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Characteristics of Community Cats and Their Caregivers
- Population characteristics of feral cats admitted to seven trap-neuter-return programs in the United States.
- Number of unowned free-roaming cats in a college community in the southern United States and characteristics of community residents who feed them.
- Body condition of feral cats and the effect of neutering.
- Characteristics of free-roaming cats evaluated in a trap-neuter-return program.
- Characteristics of free-roaming cats and their caretakers.
Community Cat Management
- Humane strategies for controlling feral cat populations.
- Evaluation of the effect of a long-term trap-neuter-return and adoption program on a free-roaming cat population.
- Analysis of the impact of trap-neuter-return programs on populations of feral cats.
- 2008 American Association of Feline Practitioners’ feline retrovirus management guidelines.
- Seroprevalence of feline leukemia virus and feline immunodeficiency virus infection among cats in North America and risk factors for seropositivity.
- Prevalence of infectious diseases in feral cats in Northern Florida.
- Prevalence of feline leukemia virus infection and serum antibodies against feline immunodeficiency virus in unowned free-roaming cats.
Vaccination of Cats
- Effects of anesthesia and surgery on serologic responses to vaccination in kittens.
- Response of feral cats to vaccination at the time of neutering.
Cats and Anesthesia
- Evaluation of medetomidine, ketamine and buprenorphine for neutering feral cats.
- Anesthetic and physiologic effects of tiletamine, zolazepam, ketamine, and xylazine combination (TKX) in feral cats undergoing surgical sterilization.
- Use of the anesthetic combination of tiletamine, zolazepam, ketamine, and xylazine for neutering feral cats.
Nonsurgical Contraception in Cats
- Long-term fertility control in female cats with GonaCon™, a GnRH immunocontraceptive.
- Contraceptive vaccines for the humane control of community cat populations.
- GnRH immunocontraception of male cats.
- Developmental uterine anomalies in cats and dogs undergoing elective ovariohysterectomy.
- The Association of Shelter Veterinarians veterinary medical care guidelines for spay-neuter programs.
Population characteristics of feral cats admitted to seven trap-neuter-return programs in the United States.
Wallace JL, Levy JK. J Feline Med Surg. 2006 Aug;8(4):279-84. Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, PO Box 100126, Gainesville, FL 32608, USA.
Internationally, large populations of feral cats constitute an important and controversial issue due to their impact on cat overpopulation, animal welfare, public health, and the environment, and to disagreement about what are the best methods for their control. Trap-neuter-return (TNR) programs are an increasingly popular alternative to mass euthanasia. The objective of this study was to determine the population characteristics of feral cats admitted to large-scale TNR programs from geographically diverse locations in the United States.
Data from 103,643 feral cats admitted to TNR programs from 1993 to 2004 were evaluated. All groups reported more intact females (53.4%) than intact males (44.3%); only 2.3% of the cats were found to be previously sterilized. Overall, 15.9% of female cats were pregnant at the time of surgery. Pregnancy was highly seasonal and peaked between March and April for all of the groups. The average prenatal litter size was 4.1+/-0.1 fetuses per litter. Cryptorchidism was observed in 1.3% of male cats admitted for sterilization. A total of 0.4% of cats was euthanased because of the presence of debilitating conditions, and 0.4% died during the TNR clinics.
Remarkably similar populations of cats with comparable seasonal variability were seen at each program, despite their wide geographical distribution. These results suggest that it is feasible to safely sterilize large numbers of feral cats and that the experiences of existing programs are a consistent source of information upon which to model new TNR programs.
Number of unowned free-roaming cats in a college community in the southern United States and characteristics of community residents who feed them.
Levy JK, Woods JE, Turick SL, Etheridge DL. J Am Vet Med Assoc. 2003 Jul 15;223(2):202-5. Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL 32610, USA.
Objective: To estimate the number of unowned free-roaming cats in a college community in the southern United States and identify the characteristics of community residents who feed these cats.
Design: Cross-sectional, random-digit telephone survey.
Sample Population: 587 households in Alachua County, Florida, surveyed between March 1 and May 10, 1999.
Procedure:Telephone surveys were conducted, and respondents were asked questions about feeding of unowned free-roaming cats.
Results: 70 (12%) households fed free-roaming cats; mean +/- SD number of free-roaming cats fed per household was 3.6 +/- 1.9. Households that fed free-roaming cats were more likely to own pet cats than were households that did not feed free-roaming cats; however, 30 of 70 (43%) households feeding free-roaming cats did not own cats or dogs. Although the percentage of pet cats that were neutered was high (90%), only 8 (11%) households that fed free-roaming cats attempted to have such cats neutered. The free-roaming cat population was estimated to represent approximately 44% of the population of cats in the county.
