Gunther I, Raz T, Berke O, E, Klement E. Nuisances and welfare of free-roaming cats in urban settings and their association with cat reproduction. Preventive Veterinary Medicine 119:203–210, 2015.
This is a retrospective study that sourced a citizen complaint database consisting of calls about free-roaming cat (FRC) nuisance and welfare issues. The authors looked at time-based distribution of complaint calls and their association with FRC population dynamics. Five Israeli cities participated, with total area 335.2 km2. Approximately 90,000 complaint calls were categorized as cat carcass, kittens, kitten births, aggressive cat, invading cat, injured cat, cat feeder nuisance, request to sterilize. Events were categorized also by month of occurrence, over a five-year period. Summarizing the data analyses, cat carcasses were 55% of calls, births-5%, kittens-11%, aggression–3%, invasions–10%, injuries–16%. Evaluation by month of occurrence revealed expected seasonality of reproduction-related complaints, but carcass, aggressiveness, invasion, and injury also were seasonal complaints. In general, cat nuisance–welfare complaints related to reproductive activity. The authors called for studies to assess FRC population control efforts on these complaints.
Urban, Israel, Database study
Fagundes AKF, Oliveira ECS, Tenorio BM, Melo CCS, Nery LTB, Santos FAB, Alves LC, Douglas RH, Silva VAJr. Injection of a chemical castration agent, zinc gluconate, into the testes of cats results in the impairment of spermatogenesis: A potentially irreversible contraceptive approach for this species? Theriogenology 81:230-236, 2014.
This study used 6 control cats and 6 test cats to evaluate serum testosterone before and following intratesticular injection with isotonic saline or zinc gluconate, and to evaluate histological and ultrastructural testicular features at 120 days post-injection. Injection volumes were standardized, calculated based on testicular width.
Control cats remained normal by all measures. Plasma testosterone in treated cats declined to very low levels, averaging 6 pg/ml. Histological and ultrastructural studies confirmed atrophy of seminiferous tubules, germ cell degeneration, fibrosis, impaired spermatogenesis, and degenerative changes in Sertoli and Leydig cells.
Brazil, experimental
Johnson KL, Cicirelli J. Study of the effect on shelter cat intakes and euthanasia from a shelter neuter return project of 10,080 cats from March 2010 to June 2014. PeerJ 2:e646; DOI 10.7717/peerj.646
This study was conducted to evaluate the effect of a TNR program on shelter intakes of cats over a 4-year time period. During this time, 10,080 feral cats were sterilized surgically and returned to capture sites. After 4 years, cat and kitten shelter intakes declined 29%. Euthanasia constituted 70% of shelter intakes before the study, declining to 23% of intakes in 2014. Cat upper respiratory disease and calls for cat carcass removals also declined. This report is further interesting in that the authors defined euthanasia rate and save rate, and excluded owner-requested euthanasia and dead-on arrivals from the data, as well as cats that died of natural causes after shelter entry. Thus, an effort was made to include, insofar as they could, just the free-roamers in the study. Also noteworthy is that the shelters made a strong effort to home as many intakes as they could. The data support that TNR, done properly, does reduce roaming cat numbers. It is important to recognize the large number of cats that were involved, supporting ACCD study models that point to a need for sufficiently intensive program efforts.
TNR, San Jose and Santa Clara County, CA, USA
Levy JK, Isaza NM, Scott KC. Effect of high-impact targeted trap-neuter-return and adoption of community cats on cat intake to a shelter. Vet J 201:269-274, 2014.
The study purpose was to assess the effect of concentrating cat TNR in a high shelter impoundment area. A 2-year program was implemented to capture and neuter at least 50% of the estimated community cats in a defined zip code area of 11.9 km2 followed by adoption or return (TNReturn or TNAdopt), and to compare cat demographics with a county-wide non-target region.
The effort included 2366 cats, 54% of the target area estimated population. Two years later, shelter intake in the target was reduced 66%, compared to 12% non-target decline. Per capita, non-target shelter cat intake was 3.5 times that of the target area, and cat euthanasia was 17.5 times greater. TNR with adoption of acceptably socialized cats clearly resulted in favorable reduction of the roaming cat population.
