Multi-year Effectiveness of PZP-22 in Free-roaming Suburban White-tailed Deer

To address the challenge that is posed to the use of fertility control to mitigate human–deer (Cervidae) conflicts by the need to regularly re-inoculate free-roaming animals, we captured, ear-tagged, and hand-injected 68 individual adult female white-tailed deer (Odocoileus virginianus) with the PZP-22 immunocontraceptive vaccine from February through April, 2014 to 2017, in the Village of Hastings-on-Hudson, New York, USA. Approximately 2.5 years after initial treatments, we booster-darted 29 of the previously treated females with either PZP-22 or native PZP (ZonaStat-D). We observed fawn production between 2014 and 2021. The combination of initial PZP-22 hand-treatments followed by single dart-delivered PZP boosters reduced fawning by >80% relative to pre-treatment fawning rates over at least 5 years, with no difference in efficacy between the 2 booster preparations. This PZP-based protocol should significantly expand the potential for practical application of deer fertility control in urban and suburban environments.