Conclusions and Clinical Relevance: Results suggest that unowned free-roaming cats may represent a substantial portion of the total cat population in a region. Public policies and education programs aimed at reducing cat overpopulation should include provisions for neutering unowned free-roaming cats, and efforts should target the general public, not only pet owners, because not all households that feed unowned free-roaming cats own pets.
Body condition of feral cats and the effect of neutering.
Scott KC, Levy JK, Gorman SP, Newell SM. J Appl Anim Welf Sci. 2002;5(3):203-13. College of Veterinary Medicine, University of Florida, Gainesville, USA.
Considerable debate exists regarding the most appropriate methods for controlling feral cat populations, both from humane and logistical points of view. The physical condition of feral cats has not been reported, and it is not known if these cats benefit from neutering.
This study investigates the body condition of feral cats by measuring body weight (BW), body condition score (BCS; Burkholder, 2000; Laflamme, Kealy, & Schmidt, 1994), and falciform fat pad. The study includes lateral abdominal radiographs taken at the time of neutering of 105 adult feral cats for measurement of falciform fat pad depth and area. At that time we also assessed BW and BCS.
One year later we assessed the effects of neutering on body condition by evaluating a subsample of 14 cats. At the time of surgery, the cats were lean but not emaciated (BW 3.1 +/- 0.9 kg; BCS 4 +/- 1; based on a 1 to 9 scale ranging from 1 [emaciated] to 9 [grossly obese]). Falciform fat pad depth and area averaged 7.1 mm and 197.4 mm2, respectively, indicating a small amount of fat. Fourteen cats, reevaluated 1 year after neutering, increased 260% + 90% in falciform fat pad depth, 420% +/- 390% in fat pad area, 40% +/- 4% in BW, and 1 level in BCS ranking (1 to 9 scale; all differences p <.001).
Similar to confined socialized cats, feral cats gained significant weight and body fat after neutering.
Characteristics of free-roaming cats evaluated in a trap-neuter-return program.
Scott KC, Levy JK, Crawford PC. J Am Vet Med Assoc. 2002 Oct 15;221(8):1136-8. Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville 32610, USA.
Objective: To determine characteristics of free-roaming cats evaluated in a trap-neuter-return program.
Design: Cross-sectional study.
Animals: 5,323 free-roaming cats.
Procedure: Data collected included sex, maturity, pregnancy status, number of fetuses per pregnancy, cryptorchidism, and occurrence of complications or euthanasia.
Results: Adult cats represented 85% of the population, and 57% were female. Overall, 19% of adult females were pregnant, and mean litter size was 3.6 fetuses. Pregnancy rate peaked at 36 to 47% of all females evaluated in March and April and decreased to < or = 4% from October through January. Cryptorchidism was observed in 1.9% of the males; 0.4% of the adult females had pyometra. Only 1.9% of the cats were already neutered. Euthanasia and unexpected death rates were 0.4 and 0.3%, respectively. The most common severe problems encountered included pyometra, neoplasia, surgical complications, diaphragmatic hernia, debilitation, and chronic inflammatory diseases.
Conclusions and Clinical Relevance: Neutering programs for free-roaming cats should include preparations to perform more spays than castrations. Typically, almost half of the female cats trapped during spring will be pregnant. Cryptorchidism is uncommon but is encountered on a consistent basis, so care should be taken to differentiate previous castration from retained testicles. Euthanasia of debilitated cats for humane reasons is rarely necessary, and unexpected deaths occur at a low rate. It is feasible and safe to neuter large numbers of free-roaming cats in large-scale clinics.
Characteristics of free-roaming cats and their caretakers.
Centonze LA, Levy JK. J Am Vet Med Assoc. 2002 Jun 1;220(11):1627-33. Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville 32611, USA.
Objectives: To describe the characteristics of unowned, free-roaming cats and their caretakers who participated in a trap-neuter-return (TNR) program and to determine the effect of the program on free-roaming cat colonies.
Design: Prospective study.
Sample Population: 101 caretakers of 920 unowned, free-roaming cats in 132 colonies in north central Florida.
Results: Most (85/101; 84%) caretakers were female. The median age was 45 years (range, 19 to 74 years). Most (89/101; 88%) caretakers owned pets and of those, most (67/101; 66%) owned cats. The major reasons for feeding free-roaming cats were sympathy and love of animals. Most caretakers reported that the cats they cared for were too wild to be adopted, but many also reported that they considered the cats to be like pets. The total surveyed cat population was 920 before participation in TNR and 678 after TNR. Mean colony size was 7 cats before TNR and 5.1 cats after TNR. Most cats lived on the caretaker’s property. At the time of the survey, 70% (644/920) of the cats had been neutered.
