Summarizing Research on Companion Animal Population Dynamics and
Control Practices, and Exploring Factors Impacting Dogs’ Time to Adoption
in a Shelter System
by
Aileigh Kay
A Thesis
presented to
The University of Guelph
In partial fulfilment of requirements
for the degree of
Master of Science
in
Population Medicine
Guelph, Ontario, Canada
© Aileigh Kay, May, 2016
ABSTRACT
SUMMARIZING RESEARCH ON COMPANION ANIMAL POPULATION DYNAMICS
AND CONTROL PRACTICES, AND EXPLORING FACTORS IMPACTING DOG’S
TIME TO ADOPTION IN A SHELTER SYSTEM
Aileigh Kay Advisor:
University of Guelph, 2016 Dr. Jason B. Coe
A scoping review was conducted to identify all globally published literature investigating
population dynamics and control practices of companion animals. There were 7810 unique
citations initially identified, 869 articles (450 primary research and 419 reviews) were confirmed
relevant. Most articles were conducted in the United States (359; 41.3%) and the main focus was
on control practices (697; 80.2%). Among primary research articles, 204 (45.3%) investigated
reproduction control, identifying an opportunity for further knowledge synthesis efforts. A Cox
proportional frailty hazard analysis was conducted to determine factors that affect dogs’
(n=8,325) time to adoption within the British Columbia Society for the Prevention of Cruelty for
Animals’ shelter system, between January 2010 and July 2014. Results demonstrated surrender
reason, age, where animal was obtained, coat colour, breed, human population density of shelter
location and incoming year significantly influenced dogs’ time to adoption. Findings suggest
areas for targeted adoption promotion by shelters.
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ACKNOWLEDGEMENTS
I would not have been able to complete my thesis without the support and help from
many important and special people. First, I would like to thank my advisor Dr. Jason Coe,
throughout this process you provided not only an opportunity for me to conduct research but on-
going expertise, guidance and support, which I am extremely grateful for. During this process,
you also pushed me to improve my writing, thinking and research skills. I would also like to
thank you for the time and resources you dedicated to aid in my success. To my advisory
committee, to Dr. David Pearl specifically, thank you for providing extra time to help me
through the survival analysis statistics; it made statistics easier to complete and understand. I
appreciate your on-going patience. To Dr. Ian Young thank you for providing your expertise and
expanding my knowledge by teaching me different research methods. I appreciate the support
and advice you have provided.
Thank you to Nestlé Purina Pet Care Canada Chair in Communications for funding these
projects.
I would like to thank the British Columbia Society for the Prevention of Cruelty to
Animals (BC SPCA) for providing access to their database. I appreciate all the work and time
you dedicated to ensure all my questions were answered either through email correspondence or
phone calls.
These projects would not have been successful without the help of my colleagues Dr.
Kim Lambert and Rachel O’Connor. Dr. Kim Lambert, you provided excellent guidance for my
scoping review chapter. I appreciated your patience when I asked you question after question and
your willingness to help, it allowed this project to progress smoothly and successfully. Rachel,
words cannot begin to describe how thankful I am for all the work you have done. You helped
iv
with many aspects of the scoping review chapter and your dedication and hard work were vital to
this project’s success. I would also like to thank you both of you for your emotional support:
your advice, kindness and stories made this experience a little less stressful and way more
enjoyable.
To the many research assistants I had reading articles for me. I know reading article after
article and answering the same questions over again is not the most exciting work, but it was
greatly appreciated. Each one of you were an extremely important member of this research
project. I want to thank Chandi Priyanatha, you worked for me the longest. You were dedicated
to your work and you were flexible when it came to extending your work periods and flexible
with tasks that were assigned. All your hard work helped move this thesis along.
Friends, old and new, your support was one of the reasons why I made it through this
program. I met many amazing, intelligent and driven people while completing this program and
together we were able to be successful. You were there for all the ups and downs; to listen,
provide support and comfort, or just comfort food. You embraced my hedgehog obsession by
sharing photos and videos which always brightened my days. After I moved to Toronto, many of
you provided me with a place to stay; I was a travelling nomad and you definitely made
commuting a lot easier and more enjoyable. I enjoyed all the laughs and tears we shared. I was
truly blessed to have met each and every one of you and I am proud of all that we have
accomplished. Old friends, this is not the first time you have been there for me throughout my
educational career. You have provided unconditional support, a place to escape to when it was
necessary and when all I needed was some company. You always believed in me and words
cannot express how much that meant. You rock!
v
Lastly, I want to thank my parents and my sister. I am very grateful for all the love and
support you have provided during this journey. I appreciate your interest in my research and for
listening to my rants even though I know sometimes it sounded like complete gibberish to you.
You have always supported my ambition and goals even when I was not sure I could achieve
them. Your unwavering belief in me and my abilities made it possible to keep going; thank you
for always pushing me forward and keeping me well fed along the way.
vi
STATEMENT OF WORK DONE
Aileigh Kay designed the methodology and the statistical approach to analyze the results
for both the scoping review and quantitative study of this thesis with the advisement of Dr. Jason
Coe and cooperation of her advisory committee, Dr. Ian Young and Dr. David Pearl.
Chapter 1: Literature Review
Aileigh Kay wrote the literature review under the direction of Dr. Jason Coe. Carol Tinga
provided editorial coaching on this chapter. Dr. Ian Young and Dr. David Pearl contributed
additional feedback and revision recommendations.
Chapter 2: Scoping Review
The research question was derived through collaboration with Drs. Jason Coe and Kim Lambert.
Aileigh Kay wrote the scoping review protocol and developed review materials with support and
inputs from Dr. Jason Coe and Dr. Ian Young. The search string was created by Aileigh Kay and
lab colleague Dr. Kim Lambert, it was initially implemented by colleagues Dr. Kim Lambert and
Elpida Artemiou and later re-implemented by Aileigh Kay and Elpida Artemiou. Aileigh Kay
was responsible for citation management and deduplication. Relevance screening was completed
by Aileigh Kay and lab colleague Rachel O’Connor, relevant articles were procured by Aileigh
Kay, Rachel O’Connor and research assistant Chanditha Priyanatha. Data extraction was
completed by Aileigh Kay, Rachel O’Connor and research assistants: Chanditha Priyanatha, Lea
Nogueira Borden, Jennifer MacNicol, Olivia Pereira, Emilie Belage, and Luz Kisiel. Aileigh Kay
characterised and analysed the results with advice and feedback from Dr. Jason Coe, and Dr. Ian
Young. The first draft manuscript was written by Aileigh Kay. The manuscript was edited and
reviewed by Drs. Jason Coe, David Pearl, and Ian Young.
vii
Chapter 3: Quantitative Study: Survival Analysis
Dr. Jason Coe and Aileigh Kay worked together to determine the methodology with
contributions from Dr. David Pearl and Dr. Ian Young. Data were extracted and initially cleaned
and organized by Chanditha Priyantha with guidance from Aileigh Kay and Dr. Jason Coe. Dr.
David Pearl provided additional consultation on the survival analysis process and analysis.
Aileigh Kay recoded the data, prepared, completed and interpreted the results with the aid of Dr.
Jason Coe, and Dr. David Pearl. The first draft of the manuscript was written by Aileigh Kay.
The manuscript was reviewed and edited by Dr. Jason Coe throughout development. Additional
edits and comments were received from Dr. David Pearl and Dr. Ian Young.
Chapter 4: Conclusions
Aileigh Kay wrote the first draft of the conclusions with feedback and edits from Dr. Jason Coe.
Dr. Ian Young and Dr. David Pearl provided additional recommended edits and remarks.
viii
TABLE OF CONTENTS
CHAPTER ONE ...………………………………………………………………………………. 1
Introduction, Literature Review, Rationale and Objective……….……………………… 1
1.0 Introduction..…………………………………………………………………. 2
1.1 Literature Review…………………………………………………………….. 3
1.1.1 Number of owned and unowned companion animals……. 3
1.1.2 Role of companion animals in human lives……………… 4
1.1.3 Stakeholders……………………………………………… 8
1.1.4 International scope……………………………………… 10
1.1.4.1 Values…………………………………... 10
1.1.4.2 Laws…………………………………….. 11
1.1.4.3 Socio-Economics……………………….. 12
1.1.4.4 Climate………………………………….. 14
1.1.5 Control Practices………………………………………... 14
1.1.5.1 Spay and Neuter………………………… 15
1.1.5.2 Trap Neuter Release…………………….. 17
1.1.5.3 Non-Surgical Contraception…..……….. 19
1.1.5.4 Euthanasia………………………………. 22
1.1.5.5 Other Control Practices…………………. 23
1.1.6 Shelter Management……………………………………. 25
1.1.7 Characteristics of shelter animals being adopted or
euthanized………………………………………………. 29
1.1.8 Methodology……………………………………………. 32
1.2 Thesis Rationale…………………………………………………………….. 33
ix
1.3 Thesis Objectives…………………………………………………………… 34
References………………………………………………………………………. 35
CHAPTER TWO...……...……………………………………………………………………… 45
A Scoping Review of Published Research on the Population Dynamics and Control Practices of
Companion Animals……………………………….…………………………..……………….. 45
Abstract…………………………………………………………...…………………….. 46
Introduction………………………..……………………………………………………. 47
Methods……………………...……..……………………………………….................... 49
Review protocol, team, question and scope…………………………………….. 49
Search Strategy…………………………………………………………………. 50
Relevance Screening……………………………………………………………. 51
Article Procurement…………………………………………………………….. 52
Data Characterization and Extraction…………………………………………... 52
Review Management, Data Charting and Analysis…………………………….. 53
Results.................................................................................................................….......... 54
Descriptive characteristics of published research on population dynamics and
control practices………………………………………………………………… 54
Characteristics of Primary Research……………………………………………. 56
Discussion………………………………………………………………………………. 58
Conclusion…………………………………………………………………………….... 66
References……………………………………………………………………………….68
CHAPTER THREE.…………………………………………………….……………………… 92
Factors influencing time to adoption for dogs in a provincial shelter system in Canada….…… 92
x
Abstract.………………………………………………………………………...………. 93
Introduction…………….……………………………………………………………….. 94
Methods...……………………………………………………………………………….. 95
Description of Data Set…………………………………………………………. 95
Statistical Analysis…………………………………………………………….... 99
Results ….…………………………………………………………………………...… 100
Study Population………………………………………………………………. 101
The Effect of Shelter and Animal Characteristics on Length of Stay in the
Shelter………………………………………………………………………..... 102
Discussion……………………………………………………………………………... 104
Conclusions………………………………...………………………………………….. 113
References……………………………………………………………………………... 114
CHAPTER FOUR.…………………………………………………………………………….. 128
Conclusions………...………………………………………………………………….. 128
Summary of Findings………...………………………………………………………... 130
A Scoping Review of the Published Research on the Population Dynamics and
Control Practices of Companion Animals…………………………………….. 131
Factors Influencing Time to Adoption for Dogs in a Provincial Shelter System in
Canada…………………………………………………………………………. 132
Key Recommendations…………………………………….………………………….. 134
Thesis Limitations..….………………………………………………………………… 135
Future Directions for Research……….……………………………………………..… 136
References………………………………………………………………..……………. 139
APPENDIX A ……………………………..………………………………………………….. 141
A.1: Database Specific Search Strings………………………..…………………….... 142
xi
A.2: Relevance Screening Form……………………………………………………… 147
A.3: Data Extraction and Characterization Form…………………………………….. 152
A.4: Reference list of included 869 articles…….…………………………………..… 167
A.5: Description of non-English articles excluded from the study…........................... 219
A.6: Description of articles unable to obtain excluded from the study………………. 225
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LIST OF TABLES
2.1: Key definitions used in the relevance screening and data extraction form.......………....… 73
2.2: Descriptive characteristics of 869 primary research and review and commentary articles
investigating or discussing the issue of companion animal population dynamics…..….…. 75
2.3: Main areas of focus in the 869 primary research and review and commentary articles
investigating or discussing the issue of companion animal population dynamics……….... 77
2.4: Author-reported recommendations from the 869 primary research and review and
commentary articles investigating or discussing the issue of companion animal population
dynamics……………………...………………………………………………………….… 81
2.5: Methodological, outcomes and reporting characteristics of 450 primary research articles
investigating the issue of companion animal population dynamics……………………….. 84
2.6: Scoping review evidence map identifying the number of studies investigating control
practices among 301 primary research articles…………………………………………….. 86
3.1: Descriptive statistics of categorical independent variables on dog and shelter characteristics
among BC SPCA shelters, 2010–2014…………………………………………………… 117
3.2: Survival analysis main effects model of 8325 dogs that entered a BC SPCA shelter between
January 2010 and July 2014……………………………………………………………… 120
3.3: Significant categorical variable contrasts of the survival analysis of dogs that entered a BC
SPCA shelter between January 2010 and July 2014……………………………………... 123
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LIST OF FIGURES
2.1: Scoping review flow-chart………………………………………….……………………… 88
2.2: Frequency of published articles by year……………………………….…..………….…… 89
2.3: Scoping-review evidence map of the key aspects and themes among 450 primary-research
articles stratified by year of publication…………………...…………….………………… 90
2.4: Scoping-review evidence map of the key aspects and themes among 450 primary-research
articles stratified by study location.…………….………………………………..………… 91
3.1: Hazard ratios of the breed categories against the natural log of the length of time illustrating
the changing time to adoption of various breed categories relative to Border Collie
mixes................................................................................................................................… 124
3.2: Hazard ratios of the surrender reason categories against the natural log of time illustrating
the changing time to adoption of various surrender reason categories relative to
accommodation change......…………………………………………………………..…... 125
3.3: Hazard ratios of the original source categories against the natural log of time illustrating the
changing time to adoption of various original source categories relative to animal rescue 126
3.4: Hazard ratios of the population centres against the natural log of time illustrating the
changing time to adoption of various population centre categories relative to large
population centres…………………………………………………………..………….…. 127
2
1.0 Introduction
Humans have been keeping companion animals for centuries with the belief that animals
contribute to human survival, health and healing (Walsh, 2009a). The role of companion animals
in human lives has increased over time; humans have increased the amount of money they spend
on their pets, are willing to do more to care for their pets and many humans even see their pets as
family members (Walsh, 2009a). The increase in this interspecies relationship (commonly
known as the human-animal bond (HAB) (Hines, 2003)), has led to an increase in the amount of
research that focuses on this relationship (Blazina, Boyraz and Shen-Miller, 2011). Much
evidence exists demonstrating that a successful HAB has a variety of beneficial effects for the
human involved including social, psychological, physiological and physical benefits (Edney,
1995; Jennings, 1997; Walsh, 2009a; Friedmann and Son, 2009). A successful human-animal
bond can also provide physiological benefits for the companion animal involved (Kostarczyk and
Fonberg, 1982; McGreevy, Righetti and Thomson, 2005). Although many positive benefits have
been identified, evidence also exists that unsuccessful HABs can have a variety of negative
consequences, that mainly effect the companion animal involved and often contribute to
companion animal overpopulation (Kass et al., 2001; Kass, 2007).
To date, a specific definition for “companion animal overpopulation” does not exist within
published literature. Given the lack of consensus regarding a definition, for the purpose of this
thesis, the term companion animal population dynamics will be used. Companion animal
population dynamics, which in part influence “overpopulation”, are affected by many factors
including reproduction, control practices, abandonment, relinquishment, and the environment.
Ultimately, these factors can result in the development of unowned free roaming and feral
populations, which contribute to overcrowded shelters. Overcrowded shelters can result in
3
negative outcomes for the animals in the shelters including increased stress, disease spread and
potentially lead to decreased adoptions (Hurley, 2005). Methods that have been identified to
prevent overcrowding are limiting admissions, euthanasia, and various approaches for decreasing
length of stay for each animal (Hurley, 2005). A variety of ownership practices can contribute to
companion animal population dynamics. For example, allowing pets to roam freely and choosing
not to spay and neuter them can lead to unwanted pregnancies. In addition, different ownership
and cultural practices can lead to differences in accepted management strategies and
interventions that can be used to control free roaming and feral animal populations.
Companion animal population dynamics is complex and affects countries worldwide, with many
different stakeholders being invested and interested in addressing the topic. As such, a variety of
control interventions have been attempted and researched. Stakeholders including public health
professionals, animal welfare professionals, and ecologists/conservationists have approached the
issue from different perspectives largely influenced by different objectives, resulting in different
recommendations for intervention.
1.1. Literature Review
1.1.1. Number of owned and unowned companion animals
Companion animals, mainly dogs and cats are commonly kept around the world. It was estimated
that in the United States in 2012 there were 70 million owned dogs and 74 million owned cats
(AVMA, 2012). In 2011, there were an estimated 5.9 million dogs and 7.9 million cats owned in
Canada (CVMA, 2011). Despite the difference in total numbers, the percentage of dogs and cats
owned in these two countries are similar. It has been reported that 36.5% of households in the
United States (AVMA, 2012) and 35% of households in Canada own a dog (CVMA, 2011). Also
30.4% of American households (AVMA, 2012) and 38% of Canadian households own a cat
4
(CVMA, 2011). In 2014, 9 million dogs and 7.9 million cats were owned in the United Kingdom
(U.K.) (PFMA, 2014). The percentage of dogs and cats owned in the U.K. is less compared to
Canada and the United States with 24% of households owning a dog and 18% owning a cat in
2014 (PFMA, 2014). Jayakumar (1997) completed a survey (year not specified), which estimated
there is 1 owned dog for every 11 households in India.
While the prevalence of companion animal ownership is important to know, it is perhaps more
important to know the population size of owned and unowned free roaming populations because
of their impact on companion-animal population dynamics. However, obtaining the latter can be
difficult. Studies have used community member surveys (Brooks, 1990; Levy et al., 2003a;
Toukhsati, et al., 2012; Otolorin, Umoh and Dzikwi, 2014) and various surveillance methods
(Jayakumar, 1997, MengChih et al., 2010; Hiby et al., 2011; Punjabi et al., 2012; Otolorin,
Umoh and Dzikwi, 2014; Tenzin et al., 2015) to estimate the size of owned and unowned, free-
roaming companion animal populations. The American Society for the Prevention of Cruelty to
Animals (ASPCA) (2014) stated that twice as many strays enter their shelters compared to
relinquished animals. Also, they estimated (methods not stated) that there were approximately 70
million stray cats in the United States (year not stated), but no estimation was provided for stray
dogs (ASPCA, 2014). The Canadian Federation of Humane Societies (CFHS) (2015a) stated that
53% of cats and 45% of dogs entering their shelters were stray in 2014. It is evident that there is
a large presence of companion animals, including free roaming and unwanted animals; however,
many countries likely have inaccurate estimates of their overall companion animal population
size since obtaining accurate data can be difficult.
1.1.2. Role of companion animals in human lives: benefits and consequences
5
Companion animals have been a common part of society for hundreds of years with a changing
role over recent decades, where obtaining companion animals for companionship and not
function has become more common (Grier, 2006; Walsh, 2009a). Many factors have contributed
to this change including increased wealth (in America), changes in demographics, the desire to
follow popular trends and curiosity of animal ownership (Grier, 2006). In the United States, 95%
of pet owners considered their pet as a friend and 87% considered their pet as a family member
(Walsh 2009a). Similarly, in the United Kingdom (U.K.), over 90% of pet owners considered
their pet as a family member (McNicholas et al., 2005). This type of relationship between the
owner and companion animal is called the human-animal bond (HAB) and has become widely
accepted over the past 30 years (Hines, 2003). Pet owners have stated that they share an
unconditional love with their pet and that their pet makes them feel safe (Rew, 2000; Walsh
2009b; Zilcha-Mano, Mikulincer and Shaver, 2011). For example, Rew (2000) interviewed
homeless youth and one youth stated that “dogs were companions that could provide safety,
unconditional love, and a reason to keep going because they needed care in return.” A study
comparing the feeling of security in human (romantic) relationships to pet relationships, found
participants felt less secure in their romantic relationships compared to their pet relationships
(Beck and Madresh, 2008). Furthermore, 52% of participants (N=182) strongly agreed with the
statement “I know my pet really loves me” compared to 39% of participants who strongly agreed
with the statement “I know my partner really loves me” (Beck and Madresh, 2008).
A positive bond can provide many health, social, physical, and psychological benefits for the
owner (Edney, 1995; Jennings, 1997; Walsh, 2009a; Friedmann and Son, 2009). A companion
animal can be part of an owner’s support system providing as much social support as a parent or
sibling (McConnell et al., 2011). Pet owners have been found to receive greater fulfillment of
6
their social needs from their pets and to be less lonely, happier, experience less stress
(McConnell et al., 2011), have greater self-esteem (Edney, 1995; McConnell et al., 2011) and
have fewer minor health problems (Serpell, 1991; Edney, 1995) compared to non-pet owners.
These results agree with a study examining the influence of owning a pet on stressful life events
and doctor services in elderly citizens. The study was a one year prospective study that
implemented telephone interviews (or face-face when necessary) every two months. The authors’
found that elderly pet owners had less stressful life events and less contact with doctors
compared to non-pet owners (Siegel, 1990). Furthermore, results supported that single
individuals with pets had fewer doctor visits, took less medication and were less lonely than
single individuals without pets (Zasloff and Kidd, 1994; Heady, 1999). Owning a pet can
increase physical activity (Siegel, 1990; Serpell, 1991; Edney, 1995; Brown and Rhodes, 2006),
as dog owners walk significantly more than non-dog owners (Serpell, 1991; Brown and Rhodes,
2006). In a qualitative study, a homeless youth expressed that owning a dog got them up for
exercise, which made them feel healthier (Rew, 2000).
Not all research has found a positive association between pet ownership and health benefits. A
study conducted on 60-64 year olds in Australia found that pet owners/carers were significantly
more depressive, had worse physical health, and were more likely to use pain relief medication
than non-pet owners/carers (Parslow et al., 2005). The pet owners/carers also had higher levels
of psychoticism than non-pet owners/carers. Participation was based on whomever was the
primary carer of the animal and not on pet attachment (Parslow et al., 2005). In Australia,
Parslow and Jorm (2003) conducted a cross-sectional study on pet ownership and cardiovascular
disease using a random sample of participants from two age groups, 40-44 years old and 60-64
years old. The authors’ found that pet owners had higher diastolic blood pressure, BMI and
7
increased risk of smoking than non-pet owners. As the study was cross-sectional, a temporal
pattern could not be determined. The authors’ suggested that the increased health risk could be
linked to the different levels of hypertensive risk factors (weight, alcohol consumption, smoking
and physical activity) that are indirectly associated with pet ownership (Parslow and Jorm,
2003).
Domesticated animals are not seen to be companion animals by everyone. A number of
individuals consider domesticated animals to be nuisances, especially free roaming animals
(Fielding and Mather, 2001). Free roaming and feral colonies can cause many public health and
ecological issues including predation on native species, the spread of disease, and attacks on
humans. Slater (2008) investigated public perceptions of free roaming dogs and cats in Italy, and
90% of respondents said they were an issue. A study conducted in the Bahamas investigating
complaints on free roaming and feral companion animal populations found that 88% of
Bahamians thought stray dogs were a nuisance and were worried about disease (Fielding and
Mather, 2001). In El Paso, Texas, 97% of households reported free roaming dogs were an issue
and 84% of households were worried about their own safety (Poss and Bader, 2007). Gunther et
al., (2015) conducted a study concerning the number of free-roaming cat complaints filed in five
cities in Israel during 2007 to 2011. In those years, a total of 101,415 complaints were reported
which included carcasses (55%), cat injuries (16%), kittens (11%), cats invading buildings
(10%), parturition (5%) and cat aggression towards humans (3%). The authors believed that
aggression and cats invading buildings could present public health hazards (Gunther et al.,
2015). Incidents of aggression have also been reported for free roaming dogs with attacks
occurring more frequently among youth under 20 years old (Sriaroon, 2006; Farnworth et al.,
2012; Lone et al., 2014; Jain and Jain, 2014). Dog attacks have been shown in a study to lead to
8
an increase in anxiety disorders of children in Kashmir, India (Lone et al., 2014). In addition,
more than 99% of human rabies cases are transmitted from dogs (with canine rabies being most
prominent in developing countries) (WHO, 1992), and dog attacks can lead to human deaths
either due to the transfer of rabies or due to the severity of the attack. Despite the many benefits
that owning companion animals can provide humans, free roaming companion animals have the
ability to severely impact human health and safety.
1.1.3. Stakeholders
Due to the difference in how companion animals are viewed and the impacts they can have,
many different stakeholders are interested in companion animal population dynamics including
animal welfare professionals, ecologists/conservationists, and public health professionals. A
study conducted in Hawaii, in 2011, involved the distribution of a survey to stakeholders
(n=5,407) to determine their perceptions on how feral cat colonies should be controlled (Lohr
and Lepczyk, 2014). The survey responses on cat colony control indicated that 78.2% of all
respondents believed cats should be removed permanently (i.e. euthanized) from areas with
threatened or endangered fauna (Lohr and Lepczyk, 2014). When these results were further
refined, accounting for stakeholders’ perspectives, almost all conservationists (98.1%) agreed
cats should be euthanized, while only 35.5% of animal welfare professionals believed euthanasia
was necessary, with 41.1% stating relocation was the best answer. Similarly, cat colony feeders
responded with 43.5% for euthanasia and 35.1% for relocation (Lohr and Lepczyk, 2014). The
American Veterinary Medicine Association’s (AVMA) Committee on Environmental Issues
(CEI) stated that maintenance of free roaming colonies through trap neuter release (TNR) does
not stop the predation on native species including birds and small mammals and does not
improve cats’ suffering (Barrows, 2004). They also support humane elimination of feral cat
9
colonies and laws that keep cats indoors and prevent the feeding of feral cat colonies (Barrows,
2004). An opinion piece of environmental conservationists against TNR expressed the belief that
euthanasia is more humane than allowing cats to live in poor health conditions. The authors
stated TNR allowed cats to return to these poor living conditions and likened it to “cat hoarding
without walls”. The authors then further stated that if animal welfare professionals are against cat
hoarding they should not support TNR (Lepczyk et al., 2010).
A study comparing stakeholders’ views (TNR groups, Audubon groups
(conservationists/ecologists) and the general public) on free roaming cats and the control
practices that should be used, found that TNR group members supported TNR (77%) and that
many of the TNR members did not support the implementation of long-term no kill shelters
(18% of TNR members supported long-term no kill shelters) (Wald, 2012). TNR group members
did not believe that cats kill wildlife and believed that cats should have access to outdoors.
Compared to Audubon group members and the general public, TNR group members had
significantly more positive feelings towards outdoor cats (Wald, 2012). In contrast, the Audubon
group members supported cat confinement and believed that cats competed with wildlife and
spread disease to wildlife. Most of the Audubon members supported TNR (49%). Compared to
members of TNR groups and the general public, a higher percentage of Audubon group members
supported the implementation of no kill shelters. As well as, a higher percentage of Audubon
group members supported trapping and euthanizing compared to TNR members and the general
public (Wald, 2012).
Although public health professionals are stakeholders in companion animal population
dynamics, their position is not as prominently evident in the literature on the topic of free-
roaming companion animals. However, several studies have investigated the role companion
10
animals play in the spread of zoonotic diseases (Kamoltham et al., 2003; Chomel, et al., 2006;
Macpherson, C.N.L., 2013; Dabritz and Conrad, 2010). Stakeholders have very different views
on companion animal population dynamics. As a result, achieving collaboration and determining
control methods that will please all interested parties and lead to successful control of free
roaming and unwanted companion animals is challenging.
