Study: High body condition scores, good overall health among exurban feral cats

Study

“Exurban Feral Cat Seroprevalence of Feline Leukemia and Feline Immunodeficiency Viruses and Adult Survival,” published in the Southeastern Naturalist, 2017. Abstract available online here.

Overview

Over the course of 11 months, researchers humanely trapped 101 individual free-roaming cats in Russellville, Arkansas, “an exurban city comprised of populous urban areas intermixed with relatively natural areas” [1]. Ninety-three cats were examined for general health with their blood samples screened for common cat infections.

Key points

Researchers reported feline immunodeficiency virus (FIV) and feline leukemia virus (FeLV) prevalence rates of 12.7% and 16.7%, respectively. These rates are considerably higher than those typically reported in the literature (see below), and are likely a reflection of what the study author describes as a “hotspot” for these diseases as well as the cats’ presumably unsterilized status (few details on sterilization status were provided) [2].

Rates of FIV and FeLV were higher than expected, likely a reflection of “hotspots” resulting from colonies of unsterilized cats.

A study of unowned free-roaming cats admitted to trap-neuter-vaccinate-return (TNVR) programs in Raleigh, North Carolina (733 cats), and Gainesville, Florida (1,143 cats), by contrast, revealed overall infection rates of 3.5% for FIV and 4.3% for FeLV, “similar to infection rates reported for owned cats” [3]. Likewise, a study of managed free-roaming cats in Key Largo, Florida, reported infection rates of 3.3% and 3.6%, respectively, among the 2,327 cats tested [4]. These results correspond reasonably well with those from large-scale studies examining prevalence rates in U.S. and Canadian cat populations (owned and unowned) [5–7].

Body condition scores

Results showed that 58 of 93 cats evaluated (62.4%) were in “ideal body condition,” receiving a body condition score (BCS) of 5 (on a scale of 1–9). Another 22 (23.7%) were considered underweight and 13 (14.0%) were considered overweight. These findings are comparable to those reported by other researchers [8–10] who have also documented improved BCS values following sterilization [8,9].

Trap-nights dependent on population density

Over the course of the study, these researchers trapped cats at both “developed” (i.e., dense human population, industrial and commercial buildings, etc.) and natural areas, observing “greater trapping success” in Russellville’s developed areas. Whereas capturing each individual cat in the developed areas required an average of 16.7 trap-nights (one trap-night being the equivalent of one trap set over one night), each cat in the natural areas required an average 50 trap-nights [1]. This is likely the result of relatively higher cat densities in areas of dense human population [11], and the cats’ reliance on food provided by residents [12,13].

See related Issue Brief: Cat health and welfare after TNR: Considerations and concerns

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References

1. Normand, C.M.; Urbanek, R.E. Exurban Feral Cat Seroprevalence of Feline Leukemia and Feline Immunodeficiency Viruses and Adult Survival. Southeastern Naturalist 2017, 16, 1–18.

2. Normand, C.M. Feral cat virus infection prevalence, survival, population density, and multi-scale habitat use in an exurban landscape. M.S., Arkansas Tech University: Ann Arbor, 2014.

3. Lee, I.T.; Levy, J.K.; Gorman, S.P.; Crawford, P.C.; Slater, M.R. Prevalence of feline leukemia virus infection and serum antibodies against feline immunodeficiency virus in unowned free-roaming cats. Journal of the American Veterinary Medical Association 2002, 220, 620–622.

4. Kreisler, R.E.; Cornell, H.N.; Levy, J.K. Decrease in Population and Increase in Welfare of Community Cats in a Twenty-Three Year Trap-Neuter-Return Program in Key Largo, FL: The ORCAT Program. Frontiers in Veterinary Science 2019, 6.

5. Levy, J.K.; Scott, H.M.; Lachtara, J.L.; Crawford, P.C. Seroprevalence of feline leukemia virus and feline immunodeficiency virus infection among cats in North America and risk factors for seropositivity. Journal of the American Veterinary Medical Association 2006, 228, 371–376.

6. Little, S.; Sears, W.; Lachtara, J.; Bienzle, D. Seroprevalence of feline leukemia virus and feline immunodeficiency virus infection among cats in Canada. Canadian Veterinary Journal 2009, 50, 644–648.

7. Burling, A.N.; Levy, J.K.; Scott, H.M.; Crandall, M.M.; Tucker, S.J.; Wood, E.G.; Foster, J.D. Seroprevalences of feline leukemia virus and feline immunodeficiency virus infection in cats in the United States and Canada and risk factors for seropositivity. J Am Vet Med Assoc 2017, 251, 187–194.

8. 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.

9. 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.

10. Zito, S.; Walker, J.; Gates, M.C.; Dale, A. A Preliminary Description of Companion Cat, Managed Stray Cat, and Unmanaged Stray Cat Welfare in Auckland, New Zealand Using a 5-Component Assessment Scale. Frontiers in Veterinary Science 2019, 6, 40.

11. Liberg, O.; Sandell, M.; Pontier, D.; Natoli, E. Density, spatial organisation and reproductive tactics in the domestic cat and other felids. In The Domestic Cat: The biology of its behaviour; Turner, D.C., Bateson, P.P.G., Eds.; Cambridge University Press: Cambridge, 2000.

12. Silva-Rodríguez, E.A.; Sieving, K.E. Influence of Care of Domestic Carnivores on Their Predation on Vertebrates. Conservation Biology 2012, 25, 808–815.

13. Cove, M.V.; Gardner, B.; Simons, T.R.; Kays, R.; O’Connell, A.F. Free-ranging domestic cats (Felis catus) on public lands: estimating density, activity, and diet in the Florida Keys. Biological Invasions 2018, 20, 333–344.