Dog and cat management through sterilization: Implications for population dynamics and veterinary public policies.
The present study aimed to compare different sterilization scenarios allowing the adoption of the most adequate strategy to control owned dog and cat population sizes as the official veterinary public policy for animal control in an urban area of Campinas municipality, Brazil. To achieve this goal, the vital parameters of the owned pet population were measured in a neighborhood of Campinas called Jardim Vila Olimpia through questionnaires used in two census studies performed in February 2012 and June 2013. Different hypothetical sterilization scenarios were compared with the scenario of a single sterilization campaign performed in the study area between the census studies. Using a deterministic mathematical model, population dynamics were simulated for these different scenarios. We have observed that for both owned dogs and cats, the impact on the population size achieved by a single sterilization campaign would be diluted over the years, equating to the impact achieved by the usual sterilization rate practiced before the sterilization campaign yearly. Moreover, using local and global sensitivity analyses, we assessed the relative influence on animal population evolution of each vital parameter used in the mathematical models. The more influential parameters for both species were the carrying capacity of the environment and sterilization rates of males and females (for both species). We observed that even with sterilizing 100% of the intact animals annually, it would not be possible to obtain proportions greater than 86% and 88% of sterilized dogs and cats, respectively, after 20 years due to the high introduction of new intact animals. There is no public dog and cat sterilization service in place in the city, and sporadic and local sterilization campaigns are performed with a prior communication to the owners to bring their animals to be sterilized in a selected veterinary facility. If a sterilization campaign was performed annually in the study area, it would have the most favorable cost effectiveness ratio after 20 years compared to the scenarios of 50% and 100% sterilization of intact animals annually. These results allowed the veterinary public policy stakeholders to make decisions based on scientific evidence to implement adequate control of dog and cat populations in urban areas, aiming to reduce zoonosis transmission to humans and other problems associated with uncontrolled animal populations.
Department of Preventive Veterinary Medicine and Animal Health, School of Veterinary Medicine, University of Sao Paulo, Brazil. Electronic address: dias@vps.fmvz.usp.br.
Ricardo Augusto
RA
Dias
Department of Preventive Veterinary Medicine and Animal Health, School of Veterinary Medicine, University of Sao Paulo, Brazil.
Oswaldo Santos
OS
Baquero
Department of Preventive Veterinary Medicine and Animal Health, School of Veterinary Medicine, University of Sao Paulo, Brazil.
Aline Gil Alves
AG
Guilloux
Department of Preventive Veterinary Medicine and Animal Health, School of Veterinary Medicine, University of Sao Paulo, Brazil.
Caio Figueiredo
CF
Moretti
Vigilância em Saúde, Prefecture of Campinas, Campinas, Brazil.
Tosca
T
de Lucca
Unidade de Vigilância em Zoonoses, Prefecture of Campinas, Brazil.
Ricardo Conde Alves
RC
Rodrigues
Unidade de Vigilância em Zoonoses, Prefecture of Campinas, Brazil.
Cláudio Luiz
CL
Castagna
Unidade de Vigilância em Zoonoses, Prefecture of Campinas, Brazil.
Douglas
D
Presotto
Vigilância em Saúde, Prefecture of Campinas, Campinas, Brazil.
Yury Cezar
YC
Kronitzky
Department of Preventive Veterinary Medicine and Animal Health, School of Veterinary Medicine, University of Sao Paulo, Brazil.
José Henrique Hildebrand
JH
Grisi-Filho
Department of Preventive Veterinary Medicine and Animal Health, School of Veterinary Medicine, University of Sao Paulo, Brazil.
Fernando
F
Ferreira
Department of Preventive Veterinary Medicine and Animal Health, School of Veterinary Medicine, University of Sao Paulo, Brazil.
Marcos
M
Amaku
D000818:Animals; D001938:Brazil; D002415:Cats; D002947:Cities; D004285:Dogs; D005260:Female; D008297:Male; D008962:Models, Theoretical; D009919:Orchiectomy / Q000331:legislation & jurisprudence / Q000706:statistics & numerical data / Q000662:veterinary*; D010052:Ovariectomy / Q000331:legislation & jurisprudence / Q000706:statistics & numerical data / Q000662:veterinary*; D010067:Ownership; D011156:Population Density; D011157:Population Dynamics; D011640:Public Policy
Cat; Cost-effectiveness; Dog; Population control; Sterilization