1.1.4. International Scope
Location can affect companion animal population dynamics. Different areas around the world
face different societal problems. Understanding companion animal population dynamics is of
international interest, as a result control practices of free roaming and unwanted companion
animals need to consider country specific factors. Described below are some studies to
contextualize and consider this topic within its international scope.
1.1.4.1. Values
Different cultures and cultural values around the world result in different ownership practices,
and considerations concerning management of population dynamics of free roaming companion
animals. In the Bahamas, there are purebred dogs and potcakes (local mongrels), and their
perceived value is different (Fielding and Mather, 2001; Fielding, 2010a; Fielding, 2010b). A
study conducted by Fielding (2010a) on female dogs that had been bred (during the year prior)
found that purebreds were more likely to be kept inside or in an enclosure, and owners were
more likely to breed purebred dogs on purpose for the sale of puppies compared to potcakes.
Owners of purebred dogs were also more likely to plan on rebreeding their dogs compared to
potcake owners (Fielding, 2010a). Potcakes are often considered of no value (Fielding and
Mather, 2001; Fielding, 2010a; Fielding, 2010b), and although they are more likely to roam
11
freely (Fielding, 2010a), it has been suggested that they contribute less to population dynamics
because they are more likely to be spayed or neutered compared to purebreds (Fielding, 2010b).
A telephone survey conducted in Taiwan by Hsu, Severinghaus and Serpell (2003) determined
that Taiwanese individuals are less likely to pay for a dog from a pet store and more likely to
acquire a stray dog from the street. Taiwanese dogs are almost as likely to be obtained for
security/guarding purposes (47.3%) or fun (45.6%) as for companionship (41%) (Hsu,
Severinghaus and Serpell, 2003) unlike the United States and the U.K. where the majority of
owners view their pets as friends and family members (McNicholas et al., 2005; Walsh, 2009a).
The reason for obtaining a dog in Taiwan also affected how the dog was housed; it is common
practice to keep dogs obtained as guard dogs indoors and confined, while dogs kept for
companionship were kept indoors but unconfined. Further, individuals who were found to have
obtained a dog because they felt bad for the animal were more likely to keep the dog outdoors
(Hsu, Severinghaus and Serpell, 2003). The authors’ believed that the human-animal bond in
Taiwan is less prevalent than in Western countries. Yet, Taiwan’s cultural and religious beliefs
discourage euthanasia of unwanted animals (Hsu, Severinghaus and Serpell, 2003) adding
another cultural dimension to population dynamics.
1.1.4.2. Laws
Laws have been implemented around the world to help combat free roaming and unwanted
companion animals. Certain laws have been established that reflect the country’s societal values.
The Czech Republic has a law that states euthanasia of stray animals is only allowed in
conditions that would impose permanent suffering such as weakness, terminal illness, serious
injury, genetic or congenital defect, overall exhaustion, or old age (Voslářá and Passantino,
2012). Similarly, Italy has a no kill policy that has been in place since 1991 (Natoli et al., 2006;
12
Voslářá and Passantino, 2012). Voslářá and Passantino (2012) further explained Italy’s law
stating that a captured dog or cat cannot be killed unless they are “seriously or incurably ill or
proven to be dangerous.” The Czech Republic and Italy implemented these laws as part of a
treaty that 22 European countries signed called the European Convention for the Protection of
Pets. This treaty aimed to improve animal welfare and reduce the number of stray animals.
Despite the implementation of these laws, animals are still being abandoned in the Czech
Republic, and in Italy there are still concerns regarding human health, animal welfare and social
costs associated with free roaming and unwanted companion animals (Voslářá and Passantino,
2012). The authors stated that these laws will not change the situation alone, public education on
responsible ownership practices needs to be included. Voslářá and Passantino (2012) further
stated cultures and cultural values need to be consider when implementing laws around
companion animal control. In Hawaii, California and Florida, it is illegal to abandon animals
and feed stray animals (Winter, 2004). In addition, unlike the European countries noted above,
in North America, there are at least two types of shelters, no kill and traditional. No kill shelters
only euthanize for behavioural and medical reasons (THS, 2013), while traditional shelters are
able to euthanize healthy surrendered animals for capacity reasons alone (CFHS, 2015a). For
stray or free roaming animals traditional shelters cannot euthanize until the mandatory holding
time (determined by the municipal code) lapses to aid in the return of lost animals to their
owners. For example, according to the Toronto municipal code, the largest city in Canada, a dog
at large that is seized and is not redeemed after 5 days becomes property of the city and the city
can choose to have the dog euthanized (City of Toronto, 2013).
1.1.4.3. Socio-Economics
13
Samoa has one of the highest reported rates of ownership of dogs in the world at 88% of
households (Farnworth et al., 2012). Farnworth et al. (2012) interviewed 327 inhabitants of
Samoa to determine their attitudes towards free roaming dogs; 75% of respondents believed dogs
are important to Samoa, yet only 16% had received any education about dogs. The results
indicated 46% of respondents believed female dogs should go through at least one litter. Despite
56% of respondents stating that it is important to sterilize their dogs, the sterilization rate is only
19% (Farnworth et al., 2012). Veterinary care is limited in Samoa and 52% of respondents
reported cost was a factor in their decision whether or not to sterilize their dog(s) (Farnworth et
al., 2012). Haiti also suffers from a large population of dogs, similar to Samoa, and its low
neutering rate is likely due to limited access to veterinary care and the cost of neutering (Fielding
et al., 2012). A study conducted in Israel investigating cat owner’s attitudes and behaviour
towards free roaming cats sent out a questionnaire. The results indicated that respondents from a
lower than average income bracket believed neutering to be cruel compared to respondents in the
above average income bracket (Finkler and Terkel, 2012). This study also found that respondents
with a lower education level were significantly more likely to believe free roaming cats were not
an issue and more likely to feed them compared to individuals of a higher education level
(Finkler and Terkel, 2012). Furthermore, a study conducted in Nigeria found that the proportion
of respondents that confined their dogs and castrated them differed between literacy levels. The
results indicated that 100% of illiterate (n=103), 88.5% of semi-illiterate (n=96) and 79.6% of
literate (n=59) respondents did not confine their dogs, and 61.1% of illiterate, 87.5% of semi-
illiterate and 98.3% of literate respondents castrated their dogs (Eze and Eze, 2002). Moreover, a
Canadian study conducted on free roaming cats by Flockhart, Norris and Coe (2016) found that
as median income increased the free roaming cat density decreased. It was suggested that income
14
level therefore impacts sterilization rate, number of owned cats and cats’ access to outdoors
(Flockhart, Norris and Coe, 2016).
1.1.4.4. Climate
Temperature can also have an impact on the population dynamics of free roaming companion
animals. Colder climates are associated with decreased survival of free roaming cats and a
decrease in the number of estrus cycles a cat has per year (Gunther and Terkel, 2002). One study
inferred that the temperate climate in Tel Aviv, Israel allows for cats to achieve their maximum
reproductive rates in cats (Finkler and Terkel, 2012). Lohr, Cox and Lepczyk (2012) reached a
similar conclusion stating that Hawaii’s free roaming cat issue may be due to its tropical climate.
A study conducted on stray dogs in the tropics found that female dogs were able to ovulate and
exhibit estrus all year round, yet in months with high temperatures and humidity the frequency of
estrus decreased (Ortega-Pacheco et al., 2007).
There are many factors to consider when addressing companion animal population dynamics,
and not every country views free roaming and unwanted companion animals in the same way.
Before implementing a control practice, the public’s beliefs, attitudes and ownership practices
need to be taken into account, as well as environmental and socioeconomic factors for a program
to be successful.
1.1.5. Control Practices
Control practices play an important role in companion animal population dynamics, many
different practices have been implemented to control free roaming (owned and unowned) and
unwanted companion animals. Control practices are implemented depending on the outcome of
interest, which can vary between stakeholders. Overall, it is evident that the literature does not
15
support the use of one particular control practice and suggests combinations of control practices
may be more successful.
1.1.5.1. Spay and Neuter
Spay and neuter is one of the most common control methods used for reproduction control, and
is implemented in a variety of ways. Surgically removing the gonads (i.e., spay and neuter) is the
most successful method to prevent pregnancy in dogs and cats (Olson et al., 1986; Anderson,
1992). It is believed that spaying and neutering also has a variety of health benefits (e.g., reduced
chance of uterine disease and androgen-dependent diseases) (Olson et al., 1986; Anderson, 1992)
and results in behavioural changes (e.g., less aggression and less roaming) (Olson et al., 1986;
Root Kustritz, 2012). Historically for an owned pet, it has been recommended that the animal is
spayed or neutered at approximately 6 months of age (Olson et al., 1986). To get animals out of
shelters as quickly as possible and to combat unwanted pregnancies, early age (also known as
pre-pubertal or pediatric) spaying and neutering has been more recently introduced (Olson, Root
Kustritz and Johnston, 2001; Bushby, 2012). Early age spaying and neutering generally occurs
between 6 to 14 weeks of age and before the animal goes through puberty (Stubbs and
Bloomberg, 1995). There is a lot of disagreement in the literature as to whether early spaying and
neutering is safe. A study conducted by Spain et al. (2004) on the medical and behavioural
conditions of 1,659 adopted dogs that were spayed or neutered at either an early age or the
traditional age, found an increased rate of cystitis, hip dysplasia and urinary incontinence, and a
decreased rate of overweight body scores in the dogs that received early aged spaying and
neutering (Spain et al., 2004). In the study, dogs’ spayed or neutered early in life also showed an
increased incidence of developing noise phobias and sexual behaviours, and a decreased
incidence of escaping behaviours, urination in the house and separation anxiety (Spain et al.,
16
2004). Other behaviours affected by early age spaying and neutering were sex specific, with
early-age neutered males showing increased aggression, a greater probability of barking at
strangers or visitors, and excessive barking in general (Spain et al., 2004). Another study
comparing traditional spay and neuter to early spay and neuter, in which all dogs were followed
for 4 years, found that early spay and neuter did not increase behavioural problems, but early
spay and neuter were associated with higher incidences of infectious diseases (parvoviral
enteritis and upper respiratory infections)(Howe et al., 2001). The study also found no increased
incidence of hip dysplasia, musculoskeletal disorders, urinary incontinence and less
gastrointestinal problems (Howe et al., 2001). Although these results are contrary to the previous
study, Spain et al. (2004) speculated the increase in hip dysplasia may not warrant much concern
since it was reported based on signs such as arthritis, and some dogs were diagnosed at an early
age when this diagnosis is often unreliable. Further, despite the increase in cystitis reported, no
more than 2 episodes were reported for females that underwent early age spaying suggesting
long-term effects are unlikely (Spain et al., 2004). This could explain some of the differences in
the results found between the two studies. Obesity was also not found to be associated with early
spaying and neutering in the study by Howe et al. (2001), however it relied on the owner’s
perception of their dog being overweight, which may not be reliable (Howe et al., 2001).
Similarly among cats, two separate studies have found no behavioural differences (Stubbs et al.,
1996; Porters et al., 2014a) and no body weight composition differences as well as normal
skeletal development (Stubbs et al., 1996) between early aged and traditional aged spays and
neuters. Howe et al. (2000) conducted a long term study comparing the effects of early spay and
neuter (less than 24 weeks of age, N=188) to traditional spay and neuter (at 24 weeks of age or
older, N=75) in shelter cats. The results indicated that there was no difference in incidences of
17
infectious diseases (feline leukemia, feline immunodeficiency virus, viral enteritis, feline
infectious peritonitis and spirochetes causing diarrhea or upper respiratory infections), as well as
no differences in gastrointestinal, musculoskeletal and cardiopulmonary problems between cats
sterilized at an early or traditional age. There were also no differences in incidences of
destructive behaviour, inappropriate elimination and other behaviour problems (Howe et al.,
2000). Howe et al. (2000) found that cats sterilized at the traditional age had higher incidences of
urinary problems compared to cats sterilized early in life.
Early spay and neuter programs remain controversial. A commentary written by Bushby (2012)
stated that many American veterinarians are against early spays and neuters. However, it was
also stated that despite the opposition towards early spays and neuters, many American
veterinarians acknowledge that they are “easier, faster, and result in quicker recoveries”
(Bushby, 2012). Porters et al.’s (2014b) study offers support toward this belief. In this study
kittens, were spayed and neutered at either an early age (8-12 weeks) or the traditional age (6-8
months), and surgical times were significantly shorter for early spays and neuters compared to
traditional (Porters et al., 2014b).
1.1.5.2. Trap Neuter Release (TNR)
TNR is another type of control practice that has been implemented to control free roaming and
feral colonies of companion animals. Studies conducted on TNR have produced mixed results on
whether this type of program works. A study conducted in Florida on feral cats found that
although the original population size decreased with TNR, animals being abandoned or other
stray cats being attracted to food provisions counteracted the effect by replacing the cats that had
died or migrated out of the population after TNR (Castillo and Clarke, 2003). A theoretical
18
model conducted based on the Feral Cat Coalition trapping data across San Diego County,
California (1992-2003) and the Operation Catnip Inc. trapping data in Alachua County, Florida
(1998-2004) by Foley et al. (2005) found similar results in that the model indicated TNR did not
reduce the feral cat population size or decrease the number of females becoming pregnant. In
another study, Zaunbrecher and Smith (1993) suggested that neutering is an alternative to
eradication programs. The authors conducted a TNR program on a population of 41 feral cats.
During the 36 months follow-up period after the TNR program was initiated no kittens were
born, the health of the colony improved and there was a low turnover rate with a final population
of 36 cats at the end of the follow-up period (Zaunbrecher and Smith, 1993). Also during the
study period 10 cats died or went missing, but six new cats were added to the colony during the
last 18 months; the authors speculated that migration and abandonment of the cats could explain
the addition, but believed abandonment was more likely (Zaunbrecher and Smith, 1993). In
comparison, a study by Levy et al. (2003b) found that TNR can lead to long term reduction of
free roaming cats. The organization Friends of Campus Cats implemented a trap, neuter and
return program at the University of Central Florida from 1991 to 1996 (Levy et al., 2003b).
There were originally 155 cats in the colony and after adoption, euthanasia, deaths and
disappearances by 1996 there were 68 cats left (Levy et al., 2003b). The study continued for
another six years and by the end there were only 23 cats left in the colony (Levy et al., 2003b).
Levy et al. (2003b) stated no kittens were seen after 1995 and any new cats to the colony (either
stray or abandoned) were sterilized. Construction on the University campus is common and can
affect cat habitats (Levy et al., 2003b), which could have limited the number of cats living on or
immigrating to campus explaining to the success of this TNR program. Levy et al. (2003b) also
19
included an adoption program for the socialized cats, which increased the rate of decline of the
population.
1.1.5.3. Non-Surgical Contraception
More recently, non-surgical contraception methods have become popular as a method to control
unowned free roaming companion animals. Many different types have been designed and tested
in labs since the year 2000, however, not all have been approved for broader use.
Immunocontraception is a form of non-surgical contraception with research being focused on
two main types: gonadotropin-releasing hormone (GnRH) and zona pellucida (ZP). Research
conducted on ZP has found mixed results among species, ZP as an immoncontraceptive shows
promise in dogs, yet has not been successful in controlling reproduction in cats. Levy et al.
(2005) tested porcine ZP (pZP) vaccines on fifteen cats and completed a breeding trial, all cats
became pregnant proving the vaccine to be ineffective. Similarly, a study conducted on SpayVac,
a pZP vaccine, found that all cats showed signs of estrus and it did not have an effect on the
number of kittens born (Gorman et al., 2002). Results showed that the vaccine did not interact
with the targeted tissues and did not produce a titer in the cats (Gorman et al., 2002). Another
study testing different feline ZP sub-unit vaccines, instead of pZP, found an increase in
unsuccessful pregnancies in the ZPA-DNA vaccine and in the ZPB+C DNA vaccine, but the
study had a small sample size (n = 7 and n = 5, respectively) and the results were not statistically
significant (Eade, Robertson and James, 2009). Research has shown that dogs do react to either
crude or pure pZP (Mahi-Brown et al., 1985). The study conducted by Mahi-Brown et al. (1985)
found that female dogs vaccinated with pZP became infertile when the vaccine was combined
with an adjuvant. The authors do suggest that caution should be applied as the immunization also
caused steroid changes leading to abnormal estrus cycles and the authors could not explain the
20
mechanism behind these changes (Mahi-Brown et al., 1985). In a more recent study, four female
dogs were immunized using E. coli expressing recombinant dog ZP3-DT, the results of which
indicated fertility was blocked, however the dogs were injected 6 to 7 times over a span of a year
to achieve vaccine efficacy (Srivastava et al., 2002). Applying this in a practical situation would
be difficult as recapturing a feral dog or keeping a feral dog for a year period is unfeasible.
GnRH is a hormone that has been researched for immunocontraception methods as well.
Samoylov et al. (2012) conducted an experimental study in mice using dog and cat anti-GnRH
sera to determine if commercial phage-GnRH peptide conjugates could stimulate an immune
response. The researchers observed that anti-GnRH antibodies were created. This immune
response caused sterility by neutralizing antibodies, suggesting potential use for feral population
control (Samoylov et al., 2012). As this study was conducted in mice, further studies on dogs and
cats need to be conducted to validate these results in the target species. Levy et al. (2011)
completed an experimental study to test a synthetic GnRH peptide vaccine, GonaconTM (United
States Department of Agriculture, Animal and Plant Health Inspection Service, Wildlife
Services, National Wildlife Research Centre, Fort Collins, CO, USA), on female cats; all cats
vaccinated with the GonaconTM became infertile for 5 months to 5 years with 93% of the cats
remaining infertile for the first year. They also found that the cats who regained their fertility
during the study period and were bred had smaller litters compared to the control group. Levy et
al. (2004) also conducted an earlier study on male cats testing 3 different quantities of GnRH
vaccines against a control group. Within each of these 3 groups, some cats developed low
antibody titres and some cats developed high titres. Levy et al. (2004) suggested that cats that
developed low titres may not be completely suppressed and remain fertile. Unfortunately, a
breeding trial was not conducted and a relatively short follow up period of six months was used
21
(Levy et al. 2004). As a result, infertility was not verified and it was not determined if GnRH
vaccines would be effective for long-term fertility control in male cats.
The first study investigating the GnRH vaccine (GonaConTM) in female dogs was conducted in
2009 by Bender et al., with another conducted by Vargas-Pino et al. in 2013. Both studies
investigated the administration of injecting the GnRH immunocontraceptive vaccine at the same
time as the rabies vaccine. Similar results were found in both studies showing that concurrent
administration of the vaccines had no effect on the efficacy of either, although both studies found
GonaConTM to be an effective contraceptive, but the researchers suggested more research still
needs to be completed on GonaConTM (Bender et al., 2009; Vargas-Pino et al., 2013). The
literature has indicated that GnRH vaccines show promise as a non-surgical method to control
both free roaming dogs and cats.
In addition to GnRH vaccines, the GnRH agonist deslorelin has been tested as an implant for
long-term reproduction control. Researchers implanted cats (10 controls and 10 with a 6mg
deslorelin implant) with results showing that the treatment group had significantly lower
oestradial levels over a 13 month period, excluding the first month after treatment, yet length of
suppression of folliculogenesis varied, ranging from 4 to 14 months (Munson et al., 2001).
Deslorelin has also been tested in dog populations investigating its ability to delay puberty.
Implantation occurred in 8 dogs at 4 months of age with either 4.7 mg or 9.4 mg of GnRH
agonist deslorelin and puberty was delayed for 2 years and in excess of 2 years, respectively
(Sirivaidyapong, Mehl and Trigg, 2012). A larger study conducted in Australia using 30 male
and 52 female dogs also tested the impact of deslorelin implants (Trigg et al., 2001). Animals
were assigned to four different groups: 3 mg, 6 mg, 12 mg and a control group. Results showed
suppressed reproductive function for both males and females treated with these implants. For
22
males, the effect was dose-dependent with a minimum of 12-month suppression, whereas for
females, suppression lasted up to 27 months and was effective at any stage of the estrus cycle
(Trigg et al., 2001). The results above suggest that implantation of GnRH agonist deslorelin is a
promising non-surgical form of contraception for companion animal populations. Further
development of deslorelin is needed to examine its impact on free roaming cats and dogs.
1.1.5.4. Euthanasia
Euthanasia as a control practice appears to results in a great deal of concern and controversy
among different stakeholders. A model generated by Schmidt et al. (2009) found that euthanasia
rates need to be 75% or higher to account for immigration and to keep population sizes below
initial levels. The model tested three different interventions: euthanasia alone, TNR alone and a
combination of TNR and euthanasia, each at three different treatment rates, 25%, 50% or 75%.
The model also accounted for immigration rates of either 0%, 25% or 50% which was applied to
each intervention at each treatment level. From this model, the authors concluded that euthanasia
alone, at any treatment rate when accounting for immigration rates of either 0%, 25% or 50%
leads to higher population declines compared to TNR alone or compared to a combination
approach of TNR and euthanasia (except for a treatment rate of 25% combined with a 50%
immigration rate) (Schmidt et al., 2009). A large portion of the primary research on euthanasia as
a population control strategy has investigated eradication programs on islands overrun with feral
cats (Twyford et al., 2000; Bester et al., 2002; Algar, Burbidge and Angus, 2002; Ratcliffe et al.,
2010 ; Ramsey et al., 2011; Algar, Angus and Onus, 2011; Robinson and Copson, 2012).
Various island-based eradication programs have been attempted with varying results. Marion
Island, an island of South Africa located in the Southern Indian Ocean, successfully eradicated
feral cats using a 7 phase program over a 19 year period (Bester et al., 2002). Marion Island is
23
29,000 hectors consisting of montane and coastal regions and has an average temperature of 5oC
and an average precipitation of 2576 mm in the form of rain, sleet and snow. It was estimated
that 2139 cats lived on Marion Island (Bester et al., 2002). The first two phases of the eradication
program on Marion Island included obtaining information about the cat population, and
determining the utility of using various pathogens for biological control. The last five phases
included biological control, hunting, trapping and poisoning as well as studies to determine the
effectiveness of each control method. Eradication of feral cats on Hermite Island which is
located off the coast of Western Australia, was complete in a matter of weeks, using a trap and
bait program (Algar, Burbridge and Angus, 2002). Hermite Island is 1,020 hectors with sandy
beaches, areas of mangroves, cliffs and limestone ridges and peninsulas and had a population of
at least 20 cats (Algar, Burbridge and Angus, 2002). Whereas, the eradication program on
Macquarie Island (an island of Australia located in the southwest Pacific Ocean) which included
trapping, shooting, gassing, and baiting, took 5 years to complete (Robinson and Copson, 2013).
Macquarie Island is larger at 12,800 hectors and had a population of 761 cats (Robinson and
Copson, 2013). Algar, Burbridge and Angus (2002) stated that eradication on Hermite Island was
fast and their results cannot be compared to other studies as temperature, size and shape of the
island, and prey all play a role in the effectiveness of an eradication program. Researchers have
demonstrated euthanasia can be a successful method of eradication for feral populations,
particularly in closed populations.
1.1.5.5. Other Control Practices
Other population control practices have been studied to a limited extent including education and
legislation. There is little research on the effect of educational programs as a control practice to
manage companion animal populations. In Sri Lanka, research examined knowledge, attitude and
24
practice (KAP) scores to assess the impact of knowledge on pet ownership, pet care and rabies
(Matibag et al., 2009). KAP scores improved after reading the information and education
campaign (IEC) material, owners knew more about rabies, and owners started to register their
pets and build shelters for them. However, following the campaign, an increase was found in the
number of owners that would allow their dogs to roam unsupervised (Matibag et al., 2009). This
increase in the willingness of owners to allow their dogs to roam freely may have occurred as a
result of educational material misleading owners to believe that following rabies vaccinations it
was safe to allow their dogs to roam (Matibag et al., 2009). In another study, researchers in
Taiwan recruited 15 veterinary clinics to be part of a randomized control study to see the effect
of educational material on ownership practices (Weng et al., 2006). Owners found the material
useful, with 84.6% of the intervention group during the first three months indicating they used
the material to help care for their pet(s). However, the educational material was found to have no
effect on owners’ decisions whether to spay or neuter their dogs. The authors believed this could
be due to the strong beliefs the Taiwanese have on dog reproduction including the belief that
dogs should be sterilized post-puberty and female dogs should have at least one litter before
being spayed (Weng et al., 2006). Interestingly in this study, during the first 4 months of
ownership, the intervention group had an increased rate of relinquishment compared to the
control group. This trend reversed after the first 4 months of ownership. The authors’ suggested
that the educational material on behaviour may have increased the owner’s ability to recognize
behavioural problems leading to the increased relinquishment in the first four months (Weng et
al., 2006). The authors’ also acknowledged certain limitations of their study including
convenience sampling, and limiting the generalizability of the study (Weng et al., 2006). In
addition, the sample size was relatively small (N = 126), suggesting the possibility of insufficient
25
power to detect the effects of the intervention (Weng et al., 2006). Education is an important
tool that can be used to inform the public on better ownership practices. Future research into the
effects of education efforts is warranted including the accompaniment with other control
methods.
1.1.6. Shelter Management
One consequence of companion animal population dynamics is unwanted companion animals,
which can lead to overcrowded shelters. Animals enter shelters worldwide, and without the space
to hold the healthy, adoptable animals, they can be euthanized (Kass, 2007). Wenstrup and
Dowidchul (1999) conducted a survey in the summer of 1998 of 186 shelters and animal control
facilities in the United States to collect shelter data. The authors reported that in total, shelters
only had the capacity to house 2.6% of the animals that entered the shelters during the previous
year. A combined total of 764,879 animals went through the shelter with only 19,998 kennels to
house them. In total, 59% of the animals that entered these shelters were euthanized, and 34% of
euthanasia were due to limited capacity (Wenstrup and Dowidchul, 1999). Wenstrup and
Dowidchul (1999) reported, that according to the shelters staff, 52% of the euthanized animals
were adoptable. These results are similar to a survey conducted in 1991, which reported on
intake and euthanasia data from Massachusetts, New Jersey and Washington shelters, with
60.7% of the animals that entered the shelter that year being euthanized (Rowan, 1992). In
Canada, a survey conducted on shelter trends in Canadian humane societies and Societies for the
Prevention of Cruelty to Animals (SPCAs) in 2014 reported that 11% of dogs admitted and 37%
of cats admitted were euthanized, of this 2% of dogs and 6% of cats were healthy when
euthanized (CFHS, 2015).
