Managing horse populations humanely, particularly wild and feral horses, requires contraceptive approaches that avoid the welfare costs of lethal control and capture.
Equine population management through contraception represents a welfare-superior approach to the alternatives of culling or mass roundup-and-holding for both wild and domestic overpopulation contexts. PZP vaccine delivered remotely by dart achieves population management without the welfare costs of capture: no transport stress, no handling stress, no disruption of social bonds, and no holding facility welfare compromise. Treated mares maintain their normal behavioral repertoires and social positions within bands. The reversibility of PZP is also welfare-important — if population dynamics change, treatment can be discontinued and fertility restored. For companion horses, gelding stallions is the most effective overpopulation prevention strategy and also improves the welfare of the individual horses through reduced hormonal aggression and territorial behavior.