Conclusions and Clinical Relevance: The decrease in the surveyed free-roaming cat population was attributed to a reduction in births of new kittens, adoptions, deaths, and disappearances. Recognition of the human-animal bond that exists between caretakers and the feral cats they feed may facilitate the development of effective control programs for feral cat populations.
Humane strategies for controlling feral cat populations.
Levy JK, Crawford PC. J Am Vet Med Assoc. 2004 Nov 1;225(9):1354-60. Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL 32610, USA.
Evaluation of the effect of a long-term trap-neuter-return and adoption program on a free-roaming cat population.
Levy JK, Gale DW, Gale LA. J Am Vet Med Assoc. 2003 Jan 1;222(1):42-6. Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL 32610, USA.
Objective: To evaluate the effect of a long-term trap-neuter-return program, with adoption whenever possible, on the dynamics of a free-roaming cat population.
Design: Observational epidemiologic study.
Animals: 155 unowned free-roaming cats.
Procedures: Free-roaming cats residing on a university campus were trapped, neutered, and returned to the environment or adopted over an 11-year period.
Results: During the observation period (January 1991 to April 2002), 75% of the cats were feral, and 25% were socialized. Kittens comprised 56% of the original population. Male cats were slightly more numerous (55%) than females. At the conclusion of the observation period, 47% of the cats had been removed for adoption, 15% remained on site, 15% had disappeared, 11% were euthanatized, 6% had died, and 6% had moved to the surrounding wooded environment. Trapping began in 1991; however, a complete census of cats was not completed until 1996, at which time 68 cats resided on site. At completion of the study in 2002, the population had decreased by 66%, from 68 to 23 cats (of which 22 were feral). No kittens were observed on site after 1995, but additional stray or abandoned cats continued to become resident. New arrivals were neutered or adopted before they could reproduce.
Conclusions and Clinical Relevance: A comprehensive long-term program of neutering followed by adoption or return to the resident colony can result in reduction of free-roaming cat populations in urban areas.
Analysis of the impact of trap-neuter-return programs on populations of feral cats.
Foley P, Foley JE, Levy JK, Paik T. J Am Vet Med Assoc. 2005 Dec 1;227(11):1775-81. Department of Biological Sciences, California State University, Sacramento, CA 95819, USA.
Objective: To evaluate 2 county trap-neuter-return (TNR) programs for feral cat population management via mathematical modeling.
Design: Theoretical population model.
Animals: Feral cats assessed from 1992 to 2003 in San Diego County, California (n = 14,452), and from 1998 to 2004 in Alachua County, Florida (11,822).
Procedure: Data were analyzed with a mathematical Ricker model to describe population dynamics of the feral cats and modifications to the dynamics that occurred as a result of the TNR programs.
Results: In both counties, results of analyses did not indicate a consistent reduction in per capita growth, the population multiplier, or the proportion of female cats that were pregnant.
Conclusions and Clinical Relevance: Success of feral cat management programs that use TNR can be monitored with an easily collected set of data and statistical analyses facilitated by population modeling techniques. Results may be used to suggest possible future monitoring and modification of TNR programs, which could result in greater success controlling and reducing feral cat populations.
2008 American Association of Feline Practitioners’ feline retrovirus management guidelines.
Levy J, Crawford C, Hartmann K, Hofmann-Lehmann R, Little S, Sundahl E, Thayer V. J Feline Med Surg. 2008 Jul;10(3):300-16. Epub 2008 May 2. Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL 32610, USA. email@example.com.
Feline leukemia virus (FeLV) and feline immunodeficiency virus (FIV) are among the most common infectious diseases of cats. Although vaccines are available for both viruses, identification and segregation of infected cats form the cornerstone for preventing new infections. Guidelines in this report have been developed for diagnosis, prevention, treatment, and management of FeLV and FIV infections.
All cats should be tested for FeLV and FIV infections at appropriate intervals based on individual risk assessments. This includes testing at the time of acquisition, following exposure to an infected cat or a cat of unknown infection status, prior to vaccination against FeLV or FIV, prior to entering group housing, and when cats become sick.
No test is 100% accurate at all times under all conditions; results should be interpreted along with the patient’s health and risk factors. Retroviral tests can diagnose only infection, not clinical disease, and cats infected with FeLV or FIV may live for many years. A decision for euthanasia should never be based solely on whether or not the cat is infected.
