An economic analysis of alternative fertility control and associated management techniques for three BLM wild horse herds
[摘要] Contemporary cost projections were computed for several alternative strategies that could be used by BLM to manage three wild horse populations. The alternatives included existing gather and selective removal methods, combined with potential contraceptive applications of varying duration and other potentially useful management techniques. Costs were projected for a 20-year economic life using the Jenkins wild horse population model and cost estimates from BLM that reflect state-by-state per horse removal, adoption, long-term holding, and contraceptive application expenses. Important findings include:
- Application of currently available 2-year contraceptives appears capable of reducing variable operating costs for wild horse populations by about 21% on average.
- Application of 3-year contraceptives, when fully tested and available, may be capable of reducing variable operating costs by about 27% on average.
- Combining contraceptives with modest changes to herd sex ratio (e.g., 55-60% males) can trim existing costs by about 31%.
- All savings are predicted to increase when contraception is applied in conjunction with the proposed removal policy that targets horses age zero to four, instead of zero to five.
- Reductions in herd size result in greater predicted variation in annual operating expenses for each herd, especially below about 200 animals, but are always at least ±20%.
- Because the horse program’s variable operating costs only make up about one half of the total program costs (which include fixed and sunk costs), even with aggressive contraceptive management, total program costs could only be reduced by about 17%. This would still save about $7.7 million per year.
- None of the contraceptive options examined eliminated the need for long-term holding facilities over the 20-year period simulated, but the number of horses held may be reduced by about 23% with aggressive contraceptive treatment.
- Cost estimates are most sensitive to adoption age and per day holding costs.
- There are opportunities to improve both the population modeling software and the modeling processes used in assembling Herd Management Area environmental assessments.