Alachua County, Florida USA
Roebling AD, Johnson D, Blanton JD, Levin M, Slate D, Fenwick G, Rupprecht CE. Rabies Prevention and Management of Cats in the Context of Trap–Neuter–Vaccinate–Release Programmes. Zoonoses and Public Health, 2014, 61, 290–296, 2014.
This essay is essentially an argument against TNR, based on incorrect interpretation of infectious disease biology, misinterpretation of some existing TNR literature, and exclusion of data contrary to the authors’ evident goals. The first author is a recent graduate of a DVM-MPH curriculum, and is thus inexperienced. The acknowledgements include a statement that the stated views are not necessarily those of the contributing authors located at CDC. Because of the poor quality of this work, the reviewer (DFL) does not view it as credible.
Seimenis A, Tabbaa D. Stray animal populations and public health in the South Mediterranean and the Middle East regions. Vet Italiana 50(2): 131-136, 2014.
This report describes the most significant health hazards associated with stray dogs and cats in unmanaged urban growth in the South Mediterranean and Middle East.
Several social factors that promote disease dissemination during rapid urban growth include: increased human population density; close human-animal proximity; high numbers of stray animals; intense animal production that often is illegal and unsanitary; cultural norms; lack of awareness; weak official collaborations; financial and resource limitations, poor decisions.
Specific diseases of greatest primary zoonotic concern are rabies (virus), Echinococcus (tapeworm) hydatidosis, leishmaniasis (protozoon), and toxoplasmosis (protozoon).
Primary possible actions include: establishing roaming animal policies, including adequate and enforced legislation; improving environmental sanitation and dead animal removals; exclude animal access to slaughter houses and dumps; improve public education about human-animal interactions and disease, including preventive medicine for both.
Public health and animal practices and policies.
Alberthsen C, Rand JS, Bennett PC, Paterson M, Lawrie M, Morton JM. Cat admissions to RSPCA shelters in Queensland, Australia: description of cats and risk factors for euthanasia after entry. Aust Vet J 91:35-42, 2013.
The authors focused on describing population characteristics of feline shelter admissions. This was done by shelter database analysis from years 2006-2008. The evaluation included nearly 34,000 cats, of which 54% were kittens under age 3 months. Members of the general public presented 88% of the kittens, with 54% being strays and 44% owner-surrendered. Overall, 54% of all admissions were presented as strays. Euthanasia was the most frequent outcome at 65%, followed by homing of 30%. Kittens had lower odds of euthanasia, as did cats that were sterilized. The authors indicate the need for programs to reduce admissions and euthanasia, especially for kittens. Reducing delayed sterilization is one important avenue for the latter. Additional stray population studies are needed. Tables 1 and 2 of this report provide a considerable level of demographic information, but no financial data are included.
Australia: Database study of shelter admissions and outcomes.
Gerhold RW, Jessup DA. Zoonotic diseases associated with free-roaming cats. Zoonoses and Public Health 60:189-195, 2013.
This paper is a literature synthesis, describing cats as zoonotic risks for rabies, toxoplasmosis, larval migrans, tularemia, and plague. The primary point the authors make seems to be that TNR programs may lead to increased local numbers of disease-naïve cats through immigration, thus increasing zoonosis risk.
Some of their main supportive concerns are: a) free-roaming cats lack necessary preventive health care; b) a societal philosophy exists toward non-euthanasia of free-roaming “animals”; c) rabies numbers suggest increasing identification of the disease in cats, as compared to dogs; d) a majority of post-potential exposure prophylaxis given to humans is cat-associated.
They make incomprehensible statements such as “17% of all confirmed human rabies exposures in Georgia were attributable to cat bites from 2004 – 2006, whereas dogs comprised 5% of all confirmed human rabies in Georgia during the same time period”. Such statements suggest that the authors are not distinguishing in every case the difference between potential and actual rabies exposure, or between true feral cats, unowned free-roaming cats that are not truly feral, and wandering owned pets.
