Lin Chen, Shangquan Gan
Immunocastration (active immunization targeting GnRH) inhibits testosterone secretion, controls boar taint, and reduces aggressive behavior while avoiding surgical castration. Commercial two-dose regimens such as Improvac®/Improvest® are now established. This review covers the immunological mechanisms of GnRH immunocastration, vaccine preparation and delivery strategies, and effects on endocrine suppression, growth performance, carcass quality, and animal welfare. Sources of efficacy variation are summarized: antibody titer thresholds and individual non-response, the decisive effect of first-immunization age and inter-dose interval, and breed-specific lipid metabolism backgrounds. Current research still lacks key data on immunization schedule optimization, standardized carcass-quality thresholds, and field implementation constraints. A "schedule window-antibody threshold-carcass threshold" framework is proposed to support the precision application of immunocastration.