University of Florida researchers worked with the U.S. Department of Agriculture to test the success of the immunocontraceptive vaccine GonaCon on female cats in an effort to reduce the feral cat population.
Researchers are optimistic that their work will aid in the registration and use of the contraceptive vaccine on abundant feral cat populations. The vaccine is currently registered by the U.S. Environmental Protection Agency for use on female white-tailed deer.
"We’re hoping this research will lead to a nonlethal method of control for feral cat populations that is less expensive, labor-intensive and invasive than current methods, such as surgical sterilization," Julie Levy, DVM, said in a news release from UF.
The five-year study, funded by the Morris Animal Foundation, studied 20 adult female cats, 15 of which received a single dose of the vaccine and five of which received a placebo. All of the female cats were allowed access to a breeding male cat after the injections; all five female cats that received the placebo became pregnant within seven to 28 days, while the vaccinated females remained infertile for five months to five years.
Ninety-three percent of the cats vaccinated with GonaCon remained infertile for the first year after the injections. That number dropped in subsequent years, though numbers still remained fairly high with 73 percent of cats remaining infertile in the second year, and 53 percent infertile in the third year.
The vaccine stimulates the production of antibodies that ultimately help block the production of sex hormones, which inhibits sexual activity as long as an adequate level of antibody activity is available.