26
Euthanizing mass numbers of healthy animals can also take an emotional toll on shelter
employees working in this environment (White and Shawhan, 1996; Gardner, 2008). This
phenomena called compassion fatigue, has been identified as a post-traumatic stress disorder
“due to exhaustion of compassion stressors” (Figley and Roop, 2006). The majority of research
on euthanasia as a traumatic stressor has been conducted in the United States. Research has
shown that euthanasia-related stress can lead shelter employees to feel depressed, suffer from
lack of sleep and nightmares, cause them to question their self-worth, and affect their personal
lives (White and Shawhan, 1996; Reeve et al., 2005). For example, when shelter workers were
asked to describe their feelings and thoughts about euthanasia, one individual stated “I entered
therapy in the beginning of June and am being medicated for severe depression. Much of my
anger, guilt, frustration, and outright sadness is connected to my work and my passion for
wanting to save animals I kill” (White and Shawhan, 1996). Reeve et al., (2005) reported that
44.4% of their participants (N=335), who were shelter workers, agreed euthanasia caused them
great stress, 29.6% agreed it made them feel depressed, 29.4% lost sleep and 23.5% had
nightmares. Individuals who were directly involved with euthanasia had higher stress and lower
job satisfaction levels (Reeve et al., 2005). Furthermore, a study found that as dog euthanasia
increased, shelter employee turnover increased (Rogelberg et al., 2007). The study did not find
the same relationship for cat euthanasia. This difference was explored further and the attachment
levels between shelter workers and dogs were found to be stronger than for cats (Rogelberg et
al., 2007). Results also indicated that if euthanasia was due to behavioural or health reasons,
employee turnover was less (Rogelberg et al., 2007).
Not every study supports the results of euthanasia-related traumatic experience among shelter
workers. Two studies found that only a few shelter workers experienced traumatic symptoms in
27
association with experiences working in a shelter (Rohlf and Bennett, 2005; Roberts, 2015). In
the one, a qualitative study (N=22), conducted by Roberts (2015), the trauma had to be directly
reported by the individual themselves in an effort to see if the shelter workers would talk about
their trauma symptoms on their own accord. Specific prompts about trauma symptoms were not
asked, only general coping prompts were used (Roberts, 2015). Many efforts have been made in
recent years to decrease the amount of euthanasia occurring in shelters; this may be another
explanation for the lack of trauma symptoms in shelters workers found by Roberts (2015). There
was also no use of standardized measurements to determine if an individual suffered from trauma
(Roberts, 2015). Although only one respondent reported a traumatic experience associated with
animal euthanasia within this study, the other 21 respondents reported euthanasia was a stressor
(Roberts, 2015). In both papers, by Rohlf and Bennett (2005) and Roberts (2015), the authors
suggested that the lack of trauma reported may be due to the resignation of the employees that
experienced trauma prior to the studies being conducted. Another explanation for these findings
could be the workers themselves; not every employee is affected by euthanasia to the same
degree as others (White and Shawhan, 1996; Reeves et al., 2005). One of the shelter employees
from the study conducted by White and Shawhan (1996) stated, “I have no feelings about
euthanasia. It doesn’t bother me. I’ve been at it too long.” Certain individuals experience and
deal with stress differently (Reeves et al., 2005), some employees pretend the euthanasia never
happened or do not allow themselves to become attached to the animals, while others use “sick
humour” or physical exercise to relieve stress (White and Shawhan, 1996).
Due to overcrowding, resulting in the euthanasia of healthy adoptable animals and health effects
on shelter workers, shelters have been changing their approach to managing shelter populations.
In recent years, Capacity for Care (C4C) shelter management has been recommended as a
28
solution to overcrowding in shelters. The idea of this management practice is to decrease the
number of animals in a shelter at one time and decrease their length of stay, ultimately increasing
the number of animals they help (Karsten, 2014). C4C aims to improve the welfare of animals in
shelters by using the following to provide the 5 freedoms as a standard: (1) Monitoring feed
intake by the pets to ensure the animals do not suffer from hunger and thirst, providing larger
housing facilities to ensure (2) the animals do not suffer from discomfort and, (3) allow to
express normal behaviours; (4) include a hiding spot to ensure the animals are free from fear and
distress; and (5) decrease disease through decreased overcrowding allowing the animals to be
free from pain, injury and disease (Karsten, 2014). According to the C4C model, the true
capacity of a shelter is calculated using the following parameters: the number of appropriate
housing units; staffing for programs or services; staff training; average length of stay; and the
total number of reclaims, adoptions, transfers, release, or other outcomes (Newbury et al., 2010).
One of the ultimate goals of C4C is to decrease the length of stay of each animal. To date, there
has been very little empirical research conducted on C4C management style comparing its
efficacy to other management styles or its potential effect on the size of stray and abandoned
companion animal population sizes, and stray intakes to shelters. The majority of information
informing the current understanding of C4C has been from case studies. Recent case studies
were conducted on the implementation of C4C at the Guelph Humane Society (Guelph HS) and
the Prince Edward Island Humane Society (PEI HS) (CFHS, 2015b). Information on shelter care
was compared before and after C4C was implemented at each shelter. Data were collected for the
same period of time a year apart (August 2013 – January 2014 pre-C4C and August 2014-
January 2015 post-C4C). Both shelters demonstrated a reduction in the number of cats entering
their sickbays and an increase in adoptions when comparing these two time periods. The PEI HS
29
had a reduction in average length of stay from 23.4 to 13.1 days while the Guelph HS maintained
their average length of stay of 6-7 days. Guelph HS showed a decrease in the number of cats
euthanized from 35 to 11 comparing these two time periods, while the PEI HS increased from 21
to 22 cats. It was noted that the PEI HS had a large number of diseased feral cats enter the shelter
following the period they implemented C4C, which increased their euthanasia number for the
following year. Both PEI HS and Guelph HS reported being impressed with the changes that
occurred due to implementing C4C (CFHS, 2015b). The Vancouver SPCA in British Columbia
(BC) also assessed the implementation of C4C. In this case, shelter data were collected in 2012
after C4C was implemented and was compared to 2011 shelter data before C4C was
implemented. Findings showed a 9% decrease in cat intake, length of stay (LOS) decreased from
40 days to 22 days, and the average number of cats in isolation went from 12 to 1 (Karsten,
2014). These case studies suggest that C4C has promising effects that could potentially decrease
euthanasia and length of stay of animals in shelters. As C4C uses the five freedoms to improve
animal welfare in the shelter, research investigating the health and welfare benefits of C4C is
needed to determine if the animal’s welfare is truly improved. Further research on a larger
sample size and accounting for multiple variables that may impact C4C needs to be conducted.
In addition, while C4C has shown improvement to the shelter management of unwanted
companion animals, it is not known the effects on companion-animal populations outside of the
shelter including the free roaming population and animals not accepted into a shelter system
because of capacity restrictions.
1.1.7. Characteristics of shelter animals being adopted or euthanized
Research has been conducted on characteristics of animals in shelters to determine factors
leading to relinquishment, euthanasia, and adoption. The majority of this research has been
30
conducted in the United States and no research at this time has been done in Canada. Research
has been conducted in both no kill (Diesel et al., 2007; Nĕmcová and Novák, 2003; Cannas et
al., 2014) and traditional shelters (Clevenger and Kass, 2003; DeLeeuw, 2010, Lepper, Kass and
Hart, 2002; Marston et al., 2004; Posage, Bartlett and Thomas, 1998). Understanding factors and
characteristics that affect an animal’s final disposition once in a shelter is important for
increasing positive outcomes for the animals. Adopter preferences for female dogs (Lepper, Kass
and Hart, 2002; Diesel, Smith and Pfeiffer, 2007; DeLeeuw, 2010; Davidson and Zueffle, 2013;
Cannas et al., 2014), puppies under a year of age (Lepper, Kass and Hart, 2002; Diesel, Smith
and Pfeiffer, 2007; DeLeeeuw, 2010; Brown, Davidson and Zueffle, 2013; Cannas et al., 2014),
purebreds (Lepper, Kass and Hart, 2002; Diesel, Smith and Pfeiffer, 2007; DeLeeuw, 2010;
Brown, Davidson and Zueffle, 2013) and small dogs (Posage, Bartlett and Thomas, 1998;
Lepper, Kass and Hart, 2002; Diesel, Smith and Pfeiffer, 2007; DeLeeuw, 2010; Protopopova et
al., 2014; Brown, Davidson and Zueffle, 2013; Cannas et al., 2014) have been reported. One
study completed in the Czech Republic found mixed breed puppies (2-4 months of age) were
more likely to be adopted compared to dogs with specific breed characteristics and there was no
preference for sex (Nĕmcová and Novák, 2003). Studies conducted in the United States on more
specific breed types found that giant companion dog breeds had a higher rate of being adopted
and guard dogs had a lower rate of being adopted (Lepper, Kass and Hart, 2002; Brown,
Davidson and Zueffle, 2013). In the U.K., a study found gundogs and utility dogs had higher
rates of adoption compared to hounds (Diesel, Smith and Pfeiffer, 2007), which was
contradictory to an American study where hounds had a greater adoption rate (DeLeeuw, 2010).
Understanding the role of breed in adoption is challenging; differences in adoption rates between
breeds could be due to country specific preferences or due to how each study combined the large
31
number of breed categories that exist as each study appears to use a slightly different
methodology. The literature has not identified a consistent trend relating to coat colour
preferences and adoption. Research in the U.K. shows that black and white coat coloured dogs
were the least preferred resulting in an increased length of stay (Diesel, Smith and Pfeiffer,
2007), whereas in the United States brindle or black and tan patterns have been associated with
decreased adoption (Lepper, Kass and Hart, 2002). Other studies in the Czech Republic and
United States showed coat colour had no measurable effect on length of stay (Brown, Davidson
and Zueffle, 2013; Protopopova, et al., 2014). Furthermore, studies investigating euthanasia
trends found black dogs (Posage. Bartlett and Thomas, 1998; DeLeeuw, 2010), adults (Clevenger
and Kass, 2003) and males (Martson, Bennett and Carson, 2004) were more likely to be
euthanized. These results follow the same trends as adoption, as animals with a decreased chance
of adoption have been shown to have an increased chance of euthanasia in traditional shelters.
Much research has been conducted on reasons for relinquishment (Coe et al., 2014), but few
studies have looked at how it affected the dog’s probability of being adopted. Researchers
investigating reasons for relinquishment and its effect on dog adoption found that dogs
surrendered due to owner-related reasons such as expense, moving and agency holds (animal is
in shelter due to owner being in jail or hospitalized) were adopted more frequently compared to
animals surrendered for behavioural reasons or health reasons (Lepper, Kass and Hart, 2002;
DeLeeuw, 2010)
A study conducted in Florida, United States focused on how behaviour impacted a dog’s length
of stay in Alachua County Animal Services from May to December, 2012. Dogs who stood still,
faced away from potential adopters, paced back and forth, or engaged in any contact with the
enclosure increased their length of stay by 5, 15, 15-20, and 30 days respectively (Protopopova et
32
al. 2014). Researchers have suggested that online photos of shelter animals can improve median
days to adoption (MDA) (Lampe and Witte, 2005). Researchers studying black labs in United
States shelters found that photos where the dog was making eye contact with the camera, where
the dog was standing, and photos taken outdoors all decreased the MDA (Lampe and Witte,
2005). Higher quality photos were also found to decrease the MDA.
Increased length of stay can have negative health impacts on the animals staying in the shelter.
Two studies conducted on cats found that cats who stayed longer than 6 days in a shelter had an
increased chance of getting an upper respiratory infection (URI) (Bannash and Foley, 2005;
Dinnage, Scarlett and Richards, 2009). Dinnage, Scarlett and Richards (2009) found that URI
was the top reason given for euthanasia, and kittens with URI’s were two times more likely to be
euthanized compared to healthy kittens. There is no literature at this time investigating how
length of stay impacts dogs’ health indicating an opportunity for further research.
Characteristics of cats in relation to adoption and euthanasia have also been investigated but less
frequently than those of dogs. According to the research, male cats were adopted more quickly
than females (Lepper, Kass and Hart, 2002; Brown and Morgan, 2015) and just like puppies,
kittens were preferred compared to adult cats (Lepper, Kass and Hart, 2002; Brown and Morgan,
2015). Coat colour also affected a cat’s length of stay, torbie (tortoiseshell cats with tabby
patterns) having the shortest and tuxedo having the longest stays. Exotic breeds spent less time in
the shelter compared to the common domestic shorthaired which spent the longest time in
shelters (Brown and Morgan, 2015).
1.1.8. Methodology
33
Knowledge synthesis is an important methodology to inform evidence-based decisions (Tricco,
Tetzlaff and Moher, 2011). It includes identifying, assessing and synthesizing all available
research evidence on a given topic using structured and transparent methods (Graham et al.,
2006). Scoping reviews are a commonly used knowledge synthesis method (Arksey and
O’Malley, 2005). They are conducted on broad topics with intricate research questions, which
tend to be policy driven (Arksey and O’Malley, 2005). Scoping reviews aim to provide a
description (characterization) of the relevant research. Unlike a systematic review, they usually
do not include a quality assessment of the research included (Arksey and O’Malley, 2005). There
are multiple purposes for conducting a scoping review: to identify the breadth and depth of the
research in a topic area, to summarize and describe the available research and determine research
gaps, and to determine if a systematic review meta-analysis (SR-MA) (another common
knowledge synthesis) can be conducted (Arksey and O’Malley, 2005). Scoping reviews follow a
systematic protocol that includes five stages. First is identifying the research question, second is
identifying available studies (search strategy), third is determining relevance, fourth is data
extraction and characterization, and last is reporting and summarizing the results (Arksey and
O’Malley, 2005).
1.2. Thesis Rationale
Understanding companion animal population dynamics is complex and is being considered by
many countries throughout the world. Due to this, different stakeholders are interested in this
topic, which has contributed to a vast amount of research and published information. The
resulting data are published in a variety of sources representing stakeholders invested in this
topic. Combining the existing knowledge on companion animal population dynamics in order to
determine the breadth and depth of the present research on this topic offers a valuable
34
opportunity to further stakeholders’ understanding of companion animal population dynamics.
Assimilating and summarizing the published research on companion animal population dynamics
will assist in identifying areas for more in-depth knowledge synthesis activities as well as gaps to
direct areas for future research. It is important to know what research has already been completed
to avoid unnecessary repetition, to determine the effectiveness of interventions, and to know
where future research should be targeted.
A common consequence of companion animal population dynamics is overcrowding in shelters.
Research on characteristics and factors that lead to adoption are important to help decrease
overcrowding. Currently, there is no research conducted on this topic in Canada. This research
could provide shelters with information to help identify which factors are under the direct control
of the shelter and which factors could be addressed via outreach to maximize successful
adoptions, minimize unnecessary euthanasia or returns, and decrease length of stay.
1.3. Thesis Objectives
The specific objectives of this thesis are:
1) To identify all published research up to May 2015 investigating approaches to
managing companion animal population dynamics to control the number of owned
free roaming, unowned free roaming, and unwanted companion animals (Chapter 2).
2) To determine which factors, based on individual dog characteristics, animal source
and shelter demographics, affected the time to adoption for dogs entering the BC
SPCA shelter system between January 2010 and July 2014 (Chapter 3).
35
References
Algar, D., Angus, G. J., & Onus, M. L. (2011). Eradication of feral cats on Rottnest Island
Western Australia. Journal of the Royal Society of Western Australia, 94, 439-443.
Algar, D. A., Burbridge, A. A., & Angus, G. J. (2002). Cat eradication on Hermite Island,
Montebello Island, Western Australia. In C. R. Veitch & M. N. Clout (Eds.), Turning the tide:
The eradication of invasive species (pp. 14-18).
Anderson, D. G. (1992). The control of pet overpopulation. Veterinary Technician, 13, 119-123.
Arksey, H., & O’Malley, L. (2005). Scoping studies: towards a methodological framework.
International Journal of Social Research Methodology, 8, 19-32.
ASPCA. (2014). Pet Statistics. Retrieved from http://www.aspca.org/animal-
homelessness/shelter-intake-and-surrender/pet-statistics
AVMA. (2012). Pet Ownership & Demographics Sourcebook. Schaumberg IL: American
Veterinary Medical Association.
Bannasch, M. J., & Foley, J. E. (2005). Epidemiologic evaluation of multiple respiratory
pathogens in cats in animal shelters. Journal of Feline Medicine and Surgery, 7, 109-119.
Barrows, P. L. (2004). Professional, ethical, and legal dilemmas of trap-neuter-release. Journal
of the American Veterinary Medical Association, 225, 1365-1369.
Beck, L., & Madresh, E. A. (2008). Romantic partners and four-legged friends: An extension of
attachment theory to relationships with pets. Anthrozoös, 21, 43-56.
Bender, S. C., Bergman, D. L., Wenning, K. M., Miller, L. A., Slate, D., Jackson, F. R., &
Rupprecht, C. E. (2009). No adverse effects of simultaneous vaccination with the
immunocontraceptive GonaConTM and a commercial rabies vaccine on rabies virus neutralizing
antibody production in dogs. Vaccine, 27, 7210-7213.
Bester, M. N., Bloomer, J. P., van Aarde, R. J., Erasmus, B. H., van Rensburg, P. J. J., Skinner, J.
D., … Naude, T. W. (2002). A review of the successful eradication of feral cats from sub-
Antarctic Marion Island, southern Indian Ocean. South African Journal of Wildlife Research, 32,
65-73.
Blazina, C., Boyraz, G., & Shen-Miller, D. (2011). Introduction: Using context to inform clinical
practice and research. In C. Blazina, G. Boyraz, & D. Shen-Miller (Eds.), The psychology of the
human-animal bond (pp. 3). New York: Springer.
Brooks, R. (1990). Survey of the dog population of Zimbabwe and its level of rabies vaccination.
The Veterinary Record, 127, 592-596.
Brown, S. G., & Rhodes, R. E. (2006). Relationships among dog ownership and leisure-time
walking in western Canadian Adults. American Journal of Preventive Medicine, 30, 131-136.
36
Brown, W. P., Davidson, J. P., & Zuefle, M. E. (2013). Effects of phenotypic characteristics on
the length of stay of dogs at two no kill animal shelters. Journal of Applied Animal Welfare
Science, 16, 2-18.
Brown, W. P., & Morgan, K. T. (2015). Age, breed designation, coat color, and coat pattern
influence the length of stay of cats at a no-kill shelter. Journal of Applied Animal Welfare
Science, 18, 169-180.
Bushby, P. (2012). Early-age spay/neuter. NAVC Clinician’s Brief, 71-73.
Cannas, S., Rampini, F., Levi, D., Costa, E. D., Talamonti, Z., Minero, M., & Palestrini, C.
(2014). Shelter dogs and their destiny a retrospective analysis to identify predictive factors: A
pilot study. Macedonian Veterinary Review, 37, 151-156.
Castillo, D., & Clarke, A. L. (2003). Trap/Neuter/Release methods ineffective in control
domestic cat “colonies” on public lands. Natural Areas Journal, 23, 247-253.
CFHS. (2015a). Animal Shelter Statistics. Retrieved from
http://cfhs.ca/athome/shelter_animal_statistics/
CFHS. (2015b). Capacity for Care (C4C) Case Studies. Retrieved from
http://cfhs.ca/athome/capacity_for_care/
City of Toronto. (2013). Chapter 349: animals. Toronto Municipal Code (pp. 11).
Clevenger, J., & Kass, P. H. (2003). Determinants of adoption and euthanasia of shelter dogs
spayed or neutered in the University of California veterinary student surgery program compared
to other shelter dogs. Journal of Veterinary Medical Education, 30, 372-378.
CVMA. (2011). Canada’s pet wellness report: A snapshot of Canada’s pet health and wellness
from the Canadian Veterinary Medical Association (CVMA), in partnership with Hill’s Science
Diet. Retrieved from https://www.canadianveterinarians.net/documents/canada-s-pet-wellness-
report2011
Diesel, G., Smith, H., & Pfeiffer, D. U. (2007). Factors affecting time to adoption of dog re-
homed by a charity in the UK. Animal Welfare, 16, 353-360.
DeLeeuw, J. L. (2010). Animal shelter dogs: Factors predicting adoption versus euthanasia
(Doctoral Dissertation). Wichita State University.
Dinnage, J. D., Scarlett, J. M., & Richards, J. R. (2009). Descriptive epidemiology of feline
upper respiratory tract disease in an animal shelter. Journal of Feline Medicine and Surgery, 11,
816-825.
Eade, J. A., Robertson, I. D., & James, C. M. (2009). Contraceptive potential of porcine and
feline zona pellucida A, B, C subunits in domestic cats. Reproduction, 137, 913-922.
Edney, A. T. B. (1995). Companion animals and human health: an overview. Journal of the
Royal Society of Medicine, 88, 704-708.
37
Eze, C. A., & Eze, M. C. (2002). Castration, other management practices and socio-economic
implications for dog keeps in Nsukka area, Enugu state, Nigeria. Preventative Veterinary
Medicine, 55, 273-280.
Farnworth, M. J., Blaszak, K., Hiby, E. F., & Waran, N. K. (2012). Incidence of dog bites and
public attitudes towards dog care and management in Samoa. Animal Welfare, 21, 477-486.
Fielding, W. J. (2010a). Dog breeding in New Providence, the Bahamas, and its potential impact
on the roaming dog population I: planned and accidental. Journal of Applied Animal Welfare
Science, 13, 250-260.
Fielding, W. J. (2010b). Dog breeding in New Providence, the Bahamas, and its potential impact
on the roaming dog population II: the fate of puppies. Journal of Applied Animal Welfare
Science, 13, 300-313.
Fielding, W. J. Gall, M., Green, G., & Eller, W. S. (2012). Care of dogs and attitude of dog
owners in Port-au-Prince, the Republic of Haiti. Journal of Applied Animal Welfare Science, 15,
236-253.
Fielding, W. J., & Mather, J. (2001). Dog ownership in the West Indies: A case study form the
Bahamas. Anthrozoös, 14, 72-80.
Figley, C. R. & Roop, R. G. (2006). The definition of terms and the nature of compassion. In C.
R. Figley & R. G. Roop (Eds), Compassion Fatigue in the Animal-Care Community (pp. 7-16).
Washington, Humane Society Press.
Finkler, H., & Terkel, J. (2012). The contribution of cat owners’ attitudes and behaviours to the
free-roaming cat overpopulation in Tel Aviv, Israel. Preventive Veterinary Medicine, 104, 125-
135.
Foley, P., Foley, J. E., Levy, J. K., & Paik, T. (2005). Analysis of the impact of trap-neuter-
return programs on population of feral cats. Journal of the American Veterinary Medical
Association, 227, 1775-1781.
Friedmann, E., & Son, H. (2009). The human-companion animal bond: How humans benefits.
Veterinary Clinics of North America: Small Animal Practice, 39, 293-326.
Gardner, D. (2008). Managing grief associated with euthanasia.
Gorman, S. P., Levy, J. K., Hampton, A. L., Collante, W. R., Harris, A. L., Brown, R. G. (2002).
Evaluation of a porcine zona pellucida vaccine for the immunocontraception of domestic kittens
(Felis catus). Theriogenology, 58, 135-149.
Graham, I. D., Logan, J., Harrison, M. B., Straus, S. E., Totroe, J., Caswell, W., & Robinson, M.
(2006). Lost in knowledge translation: time for a map? The Journal of Continuing Education in
the Health Professions, 26, 13-24.
Gunther, I., Raz, T., Berke, O., & Klement, E. (2015). Nuisances and welfare of free-roaming
cats in urban settings and their association with cat reproduction. Preventive Veterinary
Medicine, 119, 203-213.
38
Gunther, I., & Terkel, J. (2002). Regulation of free-roaming cat (Felis silvestris catus)
populations: A survey of the literature and its application to Israel. Animal Welfare, 11, 171-188.
Heady, B. (1999). Health benefits and health cost savings due to pets: Preliminary estimates
from an Australian national survey. Social Indicators Research, 47, 233-243.
Hiby, L. R., Reece, J. F., Wright, R., Jaisinghani, R., Singh, B., & Hiby, E. F. (2011). A mark-
resight survey method to estimate the roaming dog population in three cities in Rajasthan, India.
BMC Veterinary Research, 7, 46-54.
Hines, L. (2003) Historical perspectives on the human-animal bond. American Behavioural
Scientist, 47, 7-15.
Howe, L. M., Slater, M. R., Boothe, H. W., Hobson, H. P., Fossum, T. W, Spann, A. C., &
Wilkie, W. S. (2000). Long-term outcome of gonadectomy performed at an early age or
traditional age in cats. Journal of the American Veterinary Medical Association, 217, 1661-1665.
Howe, L. M., Slater, M. R., Boothe, H. W., Hobson, H. P., Holcom, J. L., & Spann, A. C.
(2001). Long-term outcome of gonadectomy performed at an early age or traditional age in dogs.
Journal of the American Veterinary Medical Association, 218, 217-221.
Hsu, Y., Severinghaus, L. L., & Serpell, J. A. (2003). Dog keeping in Taiwan: Its contribution to
the problem of free-roaming dogs. Journal of Applied Animal Welfare Science, 6, 1-23.
Hurley, K. F. (2005). Feline infectious disease control in shelters. Veterinary Clinics of North
America: Small Animal Practice, 35, 21-37.
Jain, P., & Jain, G. (2014). Study of general awareness, attitude, behaviour, and practice study on
dog bites and its management in the context of prevention of rabies among the victims of dog
bite attending the OPD services of the CHC Muradnagar. Journal of Family Medicine and
Primary Care, 3, 355-358.
Jayakumar, R. (1997). A pilot survey of the dog population and rabies vaccination in India.
Biomedicine, 17, 25-27.
Jennings, L. B. (1997). Potential benefits of pet ownership in health promotion. Journal of
Holistic Nursing, 15, 358-372.
Kamoltham, T., Singhsa, U., Promsaranee (2003). Elimination of human rabies in a canine
endemic province in Thailand: five-year programme. Bulletin of the World Health Organization,
81, 375-381
Karsten, C. (2014). Calculating your humane capacity [Powerpoint Slides]. Retrieved from
http://www.petpoint.com/summits/past-summits.asp
Kass, P. H., New, J. C., Scarlett, J. M., & Salman, M. D. (2001). Understanding animal
companion surplus in the United States: relinquishment of nonadoptables to animal shelters for
euthanasia. Journal of Applied Animal Welfare Science, 4, 237-248.
39
Kass, P. H. (2007). Cat overpopulation in the United States. In I. Rochlitz (Ed.), The welfare of
cats (pp. 119-139). New York: Springer.
Kostarczyk, E., & Fonberg, E. (1982). Heart rate mechanisms in instrumental conditioning
reinforced by petting in dogs. Physiology & Behavior, 28, 27-30.
Lampe, R., & Witte, T. H. (2015). Speed of dog adoption L Impact of online photo traits.
Journal of Applied Animal Welfare Science, 18, 343-354.
Lepczyk, C. A., Dauphiné, N., Bird, D. M., Conant, S., Cooper, R. J., Duffy, D. C., … Temple,
S. A. (2010). What conservation biologists can do to counter trap-neuter-return: response to
Longcore et al.. Conservation Biology, 24, 627-629.
Lepper, M., Kass, P. H., Hart, L. A. (2002). Prediction of adoption versus euthanasia among
dogs and cats in a California animal shelter. Journal of Applied Animal Welfare Science, 5, 29-
42.
Levy, J. K., Gale, D. W., & Gale, L. A. (2003b). Evaluation of the effect of a long-term trap-
neuter-release and adoption program on a free-roaming cat population. Journal of the American
Veterinary Medical Association, 222, 42-46.
Levy, J. K., Friary, J. A., Miller, L. A., Tucker, S. J., & Fagerstone, K. A. (2011). Long-term
fertility control in female cats with GonaConTM, a GnRH immunocontraceptive. Theriogenology,
76, 1517-1525.