The authors do correctly suggest that a colony of TNR-sterilized cats may attract new unsterilized immigrants, but do not address abandonment. They state that greater kitten survival occurs in these integrated TNR-immigrant colonies, based on one study.
Most of their parasite-associated observations are referenced but not accompanied by descriptions of comprehensive research data.
The report seems to equate potential risk with actual disease transmissions, presumably as an argument for collection and euthanasia of free-roaming cats, without addressing re-population of the then-opened ecological space.
USA, Literature synthesis
Kass PH, Johnson KL, Weng H-Y. Evaluation of animal control measures on pet demographics in Santa Clara County, California, 1993–2006. PeerJ 1:e18; DOI 10.7717/peerj.18
The authors examined dog and cat populations, owned and unowned, in Santa Clara Co, CA. This population area has been studied several times. For this study, a random telephone survey (1000 responders) provided estimates for numbers of owned pets, strays fed or sterilized, among other parameters. Animal entry and sterilization data were gathered from shelter records. Costs and other statistics were obtained from local government records.
Data from 1982-1993 were used to project shelter entry expectations from 1994-2005. US Census data were used to estimate county households and were combined with survey results to estimate owned pet numbers. Survey results also were used to estimate numbers of fed, unowned dogs and cats, and numbers of strays in the study area. Described statistical methods were used to examine shelter intakes associated with a county spay/neuter program, and to compare those numbers to projected numbers. A benefit-cost analysis also was done.
Veterinarians initially were reimbursed $25 per female and $15 per male. Pregnancy or complications increased reimbursements over $50 - $150. Adding $5 citizen co-pay and $5 fee for rabies vaccine and license appeared had negative effects on use of the program.
Cats in the spay-neuter program, if not sterilized, would have produced 312,000 kittens (1994-2005), resulting in 8,600 surrenders at $250 per cat, or $2.15 million. At an average $23 per spay-neuter, the program would have cost $0.6 million; thus the program reduced shelter intakes and saved taxpayers $1.5 million. Further, projections indicated that, under plausible scenarios (20-80% of sterilized cats being feral), shelter costs would have exceeded $2 million, but could have exceeded $6 million at the high end.
Sparkes AH, Bessant C, Cope K, Ellis SLH, Finka L, Halls V, Hiestand K, Horsford K, Laurence C, MacFarlaine I, Neville PF, Stavisky J, Yeates J. ISFM Guidelines on Population Management and Welfare of Unowned Domestic Cats (Felis catus). J Fel Med Surg 15(9):811-817, 2013.
This report presents guidelines from the International Society of Feline Medicine’s Welfare Advisory Panel. The guidelines are published to provide reference for unowned or rehoming cats with respect to welfare and population control. The stated intent is to define guiding principles, provide direction for interactions between humans and cat populations, and establish welfare assumptions. No financial data are included.
The sections provided include cat-human interactions, aspects of welfare for cats, cats in populations, TNR programs, housing, homing, rehoming of cats, categorizations of unowned cats, discussion of euthanasia, and a glossary of terms. Overall is a theme of defining appropriate human activities and behaviors for population interventions.
Essay, cat welfare and interventions
Thomas RL, Fellowes MDE, Baker PJ. Spatio-Temporal Variation in Predation by Urban Domestic Cats (Felis catus) and the Acceptability of Possible Management Actions in the UK. PLOS One 7(11):1-13, 2012.
Cat density, predation rates, and citizen attitudes were collected in 12 random 1-km squares that included varying types of human housing and socioeconomic status. Questionnaire information requested from cat owners included number owned, sterilization status, use of anti-predation devices, roaming habits, and prey brought home.
Proportion of non-responding cat-owning households was estimated in a 50-100 random contact second phase. Cat density was estimated from (un-surveyed households); (phase II proportion with owned cats); (mean number of owned cats in responding phases I-II homes). Other calculations included human housing density associated with proportion of cat-own households; mean cat number per household; and total cat density.
