European explorers used feral swine as a food source; they are not native to North America and are considered a destructive invasive species. In the early 1900s, closed-range or fencing for livestock was not a common practice. Since domestic swine were allowed to roam freely, many swine became feral. In the 1930s, Russian wild boars that are native to Europe and Asia were imported into areas of the United States for sport hunting. As wild boars escaped or boars were released to roam, crossbreeding occurred between feral swine and the Russian wild boar. Reproduction occurred as early as six months with a litter as big as 12 piglets. To-date 74 out of 77 counties in Oklahoma have reported feral swine; the feral swine population is reported to be over one million.
Feral swine have caused damage to numerous soybean producers in Oklahoma with some areas having to be replanted due to swine impacts. Wildlife Services (WS) has assisted with Oklahoma agriculture producers to remove 14,114 feral swine, corral-type traps removed 6,717 and 899 were removed with thermal imaging. Some of the corral traps and thermal imaging devices were purchased with checkoff funding from the Oklahoma Soybean Board.
Plant damage occurs from the consumption of agricultural resources and from trampling, rooting, and/or wallowing, which is common for feral swine. Rooting is a common activity of feral swine during their search for food. Along with damages occurring from consumption, there is also a potential disease threat associated with feral swine. WS program in Oklahoma conducts disease surveillance as part of the National Wildlife Disease Surveillance Program. Although there are numerous diseases that feral swine carry and transmit, Oklahoma tests for the two most common: Swine Brucellosis and Pseudorabies, also known as mad itch.