Reproductive capacity of free-roaming domestic cats and kitten survival rate

OBJECTIVE: To determine reproductive capacity of naturally breeding free-roaming domestic cats and kitten survival rate. DESIGN: Prospective cohort and retrospective cross-sectional study. ANIMALS: 2,332 female cats brought to a trap-neuter-return clinic for neutering and 71 female cats and 171 kittens comprising 50 litters from a cohort study of feral cats in managed colonies. PROCEDURE: Data collected for all cats included pregnancy, lactation, and estrus status and number of fetuses for pregnant cats. Additional data collected for feral cats in managed colonies included numbers of litters per year and kittens per litter, date of birth, kitten survival rate, and causes of death. RESULTS: Pregnant cats were observed in all months of the year, but the percentage of cats found to be pregnant was highest in March, April, and May. Cats produced a mean of 1.4 litters/y, with a median of 3 kittens/litter (range, 1 to 6). Overall, 127 of 169 (75%) kittens died or disappeared before 6 months of age. Trauma was the most common cause of death. CONCLUSIONS AND CLINICAL RELEVANCE: Results illustrate the high reproductive capacity of free-roaming domestic cats. Realistic estimates of the reproductive capacity of female cats may be useful in assessing the effectiveness of population control strategies.