Jay Kirkpatrick, PhD, credited with pioneering the use of the fertility control drug porcine zona pellucida (PZP) as an alternative to wild horse gathers, died on Dec. 16 after a short illness.

Kirkpatrick was the founder of the Science and Conservation Center in Billings, Montana, which produces PZP on a nonprofit basis for use worldwide and trains volunteers in how to administer the vaccine. In addition to controlling wild horse herd populations, PZP has been used to manage populations of bison, urban deer, captive zoo animals, and even elephant.

In a written statement Science and Conservation Center Chief Operating Officer Kimberly M. Frank, lamented Kirkpatrick’s loss, but said the center’s work will continue.

“(Kirkpatrick) was the face of the wildlife fertility control endeavor for the past 45 years and he will be sorely missed in more ways than we can count,” Frank said. “The Science and Conservation Center remains active and continues to produce and carry out the quality control for the PZP vaccine, distribute it, maintain the database, and train field personnel to deliver it effectively; In short, our operation and progress continues to move forth