Prey return rates were estimated in some squares by owner records for 6 weeks each season, calculated as dead and live prey divided by number of cats under observation. Data also were segregated as single- and multiple-cat households that saw no prey, and minimum number of cats (multiple) delivering no prey.
Predation rates were calculated as return rates x 2.17 (adjustment for 6-week seasonal observations and a conversion factor estimating number of kills that were brought home - 30%). Breeding density of 6 bird species in 6 squares was estimated by point counts to evaluate potential predation effects.
Attitudes to management options were measured for: ecologically sensitive exclusion; urban center exclusion; anti-predation devices; confining cats outdoors in owner gardens; forbidding all outdoors roaming; registering cats; compulsory cat sterilization; and de-clawing to decrease harm to prey species.
Completing all the surveys, estimates, data analyses indicated that prey kills were only moderately dependent on adult cat density, but could decrease local bird populations in urban areas for some species in some situations. Most urban residents did not regard cat predation as a significant concern. Anti-predation devices were the only acceptable management approach.
Reviewer (DFL) comment: While intuitively sensible conclusions were reached, there should be some concern surrounding the fact that a good deal of serial data calculation was employed, from generally small actual numerical data sets. Possibilities for judgmental errors could be significant and serially magnifying.
Reading, United Kingdom (city); study conducted 2008-2010
Devillard S, et al. Linking genetic diversity and temporal fluctuations in population abundance of the introduced feral cat (Felis silvestris catus) on the Kerguelen archipelago. Mol Ecol 20:5141-5153, 2011.
The Kerguelen archipelago is in the sub-antarctic Southern Indian Ocean, covering about 7200 km2. The cat population was founded during the 1950s by an estimated 5 cats introduced for rodent and rabbit control. The present population size approximates 7000 cats, the estimated carrying capacity. Cats hold large territories at a low density of about 1.5 cats/km2. The study was conducted from 1996-2007, with structured observations and sampling on 3 transects. Total transect counts were 1332 by the end of the study. DNA samples were acquired by hair sampling following trapping and sedation. Eighteen microsatellites were selected for PCR amplification and evaluation. Genotyped cats were n=281. Cat populations were estimated at the island and site-specific levels, thus allowing, with genetic data, annual estimation of genetic diversity at each population or level. Summer populations increased over the study time, but fluctuated widely, paralleled by genetic indices for diversity. Local population abundance was a significantly influential factor on outcomes. Genetic diversity was high when local populations were larger, and study sites were synchronous in size fluctuations. The number of adults reproducing moderately impacted the genetic diversity of offspring. Kerguelen archipelago, introduced free-roaming cat population, growing from 5 to 7000 individuals in about 50 years.
Key findings: The authors suggest that the rate of change model for summer population size best explains yearly fluctuations in genetic diversity. The changes were insufficient to effect permanent alterations in genetic diversity. Natal dispersal and recruitment were facilitated by higher juvenile survival rates when adult numbers were lower, and were important factors in the study outcome.
Ferreira JP, et al. Human-related factors regulate the spatial ecology of domestic cats in sensitive areas for conservation. PLoS One 6(10):1-10, 2011. e25970.
This study was conducted during 2006 and 2007 in the Moura-Barrancos Nature 2000 site and in a Bird Special Protection Area partly encompassing agroforestry areas near a village (Barrancos) in the area of the Southeast Portugal-Spain border. Limited regional human activity includes cattle rearing, agriculture, and hunting. The region is largely a combination of agricultural, sylvatic, and pastoral land. Live-trapping and evaluation of free-roaming cats was conducted in scrubland areas absent of humans, and at farms near the Natura 2000 site. No cats were found in two natural areas not near any humans, although numerous other mammalia were trapped and released. No cats were found in abandoned farmsteads. Forty-two farms with humans present yielded cats from 39, with a cat density of 0.26/km2. Among 88 trapped cats, females outnumbered males 2:1 (41 additional cats with sex not recorded). Humans did not feed the cats, but food refuse often was accessible. Data analyses demonstrated that human presence was the most important factor in cat locations. Number of cats per farm was mostly influenced by access to human refuse, as food provision. Cats avoided areas with high fox density, presumably to avoid being victims of predation. Mixed agricultural, sylvatic, and pastoral land in rural Portugal.