Vaccination against FeLV is highly recommended in kittens. In adult cats, antiretroviral vaccines are considered non-core and should be administered only if a risk assessment indicates they are appropriate. Few large controlled studies have been performed using antiviral or immunomodulating drugs for the treatment of naturally infected cats. More research is needed to identify best practices to improve long-term outcomes following retroviral infections in cats.
Seroprevalence of feline leukemia virus and feline immunodeficiency virus infection among cats in North America and risk factors for seropositivity.
Levy JK, Scott HM, Lachtara JL, Crawford PC. J Am Vet Med Assoc. 2006 Feb 1;228(3):371-6. Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL 32610-0126, USA.
Objective: To determine seroprevalence of FeLV and FIV infection among cats in North America and risk factors for seropositivity.
Design: Prospective cross-sectional survey.
Animals: 18,038 cats tested at 345 veterinary clinics (n=9,970) and 145 animal shelters (8,068) between August and November 2004.
Procedure: Cats were tested with a point-of-care ELISA for FeLV antigen and FIV antibody. A multivariable random effects logistic regression model was used to identify risk factors significantly associated with seropositivity while accounting for clinic-to-clinic (or shelter) variability.
Results: 409 (2.3%) cats were seropositive for FeLV antigen, and 446 (2.5%) cats were seropositive for FIV antibody; 58 (0.3%) cats were seropositive for infection with both viruses. Multivariable analysis indicated that age, sex, health status, and cat lifestyle and source were significantly associated with risk of seropositivity, with adults more likely to be seropositive than juveniles (adjusted odds ratios [ORs], 2.5 and 2.05 for FeLV and FIV seropositivity, respectively), sexually intact adult males more likely to be seropositive than sexually intact adult females (adjusted ORs, 2.4 and 4.66), and outdoor cats that were sick at the time of testing more likely to be seropositive than healthy indoor cats (adjusted ORs, 8.89 and 11.3).
Conclusions and Clinical Relevance: Results suggest that certain characteristics, such as age, sex, health status, and lifestyle, are associated with risk of FeLV and FIV seropositivity among cats in North America. However, cats in all categories were found to be at risk for infection, and current guidelines to test all cats at the time of acquisition and again during illness should be followed.
Prevalence of infectious diseases in feral cats in Northern Florida.
Luria BJ, Levy JK, Lappin MR, Breitschwerdt EB, Legendre AM, Hernandez JA, Gorman SP, Lee IT. J Feline Med Surg. 2004 Oct;6(5):287-96. Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, 2015 S.W. 16th Avenue, Box 100126, Gainesville, FL 32610, USA.
Objectives of this study were to determine prevalence of infection in feral cats in Northern Florida with a select group of infectious organisms and to determine risk factors for infection. Blood samples or sera from 553 cats were tested with a panel of antibody, antigen or PCR assays.
Male cats were at higher risk for FIV, Mycoplasma haemofelis, and M. haemominutum. Infection with either FeLV or FIV was associated with increased risk for coinfection with the other retrovirus, M. haemofelis, or M. haemominutum. Bartonella henselae had the highest prevalence and was the only organism that did not have any associated risk for coinfection with other organisms.
Feral cats in this study had similar or lower prevalence rates of infections than those published for pet cats in the United States. Thus, feral cats assessed in this study appear to be of no greater risk to human beings or other cats than pet cats.
Prevalence of feline leukemia virus infection and serum antibodies against feline immunodeficiency virus in unowned free-roaming cats.
Lee IT, Levy JK, Gorman SP, Crawford PC, Slater MR. J Am Vet Med Assoc. 2002 Mar 1;220(5):620-2. Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville 32610, USA.
Objective: To determine prevalence of FeLV infection and serum antibodies against feline immunodeficiency virus (FIV) in unowned free-roaming cats.
Design: Cross-sectional serologic survey.
Animals: 733 unowned free-roaming cats in Raleigh, NC, and 1,143 unowned free-roaming cats in Gainesville, Fla.
Results: In Raleigh, overall prevalence of FeLV infection was 5.3%, and overall seroprevalence for FIV was 2.3%. In Gainesville, overall prevalence of FeLV infection was 3.7%, and overall seroprevalence for FIV was 4.3%. Overall, FeLV prevalence was 4.3%, and seroprevalence for FIV was 3.5%. Prevalence of FeLV infection was not significantly different between males (4.9%) and females (3.8%), although seroprevalence for FIV was significantly higher in male cats (6.3%) than in female cats (1.5%).
