“Association of neutering with health and welfare of urban free-roaming cat population in Israel, during 2012–2014,” published in Preventive Veterinary Medicine, September 2018. Abstract available online here.
Over the span of two years, the study’s lead-author (a licensed veterinarian) conducted visual observations of free-roaming domestic (aka feral) cats and kittens across all 30 neighborhoods of the Israeli city of Rishon LeZion. The data compiled led the researchers involved to conclude that sterilization has “a favorable effect” on free-roaming cats’ health .
In general, the health of sterilized free-roaming cats was found to be superior to that of intact free-roaming cats, but the researchers’ detailed breakdown of various visible signs of illness or injury (e.g., emaciation, obesity, skin lesions, disability, etc.) illustrates considerable variability.
In general, the health of sterilized free-roaming cats was found to be superior to that of intact free-roaming cats.
Kittens were more likely than adults to be thin (72.7% of the kittens observed in the study) or emaciated (6.6%), for example, while sterilized adults were more likely to be obese (6.7% of the cats observed) than either kittens or intact adults. Skin lesions were most common among intact male adults (9%) while injury or severe disability was most common among kittens (2.2%). Permanent disability, on the other hand, was highest among neutered adults (3.4%), which, the study’s authors explain, “does not necessarily represent a higher risk of occurrence of such injuries. Rather it might be attributed to their presumably longer lifespan” .
In addition, the authors report that higher body-condition scores were associated with the presence of sterilized cats (as has been reported elsewhere ) and were observed among both sterilized and intact cats in the area. This positive health association could be the result of behavior changes among the neutered cats: “Less aggressive behavior may result in a reduction of competitive behavior by neutered cats, which may enable other cats to gain additional access to vital resources” .
Researchers reported that 13.7% of the cats studied had “at least one external sign of illness (any external injury or disability, any skin lesion or emaciation),” noting that this is higher than what has been reported in similar studies from the U.S. [3,4]. It is unclear whether this discrepancy is the result of differences in various health factors or differences in research methods.
See related Issue Brief: Cat health and welfare after TNR: Considerations and concerns
Gunther, I.; Raz, T.; Klement, E. Association of neutering with health and welfare of urban free-roaming cat population in Israel, during 2012-2014. Preventive Veterinary Medicine 2018, 157, 26–33.
Scott, K.C.; Levy, J.K.; Gorman, S.P.; Neidhart, S.M.N. Body Condition of Feral Cats and the Effect of Neutering. Journal of Applied Animal Welfare Science 2002, 5, 203–213.
Scott, K.C.; Levy, J.K.; Crawford, P.C. Characteristics of free-roaming cats evaluated in a trap-neuter-return program. Journal of the American Veterinary Medical Association 2002, 221, 1136–1138.
Wallace, J.L.; Levy, J.K. Population characteristics of feral cats admitted to seven trap-neuter program in the United States. Journal of Feline Medicine & Surgery 2006, 8, 279–284.