Planned Marehood: A vaccine-based approach to animal contraception

SpayVac for Wildlife, Inc. and BioVaxys recently announced the completion of a research and production facility in Madison, Wisconsin, that will enable SpayVac to produce a single-dose veterinary contraceptive vaccine that can be used for humane population control in horses, deer, and other animals. 

“This new laboratory will significantly enhance our ability to develop new vaccine formulations for species that would benefit from humane, long-term fertility control," said Ursula Bechert, VP of research and development for SpayVac.  

Although the vaccine is currently produced exclusively at the Madison facility, the firm plans to scale up manufacturing and commercialize the product after they receive approval from the Environmental Protection Agency (EPA). The company will do this by contracting with a third-party company such as a contract development and manufacturing organization (CDMO). 

The Need for Effective Wildlife Vaccines 
BioProcess Insider spoke with Bechert, who discussed the need for such vaccines. “There are too many people, and we gobble up habitat,” she said. “We say there are too many animals, but really there are fewer than there were before.” Nevertheless, she said that because of human activity, healthy habitats have declined, leaving animals such as feral horses restricted to land that cannot fill their needs.  

According to the US Bureau of Land Management (BLM) more than 80,000 wild horses and burros lived on BLM managed lands in 2022, exceeding the resources available and leading to further habitat degradation.  

“You’ve probably heard stories of horses starving,” Bechert said. “They just keep on reproducing even when other animals would stop because there are not enough resources.” 

Traditionally, the BLM has controlled the wild horse population by capturing some of the animals and putting them in expensive long-term holding pens. The BLM also vaccinates some horse populations by using contraceptives that require a yearly booster to maintain efficacy.  

Bechert said that such a strategy can work for tame horses that are accustomed to people but is ineffective for dealing with most populations that are wild and found living in terrain that is difficult to access.

“If you can envision darting a horse, you may get lucky once, but to deliver that booster is really rough.” She emphasized that being able to deliver a vaccine in a single shot enhances its application for controlling free-range wildlife populations. 

SpayVac’s partnership with BioVaxys allows it to use the latter firm’s patented liposome-based antigen delivery platform technology to produce a long-term vaccine without the need for a booster. BioVaxys acquired that technology from Canadian biotechnology company Immunovaccine Technologies in February 2024. 

Bechert said that the licensed technology from BioVaxys enables the company to produce a single-shot vaccine without the need for a booster. “It stimulates the immune system to work more effectively and produce long-term memory cells based in the bone marrow that make antibodies.”

Single-use vaccines also help to control deer populations that often wander through neighborhoods, contribute to animal–vehicle collisions, spread tick-borne diseases, and cause damage to agricultural crops. 

In addition to contracepting wild horses and deer, SpayVac is also seeking to control problems in aquaculture. Bechert said that it’s important to prevent escaped farm-raised fish from breeding with their wild counterparts, which can have a negative environmental impact. But a contraceptive vaccine for fish also has economic implications that are beneficial to farmers. “When females start producing eggs, they put all their energy into that as opposed to making meat.” 

Should SpayVac’s vaccine achieve EPA approval for horses, the company expects the BLM to be a major US buyer. Outside the country, SpayVac hopes to market the product to the Australian government.  

“In Australia, they actually shoot horses from helicopters to manage their populations,” Bechert said. “We would offer a better option.”