Levy, J. K., Mansour, M., Crawford, P. C. Pohajdak, B., & Brown, R. G. (2005). Survey of zona
pellucida antigens for immunocontraception of cats. Theriogenology, 63, 1334-1341.
Levy, J. K., Miller, L. A., Crawford, P. C., Ritchey, J. W., Ross, M. K., & Fagerstone, K. A.
(2004). GnRH immunocontraception of male cats. Theriogeneology, 62, 1116-1130.
Levy, J. K., Woods, J. E., Turick, S. L., & Etheridge, D. L. (2003a). Number of unowned free-
roaming cats in a college community in the southern United States and characteristics of
community residents who feed them. Journal of the American Veterinary Medical Association,
223, 202-205.
Lohr, C. A., Cox, L. J., & Lepczyk, C. A. (2013). Cost and benefits of trap-neuter-release and
euthanasia for removal of urban cats in Oahu, Hawaii. Conservation Biology, 27, 64-73.
Lohr, C. A., & Lepczyk, C. A. (2014). Desires and management preferences of stakeholders
regarding feral cats in the Hawaiian Islands. Conservation Biology, 28, 392-403.
Lone, K. S., Bilquees, S., Salimkhan, M., & Ul Haq, I. (2014). Analysis of dog bites in Kashmir:
an unprovoked threat to population. National Journal of Community Medicine, 5, 66-68.
Mahi-Brown, C. A., Yanagimachi, R., Hoffman, J. C., & Huang, T. T. F. (1985). Fertility control
in the bitch by active immunization with porcine zonae pellucidae: use of different adjuvants and
patterns of estradiol and progesterone levels in estrous cycles. Biology of Reproduction, 32, 761-
772.
40
Martson, L. C., Bennett, P. C., & Coleman, G. J. (2004). What happens to shelter dogs? An
analysis of data for 1 year from three Australia shelters. Journal of Applied Animal Welfare
Science, 7, 27-47.
Matibag, G. C., Ohbayashi, Y., Kanda, K., Yamashina, H., Kumara, W. B. Gamini Perera, I. N.,
… Tamashiro, H. (2009). A pilot study on the usefulness of information and education campaign
material in enhancing the knowledge, attitude and practice on rabies in rural Sri Lanka. The
Journal of Infection in Developing Countries, 3, 55-64.
McConnell, A. R., Brown, C. M., Shoda, T. M., Stayton, L. E., & Martin, C. E. (2011). Friends
with benefits: on the positive consequence of pet ownership. Journal of Personality and Social
Psychology, 101, 1239-1252.
McGreevy, P. D., Righetti, J., & Thomson, P. C. (2005). The reinforcing value of physical
contact and the effect on canine heart rate of grooming in different anatomical areas. Anthrozoös,
18, 236-244.
McNicholas, J., Gilbey, A., Rennie, A., Ahmedzai, S., Dono, J., & Ormerod, E. (2005). Pet
ownership and human health: A brief review of evidence and issues. BMJ, 331, 1252-1255.
MengChih, T., ChangYoung, F., JengTung, C., ChungHsi, C., LihSen, Y, ChenYuan, L., …
KwongChung, T. (2010). Surveys of dog populations in Taiwan from 1999 to 2009. Journal of
the Chinse Society of Animal Science, 39, 175-188.
Munson, L., Bauman, J. E., Asa, C S., Jöchle, W., & Trigg, T. E. (2000). Efficacy of the GnRH
analogue deslorelin for suppression of oestrous cycles in cats. Journal of Reproduction and
Fertility Supplement, 57, 269-273.
Natoli, E., Maragliano, L., Cariola, G., Faini, A., Bonanni, R., Cafazzo, S., & Fantini, C. (2006).
Management feral domestic cats in the urban environment of Rome (Italy). Preventive
Veterinary Medicine, 77, 180-185.
Nĕmcová, D., & Novák, P. (2003). Adoption of dogs in the Czech Republic. Acta Veterinaria
Brno, 72, 421-427.
Newbury, S., Blinn, M. K., Bushby, P. A., Cox, C. B., Dinnage, J. D., Griffin, B., … Spindel, M.
(2010). Guidelines for standards of care in animal shelters.
Olson, P. N., Nett, T. M., Bowen, R. A., Amann, R. P., Sawyer, H. R., Gorell, T. A., …
Phemister, R. D. (1986). A need for sterilization, contraceptives, and abortifacients: Abandoned
and unwanted pets part I. Current methods of sterilizing pets. The Compendium of Continuing
Education, 8, 87-92.
Olson, P. N., Root Kustritz, M. V., & Johnston, S. D. (2000). Early-age neutering of dogs and
cats in the United States (a review). Journal of Reproduction and Fertility Supplement, 57, 223-
232.
41
Ortega-Pacheco, A., Segura-Correa, J. C., Jimenez-Coello, M., & Linde Forsberg, C. (2007).
Reproductive patterns and reproductive pathologies of stray bitches in the tropics.
Theriogenology, 67, 382-390.
Otolorin, G. R., Umoh, J. U., & Dzikwi, A. A. (2014). Demographic and ecological survey of
dog population in Aba, Abia State, Nigeria. ISRN Veternary Science, 2014, 1-5.
Parslow, R. A., & Jorm, A. F. (2003). Pet ownership and risk factors for cardiovascular disease:
Another look. Medical Journal of Australia, 179, 466-468.
Parslow, R. A., Jorm, A. F., Christensen, H., Rodgers, B., & Jacomb, P. (2005). Pet ownership
and health in older adults: findings from a survey of 2,551 community-based Australians aged
60-64. Gerontology, 51, 40-47.
PFMA. (2014). Pet Population. Retrieved from http://www.pfma.org.uk/pet-population-2014
Porters, N., de Rooster, H., Verschueren, K., Polis, I., & Moons, C. P. H. (2014a). Development
of behavior in adopted shelter kittens after gonadectomy performed at an early age or at a
traditional age. Journal of Veterinary Behaviour, 9, 196-206.
Porters, N., Polis, I., Moons, C., Duchateau, L., Goethals, K., Huyghe, S., & de Rooster, H.
(2014b). Prepubertal gonadectomy in cats: Different surgical techniques and comparison with
gonadectomy at traditional age. Veterinary Record, 175, 223-227.
Posage, J. M., Bartlett, P. C., Thomas, D. K. (1998). Determining factors for successful adoption
of dogs from an animal shelter. Journal of the American Veterinary Medical Association, 218,
478-482.
Poss, J. E., & Bader, J. O. (2007). Attitudes toward companion animals among Hispanic
residents of a Texas border community. Journal of Applied Animal Welfare Science, 10, 243-
253.
Protopopova, A., Mehrkam, L. R., Boggess, M. M., & Wynne, C. D. L. (2014) In-kennel
behaviour predicts length of stay in shelter dogs. PLoS ONE, 9, e114319.
Punjabi, G. A., Athreya, V., & Linnell, J. D. C. (2012). Using natural marks to estimate free-
ranging dog Canis familiaris abundance in a mark-resight framework in suburban Mumbai,
India. Tropical Conservation Science, 5, 510-520.
Ramsey, D. S. L., Parkes, J. P., Will, D., Hanson, C. C., & Campbell, K. J. (2011). Quantifying
the success of feral cat eradication, San Nicolas Island, California. New Zealand Journal of
Ecology, 35, 163-173.
Ratcliffe, N., Bell, M., Pelembe, T., Boyle, D., White, R. B. R., Godley, B., … Sanders, S.
(2010). The eradication of feral cats from Ascension Island and is subsequent recolonization by
seabirds. Oryx, 44, 20-29.
42
Reeve, C. L., Rogelberg, S. G., Spitzmüller, C., & DiGiacomo, N. (2005). The caring-killing
paradox: euthanasia-related strain among animal-shelter workers. Journal of Applied Social
Psychology, 35, 119-143.
Rew, L. (2000). Friend and pets as companions: strategies for coping with loneliness among
homeless youth. Journal of Child and Adolescent Psychiatric Nursing, 13, 125-140.
Roberts, J. (2015). Occupational stress in animal shelter workers (Master’s Thesis). University
of Toronto.
Robinson, S. A., & Copson, G. R. (2014). Eradication of cats (Felis catus) from subantarctic
Macquarie Island. Ecological Management & Restoration, 15, 34-40.
Rogelberg, S. G., Reeve, C. L., Spitzmüller, C., DiGiacomo, N., Clark, O. L., Teeter, L., …
Carter, N. T. (2007). Impact of euthanasia rates, euthanasia practices, and human resource
practices on employee turnover in animal shelters. Journal of the American Veterinary Medical
Association, 230, 713-719
Rohlf, V., & Bennett, P. (2005). Perpetration-induced traumatic stress in persons who euthanize
nonhuman animals in surgeries, animal shelters, and laboratories. Society & Animals, 13, 201-
219.
Root Kustritz, M. V. (2012). Effects of surgical sterilization on canine and feline health and on
society. Reproduction in Domestic Animals, 47, 214-222.
Rowan, A. N. (1992). Shelters and pet overpopulation: A statistical black hole. Anthrozoös, 5,
140-143.
Samoylov, A., Cox, N., Cochram, A., Wolfe, K., Donovan, C., Kutzler, … Samoylova, T.
Generation and characterization of phage-GnRH chemical conjugates for potential use in cat and
dog immunocontraception. Reproduction in Domestic Animals, 47, 406-411.
Schmidt, P. M., Swannack, T. M., Lopez, R. R., & Slater, M. R. (2009). Evaluation of euthanasia
and trap-neuter-return (TNR) programs in managing free-roaming cat populations. Wildlife
Research, 36, 117-125.
Serpell, J. (1991). Beneficial effect of pet ownership on some aspects of human health and
behaviour. Journal of the Royal Society of Medicine, 84, 717-720.
Siegel, J. M. (1990). Stressful life events and use of physician services among the elderly: the
moderating role of pet ownership. Journal of Personality and Social Psychology, 58, 1081-1086.
Sirivaidyapong, S., Mehl, N. S., Trigg, T. E. (2012). Delay of puberty and reproductive
performance in male dogs following the implantation of 4.7 and 9.4 mg GnRH-agonist deslorelin
at an early pre-pubertal age. Reproduction in Domestic Animals, 47, 400-402.
Slater, M. R., Di Nardo, A., Pediconi, O., Dalla Villa., P., Candeloro, L., Alessandrini, B., & Del
Papa, S. (2008). Free-roaming dogs and cats in central Italy: public perceptions of the problem.
Preventive Veterinary Medicine, 84, 27-47.
43
Spain, C. V., Scarlett, J. M., Houpt, K. A., & Houpt, K. A. (2004). Long-term risks and benefits
of early-age gonadectomy in dogs. Journal of the American Veterinary Medical Association,
224, 380-387.
Sriaroon, C., Sriaroon, P., Davirantansilpa, S, Khawplod, P., & Wilde. H. (2006). Retrospective:
Animal attacks and rabies exposures in Thai children. Travel Medicine and Infectious Disease, 4,
270-274.
Srivastava, N., Santhanam, R., Sheea, P., Mukund, S., Thakral, S. S., Malik, B. S., & Gupta, S.
K. (2002). Evaluation of the immunocontraception potential of Escherichia coli-expressed
recombinant dog ZP2 and ZP3 in a homologous animal model. Reproduction, 123, 847-857.
Stubbs, W. P., & Bloomberg, M. S. (1995). Implications of early neutering in the dog and cat.
Seminars in Veterinary Medicine and Surgery (Small Animal), 10, 8-12.
Stubbs, W. P., Bloomberg, M. S., Scruggs, S. L., Shille, V. M., & Lane, T. J. (1996). Effects of
prepubertal gonadectomy on physical and behavioural development in cats. Journal of the
American Veterinary Medical Association, 209, 1864-1871.
Tenzin, T., McKenzie, J. S., Vanderstichel, R., Rai, B. D., Rinzin, K., Tshering, Y., …Ward, M.
P. (2015). Comparison of mark-resight methods to estimate abundance and rabies vaccination
coverage of free-roaming dogs in two urban areas of south Bhutan. Preventive Veterinary
Medicine, 118, 436-448.
THS. (2013). No Kill at the Toronto Humane Society. Retrieved from:
http://www.torontohumanesociety.com/pdfs/No_Kill_Directive_-_FINAL.pdf
Tricco, A. C., Tetzlaff, J., & Moher, D. (2011). The art and science of knowledge synthesis.
Journal of Clinical Epidemiology, 64, 11-20.
Trigg, T. E., Wright, P. J., Armour, A. F., Williamson, P. E., Junaidi, A., Martin, G. B., Doyle,
A. G. & Walsh, J. (2001). Long term reversible desexing of male dogs and oestrus
postponements of bitches, using a GnRH analogue implant. Journal of Reproduction & Fertility,
Supplement, 57, 255-261.
Toukhsati, S. R., Young, E., Bennett, P. C., & Coleman, J. Wandering cats: Attitudes and
behaviors towards cat containment in Australia. Anthrozoos, 25, 61-74.
Twyford, B. K. L., Humphrey, P. G., Nunn, R. P., & Willoughby, L. (200). Eradication of feral
cats (Felis catus) from Gabo Island, south-east Victoria. Ecological Management & Restoration,
1, 42-49.
Vargas-Pino, F., Gutiérrez-Cedillo, V., Canales-Vargas, E. J., Gress-Ortega, L. R., Miller, L. A.,
Rupprecht, C. E., …Slate, D. (2013). Concomitant administration of GonaConTM and rabies
vaccine in female dogs (Canis familiaris) in Mexico. Vaccine, 31, 4442-4447.
Voslářá, E., & Passantino, A. (2012). Stray dog and cat laws and enforcement in Czech Republic
and in Italy. Annali dell’Istituto Superiore di Sanità, 48, 97-104.
44
Wald, D. (2015). Understanding stakeholder conflict: An analysis of public values, risk
perceptions and attitudes toward outdoor cat management (Doctoral Dissertation). University of
Florida.
Walsh, F. (2009a). Human-animal bonds I: the relational significance of companion animals.
Family Process, 48, 462-480.
Walsh, F. (2009b). Human-animal bonds II: the role of pets in family systems and family
therapy. Family Process, 48, 481-499.
Weng, H. Y., Kass, P. H., Chomel, B. B., & Hart, L. A. (2006). Educational intervention on dog
sterilization and retention in Taiwan. Preventive Veterinary Medicine, 76, 196-210.
Wenstrup, J., & Dowidchuk, A. (1999). Pet overpopulation: data and measurement issues in
shelters. Journal of Applied Animal Welfare Science, 2, 303-319.
White, D. J., & Shawhan, R. (1996). Emotional responses of animal shelter workers to
euthanasia. Journal of the American Veterinary Medical Association, 208, 846-849.
WHO. (1992). WHO Expert Committee on Rabies [meeting held in Geneva from 24 to30
September 1991]: eight report.
Winter, L. (2004). Trap-neuter-release programs: the reality and the impacts. Journal of the
American Veterinary Medical Association, 225, 1369-1376
Zasloff, R. L., & Kidd, A. H. (1994). Loneliness and pet ownership among single women.
Psychological Reports, 75, 747-752.
Zaunbrecher, K. I., & Smith, R. E. (1993) Neutering of feral cats as an alternative to eradication
programs. Journal of the American Veterinary Medical Association, 203, 449-452.
Zilcha-Mano, S., Mikulincer, M., & Shaver, P.R. (2011). An attachment perspective on human-
pet relationships: conceptualization and assessment of pet attachment orientations. Journal of
Research in Personality, 45, 345-357.
45
CHAPTER TWO
A Scoping Review of Published Research on the Population Dynamics and Control
Practices of Companion Animals
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Abstract
Companion animal population dynamics is a global, diverse issue and can affect society in
multiple ways, including impacts on public health, environmental destruction and shelter
management. The purpose of this scoping review was to use structured and transparent methods
to identify all published research investigating companion animal population dynamics and/or
control practices. A comprehensive search strategy was implemented using five online databases
(i.e., PubMed, CAB Direct, Agricola, PsycINFO, and Scopus) and resulted in the identification
of 7,810 unique citations. These citations were screened for relevance by two independent
reviewers. Of these, 1,353 were initially deemed relevant. Full articles were procured and 869
articles (450 primary research and 419 reviews) were confirmed relevant and relevant data
extracted. Most of the included articles were published in the United States (364, 41.4%) and 217
articles (25%) were published between 2012 and 2015. The majority of the articles investigated
or discussed control practices (705, 80.2%), more specifically on different reproduction control
practices (552, 59.4%), and euthanasia (333, 37.9%) methods. This quantity of research in these
areas indicates an opportunity for systematic reviews and meta-analysis.
47
Introduction
Companion animals, including dogs, cats, horses, and rabbits, are broadly present in today’s
society. In the United States, in 2012 there were approximately 70 million owned dogs and 74
million owned cats (AVMA, 2012). In the UK, in 2014 there were approximately 9 million dogs
and 7.9 million cats owned (PFMA, 2014), and in Canada, in 2011 approximately 5.9 million
and 7.9 million owned dogs and cats, respectively (CVMA, 2011). The owned companion
animal population is one component of determining the companion animal population size. Free
roaming and unwanted companion animals combined with owned populations create the total
population. Obtaining information on the unowned free roaming population can be difficult, but
some estimates indicate that this population may be as large as the owned population. For
example, according to the American Society of the Protection of Cruelty to Animals (ASPCA)
(2014), there are 70 million stray cats in the United States.
Many factors lead to the development of free roaming (owned and unowned) and unwanted
companion animal populations. One factor is different pet ownership practices: allowing pets to
roam freely that are sexually intact leads to unwanted litters and a lack of pet identification leads
to lost animals entering the shelter with no information to contact their owners. The unwanted
companion animal population is a result of abandonment and relinquishment, which can lead to
overcrowded shelters and larger stray or feral populations. Free roaming companion animals can
have many negative impacts on their surrounding environment. For example, if intact, they are
able to reproduce, creating larger populations potentially leading to an even greater impact. They
may spread disease to humans (Gerhold and Jessup, 2013) and other animals (Gerhold and
Jessup, 2013; Hollings et al., 2013). They may also attack humans (Mustiana et al., 2015;
Sudarshan et al., 2006) and other populations (e.g., birds, small mammals) (Hawkins, Grant and
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Longnecker, 1999; Butler, du Toit and Bingham, 2004). In addition, free roaming companion
animals may contract disease themselves (Butler, du Toit and Bingham, 2004; Daryani et al.,
2009; Zain et al., 2013) and can be the victim of an attack from another animal and suffer from
injury (Butler, du Toit and Bingham, 2004).
Due to the multitude of effects of companion animal population dynamics, it has implications for
many different stakeholders. There are three main groups of stakeholders: 1) animal welfare
professionals; 2) public health professionals; and 3) ecologists, conservationists and wildlife
managers, each approaching the management of homeless animals from different perspectives.
Animal welfare professionals often want to ensure free roaming and unwanted animals are
humanely and ethically treated (Hiby, 2010). Public health officials are interested in controlling
the spread of zoonotic diseases, preventing biting incidents and managing sanitation related to
free roaming companion animals (Ezeokoli and Umoh, 1987; Beck, 2012; Dalla Villa et al.,
2013). Lastly, ecologists, conservationist and wildlife managers are concerned about free
roaming animals’, particularly cats’, impact on populations of native animal species and their
destruction of native habitats (Lepczyk, Mertig and Liu, 2003; Ratcliffe et al., 2010; Duffy and
Capece, 2012).
Since each stakeholder has their own targets and outcomes of interest, different control practices
have been employed and researched. The public health community has investigated a
combination of vaccination and trap-neuter-release (TNR) programs (Reece, Chawla and Hiby,
2013; Roebling et al., 2014). Ecologists, conservations and wildlife managers often advocate and
use euthanasia to decrease populations of animals, which predate on native species (Algar et al.,
2011). Animal welfare professionals have employed a variety of different reproduction control
options including non-surgical and surgical approaches as well as legislation, education and
49
adoption programs (Olson and Moulton, 1993; Hiby, 2010; Greenberg et al., 2013). As a result
of the diverse interest in companion animal population dynamics, a wide variety of research has
been published on this topic, and this research has not been previously synthesized using a
formal and structured approach that provides more credible evidence for decision-making
(Tricco, Tetzlaff and Moher, 2011).
Scoping reviews are a structured and transparent knowledge synthesis method conducted on
broad topics that are often policy driven (Arksey and O’Malley, 2005). They can also be used as
the beginning step to identify areas for subsequent systematic review and meta-analysis (SR-
MA), as well as identify the research gaps (Arksey and O’Malley, 2005).
The purpose of the current study was to use scoping review methodology to map out and
characterize the breadth and depth of existing literature on approaches to managing companion
animal population dynamics on a global scale. Specifically, the objectives were to determine
well-investigated research areas, research gaps and potential areas suitable for SR-MAs. The
results have the potential to inform the direction of future research on companion animal
population dynamics and to inform policy decisions for invested stakeholders at the local,
national and or international level.
Methods
Review Protocol, Team, Question and Scope
The review was performed using an a priori protocol adapted from Coe et al. (2014). Ten
individuals with varying expertise on the topic (companion animal population dynamics),
epidemiology and research-synthesis activities comprised the review team. The review question
was “What is the current state of knowledge on approaches to managing companion animal
50
population dynamics to control the number of owned free-roaming, unowned free-roaming and
unwanted companion animals?” Primary research (quantitative or qualitative), reviews, and
commentaries investigating or discussing companion animal population dynamics were included.
A list of key definitions can be found in Table 2.1.
Search Strategy
An existing list of known relevant literature (n=42) obtained from unpublished data collected as
part of the scoping review by Coe et al. (2014) on companion-animal relinquishment was used to
create a comprehensive search strategy. Using an arrangement of multiple population terms (e.g.
canine, feline, companion animals, pets), exposure terms (e.g. homeless, abandon, unowned,
feral) and intervention terms (e.g., spay, neuter, animal control), database-specific search
strategies were created. The search strategy was applied to five bibliographic databases:
MEDLINE, Scopus, CAB Direct, PsycINFO and Agricola. Different combinations of these
terms were tested in each database: adding, subtracting and reorganizing terms to ensure that the
search was capturing all potentially relevant articles. To assess the inclusivity of the final search
strategy, the proportion of the original 42 articles captured by entering the search strategy into all
five databases was determined (39/42 =97.5%). The initial search was completed on December
10, 2013 (MEDLINE), December 11, 2013 (CAB Direct, Agricola, PsycINFO) and December
18, 2013 (Scopus). An updated search using the original population terms combined with the
terms “growth rate”, “lambda“ or “carrying capacity”, was completed on December 23, 2013
(Agricola, MEDLINE, PsycINFO), December 24, 2013 (CAB Direct) and December 27, 2013
(Scopus). The final specific database search strings are available in Appendix A. The initial
searches did not contain any filters confining them.
51
In 2015, the most comprehensive searches were repeated to capture new articles published from
the time of the first searches. The repeated searches were performed in Medline, PyscINFO and
Scopus on May 28th, Agricola on May 29th and CABDirect on June 2nd of 2015. Medline,
CABDirect and Agricola had specific date restrictions that matched the last day the initial
searches were performed. Scopus and PsycINFO had year restrictions limiting the search from
2013 and onwards.
To assure the search was thorough, reference lists from two relevant book chapters, three
relevant literature reviews, 28 randomly selected relevant primary research articles (from the
2013 search) and a government document that included a list of citations on pet population
control articles, were hand searched for additional articles.
Relevance Screening
The relevance screening process began with an a priori designed form containing one key
question. The question examined whether or not the citation described population dynamics,
surveillance and/or control practices of free roaming (owned or unowned) and unwanted
companion animals. The form was reviewed by multiple independent stakeholders before being
used, and was pre-tested by four reviewers on 30 randomly selected abstracts. Relevance
screening advanced when a kappa agreement of 0.8 or greater was reached during pre-testing. At
this stage of reviewing, two individuals from the review team independently completed
relevance screening on the titles and abstracts of the identified citations. Disagreements were
resolved by consensus between the reviewing pair, if an agreement could not be made a third-
reviewer was brought in to resolve it. The final relevance screening form can be found in
Appendix A. Citations that focused solely on vaccination to control disease of free roaming and
unwanted companion animals were excluded as the interest of this review was control practices
52
that directly, controlled population size. All languages were kept at this stage. If the citations fit
the inclusion criteria it moved forward to the next stage of article procurement, data
characterization and extraction (DCE).
Article Procurement
To obtain copies of the full articles, titles, authors and journal or book titles were searched in the
University of Guelph’s database, Primo. If full copies of the articles could not be directly
obtained from Primo, a copy of the journal was requested through the University of Guelph
Annex. Articles not available through the University were requested through Interlibrary Loans
from other Universities. If the article was not available through these approaches, a Google
search was conducted for the full article. At this stage all outstanding citations were sent to a
team of librarians at the University of Guelph, the team of librarians conducted their own search
and provided information to the research team on how the full articles could be obtained. At this
stage, articles that remained missing were checked to determine the language they were
published in. If not published in English or Spanish, they were removed from the study due to
limited resources to review articles in other languages. Articles that were missing but published
in English or Spanish were searched to determine if the authors’ email could be obtained for a
copy of the article. If this could not be found, the article was removed from the study.
Data Characterization and Extraction (DCE)
The DCE process involved an a priori form, five stakeholders and two academics with content
expertise were invited to provide feedback on the DCE form and to ensure the form was
inclusive prior to use. The stakeholders were individuals’ who held positions with either the
Canadian Federation of Humane Societies (CFHS); the Society for Prevention of Cruelty to
53
Animals (in British Colombia or Ontario); or the Toronto Feral Cat program. One academic who
provided feedback, known for their research in the area of shelter medicine, was from the United
States. The feedback obtained was integrated into the final version of the DCE form. The form
was then pre-tested by four reviewers on 10 selected articles. Disagreements were discussed and
changes were made to increase relevance and clarity of the DCE form prior to use. The final
DCE form can be found in Appendix A. All reviewers that helped with DCE had to complete the
10 pre-test articles to ensure consistency in DCE. Disagreements among reviewers were resolved
by consensus between the DCE pair, and if an agreement could not be made a third-reviewer was
brought in to resolve it. At this stage, the DCE form was used to confirm relevance and to extract
important information from the full articles of the relevant citations. The DCE form was used to
extract information including publication year and type; companion animal type; population
type; the main themes and outcomes investigated; study design and data collection methods;
control practices and their effectiveness; strengths and weaknesses; and the overall
recommendations put forward in the article. There were six reviewers involved with this stage
and each article was reviewed by two reviewers independently. Three of the six reviewers were
fluent in Spanish, two of these reviewers were specifically brought on to review the articles
published in Spanish.
Review Management, Data Charting and Analysis
Citations captured by the search were uploaded to RefWorks (Thomson ResearchSoft,
Philadelphia, PA). Citations were de-duplicated in Refworks and then imported into DistillerSR
software (DistillerSR, Evidence Partners, Ottawa, CA), an electronic review-management
program, for relevance screening and DCE.
54
Results from the DCE stage were downloaded as Excel spreadsheets (Microsoft Corporation,
Redmond, WA) and were formatted, cleaned and analyzed. As the “other” categories in main
themes or focus; reproduction control methods; euthanasia methods; outcomes of interest; and
recommendations were large, they were further searched for common terms or methods to create
new categories. Excel was used to create “heat maps” and bubble charts. The bubble charts
represent cross-tabulations between the major themes investigated in primary research articles by
the publication year and the study location. The size of the “bubbles” within each bubble chart is
proportional to the number of articles in each categorical pair (Petersen et al., 2008; Coe et al.,
2014).
