Mendes-de-Almeida F, Remy GL, Gershony LC, Rodrigues DP, Chame M and Labarthe NV. Reduction of feral cat (Felis catus Linnaeus 1758) colony size following hysterectomy of adult female cats. J Feline Med Surg. 2011; 13: 436-40.
The size of urban cat colonies is limited only by the availability of food and shelter. Population growth in urban cat colonies can challenge all known population control programs. In a number of population control situations, the resident population will initially be reduced but other feral cats could join the colony and increase numbers again. The authors tested a new population control method that consisted of performing a hysterectomy on all captured female cats over 6 months of age in a feral cat colony in Rio de Janeiro. They estimated the size of the colony and compared population from year to year with a method of capture-mark-release-recapture. Results indicated that the feral cat population remained constant from 2001 to 2004. Subsequently, there was a gradual decline in the estimated colony population in 2004 (40 cats), in 2006 (26 cats), and 2008 (17 cats) compared with the initial number found before the first intervention in 2001 (59 cats). The authors believe that a biannual program of feline population control by performing hysterectomies on sexually mature females will restrict growth of the free-roaming feral cat colony. This method reduced the number of kittens born in the colony and decreased the immigration of other feral cats into the colony. [VT]
Natoli E, Maragliano L, Cariola G, et al. Management of feral domestic cats in the urban environment of Rome (Italy). Prev Vet Med. 2006; 77: 180-5.