1. Fertility Management for Feral Swine in the US A Managers Perspective
Michael J. Bodenchuk, State Director
Texas Cooperative Wildlife Services Program
USDA-APHIS-Wildlife Services

2. Feral Swine in the US Invasive Species
Reported in 35 States- Increasing
Nationwide 6,000,000+
$1B US in damage annually
Negative impacts to agriculture, natural resources, human health and safety

3. Feral Swine Biology Age at first breeding 6-7 months
Gestation 115 days
Average Litter size 6 (r = 1-12)
3 litters every 2 years (7-8 months between litters)
Adult annual survival 60-80%
Female will have 7+ litters in her lifetime

4. Model Population Growth

5. Current Management Heavily focused on lethal control
Eradication where feasible
Damage management where eradication is impractical
Management is cost:effective but in Texas we are unable to reduce statewide populations

6. Fertility Management Suggested by numerous authors
Cowan, D.P., G. Massei and R.J.B Mellows, Model showed reduced female population with 10-90% contraception
Burton, J.L., J.D. Westervelt and S. Ditchkoff, 2013 – Model showed greatest efficacy (reduced population growth) with hunting and contraceptives used in combination
Massei, G. and D.P. Cowan, 2014 – Discuss current state of knowledge regarding human-wildlife conflicts

7. Management Complications
Feral swine are a meat animal in the US
Delivery to a sufficient number of females
Total contraception v. smaller litters
Biology with fertility management in place
Compensatory survival of juveniles
Compensatory survival of adults
Changes in damage- reduced consumption, less rooting, etc.
Seasonality, need to keep bait out year-round

8. Management Implications
Damage Management v. Eradication
Difficulty in targeting females in low density
Species specific baits
Species specific delivery systems
Herd contraception v. individual contraception
Changes in damage due to behavior, age structure, nutritional requirements or reduced population level

9. Applications
Damage Management- if population decreases, behavior or other factors affect the pigs
Disease Management- if reduced populations and changes in behavior are reflected in contact rates between pigs and wildlife/livestock
Population Management- if keeping some pigs on the landscape is desirable for alternate prey, recreational hunting, or ecological purposes (i.e. native populations in Europe/Asia)

10. Research Needs Examine free-ranging pigs with management to determine:
% population able to be targeted
Changes in fecundity/natality/survival
Changes in behavior/diet
Changes in damage (rooting, E. coli, disease prevalence)
Validate the models

11. Research Needs Validate delivery methods
Examine human risks associated with meat consumption
Examine secondary risks associated with contraceptive drugs
Examine relative costs and maximum integration of methods
Determine seasonality of application