To visualize the cross-tabulation of investigated control practices by publication year, study
location, study design, companion animal population and companion animal population type, a
“heat map” table was created. Cell values were shaded on a grey scale, which represents the
percentage of articles within in each cross-tabulation category out of the total number of articles
investigating a control practice (n=301).
Results
Descriptive Characteristics of Published Research on Population Dynamics and Control
Practices
A total of 7,810 unique citations were found through the searches (Figure 2.1). Relevance
screening indicated 1,353 citations were potentially relevant. These were procured as full
articles. Among these citations, 26 books, theses or conference proceedings were procured and
found to contain more than one relevant chapter or research article. Each of these potentially
relevant chapters or research articles was subsequently treated as a unique citation, resulting in
the edition of 410 citations (producing a total of 1753 potentially relevant citations). After
55
completing DCE, 869 of the citations were confirmed truly relevant, including 450 primary
research articles and 419 reviews (Figure 2.1). Tables 2.2 and 2.3 provide details on the main
characteristics extracted from the articles.
The majority of the articles were published from 2000 onwards (69.1%) with the median year
being 2005 and a range from 1950-2015. There were 216 articles (24.9%) published in the last
four years (Figure 2.2). Most of the articles were based on work from the United States (41.3%)
and journal articles were the most common type of document published (76.4%) (Table 2.2).
The majority of the articles did not specify a target stakeholder (52.0%); however when broken
down into primary research and reviews, reviews more frequently reported a stakeholder (62.8%)
(Table 2.2). The most common stakeholders identified in both primary research and reviews
were individuals of the veterinary community (27.5%), animal welfare
organizations/professionals (17.5%) and society (14.0%) (Table 2.2).
The relevant articles mainly focused on cats (67.4%) or dogs (59.3%) as the companion animals
of interest, with a slightly higher focus on cats (Table 2.3). Unowned free roaming companion
animals, which includes feral and stray, were the main type of population studied (69.3%).
Control practices were the main focus of the articles included (Table 2.3). The majority of the
articles that focused on control practices studied reproduction control methods or programs
(62.7%) (Table 2.3). Non-surgical (23.0%), trap neuter release (TNR) (18.4%) and low cost
(14.7%) reproduction control were the top reproduction control methods or programs
investigated. Non-surgical was further broken down into subcategories with chemical castration
(7.2%), zona pellucida immunocontraception (6.5%) and GnRH immunocontraception (6.3%)
being the three most common non-surgical methods discussed in both primary research and
reviews (Table 2.3). Euthanasia was the next most common major control practice reported.
56
The main outcome of interest reported was improving methodology (64.6%). Views and
opinions on free roaming and unwanted companion animals as well as views on factors affecting
free roaming and unwanted companion animals (35.2%) were also a main focus and outcome of
many articles (Table 2.3).
The effectiveness of control practices was reported in a majority of the articles that investigated
or discussed control practices (492, 56.6%). Effectiveness was more commonly reported in
reviews (288, 58.5%) than primary research (204, 41.5%). A total of 24 primary research articles
and 69 reviews reported the effectiveness of TNR, 16 primary research articles and 34 reviews
reported the effectiveness of chemical castration and 18 primary research articles and 27 reviews
reported the effectiveness of ZP immunocontraception.
Many different recommendations were reported in the literature (Table 2.4). Further research or
development of control practices (37.1%), recommending reproduction control (34.3%),
controlling the free roaming and unwanted population size (32.0%) and increasing public
education (31.9%) were the main recommendations.
There were also 299 articles classified as other, which indicated many articles mentioned issues
of or recommendations for free roaming and unwanted companion animals but the main focus of
the articles was not companion animal population dynamics or control practices (e.g., prevalence
of disease, population dynamics of native species).
Characteristics of Primary Research
The majority of primary research articles were cross-sectional observational studies (30.0%).
Data were most commonly collected by the research authors (329, 73.1%) compared to
veterinarians, shelter workers, public health professionals, members of society, trained
57
interviewers, and other individuals and used quantitative questionnaires (38.9%) or observations
(41.3%) (Table 2.5). Most of the primary articles reported prevalence (79.1%) outcomes. For
example, data from surveys (e.g. number or percentage of individuals who allow their dog to
roam). Many authors also provided p values and measures of variability (Table 2.5). Graphs
were commonly provided in studies as another way to report the data (229, 50.9%). Most authors
reported at least one strength (59.6%) and/or one weakness (55.3%) of the study. Further details
on the methodology, outcomes and reporting characteristics are reported in Table 2.5.
The main themes of primary research articles are stratified against location and publication date
in Figure 2.3 and 2.4. Over the years, primary research articles investigating population
dynamics, control practices and opinions on free roaming companion animals have increased.
The number of articles investigating surveillance specifically, doubled after 2009.
Table 2.6 stratifies different companion-animal control practices against publication year,
location, study design, animal population and population type. The results indicated that of the
301 primary research articles investigating control practices, reproduction control and euthanasia
were consistently focused on, with the amount of primary research articles investigating
euthanasia increasing over the years. Experimental studies were the most common study design
to investigate reproduction control while observational studies were the most common study
design to investigate euthanasia (Table 2.6). Unowned free roaming companion animals were
consistently the main target population for research on all of the different control practices
identified. An equal number of studies investigated reproduction control as a practice for
controlling population dynamics of free roaming and unwanted dogs and cats. Euthanasia,
confinement, mandatory spay and neuter and other types of control programs were more
commonly researched for controlling cat population dynamics while rehoming, vaccination,
58
legislations and education were more commonly researched for controlling the population
dynamics of dogs (Table 2.6).
Discussion
The results of this scoping review demonstrate the vast interest in and wide range of global
research into further understanding companion animal population dynamics. Further, the review
highlights the broad range of stakeholders invested in conducting research in this area.
Examining companion animal population dynamics on a global scale provides a broad
understanding of stakeholders’ perspectives and priorities from countries where the topic has
been studied. For example, the context of captured research ranged from eradication of invasive
species (i.e., feral cats) in Australia (Algar, Burbidge and Angus, 2002; Algar, Angus and Onus,
2011; Kennedy et al., 2012), to controlling free roaming dog reproduction and rabies in India
(Reece and Chawla, 2006; Totton et al., 2010; Yoak et al., 2014).
The increasing number of articles being published each year on this topic further demonstrates
the immense interest in companion animal population dynamics, and that the subject continually
gains more attention. In addition, it suggests that companion animal population dynamics are still
affecting many areas around the world. For example, in 2012 to 2013, in Bangladesh a catch
neuter vaccinate release program was conducted to control rabies and the dog population (Tenzin
et al., 2015), in Kashmir over 13852 dog bites were reported between April 2010 and May 2013
with 96% of them due to stray dogs (Lone et al., 2014) and in Hawaii a survey conducted in
2011 on stakeholders’ opinions on feral cats indicated that 86.9% respondents wanted to see the
number of cats decrease (Lohr and Lepczyk, 2014). Furthermore, as there are almost as many
reviews as there are primary research articles, it supports that this topic is highly discussed and
debated by many different stakeholders.
59
Despite companion animal population dynamics being a worldwide issue, a majority of the
relevant articles were from the United States. Only a few articles were conducted in Canada,
South America and Africa and there were pockets of research conducted in Asia (India) and
Europe (United Kingdom and Italy). The large number of articles published in the United States
could be a result of the way Americans view companion animals, as 95% of pet owners see their
pet as a friend and 87% of pet owners considered their pet a family member (Walsh, 2009). This
view suggests that Americans have a difficult time viewing free roaming companion animals as
wildlife and also have sympathy for unwanted companion animals which could impact the
control practices being researched and also increase the desire or need for research to be
conducted on these populations. In addition, the large amount of articles published in the United
States could be a result of overcrowded shelters and the desire to improve the situation. Previous
research has indicated that approximated 60% of the animals that entered U.S. shelters were
euthanized (Rowan, 1992; Wenstrup and Dowidchul, 1999). It was reported that the shelters only
had enough capacity to house 2.6% of the animals entering and that 34% of the animals
euthanized was due to capacity (Wenstrup and Dowidchul, 1999). As companion animal
population dynamics is diverse and can affect areas around the world differently, more research
needs to be conducted in these regions to understand the different issues each area faces, and to
understand different issues within each country or culture associated with controlling free
roaming and unwanted companion animals.
The total number of articles (primary research and reviews) focusing on control practices was
greater than the number of articles focusing on companion animal population dynamics,
surveillance, and views on free roaming and unwanted companion animal populations or
methods used to control them. Understanding the biological factors that influence the free
60
roaming and unwanted companion animal populations, such as migration, births and deaths
(ultimately determining the size of the population), could play a vital role in the success of
control programs being implemented. Also, society has to accept and support the type of control
program being used for the program to be successful (Mahlow and Slater, 1996; Lohr and
Lepczyk, 2014). There is an opportunity for more research to be conducted on the biological
factors that influence the population size of free roaming and unwanted companion animals, as
well as societal perceptions on control practices, to aid in the development of successful and
accepted policies surrounding the control of these populations.
The difficult nature of obtaining free roaming population sizes may also explain why
surveillance was not the main focus of the majority of articles. However, between the years 2010
and 2015, the number of articles that focused on surveillance almost doubled compared to
previous year groupings of before 2000, and 2000 to 2009, suggesting a recent increase in
research focus on this area. In addition, it could be related to the recent increase in use of the
mark-resight or sight-resight method, which was described as a simple way of obtaining the
population size of free roaming animals (Hiby et al., 2011; Punjabi, Athreya and Linnell, 2012).
Research should continue to focus on surveillance of free roaming companion animals, as
accurate data on population size are important to fully understand the effect of interventions on
companion animal population dynamics, in order to inform evidence-based control programs.
In the primary research articles, euthanasia as a control practice was more commonly researched
in the United States and Canada; and Oceanic countries compared to European, Asian or other
countries. This could be related to attitudes towards euthanasia in Europe and Asia as certain
laws and religions do not allow its promotion or practice (Hsu, Severinghaus and Serpell, 2003;
Voslářá and Passantino, 2012). The larger number of articles investigating euthanasia in Oceanic
61
countries is likely due to the many eradication programs conducted in Australia and surrounding
islands (Algar, Burbidge and Angus, 2002; Algar, Angus and Onus, 2011; Kennedy et al., 2012;
Koch, Algar and Schwenk, 2014). It has been suggested that one of the reasons the domestic cat
was brought to Australia and surrounding islands was to control rat and mice populations (Algar,
Angus and Onus, 2011). As a result, free roaming cats are considered an invasive species (Algar,
Burbidge and Angus, 2002; Koch, Algar and Schwenk, 2014); therefore, many Australians may
not have a negative view of the eradication of these cats and may be more accepting of
euthanasia as a control option.
In the current scoping review, unowned free roaming companion animals were identified as the
main population of focus, within the large body of research investigating companion animal
population dynamics. It is likely that unowned free roaming companion animal populations are
studied most often because control practices can be implemented without the consent of the pets’
owner, and in some countries members of society may consider these populations to be a
nuisance (Fielding and Mather, 2001; Poss and Bader, 2007; Gunther et al., 2015) and support
research and the control of these animal populations. In comparison, few articles investigated or
discussed owned free roaming and unwanted companion animals. Interestingly, within several
publications the authors still recommended improve animal identification use, and the promotion
of responsible pet ownership, which suggests that owned free roaming and unwanted companion
animals are still a population of interest with respect to companion animal population dynamics
and control. More research on the ecological, animal health, and public health impacts of these
populations and the methods needed to control them is required, to provide a fuller
understanding of this area.
62
Zoonotic diseases and other public health issues (animal bites and sanitation) were discussed
across much of the published research, more specifically within review articles. This indicates
that many individuals are discussing zoonotic disease and other public health issues in regards to
population dynamics but few primary research articles investigate these topics in the context of
population dynamics. The large amount of reviews discussing these topics suggest that
stakeholders believe that free roaming companion animals pose a risk to humans and other
species through disease spread, attacks and predation (Duffy and Capece, 2012; Nogales et al.,
2013; Hughes and MacDonald, 2013; Kachani and Health, 2014). The number of reviews and
commentaries that focused on the relationship between companion animal population dynamics
and public health issues suggests that more primary research is needed in this area including
research into the role of population dynamics in the spread of zoonotic diseases. Understanding
this information would not only improve the health and lives of humans living with free roaming
and unwanted companion animals, but also improve the health of free roaming companion
animals.
Almost all of the primary research articles reported at least some of their data in an extractable
way (94.5%), providing an opportunity for further synthesis and the potential for systematic
reviews. Prevalence outcomes were the most common measure reported in the results of primary
research collected during this scoping review, which aligns with the large amount of
observational studies that we identified. Many studies were looking at interventions, to
understand the effect on population size and not the risks or causality of the exposure and
outcome. Due to the nature of free roaming populations, proper experimental studies are
extremely challenging to determine the efficacy of control practices. However, studies
developing or investigating new non-surgical reproduction control products were generally
63
conducted using controlled trials, which suggests that primary research on non-surgical
reproduction control may offer a specific area for further knowledge synthesis efforts.
It has been suggested that free roaming and unwanted companion animals can negatively impact
humans (Sriaroon et al., 2006; Farnworth et al., 2012; Lone et al., 2014; Jain and Jain, 2014;
Gunther et al., 2015), other animals (Baker et al., 2008; Hervías et al., 2014), and the
environment, likely resulting in the large volume of published research focused on investigating
at least one type of control practice to manage companion animal populations. A large number of
studies have investigated and discussed different methods of reproduction control, and
euthanasia offering other potential areas for subsequent SR-MA that focus on the effectiveness
of these control practices. Specifically, prioritizing SR-MAs on the effectiveness of trap neuter
programs, non-surgical control methods, zona pellucida immunocontraception and chemical
castration, or the euthanasia method, poison, may be considered given the vast body of primary
research on these control practices reporting their effectiveness. More recent commentaries on
companion animal control measures have suggested the need for alternatives to surgical
sterilization, with a call for non-surgical reproduction control methods (Roberston, 2008;
Kuztler, 2010), which further highlights the value of prioritizing this area above all. Determining
the true effectiveness of control practices, through completing a SR-MA where possible, could
further help to inform policy decisions, allocation of resources and ultimately lead to the creation
of successful control programs. Although a wide variety of other companion animal population
control practices, such as mandatory spay and neuters, confinement, legislations and education,
have been investigated over the years, few studies investigated their effectiveness at controlling
free roaming and unwanted companion animals or mitigating the impacts caused by these
populations. As a result, further primary research into the effectiveness of other control practices
64
is likely necessary to inform the inclusion or exclusion of these practices within evidence-based
companion animal population control programs.
Few studies identified in the current review used mathematical modeling, yet it may provide a
good alternative to help inform the efficacy of control practices before investing resources.
Further research into the use of mathematical modeling and the ability to use modelling to
provide predictions on the relative performance of different control practices could result in more
successful control programs and aid in determining how to allocate resources. This said, in order
for a mathematical model to successfully assess the impact of a control practice, several
parameters need to be known including the free roaming population size, and obtaining such
information can be difficult (Flockhart, Norris and Coe, 2016). This may explain why more
mathematical models have not been developed to inform interventions to address issues relating
to companion animal population dynamics.
Despite the large amount of research that has already been conducted on this topic, a large
number of published articles are still calling for further research on the topic and further
development of control practices, indicating that free roaming and unwanted companion animals
are still an area of high interest for stakeholders. This may suggest that research on companion
animal population dynamics is complex and involves many areas and aspects of additional or
follow up research. Conducting follow-up SR-MA in this area could provide more information
on the efficacy of control practices, support mathematical models and determine if or where
further primary research is necessary.
Many reviews discuss public education and many authors of primary research and reviews
recommend increased public education on this issue, yet few primary research articles have
investigated the efficacy of education programs. Education programs that have been
65
implemented and researched include educational courses on how to prevent dog bites and
infections from dogs (Kato et al., 2003), an education curriculum for elementary schools on
overpopulation and companion animal reproduction control methods (Avanzio, 1991) to improve
the knowledge of the participants, educational booklets on rabies and rabies prevention to
improve the knowledge, attitudes and practice of participants (Matibag et al., 2009), and on pet-
care including benefits of sterilization to determine if it would improve dog retention, increase
the decision to spay or neuter and improve knowledge of pet-care (Weng et al., 2006). It is also
interesting to note that the number of primary research articles that investigated education have
been decreasing over the years. Developing an educational program that is beneficial to all pet
owners can be difficult as pet owners have different knowledge levels on pet care (Weng et al.,
2006); this may explain why few primary research articles have investigated educational
programs. Further research on education programs is needed, as they are being recommended
without a large body of supporting evidence conducted in different populations ad contexts. It is
important to understand the effects education have on the target population and in turn their
companion animal population.
The number of articles considered as ‘other’ further indicates that the research interest into the
control and population dynamics of free roaming and unwanted companion animals intersects
with many different research fields. Despite the fact that the main focus of these articles did not
align with the current scoping review’s interest, the number classified as “other” supports that
many stakeholders are interested in the impacts that can be caused by free roaming and unwanted
companion animals including the impacts on the population dynamics of native species, and
disease spread to both humans and other animals as a result of infected free roaming and
66
unwanted companion animals (Kilonzo and Komba, 1993; Forys and Humphrey, 1999; Ward et
al., 2011; Wang et al., 2012)..
Limitations
The current review did not include an exclusive grey literature search due to time and resource
constraints. The exclusion of grey literature obtained from relevant websites could have resulted
in some relevant unpublished articles being missed. However, a comprehensive hand search was
used to verify the search strategy and to minimize the number of any potential missed articles.
There is also no standardized approach to conducting a grey literature search (Eysenbach,
Tuishce and Diepgen, 2001) and it can be difficult to create precise search strategies to locate
relevant articles (Conn et al., 2003). As a result, we believe that the current scoping review still
captures the current state of knowledge on approaches to managing companion animal
population dynamics to control the number of owned free-roaming, unowned free-roaming and
unwanted companion animals.
Another limitation of the current scoping review is that we only included articles published in
English and Spanish. As almost half of the articles excluded due to language were written in
Portuguese, this could account for the lower number of articles published in South America
(Brazil) and or Europe (Portugal). The impact of excluding these articles is not known, future
researchers should try to include as many languages as is feasible. As well, some articles could
not be obtained and therefore, their relevance could not be confirmed. However, given the small
number of articles in this category, it is unlikely that their exclusion would significantly affect
the results.
Conclusion
67
A large number of published research articles on the topic of companion animal population
dynamics were captured and summarized in this review, indicating the global importance of this
research area. Reproduction control programs were the most commonly investigated control
program among the included articles, specifically TNR and non-surgical control methods such as
chemical castration and zona pellucida immunocontraception. These areas of research provide
potential opportunities for further knowledge synthesis activities in the form of SR-MAs to
determine a more accurate measure of the efficacy of such control programs. Primary research
consistently reported prevalence values which also provides opportunities for future SR-MAs.
Research gaps were identified on other control practices (such as public education), population
dynamics, surveillance, and views on free roaming and unwanted companion animals which
warrant further investigation. As more relevant research is conducted on free roaming and
unwanted companion animals, this review should continue to be updated to prioritize further
research and identify ongoing research gaps.
68
References
Algar, D., Angus, G. J., & Onus, M. L. (2011). Eradication of feral cats on Rottnest Island
Western Australia. Journal of the Royal Society of Western Australia, 94, 439-443.
Algar, D. A., Burbridge, A. A., & Angus, G. J. (2002). Cat eradication on Hermite Island,
Montebello Island, Western Australia. In C. R. Veitch & M. N. Clout (Eds.), Turning the tide:
The eradication of invasive species (pp. 14-18).
Arksey, H., & O’Malley, L. (2005). Scoping studies: towards a methodological framework.
International Journal of Social Research Methodology, 8, 19-32.
ASPCA. (2014). Pet statistics. Retrieved from http://www.aspca.org/animal-
homelessness/shelter-intake-and-surrender/pet-statistics
Avanzino, R. (1991). Pet overpopulation and humane education in schools and communities.
Journal of the American Veterinary Medical Association, 198, 1237-1240.
AVMA. (2012). Pet ownership & demographics sourcebook. Schaumberg IL: American
Veterinary Medical Association.
Baker, P. J., Molony, S. E., Stone, E., Cuthill, I. C., & Harris, S. (2008). Cats about town: is
predation by free-ranging pet cats Felis catus likely to affect urban bird populations. Ibis, 150,
86-99.
Beck, A. M. (2012). The human-dog relationship: a tale of two species. In C. N. L. Macpherson,
F. X. Meslin & A. I. Wandeler (Eds). Dogs, Zoonoses and Public Health (pp. 1-12).
Butler, J. R. A., du Toit, J. T., & Bingham, J. (2004). Free-ranging domestic dogs (Canis
familiaris) as predators and prey in rural Zimbabwe: threats of competition and disease to large
wild carnivores. Biological Conservation, 115, 369-378.
Coe, J. B., Young, I., Lambert, K., Dysart, L., Nogueira Borden, L., Rajić, A. (2014). A scoping
review of published research on the relinquishment of companion animals. Journal of Applied
Animal Welfare Science, 17, 253-273.
Conn, V. S., Isaramalai, S., Rath, S., Jantarakupt, P., Wadhawan, R., & Dash, Y. (2003). Beyond
MEDLINE for literature searches. Journal of Nursing Scholarship, 35, 177-182.
Crowther, M., Lim, W., & Crowther, M. A. (2010). Systematic review and meta-analysis
methodology. Blood, 116, 3140-3146
CVMA. (2011). Canada’s pet wellness report: A snapshot of Canada’s pet health and wellness
from the Canadian Veterinary Medical Association (CVMA), in partnership with Hill’s Science
Diet. Retrieved from https://www.canadianveterinarians.net/documents/canada-s-pet-wellness-
report2011
Dalla Villa, P., Messori, S., Possenti, L., Barnard, S., Cianella, M., & Francesco, C. (2013). Pet
population management and public health: a web service based tool for the improvement of dog
traceabilility. Preventive Veterinary Medicine, 109, 349-353.
Dayani, A., Sharif, M., Amouei, A., & Gholami, S. (2009). Prevalence of Toxocara canis in
stray dogs, northern Iran. Pakistan Journal of Biological Sciences, 12, 1031-1035.
69
Duffy, D. C., & Capece, P. (2012). Biology and impacts of Pacific Island invasive species. 7.
The domestic cat (Felis catus). Pacific Science, 66, 173-212.
Eysenbach, G., Tuische, J., & Diepgen, T. L. (2001). Evaluation of the usefulness of Internet
searches to identify unpublished clinical trials for systematic reviews. Medical Informatics and
the Internet in Medicine, 26, 203-218
Ezeokoli, C. D., & Umoh, J. U. (1987). Epidemiology of rabies in northern Nigeria.
Transactions of the Royal Society of Tropical Medicine and Hygiene, 81, 268-272.
Farnworth, M. J., Blaszak, K., Hiby, E. F., & Waran, N. K. (2012). Incidence of dog bites and
public attitudes towards dog care and management in Samoa. Animal Welfare, 21, 477-486.
Fielding, W. J., & Mather, J. (2001). Dog ownership in the West Indies: A case study form the
Bahamas. Antrhozoos, 14, 72-80.
Flockhart, D. T. T., Norris, D. R., & Coe, J. B. (2016). Predicting free-roaming cat population
densities in urban areas. Animal Conservation.
Gerhold, R. W., & Jessup D. A. (2013). Zoonotic diseases associated with free-roaming cats.
Zoonoses and Public Health, 60, 189-198.
Greenberg, M., Lawler, D., Zawistowski, S., Jöchle, W. (2013). Low-dose megestrol acetate
revisited: a viable adjunct to surgical sterilization in free roaming cats? The Veterinary Journal,
196, 304-308.
Gunther, I., Raz, T., Berke, O., & Klement, E. (2015). Nuisances and welfare of free-roaming
cats in urban settings and their association with cat reproduction. Preventive Veterinary
Medicine, 119, 203-213.
Hawkins, C. C., Grant, W. E., & Longnecker, M. T. (1999). Effect of subsidized house cats on
California birds and rodents. Transactions of the Western Section of the Wildlife Society, 35, 29-
33.
Hervías, S., Oppel, S., Medina, F. M., Pipa, T., Díez, A., Ramos, J. A., Ruiz de Ybáñez, R., &
Nogales, M. (2014). Assessing the impact of introduced cats on island biodiversity by combining
dietary and movement analysis. Journal of Zoology, 292, 39-47.
Hiby, E. (2010). Understanding the need: dog and cat reproduction control around the world. In
4th ACC&D International Symposium on Non-Surgical Contraceptive Methods of Pet Population
Control.
Hollings, T., Jones, M., Mooney, N., & McCallum, H. (2013). Trophic cascades following the
disease-induced decline of an apex predator, the Tasmanian Devil. Conservation Biology, 28, 63-
75.
Hughes, J., & Macdonald, D. W. (2013). A review of interactions between free-roaming
domestic dogs and wildlife. Biological Conservation, 157, 341-351.
Jain, P., & Jain, G. (2014). Study of general awareness, attitude, behaviour, and practice study on
dog bites and its management in the context of prevention of rabies among the victims of dog
70
bite attending the OPD services of the CHC Muradnagar. Journal of Family Medicine and
Primary Care, 3, 355-358.
Kachani, M., & Heath, D. (2014). Dog population management for the control of human
echinococcosis. Acta Tropica, 139, 99-108.
Kato, M., Yamamoto, H., Inukai, Y., & Kira, S. (2003). Survey of the stray dog population and
the health education program on the prevention of dog bites and dog-acquired infections:
comparative study in Nepal and Okayama Prefecture, Japan. Acta Medica Okayama, 57, 261-
266.
Kennedy, M., Phillips, B. L., Legge, S., Murphy, S. A., & Faulkner, R. A. (2012). Do dingoes
suppress the activity of feral cats in northern Australia? Austral Ecology, 37, 134-139.
Koch, K., Algar, D., & Schwenk, K. (2014). Population structure and management of invasive
cats on an Australian island. The Journal of Wildlife Management, 78, 968-975.
Kutzler, M. A. (2010). Non-surgical alternative or practitioners to control reproduction in dogs
and cats. Clinical Theriogenology, 2, 215-221.
Lepczyk, C. A., Mertig, A. G., & Liu, J. (2003). Landowners and cat predation across rural-to-
urban landscapes. Biological Conservation, 115, 191-201.
Lohr, C. A., & Lepczyk, C. A. (2014). Desires and management preferences of stakeholders
regarding feral cats in the Hawaiian Islands. Conservation Biology, 28, 392-403.
Lone, K. S., Bilquees, S., Salimkhan, M., & Ul Haq, I. (2014). Analysis of dog bites in Kashmir:
an unprovoked threat to population. National Journal of Community Medicine, 5, 66-68.
Mahlow, J.C., & Slater, M. R. (1996). Current issues in the control of stray and feral cats. Journal
of the American Veterinary Medical Association, 209, 2016-2020.