Conclusions and Clinical Relevance: Prevalence of FeLV infection and seroprevalence for FIV in unowned free-roaming cats in Raleigh and Gainesville are similar to prevalence rates reported for owned cats in the United States. Male cats are at increased risk for exposure to FIV, compared with female cats.
Effects of anesthesia and surgery on serologic responses to vaccination in kittens.
Reese MJ, Patterson EV, Tucker SJ, Dubovi EJ, Davis RD, Crawford PC, Levy JK. J Am Vet Med Assoc. 2008 Jul 1;233(1):116-21. Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL 32610, USA.
Objective: To determine the effects of anesthesia and surgery on serologic responses to vaccination in kittens.
Design: Prospective controlled trial.
Animals: 32 specific-pathogen-free kittens.
Procedures: Kittens were assigned to 1 of 4 treatment groups: neutering at 7, 8, or 9 weeks of age or no neutering. All kittens were inoculated with modified-live virus vaccines against feline panleukopenia virus (FPV), feline herpesvirus (FHV), and feline calicivirus (FCV) at 8, 11, and 14 weeks of age and inactivated rabies virus (RV) at 14 weeks of age. Serum antibody titers against FPV, FHV, and FCV were determined at 8, 9, 11, 14, and 17 weeks of age; RV titers were determined at 14 and 17 weeks of age.
Results: Serologic responses of kittens neutered at the time of first vaccination (8 weeks) were not different from those of kittens neutered 1 week before (7 weeks) or 1 week after (9 weeks) first vaccination or from those of kittens that were not neutered. In total, 31%, 0%, 69%, and 9% of kittens failed to develop adequate titers against FPV, FCV, FHV, and RV, respectively, by 17 weeks of age.
Conclusions and Clinical Relevance: Neutering at or near the time of first vaccination with a modified-live virus vaccine did not impair antibody responses in kittens. Many kittens that were last vaccinated at 14 weeks of age had inadequate antibody titers at 17 weeks of age. Kittens may be vaccinated in the perioperative period when necessary, and the primary vaccination series should be extended through at least 16 weeks of age.
Response of feral cats to vaccination at the time of neutering.
Fischer SM, Quest CM, Dubovi EJ, Davis RD, Tucker SJ, Friary JA, Crawford PC, Ricke TA, Levy JK. J Am Vet Med Assoc. 2007 Jan 1;230(1):52-8. Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL 32610, USA.
Objective: To determine whether administration of inactivated virus or modified-live virus (MLV) vaccines to feral cats at the time of neutering induces protective serum antiviral antibody titers.
Design: Prospective study.
Animals: 61 feral cats included in a trap-neuter-return program in Florida.
Procedures: Each cat received vaccines against feline panleukopenia virus (FPV), feline herpes virus (FHV), feline calicivirus (FCV), FeLV, and rabies virus (RV). Immediately on completion of surgery, vaccines that contained inactivated RV and FeLV antigens and either MLV or inactivated FPV, FHV, and FCV antigens were administered. Titers of antiviral antibodies (except those against FeLV) were assessed in serum samples obtained immediately prior to surgery and approximately 10 weeks later.
Results: Prior to vaccination, some of the cats had protective serum antibody titers against FPV (33%), FHV (21%), FCV (64%), and RV (3%). Following vaccination, the overall proportion of cats with protective serum antiviral antibody titers increased (FPV [90%], FHV [56%], FCV [93%], and RV [98%]). With the exception of the FHV vaccine, there were no differences in the proportions of cats protected with inactivated virus versus MLV vaccines.
Conclusions and Clinical Relevance: Results suggest that exposure to FPV, FHV, and FCV is common among feral cats and that a high proportion of cats are susceptible to RV infection. Feral cats appeared to have an excellent immune response following vaccination at the time of neutering. Incorporation of vaccination into trap-neuter-return programs is likely to protect the health of individual cats and possibly reduce the disease burden in the community.
Evaluation of medetomidine, ketamine and buprenorphine for neutering feral cats.
Harrison KA, Robertson SA, Levy JK, Isaza NM. J Feline Med Surg. 2011 Dec;13(12):896-902. Department of Large Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL 32610-0136, USA.
A combination of medetomidine (M, 100 μg/kg), ketamine (K, 10 mg/kg) and buprenorphine (B, 10 μg/kg), administered by intramuscular injection, was evaluated for spaying and castration (neutering) of feral cats (n = 101). Eleven animals (11%) required supplemental anesthesia (isoflurane by mask) to maintain an adequate plane of surgical anesthesia. Atipamezole (A, 125 μg/kg) was administered subcutaneously at the completion of surgery.