Key findings: Successful feline populations likely benefit in important ways from associations with humans.
Finkler H, et al. The Impact of Anthropogenic Factors on the Behavior, Reproduction, Management and Welfare of Urban, Free-Roaming Cat Populations. Anthrozoos 24(1):31-49, 2011.
In neighborhoods with differing socioeconomic status (SES), the authors examined caretaker relationships to eight free-roaming cat populations. High SES neighborhoods covered 12 km2, compared to 15km2 in low SES neighborhoods. Of 622 feeding groups, 392 were in high SES areas and 230 were in low SES areas.
Four hypotheses were considered: (a) caretaker behaviors and housing type (density of humans) influences cat behaviors; (b) reproduction control is influenced by city management and caretaker behaviors; (c) pregnancy rates are influenced by city management and caretaker behaviors; (d) cortisol levels are affected by caretaker attitudes and socioeconomics. City veterinary data were acquired for the years 2000-2005 for (a) number of cat groups; (b) number of cats sterilized; (c) number of veterinary visits to cat group; (d) pregnancy rate; (e) rabies vaccination rate. SES variables for selection of 8 of 63 neighborhoods included (a) educational matriculation; (b) employment rate; (c) immigration rate; (d) computer ownership; (e) income. Final neighborhood selection (n=8) also included predominant type of housing. Cat group inclusion criteria included (a) nutritional adequacy; (b) cooperating caretaker; (c) at least 10 cats; (d) cooperation of neighbors; (e) access for observation.
Density was 33 groups/km2 in high SES areas versus 15/km2 in low SES areas. In high SES areas, more cats were sterilized, more were vaccinated, and there were more veterinary visits with more captures/veterinary visit. Caretaking resulted in improved behaviors, as did sterilizing, while housing and SES did not influence behaviors. High SES areas had lower frequency of pregnancies, while housing and caretaking had no influence. Sterilized cats had lower serum cortisol, but caretaking had no influence.
Key findings: Anthropogenic factors need to be considered in municipalities that are considering cat population control measures.
Finkler H, et al. Behavioral differences between urban feeding groups of neutered and sexually intact free-roaming cats following a trap-neuter-return procedure. J Am Vet Med Assoc 238(9):1141-1149, 2011. (Same study as following paper.)
Four feeding groups of free-roaming cats (n=184), widely separated to prevent interactions, were evaluated from October 1999 to October 2000. Regular feedings and observations were conducted, although there were some differences among the four groups in observation length, cat handling, and caretaker preferences for particular cats. Cats within group varied in affinity to humans. Caretakers provided food daily, usually in excess of need, at times familiar to the cats in each group. For the study, cat group A was TNRed at 73%; group B was TNRed at 75%; groups C and D were not TNRed. TNRed cats were mixed male and female. Efforts were made to identify and track cats as individuals, with behaviors and presence/absence recorded as such. Observation periods were group-specific in length, done before and during feeding. For the first 5-7 weeks, observations were 2-3 days/week. For the following 8 months, observations were weekly. For the last 5-7 weeks, observations were 2-3 days/week.
Groups A and B, sterilized at approximately 75%, displayed fewer agonistic encounters. Male-male encounters were more agonistic between intact cats than between sterilized cats. Group A neuters appeared for feeding earlier in feeding periods than intact cats, and stayed longer. Israel, Tel-Aviv, urban.
Key findings: The authors conclude that neutered cats timed their arrival for feeding earlier than intact cats, possibly as an available response to decreased sexual and agonistic interactions, and possibly as learned behaviors related to better choices among offered foods. Further, TNR reduced fighting and vocalizations, which would be expected to result in fewer injuries and opportunities to transmit diseases.