Matibag, G. C., Ohbayashi, Y., Kanda, K., Yamashina, H., Kumara, W. B. Gamini Perera, I. N.,
… Tamashiro, H. (2009). A pilot study on the usefulness of information and education campaign
material in enhancing the knowledge, attitude and practice on rabies in rural Sri Lanka. The
Journal of Infection in Developing Countries, 3, 55-64.
Mustiana, A., Toribio, J. A., Abdurrahman, M., Suadnya, I. W., Hernandez-Jover, M., Putra, A.
A. G., & Ward, M. P. (2015). Owned and unowned dog population estimations, dog management
and dog bites to inform rabies prevention and response on Lombok Island, Indonesia. PloS one,
10, e0124092.
Nogales, M., Vidal, E., Medina, F. M., Bonnaud, E., Tershy, B. R., Campbell, K. J., & Zavaleta,
E. S. (2013). Feral cats and biodiversity conservation: the urgent prioritization of island
management. BioScience, 63, 804-810
Olson, P. N., & Moulton, C. Pet (dog and cat) overpopulation in the United States. Journal of
Reproduction and Fertility. Supplement, 47, 433-438
71
Petersen, K., Feldt, R., Mujtaba, S., & Mattsson, M. (2008). Systematic mapping studies in
software engineering. Proceeding of the 12th International Conference Evaluation and
Assessment in Software Engineering, University of Bari, Italy.
PFMA. (2014). Pet Population. Retrieved from http://www.pfma.org.uk/pet-population-2014
Poss, J. E., & Bader, J. O. (2007). Attitudes toward companion animals among Hispanic
residents of a Texas border community. Journal of Applied Animal Welfare Science, 10, 243-
253.
Punjabi, G. A., Athreya, V., & Linnell, J. D. C. (2012). Using natural marks to estimate free-
ranging dog Canis familiaris abundance in a MARK-RESIGHT framework in suburban
Mumbai, India. Tropical Conservation Science, 5, 510-520.
Ratcliffe, N., Bell, M., Pelembe, T., Boyle, D., White, R. B. R., Godley, B., … Sanders, S.
(2010). The eradication of feral cats from Ascension Island and is subsequent recolonization by
seabirds. Oryx, 44, 20-29.
Reece, J. F., &Chawla, S. K. (2006). Control of rabies in Jaipur, India, by the sterilisation and
vaccination of neighbourhood dogs. The Veterinary Record, 153, 379-383.
Reece, J. F., Chawla, S. K., & Hiby, A. R. (2013). Decline in human dog-bite cases during a street
dog sterilisation programme in Jaipur, India. Veterinary Record, 172.
Robertson, S. A. (2008). A review of feral cat control. Journal of Feline Medicine and Surgery,
10, 366-375.
Roebling, A. D., Johnson, D., Blanton, J. D., Levin, M., Slate, D., Fenwick, G., & Rupprecht, C.
E. (2014). Rabies prevention and management of cats in the context of trap-neuter-vaccinate-
release programmes. Zoonoses and Public Health, 61, 290-296.
Rowan, A. N. (1992). Shelters and pet overpopulation: A statistical black hole. Anthrozöos, 5,
140-143.
Sriaroon, C., Sriaroon, P., Davirantansilpa, S, Khawplod, P., & Wilde. H. (2006). Retrospective:
Animal attacks and rabies exposures in Thai children. Travel Medicine and Infectious Disease, 4,
270-274.
Sudarshan, M. K., Mahendra, B. J., Madhusudana, S. N., Ashwatch Narayana, D. H., Rahman,
A., Rao., …Gangaboraiah. (2006). An epidemiological study of animal bites in India: results of a
WHO sponsored national multi-centric rabies survey. Journal of Communicable Diseases, 38,
32.
Tenzin, T., Ahmed, R., Debnath, N. C., Ahmed, G., & Yamage, M. (2015). Free-roaming dog
population estimation and status of the dog population management and rabies control program
in Dhaka City, Bangladesh. PLoS Neglected Tropical Diseases, 9, e0003784.
Totton, S. C., Wandeler, A. I., Zinsstag, J., Bauch, C. T., Ribble, C. S., Rosatte, R. C., &
McEwen, S. A. (2010). Stray dog population demographics in Jodhpur, India following a
population control/rabies vaccination program. Preventive Veterinary Medicine, 97, 51-57.
72
Tricco, A. C., Tetzlaff, J., & Moher, D. (2011). The art and science of knowledge synthesis.
Journal of Clinical Epidemiology, 64, 11-20.
Walsh, F. (2009). Human-animal bonds I: the relational significance of companion animals.
Family Process, 48, 462-480.
Weng, H. Y., Kass, P. H., Chomel, B. B., & Hart, L. A. (2006). Educational intervention on dog
sterilization and retention in Taiwan. Preventive Veterinary Medicine, 76, 196-210.
Wenstrup, J., & Dowidchuk, A. (1999). Pet overpopulation: data and measurement issues in
shelters. Journal of Applied Animal Welfare Science, 2, 303-319.
Yoak, A. J., Reece, J. F., Gehrt, S., & Hamilton, I. M. (2014). Disease control through fertility
control: secondary benefits of animal birth control in Indian street dogs. Preventive Veterinary
Medicine, 113, 152-156.
Zain, S. N. M., Sahimin, N., Pal, P., & Lewis, J. W. (2013). Macroparasite communities in stray
cat populations from urban cities in Peninsular Malaysia. Veterinary Parasitology, 196, 469-477.
73
TABLE 2.1
Key Definitions used in the Relevance Screening and Data Extraction Form
Term Definition
Companion animals Any animal species kept for companionship
and enjoyment or a household animal, as
opposed to livestock, laboratory animals,
working animals or sport animals, which are
kept for economic reasons.
Owned free-roaming companion animals Owned companion animals that are straying
from the owner’s residence or property.1
Unowned free-roaming companion animals Unowned companion animals that are stray or
feral. 2, 3, 4
Unwanted companion animals Companion animals who are not free-roaming
but are being surrendered to a shelter,
abandoned, are being given away, are being
sold, killed, or euthanized by their owners.5
Owned uncertain companion animals Companion animals as owned companion
animals but roaming status was not stated.
Population dynamics Any process that affects the size and/or
structure of a companion animal population
over time (e.g., births, deaths, migration).
Surveillance Monitoring the population size. 1Slater, et al., 2008
2Slater, 2004
3Faulkner, 1975
4Feldman & Carding, 1973
5Fielding, 2010
References
Faulkner, L.C. (1975) Dimensions of the pet population problem. Journal of the American
Veterinary Medical Association, 166, 5, 477-478.
Feldmann, B. M., & Carding, T. H. (1973). Free roaming urban pets. Health Services Reports,
88(10), 956-962.
74
Fielding, W.J. (2010). Dog breeding in New Providence, the Bahamas, and its potential impact
on the roaming dog population II: The fate of puppies. Journal of Applied Animal Welfare
Science, 13, 4, 300-313.
Slater, M.R., Di Nardo, A., Pediconi, O., Dalla Villa, P., Candeloro, L., Alessandrini, B., & Del
Papa, S. (2008). Free-roaming dogs and cats in central Italy: Public perceptions of the problem.
Preventive Veterinary Medicine, 84, 27-47.
Slater, M.R. (2004). Understanding issues and solutions for unowned, free-roaming cat
populations. Journal of the American Veterinary Medical Association, 225, 9, 1350-1354
75
TABLE 2.2
Descriptive Characteristics of 869 Primary-Research and Review and Commentary Articles
Investigating or Discussing the Issue of Companion-Animal Population Dynamics
All articles
(n =869)
Primary
research
(n =450)
Reviews and
commentaries
(n =419)
Question No. % No. % No. %
Document type
Journal article 664 76.4 394 87.6 270 64.4
Book or book chapter 80 9.2 12 2.7 68 16.2
Conference proceedings paper or
abstract 56 6.4 11 2.4 45 10.7
Thesis or dissertation 29 3.3 26 5.8 3 0.7
Report 14 1.6 4 0.9 10 2.4
Lay magazine article 11 1.3 1 0.2 10 2.4
Other 15 1.6 2 0.4 13 3.1
Study location
United States 359 41.3 158 35.1 201 48.0
Australia 65 7.5 51 11.3 14 3.3
India 31 3.6 23 5.1 8 1.9
United Kingdom 23 2.6 11 2.4 12 2.9
Italy 15 1.7 15 3.3 0 0
Canada 6 0.7 4 0.9 2 0.5
Multiple countries 119 13.7 6 1.3 113 27.0
Other 171 19.7 150 33.3 21 5.0
Not reported /applicable 80 9.2 32 7.1 48 11.5
Article Language
English 843 97.0 432 96.0 411 98.1
Spanish 25 2.9 17 3.8 8 1.9
Source of Fundinga
Government 137 15.8 113 25.1 24 5.7
76
University 76 8.7 71 15.8 5 1.2
Industry 67 7.7 53 11.8 14 3.3
Public health agency 21 2.4 15 3.3 6 1.4
Other 165 19.0 130 28.9 35 8.4
Not reported 548 63.1 190 42.2 358 85.4
Author reported stakeholdersa
Not clear or not explicitly reported 452 52.0 296 65.8 156 37.2
Veterinarians or veterinary
community 239 27.5 52 11.6 187 44.6
Animal welfare (shelters, rescues,
organizations) 152 17.5 56 12.4 96 22.9
Society 122 14.0 44 9.8 78 18.6
Animal control or pound 60 6.9 26 5.8 34 8.1
Public health 54 6.2 13 2.9 41 9.8
Ecologists, conservationists and
wildlife managers 49 5.6 20 4.4 29 6.9
Government 44 5.1 15 3.3 29 6.9
Cat colony managers 19 2.2 6 1.3 13 3.1
Breeders 16 1.8 3 0.6 13 3.1
Corporation, institution or business 14 1.6 6 1.3 8 1.9
Spay neuter groups 11 1.3 6 1.3 5 1.2
Other 113 13.0 52 11.6 61 14.6
a Column percentages do not add up to a 100% as multiple selections were allowed for these
questions
77
TABLE 2.3
Main Areas of Focus in the 869 Primary-Research and Review and Commentary Articles
Investigating or Discussing the Issue of Companion-Animal Population Dynamics
All articles
(n= 869)
Primary
research
(n =450)
Reviews and
commentaries
(n =419)
Question No. % No. % No. %
Companion-animal populations studieda
Cats 586 67.4 259 57.6 327 78.0
Dogs 515 59.3 254 56.4 261 62.3
Other 84 9.7 44 9.8 40 9.5
Type of companion animal populations
studieda
Un-owned free roaming 602 69.3 301 66.9 301 71.8
Unwanted 310 35.7 116 25.8 194 46.3
Owned uncertain 279 32.1 127 28.2 152 36.3
Owned free roaming 248 23.5 131 29.1 117 27.9
Not reported 70 8.1 31 6.9 39 9.3
Primary themes of the investigation or
discussiona
Control practices 697 80.2 298 66.2 399 95.2
Population dynamics 354 40.7 233 51.8 121 28.9
Surveillance 262 30.1 206 45.8 56 13.4
Views and opinions 245 28.2 90 20.0 155 37.0
Animal welfare 52 6.0 9 2.0 43 10.3
Other 130 15.0 67 14.9 63 15.0
Type of control practice investigateda
Reproduction controla 545 62.7 204 45.3 341 81.4
Non-surgicala 200 23.0 72 16.0 128 30.5
Chemical castration 62 7.1 18 4.0 44 10.5
78
Zona pellucida glycoproteins
immunocontraceptive 55 6.3 18 4.0 37 8.8
GnRH immunocontraceptive 54 6.2 10 2.2 44 10.5
Progestins 47 5.4 4 0.9 43 10.3
Hormonal implants 38 4.4 5 1.1 33 7.9
Other 94 10.9 19 4.2 75 17.9
Not specified 15 1.7 2 0.4 13 3.1
Trap Neuter Release 160 18.4 51 11.3 109 26.0
Low cost or subsidized 128 14.7 30 6.7 98 23.4
Traditional 114 13.1 29 6.4 85 20.3
Other neuter programs 76 8.7 29 6.4 47 11.2
Early 73 8.4 15 3.3 58 13.8
Other 70 8.1 9 2.0 61 14.6
Not specified 32 3.7 16 3.6 16 3.8
Euthanasiaa 332 38.2 113 25.1 219 52.3
Poison 80 9.2 24 5.3 56 13.4
Shooting 67 7.7 22 4.9 45 10.7
Intravenous injection 31 3.6 8 1.8 23 5.5
Trap and euthanize 30 3.5 7 1.6 23 5.5
Gas 23 2.6 3 0.7 20 4.8
Biological control 22 2.5 7 1.6 15 3.6
Blunt force trauma 10 1.2 0 0.0 10 2.4
Electrocution 10 1.2 0 0.0 10 2.4
Drowning 10 1.2 0 0.0 10 2.4
Other 69 7.9 22 4.9 47 11.2
Not specified 177 20.4 58 12.9 119 28.4
Education 142 16.3 24 5.3 118 28.2
Rehoming 133 15.3 45 10.0 88 21.0
Legislation/Regulationsa 126 14.5 31 6.9 95 22.7
Licensing and registration 95 10.9 26 5.8 69 16.5
79
Breeding laws 26 3.0 2 0.4 24 5.7
Responsible Ownership Laws 11 1.3 2 0.4 9 2.1
Other 71 81.7 11 2.4 61 14.6
Not specified 7 0.8 2 0.4 5 1.2
Confinement 74 8.5 13 2.9 61 14.6
Mandatory spay and neuter 50 5.8 12 2.7 37 8.8
Do nothing 10 1.2 5 1.1 5 1.2
Other 134 15.4 52 11.6 82 19.6
Outcome investigateda
Improve methodology of control
practices 561 64.6 217 48.2 344 82.1
Views/opinions on free roaming/
unwanted companion animals 306 35.2 104 23.1 202 48.2
Free roaming/ unwanted companion
animal size 266 30.6 153 34.0 113 27.0
Zoonotic disease 221 25.4 68 15.1 153 36.5
Animal characteristics 218 25.1 165 36.7 53 12.6
Number of euthanized free roaming
unwanted companion animals 201 23.1 91 20.2 110 26.3
Animal reproduction ability 199 22.9 141 31.3 58 13.8
Other public health/safety issues (e.g.,
animal bites, sanitation) 168 19.3 56 12.4 112 26.7
Protect the environment and other
species 159 18.3 63 14.0 96 22.9
By-laws and legislations 130 15.0 30 6.7 100 23.9
Number of shelter intakes 111 12.8 61 13.6 50 11.9
Cost benefit of a control program for
free roaming/ unwanted companion
animals 91 10.5 34 7.6 57 13.6
Non-zoonotic disease 84 9.7 27 6.0 57 13.6
Number of adoptions 81 9.3 54 12.0 27 6.4
Ownership statistics 77 8.9 48 10.7 29 6.9
80
Spatial movement or data 55 6.3 44 9.8 11 2.6
Human demographics 53 6.1 46 10.2 7 1.7
Prevalence of disease in free roaming/
unwanted companion animals 47 5.4 24 5.3 23 5.5
Number of free roaming/unwanted
companion animals in shelters 41 4.7 22 4.9 19 4.5
Ectoparasites 36 4.1 11 2.4 25 6.0
Other 378 43.5 225 50.0 153 36.5
a Column percentages do not add up to a 100% as multiple selections were allowed for these
questions
81
TABLE 2.4a
Author-Reported Recommendations from the 869 Primary-Research and Review and
Commentary Articles Investigating or Discussing the Issue of Companion Animal Population
Dynamics
All
articles (n =869)
Primary
research (n =450)
Reviews and
commentaries
(n =419)
Question
No. % No. %
No. %
Further research 322 37.1 207 46.0 115 27.4
Reproduction Controla 298 34.3 116 25.8 182 43.4
Low Cost Spay and Neuter 67 7.7 21 4.7 46 11.0
Non-surgical Reproduction
Controla 49 5.6 13 2.9 36 8.6
Chemical castration 9 1.0 5 1.1 4 1.0
GnRH
immunocontraceptive 3 3.5 2 0.4 1 0.2
Zona Pellucida
glycoproteins
immunocontraceptive 4 0.5 2 0.4 2 0.5
Hormonal implants 1 0.1 1 0.2 0 0.0
Other 14 1.6 7 1.6 6 1.4
Not specified 14 1.6 0 0.0 14 3.3
Early 51 5.9 19 4.2 32 7.6
Traditional 35 4.0 9 2.0 26 6.2
Trap Neuter Release 48 5.5 20 4.4 28 6.7
Other Neuter Programs 28 3.2 16 3.6 12 2.9
Other 49 5.6 11 2.4 38 9.1
Not specified 45 5.2 20 4.4 25 6.0
82
Control free roaming/unwanted
population size 278 32.0 135 30.0 143 34.1
Increase public education 277 31.9 117 26.0 160 38.2
Enforce new and or existing
legislations/ regulationsa 134 15.4 40 8.9 94 22.4
Licensing and registration 89 10.2 23 5.1 66 15.8
Breeding laws 27 3.1 7 1.6 20 4.8
Other 78 9.0 15 3.3 63 15.0
Not specified 7 0.8 2 0.4 5 1.2
Improve data or monitoring 121 13.9 68 15.1 53 12.6
Collaboration of stakeholders 112 12.9 34 7.6 78 18.6
Control the spread of disease 101 11.6 43 9.6 58 13.8
Promote responsible pet
ownership 97 11.2 31 6.9 66 15.8
Increase vaccination 94 10.8 40 8.9 54 12.9
Confinement 78 9.0 27 6.0 51 12.2
Guidelines 70 8.1 25 5.6 45 10.7
Consider or change public
views/opinions/attitudes/religions
or gain public’s support 60 6.9 30 6.7 30 7.2
Increase the number of free
roaming/ unwanted companion
animals 55 6.3 22 4.9 33 7.9
Protect the environment and
species 53 6.1 28 6.2 25 6.0
Mandatory spay and neuter 50 5.8 8 1.2 42 10.0
Increase education or training of
stakeholders 48 5.5 19 4.2 29 6.9
Increase euthanasiaa 49 5.6 14 3.1 35 8.4
Poison 9 1.0 5 1.1 4 9.5
Shooting 5 0.6 3 0.7 2 4.8
Intravenous injection 1 0.1 0 0.0 1 2.4
Gas 1 0.1 0 0.0 1 2.4
83
Other 25 2.8 7 1.6 18 4.3
Not specified 15 1.7 3 0.7 12 2.9
Improve or promote ID use 46 5.3 16 3.6 30 7.2
Decrease euthanasiaa 45 5.2 10 2.2 35 8.4
Poison 2 0.2 1 0.2 1 0.2
Other 9 1.0 2 0.4 7 1.7
Not specified 35 4.0 8 1.8 27 6.4
Obtain or relocate funding 33 3.8 12 2.7 21 5.0
Restrict companion animal access
to resources 29 3.3 12 2.7 17 4.1
Use a multifaceted approach 21 2.4 3 0.7 18 4.3
Understand population dynamics 19 2.2 8 1.8 11 2.6
Not specified 124 14.3 66 14.7 58 13.8
Other: 283 32.6 136 30.2 145 34.6
a All column percentages do not add up to a 100% as multiple selections were allowed for these
questions
84
TABLE 2.5
Methodological, Outcomes and Reporting Characteristics of 450 Primary-Research Articles
Investigating the Issue of Companion-Animal Population Dynamics
Characteristic No. %
Study type (n = 450):
Cross-sectional 134 30.0
Cohort 19 4.2
Case-control 4 0.9
Other observational study: 23 5.1
Controlled trial 58 12.9
Quasi-experiment 21 4.7
Other experimental study: 14 3.1
Qualitative 7 1.6
Routine monitoring or surveillance data collection 67 14.9
Mathematical model or methodology study 34 7.6
Other: 68 15.1
Data collection methodsa (n =450)
Observations/field visits 186 41.3
Quantitative questionnaires or surveys 175 38.9
Analysis of records or database 122 27.1
Qualitative interviews 13 2.9
Focus groups 5 1.1
Other 201 44.7
Not specified 9 2.0
Reported data in an extractable waya 430 95.6
Prevalence outcome 356 79.1
Continuous outcome 302 67.1
P values 264 58.7
85
Measure of variability (e.g., standard deviation,
standard error, confidence intervals) 232 51.6
Dichotomous outcome 79 17.6
Spatial analysis 62 13.8
Ordinal/ Likert scale 52 11.6
Modelling coefficients/ beta parameters 46 10.2
Measure of association (e.g., odds ratio, relative risk) 45 10.0
Other: 200 44.4
Reported data in an non-extractable way (e.g., graph) 244 54.2
Reporting of study strengths and limitations (n =450 )
At least one strength reported 268 59.6
At least one limitation reported 249 55.3
a Column percentages do not add up to a 100% as multiple selections were allowed for these
questions
86
TABLE 2.6
Scoping Review Evidence Map Identifying the Number of Studies Investigating Control
Practices among 301 Primary Research Articles
Characteristics
Spay and Neuterb Euthanasiab Legislationb Rehomingb Educationb Confinementb
Mandatory SNb Otherb Totalb
Publication Year
Before 2000 45 29 13 11 11 3 4 3 119
2000-2009 81 30 8 15 10 1 3 20 168
2010-2015 77 53 10 19 3 9 5 28 204 Study Location
United States 93 46 16 31 15 9 8 25 243
Europe 14 4 6 6 0 2 2 4 38
Asia 28 9 3 1 7 1 0 1 50
Oceania 9 33 2 2 0 1 1 13 61
Multiple 3 4 1 3 0 0 0 1 12
Other 27 13 3 2 2 0 1 6 54
Study Design
Experimental 72 18 1 1 2 0 0 8 102
Observational 57 40 11 21 4 5 3 18 159 Mathematical Model 26 13 4 4 3 4 0 7 61 Routine Monitoring 20 20 10 10 7 2 5 10 84
Qualitative 2 5 1 2 0 0 1 0 11
Other 27 17 4 7 8 2 3 9 77
Companion-animal population
Dogs 113 55 24 37 22 5 7 21 284
Cats 115 81 19 27 13 10 11 42 318
Other 19 13 0 2 1 0 0 3 38 Population Type
Unowned free roaming 121 95 24 30 16 13 10 45 354 Owned free roaming 42 32 17 9 9 10 7 20 146
Unwanted 54 42 14 35 13 2 6 13 179 Owned uncertain 58 21 16 17 13 4 6 10 145
Not reported 30 1 0 0 0 0 0 0 31
Total 1133 674 207 292 159 83 83 307
87
Data are stratified by publication year and location, study design, and companion animal
population and companion animal population types investigated.
aCell shades represent the percentage of articles in each cross-tabulation category out of the total
number of articles investigating reasons for relinquishment (n = 84).
Legend:
0-5% 6-10% 11-20% 21-30% >30%
bMultiple selections were allowed (i.e., studies can be counted in more than one column and/or
row).
88
Figure 2.1 Scoping review flow-chart
Records identified through
database searches
(n = 10784)
Duplicates removed
(n = 3240)
Reference list hand search
(n = 266)
Relevance screening
(n = 7810)
Citations excluded
(n = 6457)
Data Extraction and
Characterization
(n = 1763)
Full-text articles excluded:
Non-relevant (n = 409)
Language (n = 166)
Unable to obtain (n = 20)
Other (n = 299)
26 books, thesis,
conference proceedings
(n= 410 additional citations)
Studies included in
scoping review
(n = 869)
Citations
(n = 11050)
89
Figure 2.2 Frequency of the 869 relevant published articles by year
0
146
25
50
75
100
125
Fre
que
ncy
1950 1975 2000 2015year
90
Figure 2.3.
Scoping-review evidence map of the key aspects and themes among 450 primary-research
articles stratified by study location
7
11
70
51
61
13
28
109
56
74
35
50
118
99
98
Control Practices
Surveillance
2010-2015
Other
Opinions and views
Population Dynamics
Before 2000 2000-2009
91
Figure 2.4.
Scoping-review evidence map of the key aspects and themes among 450 primary-research
articles stratified by year of publication
22
39
115
67
85
10
10
23
28
27
7
11
34
27
31
15
10
43
36
34
3
2
6
2
2
8
18
46
44
48
Other
Opinions and views
Control Practices
Population Dynamics
Surveillance
U.S. Multiple Continents
OceaniaAsiaEurope Other
92
CHAPTER THREE
Factors influencing time to adoption for dogs in a provincial shelter system in Canada
93
Abstract
Millions of animals are relinquished to shelters each year. For each animal submitted, animal
characteristics, animal history and characteristics of the shelter holding the animal influence the
dog’s time to adoption. Identifying which characteristics have the greatest effect on time to
adoption is important because only some of these factors are under the direct control of shelters,
while others may be addressed via outreach, legislation, or education. This is the first study
exploring this topic in Canada. Using a Cox proportional hazards frailty model, these issues were
explored using data from 31 shelters within of the British Columbia Society for the Prevention of
Cruelty to Animals’ shelter system. Results indicated that surrender reason, age, original source,
coat colour, breed, human population density of the shelter location, and year the animal entered
the shelter system significantly influenced time to adoption. Our study identified characteristics
of dogs that make them less likely to be adopted quickly. Given limited resources, these results
could inform shelters how best to allocate their resources particularly around targeting
interventions to improve adoption rates in their shelters.
94
Introduction
Overcrowding is an issue faced by animal shelters around the world, leading to poor animal
welfare (Turner, Berry and MacDonald, 2012), increased animal stress (Hurley, 2005; Turner,
Berry and MacDonald, 2012) and increased risk of the spreading of infectious disease agents
among animals (Hurley, 2005; Pesavento and Murphy, 2014). It also can result in hundreds of
healthy adoptable companion animals being euthanized each year (Patronek and Zawistowski,
2002; Kass, 2007). To euthanize mass numbers of animals can be extremely stressful and
emotional for shelter workers (White and Shawhan, 1996; and Gardner, 2008), causing feelings
of depression and sleep deprivation, and it can also affect their personal lives (White and
Shawhan, 1996 and Reeve et al., 2005). Shelter employees find it more difficult euthanizing
dogs compared to cats, as they generally tend to form stronger attachments to the dogs
(Rogelberg et al., 2007). The human impact of overcrowding can lead to increased shelter
employee turnover (Rogelberg et al., 2007). Due to these effects on humans and companion
animals, many shelters are trying to implement interventions that maximize the probability of
successful outcomes (adoption, reclamation) and minimize the number of unsuccessful outcomes
(euthanasia, return to shelter).
Exploring the general characteristics of companion animals entering shelters provides an
opportunity to better understand which animal and shelter characteristics maximize the
probability of successful outcomes (i.e., adoption) and decrease length of stay. Decreasing length
of stay has been suggested to decrease the stress caused from being in a shelter for the
companion animals (Karsten, 2014), which improves animal welfare. Studies conducted to date
on shelter dogs have shown that females, puppies (under a year of age), purebreds and small
dogs are preferred by adopters over males, adults, mixed breeds and medium to large dogs
95
(Lepper, Kass and Hart, 2002; Diesel, Smith and Pfeiffer, 2007; DeLeeuw, 2010). It has also
been found that relinquishment reasons can affect adoption probability; dogs relinquished due to
owner-related reasons have been found to be more likely to be adopted compared to dogs
relinquished for behavioural or health reasons (Lepper, Kass and Hart, 2002; DeLeeuw, 2010).
