SpayVac® EPA registration is in progress and available for experimental use only.

SpayVac® pZP immuno-contraceptive vaccine for wild horses & burros, deer

SpayVac® pZP immuno-contraceptive vaccine for wild horses & burros, deer

SpayVac® pZP immuno-contraceptive vaccine for wild horses & burros, deerSpayVac® pZP immuno-contraceptive vaccine for wild horses & burros, deerSpayVac® pZP immuno-contraceptive vaccine for wild horses & burros, deer

SpayVac® is a humane, non-lethal, single-dose innovation used for reducing overabundant, mammalian wildlife. 

EPA Registration is in progress

SpayVac® need


Humans have had a profound impact on Earth’s ecosystems

Humans have had a profound impact on Earth’s ecosystems

Humans have had a profound impact on Earth’s ecosystems

 The Anthropocene is proposed as the current epoch, which is “viewed as the period during which human activity has been the dominant influence on climate and the environment”.  Many wildlife species, even if they are considered endangered, are overabundant in the ever-shrinking habitat ranges they occupy.  SpayVac pzp vaccine is an effective tool to manage overpopulation.


SpayVac®: A humane alternative

Humans have had a profound impact on Earth’s ecosystems

Humans have had a profound impact on Earth’s ecosystems

Overabundant species, even native ones, can reduce biodiversity by monopolizing resources, spreading infectious diseases, and changing species composition or relative abundance. 

Download a SpayVac brochure here

You can get a general overview of SpayVac by downloading this brochure.

SpayVac® blog posts

Latest News

SFW Participating in the Governor's Business Plan Competition

(February 2020). SFW will again participate in the Wisconsin Governor's Business Plan Competition.  WE benefitted immensely from being part of the competition in 2019 and received a small award.  Moreover, being part of the competition allowed SFW to learn about valuable resources which are available to local startups.  We look forward to participating  in this competition again.

2019 Annual Review

January 23, 2020   SFW Inc.has released its 2019 annual review and 2020 outlook.  You can get a copy by clicking the 'Contact Us' button. Please specify 2019 Annual Review.

Red Deer Trial underway

December 2019 (Madison, WI) SpayVac has been tested in white-tailed deer (Odocoileus virginianus) and  mule deer (Odocoileus hemionus) in four trials. Now, SpayVac pZP is being tested in a group of 25 female red deer (Cervus elaphus). They are currently being treated with SpayVac and fitted with GPS collars for a monitoring period of 2-3 years.  Pregnancy status of the animals will be checked by analyzing fecal samples to identify individuals genetically and then quantify their steroid hormone concentrations. SpayVac has performed very well in the past (87-100% efficacy over 3+ years) with several cervids, including fallow deer (Dama dama) and white-tailed deer (Odocoileus virginianus).  This is a collaborative project, which will also be comparing behavioral differences between pregnant and non-pregnant animals.

Macaque Trial with SpayVac Initiated

November 2019 (Victoria, BC and Madison, WI)  A collaborative study was initiated to test contraceptive efficacy in a population of free-ranging macaques (Macaca mulatta).  The breeding season for these macaques is in December-March, their gestation is 5½ months long, and births typically occur in May-August.  Fifty female rhesus macaques have been vaccinated.  This study is a follow up to replicate positive results from an earlier trial conducted in Hong Kong.  Macaques are considered to be an invasive species in some parts of the world, including Florida and South Carolina.  Populations are often overabundant, which is especially problematic when they live in close proximity to humans in urban and semi-urban areas.  They can cause damage to property and agriculture in addition to spreading zoonotic diseases.  SpayVac’s ability to provide multi-year contraceptive efficacy with a single injection makes it an excellent option for free-ranging primate population control. 

Dr. Bechert and Mr. Fraker: Free-Roaming Equids and Ecosystem Sustainability

October 28, 2019 (Madison, WI)  At the end of May 2019, delegates from over 90 different organizations convened in Reno NV for the Free-Roaming Equids and Ecosystem Sustainability Summit.  Mark Fraker and Dr. Ursula Bechert participated and gave a presentation on behalf of SpayVac-for-Wildlife, Inc.  Following the Summit, the Free-Roaming Equid and Ecosystem Sustainability Network (FREES) was formed to engage diverse stakeholder groups in meaningful dialogue as they work together to realize a common goal of “healthy herds on healthy rangelands.”  Three working groups are currently focused on population management, rangeland conditions, and outreach and communication.  Dr. Bechert has been participating in the population management as well as outreach and communication working groups.  A website is being developed for FREES – more to come!  

SFW Inc to Participate in the Wisconsin Early Stage Symposium

October 25, 2019 (Madison, WI):  SpayVac for Wildlife has been selected to participate in the Wisconsin Early Stage Symposium in Madison, WI on November 6th and 7th.  SpayVac for Wildlife will give a five-minute presentation at 10:45 AM on the 6th and be participating in meetings with potential investors.  SpayVac for Wildlife's lead product is a fertility control that uses a patented technology that uniquely confers long-term infertility with a single dose.  For more information on the Wisconsin Early Stage Symposium you can visit the Wisconsin Technology Council's website:

SpayVac Manufacturing Update

August 8, 2019  (Madison, WI):  SpayVac for Wildlife Inc. is proud to announce our latest steps toward launch of our lead product-- the brand name is SpayVac. We have recently invested in, and acquired, higher throughput equipment that allows us to manufacture nanoparticles that encapsulate our active ingredients at a much higher scale.  Currently we are in the process of making batches to supply customers who will purchase SpayVac to treat Macaques (monkeys), Feral Horses, and Deer this Fall to get ahead of breeding seasons.  In addition, Dr. David Kroeger, Head of Immunology, is developing key quantitative and qualitative methods required for EPA approval this year.

SpayVac co-founder Dr. Ursula Bechert to present SpayVac Data at the International Urban Wildlife Conference

May  30,  2019.  Madison, WI.  SpayVac for Wildlife Inc co-founder, Dr. Ursula Bechert, DVM, PhD, will be giving a talk on SpayVac use at the International Urban Wildlife Conference in Portland, OR.  Her presentation is scheduled for June 4, 2019.  Dr. Bechert has extensive experience participating in field trials and doing research on SpayVac in horses and elephants.

Dr. Bechert and Mr. Fraker Presented SpayVac Data at the Wild Horse Management Conference

May  18, 2019 Mark Fraker and Ursula Bechert recently gave a presentation at a Wild Horse Management Conference in Reno, NV, where delegates from more than 90 organizations gathered to discuss possible solutions to the overpopulation problem.  SpayVac has effectively prevented pregnancies in mares for 4+ years with a single injection, making it a front-runner in the race for effective immunocontraception.  Read more about the conference: pzp vaccine

SpayVac® Proven Single-Dose Efficacy in Multiple Species

Contact us

Sign up to hear from us or ask us questions about progress on SpayVac development.