Executive summary

Feral swine populations continue to expand across Louisiana and much of the United States, causing substantial physical damage to agricultural lands. This report presents results from a statewide survey to estimate economic losses from feral swine activity on agricultural lands in Louisiana. Based on statewide expansion of 2020 survey results from more than 900 respondents, the total annual economic loss from the presence and activity of feral swine on agricultural and timber lands in Louisiana was estimated to be $91.1 million. This economic loss value is based on the estimation of $66.2 million in agricultural commodity production losses and another $24.9 million in non-production losses.

Introduction

Feral swine exist in all 64 parishes of Louisiana, causing substantial economic loss from damage to agricultural and timber lands. Due to the high reproductive rate of feral swine, statisticians have estimated that approximately 70% to 75% of the population must be harvested to control feral swine numbers. In Louisiana, hunters harvest less than half that so populations continue to grow according to the Louisiana Department of Wildlife and Fisheries. Current estimates of feral swine populations in Louisiana range as high as 900,000 animals. A 2013 study by the LSU AgCenter, published in 2015, estimated that feral swine caused annual economic damages or losses of approximately $74 million to agricultural land in Louisiana (Tanger, et al., 2015). This total loss estimate included $53 million in annual crop production losses, primarily related to yield reduction due to crop damage, and $21 million in increased costs (non-production losses) on agricultural land. In 2021, the LSU AgCenter conducted a statewide survey to provide more current estimates of economic losses from feral swine in the state. Results from the survey are presented in this report.

Background

Feral swine continue to be a growing problem to farmers, ranchers, foresters and landowners in many areas of the U.S. and are considered to be one of the most damaging invasive species in existence, causing significant economic damage to crops, forests and agricultural land. First brought to the country in the 1500s by early explorers and settlers as a source of food, free-range livestock management practices and escapes from enclosures eventually led to the first establishment of feral swine populations within the United States. In the 1900s, the Eurasian or Russian wild boar was introduced into parts of the U.S. for sport hunting. Today, feral swine are a combination of escaped domestic pigs, Eurasian wild boars and hybrids of the two according to the U.S. Department of Agriculture Animal and Plant Health Inspection Service (APHIS).

Feral swine are the most prolific large mammal in North America, and given adequate nutrition, populations can double in only four months (Kaller and Reed, 2010). Sexual maturity is reached as early as six months, with sows producing two litters per year. Litter size varies with age and nutritional intake but can average five to six young pigs per litter. As a result, where adequate food and cover are available, feral swine populations can explode and spread quickly. From 1982 to 2016, the feral swine population estimates in the United States increased from about 2.4 million to more than 6 million hogs (Kinsey, 2022). Although precise numerical estimation is difficult, current estimates of feral swine population numbers in the U.S. range as high as 9 million animals. The Louisiana Department of Wildlife and Fisheries reports that feral swine are found in all 64 parishes of Louisiana, with an estimated state population of approximately 700,000 to as many as 900,000 animals.

Feral swine have been reported in at least 35 states (APHIS, 2022). Their population is estimated at more than 6 million and is rapidly expanding. Range expansion over the last few decades is due to a variety of factors including their adaptability to a variety of climates and conditions, translocation by humans and a lack of natural predators. In Louisiana, feral hogs can be found in a wide variety of habitats ranging from tidal marshes to timbered areas (Kaller and Reed, 2010). They prefer hardwood forests that produce acorns as a primary food source but will frequent pine forests. In remote areas or where human disturbance is minimal, they can often be found in open ranges or pastures. Although feral swine generally prefer less interaction with humans, their rapidly expanding population and constant search for food sources is causing increasing interactions with producers and foresters on agricultural lands.

The expansion of feral swine population numbers over the past few decades has resulted in increased interaction with commercial agricultural and forestry operations, causing significant economic losses. Although precise estimation of economic losses from feral swine presence is difficult, current approximations of economic damage are substantial in magnitude. A 2016 APHIS report estimated crop damage totaling $190 million annually for six major agronomic row crops over 11 states in the southeastern United States (Anderson, et al., 2016). A commonly reported national value from a USDA-APHIS report in 2020 indicated that a conservative national estimate of economic loss impact could be in the range of $1.5 billion annually, using estimations of $300 of damage per animal with a conservative approximation of 5 million feral swine in existence across the country (Glow, VerCauteren, and Snow, 2020). With current national feral swine numbers of more than 6 million, annual economic loss from their activities could well exceed $2 billion per year across the United States.

Summary

The purpose of this study was to conduct a survey to obtain information to update estimates of the economic impact of feral swine presence and activity on agricultural land in Louisiana. An earlier study conducted in 2013 found that feral swine were causing significant economic loss associated with damages to agricultural crops, landscape, infrastructure and natural resources in the state. The 2013 study estimated statewide annual economic loss caused by feral swine at approximately $74.1 million. This economic loss estimated included $52.8 million in estimated production loss and another $21.3 million in non-production losses. The current study presented in this report, conducted in 2020, found similar results. Feral swine continue to be a significant and growing invasive species problem, causing substantial physical and economic damage. Almost half of the survey respondents who owned or managed agricultural land indicated that feral swine were currently present on their land and just over half of the respondents indicated that feral swine have caused some type of damage on their land and felt damage from feral swine has been increasing over the past few years. Based on statewide expansion of 2020 survey results from over 900 respondents, the current total annual economic loss from the presence and activity of feral swine on agricultural and timber lands in Louisiana was estimated to be $91.1 million. This economic loss value is based on the estimation of $66.2 million in agricultural commodity production losses and another $24.9 million in non-production losses.

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