Much of the research in this area to date has been conducted in the United States and the United
Kingdom, with no previous research conducted in Canada. In addition, no previous research has
been conducted to investigate animal and shelter characteristics associated with the probability of
successful adoption or reduced LOS for dogs having entered a shelter system using a Cox
proportional. Such research is needed because the outcome and solutions for companion animals
entering shelters may be influenced by geographical and cultural factors.
The purpose of this study was to determine the characteristics that affect a dog’s time to adoption
within a large multi-shelter system in British Columbia, Canada. Specifically, the primary
objective of the current study was to examine whether the source from where a dog was
originally obtained affects an animal’s length of stay in an animal shelter.
Methods
This study received approval from the University of Guelph Research Ethics Board.
Description of Data Set
Through a data sharing agreement, de-identified data on companion animals entering 36 British
Columbia Society for the Prevention of Cruelty Animals’ (BC SPCA) shelters, between January
2004 and July 2014, were provided to the research team at the University of Guelph. The BC
SPCA is a province wide animal sheltering system which uses shelter management practices
ascribed to Capacity for Care (C4C). C4C is a collection of shelter management approaches
96
implemented to decrease unnecessary euthanasia within shelters, decrease the amount of time an
animal spends in a shelter, decrease disease transmission risk and decrease overall animal intake
(Karsten, 2014). In addition, once capacity has been reached, under the C4C management
approach, animals are no longer allowed to be surrendered to the shelter (Newbury et al., 2010).
Due to incomplete data from 2004 to 2009 for a number of shelters in the BC SPCA system, only
data records from 2010 to 2014 were used in the current analysis. The original data were
extracted from the BC SPCA’s shelter database software, ShelterBuddy (ShelterBuddy Software,
RSPCA QLD Inc., 2012). To address the study objective, only records that contained
information relating to dogs and which identified an original source for the dog (i.e., where the
owner originally obtained the animal) were included. Furthermore, for dogs to be included in the
analysis, the dog must have had the opportunity to be adopted or euthanized, which included
shelter records where the dog was classified as: adopted (failure data), available for adoption, in
shelter, escaped, stolen, unassisted death or euthanized (censor data). Dogs in the shelter records
that did not have an opportunity for adoption or euthanasia were removed from analysis
including those classified as: returned (returned to the shelter after being adopted), redeemed,
returned to surrender (returned to the owners after they were relinquished), released, and dead on
arrival (arrived at the shelter deceased). Dogs classified as deceased (an adopted dog whose
status was updated in the system when it was reported the dog had died) were also removed as
adoption date was no longer listed. In addition, dogs that were euthanized or died on the day they
entered (i.e., had a length of stay of zero) were excluded from the analysis as they did not have a
true opportunity of being adopted. Similarly, dogs that were adopted on the day they entered the
shelter system were also excluded from the analysis. Dogs that were brought to foster-only
97
branches of the BC SPCA were excluded from the current analysis as these branches had zero
capacity to hold dogs.
Only data from the dogs’ first time of admission were included in the current analysis. Data for
dogs with repeated admissions where it was unclear which data matched their first admission
were also removed from analysis. For each dog contributing data to the study, their shelter record
included age, breed, coat color, source (how the dog was brought into the shelter) and original
source, sex (male versus female), surrender reason, incoming branch to the BC SPCA, incoming
date (year the animal entered the shelter and was available for adoption or euthanasia for the first
time), status history date (which represents the first status date of a dog that has been in a shelter
before), current status date, and outcome. The variables online source and length of stay in days
were created based on variables within the shelter records. There were four shelter-level
variables included in the analysis: branch, holding capacity for dogs, shelter type and population
centre (i.e., human population of local community where the BC SPCA branch was located).
Information on holding capacity and shelter type was provided directly by the BC SPCA. Data
on the human populations where the shelters are located were collected from Statistics Canada.
Dog age was divided into two categories (pup or dog) based on the age at which point the dog
arrived in the shelter. The classification used the BC SPCA’s cut-off of less than one year of age
for classifying a dog as a pup.
The database originally contained over 100 different categories for breed. A dog was categorized
as a purebred when only one breed was listed. Breed mixes were identified based on the primary
breed listed (e.g., Border Collie mix). In addition, Labrador mix contained breeds listed as
Labradoodles, Labradoodle mixes, Labrador retriever mixes or Labrador mixes. Husky mix
contained Siberian husky mixes and Husky mixes. Once a breed mix was referenced more than
98
400 times in the dataset, a breed mix category was added based on the primary breed identified
in the record. When a mixed breed had less than 400 data points it was included under the ‘other
mix’ category. Using this approach, breed was reduced to eight different breed categories (i.e.,
Purebred, Border Collie mix, German Shepherd mix, Husky mix, Labrador mix, Shih Tzu mix
and other mix) to facilitate analysis.
Coat colour originally contained hundreds of colours and colour combinations that were reduced
to seven categories: patterned, mixed, black, brown, white, yellow or grey. A dog was classified
as “patterned” when its coat colour was listed as a pattern (e.g., tri-colour, merle, brindle), either
in the recording of their primary or secondary coat colour. A dog was classified as mixed when
two different colours or patterns were recorded as the primary and secondary coat colour. In
situations where two colours comprise a pattern (e.g., black and tan or tan points) the dog was
categorized as having a pattern coat colour instead of mixed coat colour. Specific to the black
and tan pattern, black (or blue) had to be listed as the primary colour. In situations where tan
was listed as the primary colour (e.g., tan and black), dogs were categorized as a mixed coat
colour.
Source was how the dog was brought into the shelter and comprised four categories: owner
surrender, stray, shelter offspring, or other. Original source represented how or where the
individual relinquishing the dog had originally obtained the animal, as recorded in the shelter
record. Eight categories in total were used for original source including: free pet, offspring of
owner’s pet, shelter or pound, breeder, rescue, friend or relative, stray or abandoned and other.
There were three other identified original sources (pet shop, veterinarian, and market flyer), that
were included as part of the ‘other’ category as they had a small number of data points. Another
unique variable (i.e., online source) was constructed from information recorded under original
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source in order to differentiate whether an animal was originally acquired through an online
source or not.
Surrender reason was coded into eight categories: accommodation change; behavioural
problems; cost; household animal population; human expectation and lifestyle; owner health or
illness; unwanted animal or litter; other. These categories were based on previously identified
criteria used in a systematic review examining the proportion of dogs surrendered for dog-related
and owner-related reasons (Lambert et al., 2014). The BC SPCA shelter records provided a
maximum of one reason per dog.
Population centre categories were based on Statistics Canada’s definitions of the human
population size for each city of the 34 BC SPCA shelters with a physical location (two of the
shelters have no physical location, all animals surrendered in these locations were fostered).
Based on Statistics Canada’s (2011) criteria, the population centres were arranged into three
categories: small (1,000- 29,999 inhabitants), medium (30,000-99,999 inhabitants) and large
(100,000 and above inhabitants).
Holding capacity represents the overall number of dogs a shelter could hold at any given time.
Shelter type was classified as either “limited” which follows a C4C management style, or “other”
which captured shelters with a municipal contract which are required to keep the shelter open to
strays, though follows the capacity for care management style for all other animals being
surrendered to the shelter.
Statistical Analysis
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Descriptive statistics, including the mean, median, standard deviation, minimum and maximum
for continuous variables and frequencies and percentages for categorical variables, were
estimated for independent variables of interest.
A Cox proportional frailty hazard model was produced to determine the effect of shelter and
animal characteristics on length of stay in the shelter. Shelter (i.e., BC SPCA branch) was
introduced as a frailty. The independent variables assessed for significance in this model
included: 1) sex, 2) age, 3) coat colour, 4) breed, 5) source, 6) original source, 7) online source,
8) surrender reason, 9) incoming year, 10) capacity, 11) shelter type, and 12) population centre.
The linearity assumption between holding capacity and the outcome was assessed by examining
the statistical significance of adding a quadratic term. A causal model was built to assist in
identifying potential confounding variables.
Variables were initially considered for inclusion in the multivariable model based on pre-
screening using univariable analysis with a liberal p-value (α = 0.20). Initially, a main effects
model was fitted. The proportional hazard assumption was examined for each variable using the
proportional hazard test. Variables were modeled as time varying covariates (TVCs) if this
assumption was violated. A significance level of α = 0.05 was used. Due to convergence issues,
interactions could not be assessed. Similarly, while we found the addition of TVCs improved the
fit of the model based on the Bayesian Information Criterion (BIC), the addition of the terms
prevented the generation of residuals.
Descriptive statistics and survival analysis modeling were conducted using STATA (version 13,
StataCorps, 2009).
Results
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Study Population
There were 8,325 dogs that entered a BC SPCA shelter for the first time, eligible for adoption or
euthanasia between January 1st, 2010 and July 31st, 2014, which qualified them for inclusion in
our analysis. There were five shelters that were dropped out of the analysis, two of the shelters
were foster only and had no physical location and the other three had a dog capacity of zero,
therefore a total of 31 shelter branches were included in the following analysis. Table 3.1
provides details on the dog population and shelter characteristics included in the current study.
There were slightly more males (52.1%) than females (47.9%). More adult dogs (75.6%) entered
shelters during the time period than pups (24.3%). Adoption was the most common outcome,
with 7,567 dogs being identified as adopted (90.8%) in the analyzed dataset. The length of stay
ranged from 1 to 472 days with an average of 25.1 days, a median of 14 days and a standard
deviance (SD) of 34.3 days. Mixed breed dogs (n = 8057, 96.8%) entered the shelter system
more frequently than purebred dogs (3.2%). Of the mixed breed dogs, Labrador mixes were the
most common mix to enter the system (14.5%). Incoming dogs were also mainly mixed coloured
(40.1%). Almost all dogs entered the shelter as an owner surrender (97.9%) and were most
commonly surrendered for owner related reasons: unwanted (17.9%), number of household pets
(17.0%), expectation or lifestyle (14.7%), accommodation (12.5%), cost (9.2%), or owner health
or illness (8.3%) compared to animal related reasons: behaviour problems and “other”. Dogs
entering the shelter were most commonly obtained from a friend or relative (28.4%), from
animal control/shelter/pound (15.3%) or a breeder (15.1%). The 31 shelters included in the
current analysis were evenly distributed across the three population centre sizes: small (34.4%),
medium (30.4%) and large (35.2%). Shelters varied in holding capacity, ranging from 2 to 35
dogs with an average capacity of 19.2 dogs (median = 16; SD = 8.2).
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The Effect of Shelter and Animal Characteristics on Length of Stay in the Shelter
Univariable models indicated four non-significant independent variables of interest (source,
source online, shelter capacity and shelter type (p>0.2)), all of which were not considered
through a causal model to be potential confounders of relationships identified in the subsequent
final model. As a result, these four variables were not included in further analysis. Therefore, the
final model included: breed, coat colour, surrender reason, age, original source, population
centres and incoming year. Among these variables, the following variables were modeled as
TVCs since they did not meet the assumption of the proportional hazards: breed, surrender
reason, original source, age, year incoming and population centre.
When age and incoming year were treated as a TVC in the multivariable analysis they became
non-significant and therefore, were no longer treated as TVCs (Table 3.2).
As a TVC, Figure 3.1 shows how the effect of breed changed over time. Relative to the adoption
of Border Collie mixes, the hazard ratio for German Shepherd mixes, Labrador mixes, Shih Tzu
mixes, and other mixes significantly decreased over time. The hazard ratio for purebreds also
decreased over time compared to Border Collie mixes. While Husky mixes had lower hazard
ratio when they entered, the hazard ratio increased over time compared to Border Collie mixes.
This indicates that over time relative to the adoption of Border Collies, time to adoption
increased for German Shepherd mixes, Labrador mixes, Shih Tzu mixes, other mixes and
purebreds, while time to adoption decreased for Husky mixes.
White coat coloured and yellow coat coloured dogs had a significantly higher hazard of being
adopted compared to black coat coloured and patterned coat coloured dogs (Tables 3.2 & 3.3).
Yellow coat coloured dogs also had a significantly higher hazard rate of being adopted compared
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to mixed coat coloured and brown coat coloured dogs (Table 3.3). This indicated that white or
yellow coat coloured dogs had a faster time to adoption compared to black or patterned coat
coloured dogs, and that yellow coat coloured dogs also had a faster time to adoption compared to
mixed or brown coat coloured dogs. Table 3.3 identifies other significant contrasts between coat
colour categories.
Surrender reason was modeled as a TVC. The hazard ratio for dogs surrendered due to cost was
found to significantly increase over time relative to dogs surrendered due to accommodation
change (Figure 3.2). Similarly, relative to accommodation change, the hazard ratios for dogs
surrendered for behavioural problems, unwanted animals or litter, or for other reasons were
found to increase. Dogs surrendered due to household animal population size, human expectation
and lifestyle, or owner health or illness initially had a high hazard ratio which slightly decreased
over time compared to dogs surrendered due to accommodation change. This indicates that
relative to accommodation change the time to adoption decreased for dogs surrendered as a result
of cost, behavioural problems, unwanted animal or litter and other reasons over time, while the
time to adoption increased for dogs surrendered as a result of household animal population size,
expectation and lifestyle, or owner health or illness over time.
Initially dogs that were obtained from the offspring of the owner’s dog had a lower hazard of
adoption compared to dogs obtained from an animal rescue; however, over time the hazard ratio
approached the null (Table 3.3). Relative to dogs obtained from an animal rescue, the hazard
ratio increased over time for dogs that were obtained as stray or abandoned animal, from a friend
or relative, and from other sources. The hazard ratio decreased for dogs obtained from an animal
shelter/pound/control, a breeder, and as a free pet over time compared to dogs sourced from an
animal rescue. These results indicated, that compared to dogs sourced from an animal rescue, the
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time to adoption decreased over time for dogs sourced from the offspring of the owner’s pet, as
stray or abandoned animal, from a friend or relative, or from other sources, while time to
adoption increased over time for dogs sourced from an animal shelter/pound/control, a breeder or
as a free pet (Figure 3.3).
Puppies had a significantly greater hazard of adoption compared to adult dogs (Table 3.2),
indicating that puppies had a shorter time to adoption.
Population centre was modeled as a TVC, and as time increased the hazard ratios were found to
significantly increase for small and medium population centres relative to large population
centres. This indicates that over time, the time to adoption for dogs that entered a shelter located
in a small or medium population centre decreased compared to dogs that entered a shelter located
in a large population centre (Figure 3.4).
Dogs had a significantly lower hazard of adoption in 2010 to 2013 compared to dogs in 2014
(Table 3.2). Dogs that entered a shelter in 2011 had a significantly lower hazard of adoption
than the dogs that entered a shelter in 2010 and 2013 (Table 3.3). This indicates that dogs that
entered the shelter between 2010 and 2013 had a longer length of stay compared to dogs that
entered in 2014, and dogs that entered in 2010 and 2013 also had a shorter length of stay
compared to 2011.
The model with TVCs and without TVCs were compared using BIC, the BIC was smaller for the
model with TVCs (without TVCs BIC = 116651.7, with TVCs BIC = 116421.6).
Discussion
This study is the first, to our knowledge, in North America to use survival analysis to understand
how factors affect time to adoption among dogs in shelters. It is also the first study in Canada
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and one of the first studies in North America to use data from a large sheltering system involving
more than two shelters. The study included 31 different shelters across the province of British
Columbia allowing for a unique evaluation and interpretation of how different factors affect a
dog’s time to adoption across a wide geographical area. Understanding how animal and shelter
characteristics contribute to an animal’s time to adoption offers valuable information upon which
shelters may create targeted adoption promotions to decrease time to adoption and overall
increase the number of animals helped by the shelter.
Not surprisingly, the current study found dogs under a year of age had a decreased time to
adoption compared to dogs one year and older, which is consistent with the results of other
studies (Lepper, Kass and Hart, 2002, Diesel, Smith and Pfeiffer, 2007, DeLeeuw, 2010). As
suggested by other researchers (Diesel, Smith and Pfeiffer’s, 2007), puppies are likely more
appealing to adopters and therefore adopted much faster than mature animals. As a result,
shelters may want to consider investing more of their time and resources in promotions focused
on the adoption of animals older than a year of age to reduce their overall length of stay. As an
example, a number of sheltering organizations have already implemented adopt a senior month
(November); during this month the cost of adopting an elderly animal is decreased (BC SPCA,
2012; OSPCA, 2015; ASPCA, 2015). Continuing to expand these programs among the sheltering
community and looking to develop other promotions to encourage the adoption of adult dogs is
likely to assist with reducing an older animal’s length of stay within a shelter.
Interestingly, the current study did not find that adopters had a preference for sex of dog.
Findings on the role of sex in adopters’ preference for an animal have been inconsistent. A
number of studies have found sex to have a role in adopters preference for an animal (Lepper,
Kass and Hart, 2002; Clevenger and Kass, 2003; Diesel, Smith and Pfeiffer, 2007; DeLeeuw,
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2010); whereas, others have found no difference in adoption between sexes (Brown, Davidson
and Zueffle, 2013; Nĕmcová and Novák, 2003). Due to differences in findings relating to an
animal’s sex and adopters’ preferences, it is likely that shelters in this study population would
gain more from initiatives and resource invested in targeting the promotion of animal related
characteristics more consistently found to have an influence on adoption rates.
In the current study, Shih Tzu mixes were initially more quickly adopted compared to Border
Collie mixes. This result is similar to the research by Lepper, Kass and Hart (2002) and
DeLeeuw (2010), which found the category of lapdogs and toy breeds to be the most popular for
adopters. However, our study found that as time in the shelter increased, Shih Tzu mixes had an
increased time to adoption relative to Border Collies. Unlike previous research, which has found
purebred dogs were significantly more likely to be adopted compared to mixed breed dogs
(Lepper, Kass and Hart, 2002), the current study in general found there was initially no
difference in time to adoption between purebreds and Border Collie mixes, and that the time to
adoption increased over time for purebreds compared to Border Collies mixes. The results from
our study indicated that, as time in shelter increases, breed of the dog seems to have less of an
impact on time to adoption compared to when a dog first enters the shelter. This could suggest
that dogs which have a longer stay in the shelter have other factors affecting their time to
adoption, such as behaviour or health problems, which diminish the effect of breed on adoption
over time. Research into this area is needed, as understanding how time to adoption changes
over time for certain breeds and or breed classifications (e.g. sporting dogs and herding dogs)
may further help shelters to allocate resources toward breeds or breed classifications that are
more challenging to adopt in order to reduce the shelter’s overall length of stay.
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The results of the current study indicate that white and yellow dogs had a significantly shorter
length of stay until adoption compared to black dogs. These results are similar to a study
conducted in the United States that found white, gold and grey dogs are more likely to be
adopted (Posage, Bartlett and Thomas 1998). In addition, a UK study found yellow dogs are
adopted faster compared to black dogs (Diesel, Smith and Pfeiffer, 2007), however this study did
not find a difference between white dogs and black dogs. The study also found that grey/merle
dogs were more quickly adopted compared to black dogs. Further supporting the effect of coat
colour on adoption, Lepper, Kass and Hart (2002) found that black dogs and brindle dogs were
least likely to be adopted. In part, these findings may be related to the association of black and
tan, and brindle coat colours with breeds such as Dobermans, Boxers, Rottweilers and Bull
mastiffs, which have been shown to have a lower preference among adopters (Lepper, Kass and
Hart, 2002; Diesel, Smith and Pfeiffer, 2007; Brown, Davidson and Zueffle, 2013 ). In the
current study, we combined all patterns including brindle, black and tan and merle into one coat
colour category, therefore the effect of specific patterns was not examined. We also found that
dogs with patterned coats had a significantly longer time to adoption compared to brown, mixed,
yellow or white coat coloured dogs. There is a need for further research investigating specific
coat colour patterns on time to adoption, understanding the desirability of coat colour patterns
can aid in developing adoption promotions targeted at decreasing the length of stay for certain
coat colours or patterns found to be less desirable to adopters.
The current study found that initially when the dogs first enter the shelter, dogs surrendered for
behavioural reasons had a higher hazard of adoption compared to dogs surrendered for cost
reasons, but over time this difference became smaller. In contrast, DeLeeuw (2010) found dogs
surrendered due to owner related reasons such as cost and human expectation had a higher
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probability of adoption compared to dogs surrendered due to behavioural problems. Dogs
surrendered due to cost in the current study initially had the longest time to adoption compared to
almost every other surrender reason, although the effect became smaller over time relative to
accommodation change, suggesting that over time the reason why a dog was surrendered has less
of an effect on time to adoption. Since only one reason was provided for relinquishment, it is
possible that dogs surrendered due to cost had secondary issues such as health or injuries that
required extra money or other secondary non-cost related issues that made them less adoptable.
Lepper, Kass and Hart (2002) in their research found that animals surrendered due to health or
injury related issues had decreased odds of adoption, which could be associated with an
increased cost for care. The effect that cost had on time to adoption may decrease over time
suggests that potential adopters felt sympathy for these animals as they have been in the shelter
for a long time. It could also be inherent in that the longer a dog was in the shelter system the
more likely it would eventually be adopted or that shelters are more likely to implement adoption
programs that target these dogs. Further research verifying the success of adoption programs on
time to adoption will assist shelters to know where to dedicate their resources. In the current
study, an animal’s health status could not be investigated, so research investigating how health
affects time to adoption would provide valuable information about the effects of health and
chronic conditions on the adoptability of a dog. Research has found that surrender reasons are
complex and often involve more than one reason (Salman et al., 1998; Scarlett et al., 1999;
Lambert et al., 2014). Allowing individuals relinquishing an animal to provide more than one
reason at the time of surrender may help shelters and researchers better understand the impact of
these issues resulting in relinquishment on time to adoption.
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This is one of the first studies to investigate where a dog was sourced and how it affected the
time to adoption once in a shelter. Interestingly, dogs that were the offspring of the owner’s own
dog had the slowest rate to adoption compared to every other source when a dog first entered the
shelter. As time increased, the time to adoption decreased for these dogs obtained from the
owner’s own dog relative to dogs obtained from an animal rescue. It is possible that these owners
may have attempted selling the pups or keeping the animals for their own before relinquishing.
By the time the dog was relinquished, it is possible the dog was no longer a pup, increasing the
likelihood of a longer length of stay initially. As time increased the origin of the dog had less of a
negative impact on time to adoption. Or the opposite could be possible and that these dogs came
in as very young pups that were too young for adoption, as a result they had to stay longer before
they were even available for adoption. This scenario would explain why as time increased the
effect of original source had less of an impact. Of further interest, the current study found no
difference in time to adoption between dogs originating from online sources and other sources.
Online source was based on an animal being obtained as a result of online ads promoting
available animals from breeders and free pets; future data collection efforts by shelters and
researchers may consider trying to capture more specific details relating to the animal’s
originating online source including whether the owner obtained the animal from a shelter, an
individual or a store as a result of an online ad. As more animals become available online, it may
be important to continue to monitor the effects of online sourcing on adoption rates. A study
conducted by Lampe and Witte (2015) investigated how photos of adoptable dogs posted online
positively impacted the time to adoption and found that the quality of the photo as well as the
characteristics of the dog’s pose can affect time to adoption. Most humane organizations are now
advertising animals available for adoption online; understanding aspects of online promotion of
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an animal that contribute to a dog’s adoptability may be beneficial to shelters in decreasing the
overall length of stay for dogs in their shelter system.
Results of the current study also showed that when a dog first enters a shelter the larger the
human population was where the shelter branch was located the faster a dog was adopted. This
result is likely due to an increased demand for dogs and more individuals visiting shelters in a
community with a larger human population base, but as time increased the relative difference in
time to adoption among the dogs that entered a shelter in a small or medium population centre
decreased. The results from the current study support the development of transfer programs that
move dogs that are having problems being adopted from certain shelters to where the chances of
adoption are likely to be increased. The BC SPCA has implemented a program called Drive for
Lives (BC SPCA, 2013), transferring animals to different branches across the province to
facilitate adoptions which could provide an explanation for the results found. If an adopter wants
to adopt an animal from a non-local branch, Drives for Lives will transfer the animal to the
branch nearest to the adopter. Further research investigating the effects of transfer programs on a
dog’s time to adoption within a shelter is warranted.
In the current study, the differences in time to adoption among different incoming years could be
a result of adoption promotions that were implemented by the BC SPCA. Additionally, dogs
entering the shelters in 2011 had a slower time to adoption compared to dogs entering in 2010
and 2013, which could be due to an observed increase in the number of dog taken in by the BC
SPCA shelter system in that year. The higher time to adoption in years 2010, 2011, 2012 and
2013 compared to 2014 could also be due to the possibility the months that have a decreased
adoption rate were not included for 2014 as intake data were only available until July 31st 2014.
Limitations
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Common trends found between the results of the current study and other studies support the
generalizability of our findings. Further, the current study involved a large shelter system
representing a large region of Canada. However, caution should be taken when generalizing the
results of the current study to other parts of the world or to shelter systems. For example, it is
possible that regional or societal differences may exist in relation to peoples’ preference for dog
breed or coat colour influencing a dog’s length of stay in other shelter systems. In addition,
although the BC SPCA has implemented a number of approaches consistent with the C4C model
for shelter management (e.g., dog flow through), including changes over the course of the current
study (2013-2014), the BC SPCA has not typically experienced a level of dog surrender that
exceeds their shelter capacity. Therefore, they have not needed to implement the intake
management strategies for dogs associated with C4C. Case studies investigating the success of
C4C management have suggested adoptions increase after implementing C4C for cats (CFHS,
2015), future research exploring the role of C4C on time to adoption for dogs in areas
experiencing overpopulation issues would be beneficial. Regardless of the role of C4C in
decreasing a dog’s length of stay, the principles of C4C remain important for shelters to consider
given another focus of the program is on promoting animal welfare by utilizing the five freedoms
(i.e., freedom from pain, injury and disease, freedom from discomfort, freedom from hunger and
thirst, freedom from fear and distress, and freedom to express normal behaviours) as a standard
in order to decrease shelter-animal stress (Karsten, 2014). Future research into the various
outcomes of C4C, for both dogs and cats, would be beneficial for the sheltering community.
Within the current study, interactions between variables were not tested due to the model’s
complexity resulting in model convergence issues. It is possible the inclusion of interaction terms
in the analysis could have provided further information about time to adoption for dogs in the
112
shelter system. Residuals could not be generated due to issues associated with model
complexities; however, the lower BIC value for the model with the TVCs supports that the TVCs
should have been included.
The possibility of misclassification bias exists in relation to the current study as it can be
challenging to identify accurately the breed and coat colour of dogs, particularly for mixed
breeds. In addition, certain data were not comparable across all shelters included in the current
study; therefore, it was not possible to examine the association between certain factors and
length of stay in a shelter for dogs (e.g., behaviour assessment). Continued efforts to standardize
data collection across shelter organizations will be important to further research efforts in this
area. As an example, efforts to standardize behavioural assessments across shelters and
investigate how a dog’s behaviour affects length of stay would be valuable. Weight or size of
dogs have also been shown to be factors affecting adoption but were not available in the current
dataset.