Gunther I, et al. Demographic differences between urban feeding groups and sexually intact free-roaming cats following a trap-neuter-return procedure. J Am Vet Med Assoc 238(9):1134-1140, 2011. (Same study as preceding paper.)
Four feeding groups of free-roaming cats (n=184), widely separated to prevent interactions, were evaluated from October 1999 to October 2000. Regular feedings and observations were conducted, although there were some differences among the four groups in observation length, cat handling, and caretaker preferences for particular cats. Cats within group varied in affinity to humans. Caretakers provided food daily, usually in excess of need, at times familiar to the cats in each group. For the study, cat group A was TNRed at 73%; group B was TNRed at 75%; groups C and D were not TNRed. TNR cats were mixed male and female. Efforts were made to identify and track cats as individuals, with behaviors and presence/absence recorded as such. Observation periods were group-specific in length, done before and during feeding. For the first 5-7 weeks, observations were 2-3 days/week. For the following 8 months, observations were weekly. For the last 5-7 weeks, observations were 2-3 days/week.
Groups A and B experienced post-TNR population increases through unsterilized immigrations and few emigrations. Groups C and D experienced population decreases over one year. Groups A and B demonstrated greater kitten survival. Israel, Tel-Aviv, urban.
Key findings: The authors interpreted their observations to be reflections of lesser reproductive and competitive pressures. The authors concluded that continuous TNR would be required to maintain a high proportion of sterilized individuals in a free-roaming population.
Horn JA et al. Home range, habitat use, and activity patterns of free-roaming domestic cats. J Wildlife Management 75(5):1177-1185; 2011.
Radiotelemetry and activity sensors were used to study home ranges, habitat use, and activity of owned and unowned free-roaming cats. Groups of 11 owned and 16 unowned cats were monitored over 2544-hectares during 2007-2008. Owned cats (all sterilized) had smaller home ranges (p=0.02) than unowned cats (2 sterilized). Annual ranges of unowned cats were larger than their seasonal ranges because of season-related habitat use that did not occur in owned cats. No gender-related interactions or seasonal differences were found. Time given to denning and sleeping was less (p<0.01) among unowned cats, while time given to high activity levels was greater (p<0.01) among unowned cats. Among a group of 27 unowned and 12 owned cats, following censoring of data from 5 unowned (disappeared) cats, cumulative survival was 50% among unowned cats (392 days) and 92% among owned cats (596 days). USA, Champaign-Urbana Il, urban to rural. (Note that sample sizes were quite small.)
Key findings: The authors concluded that ranging and activity suggest that unowned cats may influence local wildlife more than owned cats, although greater effect of owned cats in smaller ranges also is possible. Feeding and owner care modify space use and activity.
Trevejo R, et al. Epidemiology of surgical castration of dogs and cats in the United States. J Am Vet Med Assoc 238:898-904, 2011.
The authors evaluated medical records of 320,172 cats and 1,339,860 dogs examined at 651 Banfield-owned USA veterinary hospitals during 2007. Conditions for inclusion were age, breed, sex, spay-neuter (castration) status, and knowledge of wellness plan enrollment status. Data were divided into six geographic regions.
In this database, intact cats' average age was 1.5 years, compared to 5.2 years for castrated cats (p<0.001). Male cats were slightly more numerous, at 83% castration versus 81% of females (P<0.001). Cats enrolled in prepaid wellness plans were more likely to be castrated (p<0.001). The lowest prevalence of cat castration was in the northeastern US, at 80% (p<0.001). Castrated dogs' average age was 4.7 years, compared to intact at 2.2 years, with slightly greater female numbers than males (p<0.001). Dogs enrolled in prepaid wellness plans were more likely to be castrated, and the lowest prevalence of dog castration was in the southeastern US, at 61% (p<0.001).
Key findings: The authors concluded that wellness communications need to be tailored to age, sex, and breed observations by geographic region, with respect to trends for intact or castrated status.
Comment: Regional societal attitudes likely are reflected in these data, but the demographics of location for Banfield-owned practices, and characteristics of employed clinicians, should be considered also.