Abstract: This study aims to promote fertility control as a non-lethal means of managing wild animal populations, specifically red deer (Cervus elaphus) in a region of Spain. This is the first time that a research plan on the use of immunocontraceptives in red deer in Spain has been laid. This plan is accompanied by a follow-up study to: (1) determine the effectiveness of the vaccine over 3 years in the prevention of pregnancy, (2) determine the possible contraindications, (3) identify any weaknesses and drawbacks of the treatment and (4) propose future improvements.