All cats recovered from surgery and were released the following day. A hemoglobin saturation (SpO(2)) value of < 95% was recorded at least once during anesthesia in all cats. This MKB combination can be used in a feral cat sterilization clinic, but isoflurane supplementation may be necessary.
Further research is indicated to determine the clinical significance of the low SpO(2) values associated with this anesthetic regimen.
Anesthetic and physiologic effects of tiletamine, zolazepam, ketamine, and xylazine combination (TKX) in feral cats undergoing surgical sterilization.
Cistola AM, Golder FJ, Centonze LA, McKay LW, Levy JK. J Feline Med Surg. 2004 Oct;6(5):297-303. Department of Small Animal Clinical Sciences, PO Box 100126, College of Veterinary Medicine, University of Florida, Gainesville, FL 32610, USA
Tiletamine (12.5 mg), zolazepam (12.5 mg), ketamine (20 mg), and xylazine (5 mg) (TKX; 0.25 ml, IM) combination was evaluated as an anesthetic in 22 male and 67 female adult feral cats undergoing sterilization at high-volume sterilization clinics. Cats were not intubated and breathed room air. Oxygen saturation (SpO(2)), mean blood pressure (MBP), heart rate (HR), respiration rate (RR), and core body temperature were recorded. Yohimbine (0.25 ml, 0.5 mg, IV) was administered at the completion of surgery.
TKX produced rapid onset of lateral recumbency (4+/-1 min) and surgical anesthesia of sufficient duration to complete surgical procedures in 92% of cats. SpO(2) measured via a lingual pulse oximeter probe averaged 92+/-3% in male cats and 90+/-4% in females. SpO(2) fell below 90% at least once in most cats.
MBP measured by oscillometry averaged 136+/-30 mm Hg in males and 113+/-29 mm Hg in females. MBP increased at the onset of surgical stimulation suggesting incomplete anti-nociceptive properties. HR averaged 156+/-19 bpm, and RR averaged 18+/-8 bpm.
Neither parameter varied between males and females or over time. Body temperature decreased significantly over time, declining to 38.0+/-0.8 degrees C at the time of reversal in males and 36.6+/-0.8 degrees C at the time of reversal in females.
Time from anesthetic reversal to sternal recumbency was prolonged (72+/-42 min). Seven cats (8%) required an additional dose of TKX to maintain an adequate plane of anesthesia at the onset of surgery, and this was associated with significantly longer recovery times (108+/-24 min).
Use of the anesthetic combination of tiletamine, zolazepam, ketamine, and xylazine for neutering feral cats.
Williams LS, Levy JK, Robertson SA, Cistola AM, Centonze LA. J Am Vet Med Assoc. 2002 May 15;220(10):1491-5. Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville 32610, USA.
Objective: To evaluate the use of the anesthetic combination tiletamine, zolazepam, ketamine, and xylazine (TKX) for anesthesia of feral cats at large-scale neutering clinics.
Design: Original study.
Animals: 7,502 feral cats.
Procedure: Cats were trapped by their caretakers for a feral cat neutering program from July 1996 to August 2000. The anesthetic combination TKX was injected IM into cats while they remained in their traps. Each milliliter of TKX contained 50 mg of tiletamine, 50 mg of zolazepam, 80 mg of ketamine, and 20 mg of xylazine. Females were spayed by veterinarians, whereas males were castrated by veterinarians or veterinary students. Yohimbine (0.5 mg, IV) was administered at the end of the procedure. Logs were kept of the individual drug doses, signalment of the cats, and any complications encountered. These data were analyzed retrospectively (1996 to 1999) and prospectively (2000).
Results: Of the 5,766 cats for which dosing records were complete, 4,584 (79.5%) received a single dose of TKX. The mean initial dose of TKX was 0.24 +/- 0.04 ml/cat, and the total mean dose of TKX was 0.27 +/- 0.09 ml. Overall mortality rate was 0.35% (26/7,502) cats, and the death rate attributable solely to potential anesthetic deaths was 0.23% (17/7,502) cats.
Conclusions and Clinical Relevance: The use of TKX for large-scale feral cat neutering clinics has several benefits. The TKX combination is inexpensive, provides predictable results, can be administered quickly and easily in a small volume, and is associated with a low mortality rate in feral cats.
Long-term fertility control in female cats with GonaCon™, a GnRH immunocontraceptive.
Levy JK, Friary JA, Miller LA, Tucker SJ, Fagerstone KA. Theriogenology. 2011 Nov;76(8):1517-25. Maddie’s Shelter Medicine Program, Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, Florida, USA. firstname.lastname@example.org.
