Cat contraception study shows promise

Vaccine Shows Significant Promise for Controlling Feline Contraception

The uncontrolled reproduction of feral cats is a substantial cause of cat overpopulation and euthanasia. Although surgical sterilization is an increasingly popular and humane method of controlling feral cat populations, it is expensive, labor-intensive, highly technical and limited in scale. In a previous MAF-funded study, researchers tested a single-dose vaccine that successfully prevented pregnancy in 73 percent of female cats during the two-year observation period. A second three-year study continued this work, for a total of five years of observation, at which point 27 percent of the cats remained infertile. The duration of the vaccine's effectiveness ranged from four months to more than five years (median = three years). It is highly likely that a second immunization would increase the percentage of cats with long-lasting and perhaps permanent contraception, but multiple treatments of free-roaming cats would be difficult. Researchers believe future work should focus on refining the single-dose approach to increase the percentage of cats that remain infertile for at least three years. Results from this study have been widely presented, and the lead researcher was appointed to the initial scientific advisory committee of the Michelson Prize and Grants program of the Found Animals Foundation in Los Angeles, which has earmarked $75 million for the development of nonsurgical sterilization options for cats and dogs.