Fertility control in horses, particularly feral populations, raises important welfare questions about the balance between individual reproductive experience and population-level management goals.
Welfare considerations in horse population management center on the comparison between different management approaches. Roundup and long-term holding in government corrals causes acute handling stress, long-distance transport trauma, and prolonged captivity for animals adapted to free-ranging — significant welfare harms. Fertility control through PZP vaccination requires approaching individual horses but can be achieved by dart rather than capture, causing minimal handling stress while preventing the welfare problems associated with growing unsustainable populations. Allowing populations to grow unchecked leads to overgrazing, food shortage, and competition that cause welfare harm to horses and degradation of habitat for other wildlife. Well-designed fertility control programs represent the most welfare-positive approach to sustainable feral horse population management.