The uncontrolled reproduction of free-roaming feral cats contributes to overpopulation and associated concerns regarding their welfare and impact on public health and the environment. Nonsurgical fertility control that could be administered to feral cats in the field would be a powerful tool for cat population control.
The objective was to test the efficacy and duration of activity of a single-dose GnRH immunocontraceptive vaccine (GonaCon™) on the fertility of adult female laboratory cats. Vaccinated cats (n = 15) received a single injection of vaccine containing a GnRH-KLH conjugate (200 μg) emulsified in a mycobacterial and oil adjuvant on study Day 0. Sham-treated cats (n = 5) received a single injection containing all vaccine components except the GnRH-KLH conjugate.
A breeding trial started on study Day 120. Vaccinated cats had a longer time to conception (median 39.7 mo) compared to sham-treated cats (4.4 mo; P < 0.001). A total of 93% of vaccinated cats remained infertile for the first year following vaccination, whereas 73, 53, and 40% were infertile for 2, 3, and 4 y, respectively. At study termination (5 y after a single GnRH vaccine was administered), four cats (27%) remained infertile.
The GnRH antibody titers declined more rapidly in short-term responding cats with < 2 y of infertility (n = 4), compared to long-term responding cats that experienced fertility control for >2 y (n = 11) (P < 0.05). Non-painful but persistent late-onset granulomatous injection site masses appeared 2 y after initial vaccination in five cats.
We concluded that GnRH immunocontraception is an ideal candidate for further development for feral cat control.
Contraceptive vaccines for the humane control of community cat populations.
Levy JK. Am J Reprod Immunol. 2011 Jul;66(1):63-70.
Maddie’s Shelter Medicine Program, College of Veterinary Medicine, University of Florida, 2015 SW 16th Avenue, Gainesville, FL 32610, USA. email@example.com. Abstract
Free-roaming unowned stray and feral cats exist throughout the world, creating concerns regarding their welfare as well as their impact on the environment and on public health. Millions of healthy cats are culled each year in an attempt to control their numbers. Surgical sterilization followed by return to the environment is an effective non-lethal population control method but is limited in scope because of expense and logistical impediments. Immunocontraception has the potential to be a more practical and cost-effective method of control.
This is a review of current research in immunocontraception in domestic cats. Functional characteristics of an ideal immunocontraceptive for community cats would include a wide margin of safety for target animals and the environment, rapid onset and long duration of activity following a single treatment in males and females of all ages, and sex hormone inhibition. In addition, product characteristics should include stability and ease of use under field conditions, efficient manufacturing process, and low cost to the user.
Two reproductive antigens, zona pellucida and GnRH, have been identified as possible targets for fertility control in cats.
- Zona pellucida, which is used successfully in multiple wildlife species, has achieved little success in cats. In contrast, immunization against GnRH has resulted in long-term contraception in both male and female cats following a single dose.
- GnRH is an ideal contraceptive target because it regulates pituitary and gonadal hormone responses in both males and females, thus suppressing nuisance behaviors associated with sex hormones in addition to preventing pregnancy. The responsiveness of cats to fertility control via GnRH suppression should encourage researchers and cat control stakeholders to continue efforts to optimize vaccines that induce multiyear contraception following a single dose in a high proportion of treated cats.
GnRH immunocontraception of male cats.
Levy JK, Miller LA, Cynda Crawford P, Ritchey JW, Ross MK, Fagerstone KA. Theriogenology. 2004 Sep 15;62(6):1116-30. Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL 32610, USA. firstname.lastname@example.org.
The development of nonsurgical contraceptives for cats may facilitate population control of the species. The purpose of this study was to investigate the utility of GnRH for immunocontraception of male cats. Male cats (n=12) were divided into groups of three and were immunized once with 0 (sham), 50, 200, or 400 microg synthetic GnRH coupled to keyhole limpet hemocyanin and combined with a mycobacterial adjuvant to enhance immunogenicity. GnRH antibody titer, serum testosterone concentration, and scrotal size were determined monthly.
At 6 months, semen was collected by electroejaculation and testes were examined histologically. GnRH antibodies were detected in all cats receiving GnRH vaccine by 1 month post-treatment and persisted throughout the study. No dose effect of GnRH was observed; titers were not different among cats treated with 50, 200, or 400 microg GnRH (P=0.5). Six of nine treated cats were classified as responders based on high GnRH antibody titers (>32,000).
By 3 months post-treatment, responder cats had undetectable testosterone concentrations and testicular atrophy. Nonresponder cats had GnRH titers of 4000-32,000 and testosterone concentrations intermediate between responder and sham-treated cats.
