Contraceptive vaccines offer a humane alternative to helicopter roundups for managing wild and feral horse populations. Understanding the science and challenges of immunocontraception advances welfare-based management.
Contraceptive management of wild horse populations represents a welfare-aligned approach that addresses population growth without the trauma of helicopter roundups or the suffering of long-term holding facilities. PZP-treated mares experience normal social lives, express natural behaviors, and remain within their herd structures. The management investment required for annual treatment is real but produces better welfare outcomes for individual animals and allows wild horse populations to persist on public lands. Expanding and defending contraceptive programs against political pressures favoring lethal control is a concrete welfare priority for wild horse advocates.