In southern Texas, USA, researchers found high removal (Campbell and Long 2007) and consumption (Campbell et al 2006) of both fish-flavored and vegetable-flavored PIGOUTt feral pig bait (Animal Control Technologies Australia P/L, Somerton, Victoria, Australia). However, removal and consumption was also great for nontarget animals (Campbell et al 2006, Campbell andLong 2007), a discovery inconsistent with findings for PIGOUT baits evaluated in Australia (Cowled et al 2006a, b). Campbell and Long (2008) subsequently determined that a strawberry-flavored feed additive (Strawberry Aroma; QualiTech Incorporated, Chaska, MN) may be a swinespecific attractant that could be incorporated into an oral delivery system for pharmaceutical delivery in the United States because of its swine-specific characteristics.…”

“…Presently, our efforts to identify a swine-specific oral delivery system for pharmaceuticals in southern Texas has determined that 1) fish-and vegetable-flavored PIGOUT baits are attractive to feral swine and to other mammalian wildlife, 2) a commercially available capsaicin-based repellent does not increase swine-specific characteristics of fishand vegetable-flavored PIGOUT baits (Campbell and Long 2007), 3) deploying fish-flavored PIGOUT baits in a cluster arrangement (8 baits within 5 m 2 ) increases removal rates by feral swine (Campbell and Long 2007), and 4) strawberryflavored PIGOUT baits, fish-and vegetable-flavored PIGOUT baits with FeralMone, and buried fish-and vegetable-flavored PIGOUT baits are not specific to feral swine. As such, we question whether a swine-specific oral delivery system exists for this region, with its diverse assemblage of opportunistic carnivores, omnivores, and herbivores.…”

Evaluation of Feral Swine-Specific Feeder Systems

“…1 Prior investigations of baits intended for pharmaceutical delivery to feral swine in the United States have found that the concept is feasible, 9 but that there are challenges in developing species-specifi c baits for feral swine. 10,11 These studies have led to the creation of relatively inexpensive prototypes of nontarget exclusion feeder systems (NEFS) for feral swine. None of these feeder systems has been evaluated in the United States.…”