At 6 months, total sperm counts were similar for sham-treated cats (3.1+/-1.8 x 10(6) sperm) and nonresponder cats (3.4+/-1.6 x 10(6) sperm; P=0.7). Only one of the six responder cats produced sperm, none of which were motile. Combined testicular weights of responder cats (1.3+/-0.1 g) were lower than sham-treated controls (5.3+/-1.3 g; P=0.02) and nonresponder cats (2.9+/-0.3 g; P=0.02).
Histologic evaluation of the testes revealed that in responder cats, the interstitial cells that were present were pale and shrunken compared to the plump, polyhedral eosinophilic cells in sham-treated cats. GnRH responder cats had marked tubular atrophy with vacuolated Sertoli cells and a paucity of germ cells. Single-dose GnRH treatment resulted in testosterone concentrations and semen quality consistent with immunocastration in a majority of cats treated.
Developmental uterine anomalies in cats and dogs undergoing elective ovariohysterectomy.
McIntyre RL, Levy JK, Roberts JF, Reep RL. J Am Vet Med Assoc. 2010 Sep 1;237(5):542-6. Maddie’s Shelter Medicine Program, Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL 32610, USA.
Objective: To describe the characteristics and frequency of gross uterine anomalies in cats and dogs undergoing elective ovariohysterectomy.
Design: Prospective and retrospective case series.
Animals: 53,258 cats and 32,660 dogs undergoing elective ovariohysterectomy at 26 clinics in the United States and Canada during 2007.
Procedures: Clinics prospectively reported gross anomalies and submitted tissues from abnormal reproductive tracts identified during surgery. Records from a feral cat spay-neuter clinic were evaluated retrospectively.
Results: Suspected congenital anomalies of the uterus were identified in 0.09% (49/53,258) of female cats and 0.05% (15/32,660) of female dogs. Uterine anomalies identified included unicornuate uterus (33 cats and 11 dogs), segmental agenesis of 1 uterine horn (15 cats and 3 dogs), and uterine horn hypoplasia (1 cat and 1 dog). Ipsilateral renal agenesis was present in 29.4% (10/34) of cats and 50.0% (6/12) of dogs with uterine anomalies in which kidneys were evaluated. Mummified ectopic fetuses were identified in 4 cats with uterine anomalies. Both ovaries and both uterine tubes were present in most animals with uterine anomalies.
Conclusions and Clinical Relevance: Urogenital anomalies were twice as common in cats as in dogs. Identification of uterine developmental anomalies in dogs and cats should trigger evaluation of both kidneys and both ovaries because ipsilateral renal agenesis is common, but both ovaries are likely to be present and should be removed during ovariohysterectomy.
The Association of Shelter Veterinarians veterinary medical care guidelines for spay-neuter programs.
Looney AL, Bohling MW, Bushby PA, Howe LM, Griffin B, Levy JK, Eddlestone SM, Weedon JR, Appel LD, Rigdon-Brestle YK, Ferguson NJ, Sweeney DJ, Tyson KA, Voors AH, White SC, Wilford CL, Farrell KA, Jefferson EP, Moyer MR, Newbury SP, Saxton MA, Scarlett JM; Association of Shelter Veterinarians’ Spay and Neuter Task Force. J Am Vet Med Assoc. 2008 Jul 1;233(1):74-86. Section of Pain Medicine, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA.
As efforts to reduce the overpopulation and euthanasia of unwanted and unowned dogs and cats have increased, greater attention has been focused on spay-neuter programs throughout the United States. Because of the wide range of geographic and demographic needs, a wide variety of programs have been developed to increase delivery of spay-neuter services to targeted populations of animals, including stationary and mobile clinics, MASH-style operations, shelter services, feral cat programs, and services provided through private practitioners.
In an effort to ensure a consistent level of care, the Association of Shelter Veterinarians convened a task force of veterinarians to develop veterinary medical care guidelines for spay-neuter programs. The guidelines consist of recommendations for preoperative care (eg, patient transport and housing, patient selection, client communication, record keeping, and medical considerations), anesthetic management (eg, equipment, monitoring, perioperative considerations, anesthetic protocols, and emergency preparedness), surgical care (eg, operating-area environment; surgical-pack preparation; patient preparation; surgeon preparation; surgical procedures for pediatric, juvenile, and adult patients; and identification of neutered animals), and postoperative care (eg, analgesia, recovery, and release).
These guidelines are based on current principles of anesthesiology, critical care medicine, microbiology, and surgical practice, as determined from published evidence and expert opinion. They represent acceptable practices that are attainable in spay-neuter programs.