Due to the way breed categories were organized for the current study, it is difficult to fully
compare results with other studies. A call has been made for greater standardization of data
collection and definitions among shelters to provide more comparable data among studies
(Lambert et al., 2014), and to minimize the risk of misclassification bias. In the United States
specifically, humane organizations have been working to create standardized shelter data across
the nation. The American SPCA (ASPCA) has also recently released a position statement on
shelter data collection and reporting, stating that there is a need for consistent definitions and
accurate data, which will allow for better comparison to other shelters and more accurate results
(ASPCA, 2016). In addition, Shelter Animals Count (2015) is an American non-profit
organization, which has been recently founded to try to get shelters across the United States to
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create a national database using standardized definitions and reporting for shelter statistics.
Standardizing shelter data on a global scale would allow for the humane community to better
leverage the existing research through knowledge synthesis activities such as systematic review
and meta-analysis. The ability to compare findings across countries is likely to offer a better
understanding of cultural preferences and their impact on different interventions or strategies, as
well as allow for the collection of more accurate information on shelter issues faced around the
world.
Conclusion
A number of factors were associated with a dog’s time to adoption within a provincial shelter
system in Canada. Shelters should continue to consider adoption programs and promotions that
target factors that lengthen a dog’s stay within a shelter system. By targeting these areas, shelters
should be able to decrease a dog’s time to adoption in the shelter system, which should decrease
the animal’s stress and improve their health and their experience while in the shelter. In shelters,
decreasing time to adoption will ultimately lead to an increase in the number animals helped by
the shelter. In Canadian shelters, cat intake and euthanasia is higher compared to dogs (CFHS,
2013), future research examining factors associated with cats’ length of stay within a shelter
system will further support shelters and cats by decreasing euthanasia and increasing the number
of cats adopted.
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References
ASPCA. (2015). November is adopt a senior pet month. Retrieved from
http://www.aspca.org/news/november-adopt-senior-pet-month
ASPCA. (2016). Position statement on data collection and reporting. Retrieved from
http://www.aspca.org/about-us/aspca-policy-and-position-statements/position-statement-data-
collection-reporting
BC SPCA. (2012). Adopt a senior animal this month. Retrieved from
http://www.spca.bc.ca/news-and-events/news/adoption-month-senior.html
BC SPCA. (2013). Drives for lives. Retrieved from http://www.spca.bc.ca/pet-
care/adoption/drive-for-lives.html
Brown, W. P., Davidson, J. P., & Zuefle, M. E. (2013). Effects of phenotypic characteristics on
the length of stay of dogs at two no kill animal shelters. Journal of Applied Animal Welfare
Science, 16, 2-18.
CFHS. (2014). Animal Shelter Statistics. Retrieved from
http://cfhs.ca/athome/shelter_animal_statistics/
CFHS. (2015). Capacity for Care (C4C) Case Studies. Retrieved from
http://cfhs.ca/athome/capacity_for_care/
Clevenger, J., & Kass, P. H. (2003). Determinants of adoption and euthanasia of shelter dogs
spayed or neutered in the University of California veterinary student surgery program compared
to other shelter dogs. Journal of Veterinary Medical Education, 30, 372-378.
DeLeeuw, J. L. (2010). Animal shelter dogs: Factors predicting adoption versus euthanasia
(Doctoral Dissertation). Wichita State University.
Diesel, G., Smith, H., & Pfeiffer, D. U. (2007). Factors affecting time to adoption of dog re-
homed by a charity in the UK. Animal Welfare, 16, 353-360.
Gardner, D. (2008). Managing grief associated with euthanasia.
Hurley, K. F. (2005). Feline infectious disease control in shelters. Veterinary Clinics: Small
Animal Practice, 35, 21-27.
Karsten, C. (2014). Calculating your humane capacity [Powerpoint Slides]. Retrieved from
http://www.petpoint.com/summits/past-summits.asp
Kass, P. H. (2007). Cat overpopulation in the United States. In I. Rochlitz (Ed.), The welfare of
cats (pp. 119-139). New York: Springer.
Lambert, K., Coe, J., Niel, L., Dewey, C., & Sargeant, J. M. A systematic review and meta-
analysis of the proportion of dogs surrendered for dog-related and owner-related reason.
Preventive Veterinary Medicine, 118, 148-160.
115
Lampe, R., & Witte, T. H. (2015). Speed of dog adoption L Impact of online photo traits.
Journal of Applied Animal Welfare Science, 18, 343-354.
Lepper, M., Kass, P. H., Hart, L. A. (2002). Prediction of adoption versus euthanasia among
dogs and cats in a California animal shelter. Journal of Applied Animal Welfare Science, 5, 29-
42.
Nĕmcová, D., & Novák, P. (2003). Adoption of dogs in the Czech Republic. Acta Veterinaria
Brno, 72, 421-427.
Newbury, S., Blinn, M. K., Bushby, P. A., Cox, C. B., Dinnage, J. D., Griffin, B., … Spindel, M.
(2010). Guidelines for standards of care in animal shelters.
OSPCA. (2015). No better time! Adopt a senior dog. Retrieved from
http://ontariospca.ca/blog/no-better-time-adopt-a-senior-dog/
Patronek, G., & Zawistowski, S. (2002). The value of data. Journal of Applied Animal Welfare
Science, 5, 171-174.
Pesavento, P. A., & Murphy, B. G. (2014). Common and emerging infectious diseases in the
animal shelter. Veterinary Pathology, 51, 478-491.
Posage, J. M., Bartlett, P. C., Thomas, D. K. (1998). Determining factors for successful adoption
of dogs from an animal shelter. Journal of the American Veterinary Medical Association, 218,
478-482.
Reeve, C. L., Rogelberg, S. G., Spitzmüller, C., & DiGiacomo, N. (2005). The caring-killing
paradox: Euthanasia-related strain among animal-shelter workers. Journal of Applied Social
Psychology, 35, 119-143.
Rogelberg, S. G., Reeve, C. L., Spitzmüller, C., DiGiacomo, N., Clark, O. L., Teeter, L., …
Carter, N. T. (2007). Impact of euthanasia rates, euthanasia practices, and human resource
practices on employee turnover in animal shelters. Journal of the American Veterinary Medical
Association, 230, 713-719
Salman, M. D., New, J. G., Scarlett, J. M., Kass, P. H., Ruch-Gallie, R., & Hetts, S. (1998).
Human and animal factors related to the relinquishment of dogs and cat in 12 selected animal
shelters in the United States. Journal of Applied Animal Welfare Science, 1, 207-226.
Scarlett, J. M., Salman, M. D., New, J. G., & Kass, P. H. (1999). Reasons for relinquishment of
companion animals in the U.S. animal shelters: selected health and personal issues. Journal of
Applied Animal Welfare Science, 2, 41-57.
Shelter Animals Count. (2015). Retrieved from http://www.shelteranimalscount.org/
Turner, P., Berry, J., & MacDonald, S. (2012). Animal shelters and animal welfare: raising the
bar. The Canadian Veterinary Journal, 53, 893.
116
White, D. J., & Shawhan, R. (1996). Emotional responses of animal shelter workers to
euthanasia. Journal of the American Veterinary Medical Association, 208, 846-849.
117
TABLE 3.1
Descriptive Statistics of Categorical Independent Variables on Dog and Shelter Characteristics
among 31 BC SPCA Shelters, January 2010– July 2014.
Variable No. %
Sex (n= 8,319)
Female 3,984 47.89
Male 4,335 52.11
Age (n=8,325)
Adult 6,297 75.64
Pup 2,028 24.36
Breed (n=8,325)
Purebred 268 3.22
Border Collie Mix 517 6.21
German Shepherd Mix 914 10.98
Husky Mix 457 5.49
Labrador Mix 1,202 14.44
Shih Tzu Mix 419 5.03
Other Mix 4,548 54.63
Coat Colour (n=8,289)
Black 895 10.80
Brown 979 11.81
Grey 115 1.39
White 413 4.98
Yellow 672 8.11
Mixed 3,309 39.92
Patterned 1,906 22.99
Source (n=8,325)
118
Owner Surrender 8,155 97.96
Stray 91 1.09
Shelter Offspring 63 0.76
Other 16 0.19
Original Source (n=8,325)
Friend or Relative 2,362 28.37
Breeder 1,256 15.09
Animal Shelter or Control / Pound 1,275 15.32
Offspring of Owner’s Pet 819 9.84
Free Pet 722 8.67
Animal Rescue Organization 686 8.24
Stray or Abandoned Animal 917 11.02
Other 288 3.46
Online ad (n=8,325)
Yes 890 10.69
No 7,435 89.31
Surrender Reason (n=8,114)
Household Animal Population 1,383 17.04
Unwanted Animal or Litter 1,452 17.89
Accommodation Change 1,014 12.50
Human Expectation and Lifestyle 1,196 14.74
Cost 745 9.18
Owner Health or Illness 673 8.29
Behavioural Problems 672 8.28
Other 979 12.07
Population Centre Size (n=8,325)
Large 2,929 35.18
Medium 2,532 30.41
119
Small 2,864 34.40
Outcome
Adopted 7,823 92.44
Euthanized 640 7.56
Available for Adoption 6 0.07
Escaped 1 0.01
In shelter 99 1.19
Stolen 4 0.05
Unassisted Death 26 0.31
120
TABLE 3.2
Cox Proportional Frailty Hazard Main Effects Model including the Time Varying Components
of 8325 dogs that Entered the BC SPCA Shelter System between January 2010 and July 2014.
Variable Coefficients Standard Error 95% C.I. p-value
Breed
Border Collie Mix Referent
German Shepherd Mix 0.272 0.167 -0.056, 0.600 0.104
Husky Mix -0.3685 0.208 -0.776, 0.039 0.076
Labrador Mix 0.268 0.161 -0.049, 0.584 0.097
Other Mix 0.269 0.146 -0.016, 0.554 0.065
Purebred 0.114 0.230 -0.336, 0.565 0.619
Shih Tzu 0.501 0.198 0.113, 0.889 0.011*
Coat Colour
Black Referent
Brown 0.062 0.051 -0.038, 0.161 0.223
Grey 0.125 0.107 -0.084, 0.334 0.242
Mixed 0.068 0.042 -0.014, 0.151 0.104
Patterned -0.043 0.045 -0.132, 0.046 0.346
White 0.175 0.066 0.046, 0.305 0.008*
Yellow 0.205 0.055 0.098, 0.312 0.000*
Surrender Reason
Accommodation
Change
Referent
Behaviour Problems -0.095 0.145 -0.383, 0.192 0.516
Cost -0.872 0.155 -1.176, -0.569 0.000*
Household Animal
Population
0.070 0.127 -0.179, 0.318 0.583
Human Expectation /
Lifestyle
0.180 0.121 -0.058, 0.418 0.139
Other -0.245 0.137 -0.514, 0.025 0.075
Owner Health or
Illness
0.066 0.140 -0.209, 0.341 0.637
Unwanted Animal or
Litter
-0.144 0.126 -0.391, 0.102 0.251
Original Source
Animal Rescue Referent
Animal Shelter or
Control / Pound
0.145 0.124 -0.098, 0.389 0.242
Breeder 0.038 0.138 -0.233, 0.309 0.784
Free Pet -0.173 0.159 -0.484, 0.138 0.274
Friend or Relative -0.201 0.127 -0.451, 0.048 0.114
Offspring of Owner’s
Pet
-0.740 0.163 -1.060, -0.420 0.000*
Other -0.098 0.208 -.505, 0.309 0.637
121
Stray or Abandoned
Animal
-0.225 0.145 -0.509, 0.060 0.121
Age
Adult Referent
Pup 0.297 0.032 0.235, 0.358 0.000*
Population Centres
Large Referent
Medium -0.958 0.124 -1.201, -0.716 0.000*
Small -1.407 0.122 -1.646, -1.167 0.000*
Year Incoming
2010 -0.117 0.048 -0.213, -0.022 0.016*
2011 -0.216 0.044 -0.302, -0.130 0.000*
2012 -0.173 0.044 -0.258. -0.087 0.000*
2013 -0.124 0.044 -0.211, -0.037 0.005*
2014 Referent
TVCS
Breed
Border Collie Mix Referent
German Shepherd Mix -0.134 0.058 -0.247, -0.0206 0.021*
Husky Mix 0.036 0.0703 -0.102, 0.174 0.611
Labrador Mix -0.140 0.0555 -0.249, -0.031 0.012*
Other Mix -0.123 0.0500 -0.221, -0.025 0.014*
Purebred -0.090 0.078 -0.243, 0.0622 0.246
Shih Tzu -0.140 0.071 -0.278, -0.001 0.048*
Surrender Reason
Accommodation Change Referent
Behaviour Problems 0.012 0.052 -0.089, 0.113 0.816
Cost 0.129 0.050 0.0308, 0.227 0.010*
Household Animal
Population
-0.053 0.045 -0.141, 0.034 0.232
Human Expectation /
Lifestyle
-0.058 0.043 -0.143, 0.028 0.185
Other 0.0593 0.047 -0.033, 0.152 0.207
Owner Health or Illness -0.035 0.050 -0.133, 0.063 0.483
Unwanted Animal or
Litter
0.030 0.044 -0.055, 0.116 0.489
Where the Animal was
Obtained
Animal Rescue Referent
Animal Shelter or
Control / Pound
-0.080 0.046 -0.170, 0.011 0.083
Breeder -0.029 0.050 -0.127, 0.069 0.562
Free Pet -0.013 0.056 -0.123, 0.096 0.810
Friend or Relative 0.042 0.460 -0.048, 0.132 0.363
Offspring of Owner’s Pet 0.217 0.057 0.106, 0.328 0.000*
Other 0.080 0.076 -0.069, 0.229 0.293
122
Stray or Abandoned
Animal
0.066 0.052 -0.037, 0.168 0.208
Population Centres
Large Referent
Medium 0.339 0.030 0.281, 0.397 0.000*
Small 0.415 0.030 0.357, 0.474 0.000*
123
TABLE 3.3
Significant Categorical Variable Contrasts of the Cox Proportional Frailty Hazard Model of the
8235 Dogs that entered the BC SPCA Shelter System between January 2010 and July 2014
Variable Hazard Ratio Standard Error 95% C.I. p-value
Coat Colour
Yellow vs. Black 1.228 0.067 1.103, 1.367 0.000
White vs Black 1.192 0.079 1.047, 1.357 0.008
Brown vs. Patterned 1.110 0.048 1.020, 1.208 0.015
Brown vs. Yellow 0.866 0.047 0.779, 0.963 0.008
Mixed vs Patterned 1.117 0.035 1.050, 1.189 0.000
Mixed vs Yellow 0.872 0.040 0.797, 0.954 0.003
Patterned vs. White 0.804 0.048 0.715, 0.904 0.000
Patterned vs. Yellow 0.780 0.038 0.709, 0.859 0.000
Incoming Year
2014 vs. 2010 0.889 0.044 0.808, 0.978 0.016
2014 vs. 2011 0.806 0.036 0.739, 0.879 0.000
2014 vs. 2012 0.841 0.367 0.772, 0.916 0.000
2014 vs. 2013 0.883 0.039 0.810, 0.963 0.005
2010 vs. 2011 1.104 0.044 1.021, 1.193 0.013
2011 vs. 2013 0.912 0.032 0.852, 0.976 0.008
124
Figure 3.1
Hazard ratios of the breed categories against the natural log (ln) of time illustrating the changing
time to adoption of various breed categories relative Border Collie mixes.
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
0 1 2 3 4 5 6 7
Haz
ard
Rat
io
Ln(days)
Breed TVC
German Shepherd Mix Husky Mix Labrador Mix Other Mix Purebred Shih Tzu Mix
125
Figure 3.2
Hazard ratios of the surrender reasons against the natural log of time illustrating the changing
time to adoption of various surrender reason categories relative to accommodation change.
0
0.2
0.4
0.6
0.8
1
1.2
1.4
0 1 2 3 4 5 6 7
Haz
ard
Rat
io
Ln(days)
Surrender Reason TVC
Behaviour problems Cost Household animal population
Expectation and lifestyle Other Owner health or illness
Unwanted
126
Figure 3.3
Hazard ratios of the original sources against the natural log of time illustrating the changing time
to adoption of various original source categories relative to animal rescue.
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
0 1 2 3 4 5 6 7
Haz
ard
Rat
io
Ln(days)
Original Source TVC
Shelter/control/pound Breeder Free Friend or relative
Offspring of pet Other Stray or abandoned
127
Figure 3.4
Hazard rations of the population centres where the shelters are located the natural of time
illustrating the changing time to adoption of various population centre categories relative to large
population centres
0
0.5
1
1.5
2
2.5
3
3.5
0 1 2 3 4 5 6 7
Haz
ard
Rat
io
Ln(days)
Population Centre TVC
Pop Centre - Med Pop Centre - Small
129
Companion animal population dynamics is multifaceted with a variety of factors that can impact
it including: ownership practices, reproduction, control practices, relinquishment and
abandonment. Research has demonstrated that human socioeconomic factors (Eze and Eze,
2002; Farnworth et al., 2012; Flockhart, Norris and Coe, 2016), cultural values and religion
(Fielding and Mather, 2001; Hsu, Severinghaus and Serpell, 2003; McNicholas et al., 2005;
Fielding, 2010a; Fielding, 2010b), laws (Winter, 2004; Voslářá and Passantino, 2012) and
climate (Gunther and Terkel, 2002; Ortega-Pacheco et al., 2007; Finkler and Terkel, 2012) all
have the ability to influence companion animal population dynamics different contexts. Different
combinations of these factors can also affect the magnitude of companion animal population
dynamics, resulting in different research interests and priorities.
As a result of the impacts companion animal population dynamics has on a number of different
areas, companion animal population dynamics receives attention from many different
stakeholders, including: animal welfare professionals, ecologists/conservationists and public
health professionals. Among these stakeholders a variety of different control practices have been
investigated and applied in practice, often based on the desired outcome of interest, to control the
free roaming (unowned and owned) and unwanted companion animal populations. Research has
identified that different stakeholders view the issues differently and for the most part have
different outcomes of interest. For example, studies investigating stakeholders’ views found that
TNR groups were less likely to believe free roaming cats posed a threat to native species and to
the environment compared to ecologists/conservationists (Wald, 2012).
Ecologists/conservationists were also more likely to support euthanasia as a control practice
compared to TNR groups and animal welfare professionals (Wald, 2012; Lohr and Lepczyk,
2014).
130
Animal shelters are also impacted by free roaming and unwanted companion animal populations
as a result of relinquishment, abandonment, and the surrendering of stray animals, which can
lead to overcrowding. Overcrowding can result in increased stress and spread of disease (Hurley,
2005) and can also lead to unnecessary euthanasia. Euthanizing animals can negatively affect
shelter workers by causing them extreme stress (White and Shawhan, 1996; and Gardner, 2008).
As a result, the shelter community has begun to explore and implement control methods to try to
mitigate the impacts of overcrowding within animal shelters, most recently by focusing on
decreasing length of stay and limiting admissions (Hurley, 2005).
As many shelters are interested in decreasing length of stay, understanding factors that influence
adoption and subsequently length of stay, is extremely important. Previous studies have indicated
that breed, age, size, sex, coat colour, and surrender reason can all impact adoption. Puppies
under a year of age, females, small dogs, and purebreds have been shown to be preferred by
adopters (Lepper, Kass and Hart, 2002; Diesel, Smith and Pfeiffer, 2007; DeLeeuw, 2010), while
dogs surrendered due to animal related reasons such as behaviour and health were less likely to
be adopted compared to dogs surrendered due to owner related reasons (Lepper, Kass and Hart,
2002; DeLeeuw, 2010).
The purpose of this thesis was to assimilate the breadth and depth of research published on
companion animal population dynamics by using a systematic process that was both rigorous and
transparent. This thesis also provides results on the first Canadian study investigating factors that
impact a dog’s time to adoption in a large, multi-shelter system.
Summary of Findings
131
There are two studies that comprise this thesis: (1) a scoping review of the published research on
the population dynamics and control practices of companion animals and (2) a survival analysis
examining factors that affect a dog’s time to adoption within an animal shelter.
A Scoping Review of the Published Research on the Population Dynamics and Control Practices
of Companion Animals
The focus of the scoping review was to summarize the current state of knowledge on approaches
to managing companion animal population dynamics to control the number of owned free-
roaming, un-owned free-roaming and unwanted companion animals. The scoping review found
869 published articles (450 primary research and 419 reviews) that investigated or provided
commentary on population dynamics, surveillance and or control practices relating to companion
animals. Journal articles were the most common document type published and most of the
research was conducted in or discussed the topic within the context of the United States. An
increasing amount of articles have been published over the years, most research was conducted
after 2000, with 25% of the articles being published between 2012 and June 2015. This indicates
that the topic of companion animal population dynamics and the control practices used are highly
discussed and many stakeholders are interested in this topic. Dogs and cats were the main
companion animals investigated with cats having a slightly higher focus than dogs. Unowned
free roaming companion animals was the main type of population studied within the articles. The
majority of the articles investigated control practices, specifically different methods of
reproductive control, and methods of euthanasia. The main outcome of interest was improving
the methodology of control practices. Other main outcomes of interest were views and opinions
on free roaming and unwanted companion animals or control practices used to manage them and
the free roaming and unwanted companion animal population size. Most articles (primary
132
research and reviews) reported or discussed the effectiveness of the control practices investigated
with a main focus on TNR, zona pellucida immunocontraception, and chemical castration
indicating an opportunity for future SR-MAs to be conducted on these specific control practices
to determine their overall effectiveness. Most authors recommended further research or further
development of control practices; reproduction control; control of the free roaming and or
unwanted companion animal populations; or increasing public education. The call for public
education by authors indicates that education is considered an important control practice,
however little primary research has been conducted to determine its effectiveness and the
number of primary research investigating its effectiveness has actually decreased over the years.
Of the primary research articles included, many were observational studies, specifically cross
sectional studies, and the next main study design used was routine surveillance. Study design
changed depending on the control practice investigated, experimental studies were more
commonly used when investigating reproduction control while observational studies were more
commonly used when investigating different methods of euthanasia. Quantitative questionnaires
or surveys and observations or field visits were the most common methods of data collection.
Primary research studies focusing mainly on surveillance (i.e., estimates of population size) have
approximately doubled since 2009. Data were commonly reported as a prevalence outcome,
allowing for the opportunity of future SR-MAs to be conducted. P-values and measures of
variability were commonly reported. The majority of primary research articles identified at least
one weakness and/or one strength of the study.
Factors Influencing Time to Adoption for Dogs in a Provincial Shelter System in Canada
The second study, comprising this thesis, used a Cox proportional hazard frailty model to
determine which factors (animal characteristics, animal source or shelter demographics) affect a
133
dog’s length of stay until adoption in shelters managed by the BC SPCA between January 1st,
2010 and July 31st, 2014. The data included 8,325 dogs that entered the shelter during this time
period, with a majority of the dogs over a year of age and a relatively even proportion of male
and female dogs. Dogs of mixed breeds and dogs with mixed coat colour were the most common
types of dog that entered the shelter system. The most common original source of a dog in the
BC SPCA system was through a friend or relative, and dogs were mainly surrendered due to
owner related reasons (e.g. accommodation, expectation or lifestyle, unwanted or number of
household population). The majority of dogs included in the study entered the BC SPCA shelter
system by owner surrender. The 31 BC SPCA shelters contributing data to the current study were
evenly located across small (1,000- 29,999 inhabitants), medium (30,000-99,999 inhabitants) and
large (100,000 and above inhabitants) human population centres. The shelter holding capacity for
the 31 shelters ranged from 2 to 35 dogs (mean 19.2 dogs; median 16 dogs). The majority of
dogs included in the study were adopted, and the average length of stay was 25.1 days (median
14 days; range 1-472 days).
The multivariable Cox proportional frailty hazard model indicated that age, breed, coat colour,
surrender reason, original source, human population centre size and incoming year were all
found to impact a dog’s time to adoption (p<0.05). Time varying components were included for
the variables: breed, surrender reason, original source and human population centres, as these
variables violated the assumption of the proportional hazard test (i.e. the relative difference in
time to adoption does not remain constant).
Pups under a year of age had a shorter length of stay until adoption compared to adult dogs. Shih
Tzu mixes had a decreased time to adoption compared to Border Collie Mixes when they first
enter the shelter. As time increased, the time to adoption increased for Shih Tzu mixes, Labrador
134
mixes, German Shepherd mixes compared to Border Collie mixes. Husky mixes had the longest
stay in the shelters prior to adoption compared to all other breeds when the dogs first enter the
shelter. As time increased, the time to adoption decreased for Husky mixes relative to Border
Collie mixes. Dogs with yellow coat colours had a shorter time to adoption compared to black,
brindle, mixed or brown coat coloured dogs. As well, white coat coloured dogs had a shorter
time to adoption compared to black or patterned coat coloured dogs. When a dog first entered the
shelter, cost as a surrender reason had a negative impact on time to adoption compared to
surrender due to accommodation changes. As time increased, the time to adoption due to cost
decreased. Dogs obtained from the offspring of the surrendering owner’s dog initially had an
increased time to adoption compared to all of the other original sources. As time increased the
time to adoption decreased for dogs obtained from the offspring of the surrendering owner’s dog
compared to dogs sourced from animal rescues. The human population size of where the shelter
was located also influenced time to adoption. Dogs brought into shelters located in larger
population centres had a shorter time to adoption compared to dogs brought into shelters located
in smaller population centres. As time increased, the time to adoption for dogs brought into
shelters located in small and medium population centres decreased relative to dogs brought into
shelters located in large populations. Understanding which risk factors contribute to a slower
time to adoption and how this may change over time, allows shelters to use this information to
develop adoption programs that could decrease time to adoption for these dogs.
Key Recommendations
The findings of this thesis form a foundation for various key recommendations:
135
Further knowledge synthesis efforts should be considered to determine the efficacy of
control practices, with a specific opportunity to focus on non-surgical reproduction
control methods.
Other control practices for managing free roaming (unowned and owned) and unwanted
companion animals should be researched to provide more information on their
effectiveness such as education and legislations.
Educational programs should be developed to improve knowledge on pet care and
ownership, as well as inform individuals about the issues relating to free roaming
companion animals.
Standardization of shelter data collection and recording should be pursued to enhance
research opportunities and compare shelter information at local, national and
international levels.
Animal characteristics as well as shelter characteristics should be considered when
creating programs to reduce time to adoption.
Shelters should continue to evaluate adoption programs and promotions, specifically
assessing and targeting characteristics that currently increase time to adoption (e.g.,
Adopt-a-Senior Month).
Future studies should be focused on determining how effective current adoption
programs and promotions are at improving time to adoptions.
Thesis Limitations
Limitations were present in both studies comprising this thesis. The results from the scoping
review indicated that free roaming and unwanted companion animals are a global issue as 509
articles of the 869 articles included were conducted outside of the United States or Canada.
136
However, due to the language restrictions, only articles published in English and Spanish were
included in the review, signifying that some relevant articles in other languages could have been
excluded (n=166). However, this scoping review included a large number of articles, articles
excluded as result of the language restriction likely did not have a considerable effect on the
results. In addition, a small number of articles (n=20) identified by the search strategy were not
retrievable and therefore, relevance could not be confirmed. The number of articles excluded
because they could not be obtained was small, suggesting they had limited impact on the results
of the scoping review.
Due to the complexity of the Cox proportional frailty hazard model, variable interactions were
not assessed. Therefore, it is possible that the inclusion of interaction terms could have provided
more information on factors affecting a dog’s time to adoption. Misclassification bias could also
be present within the model due to the difficulty of accurately determining the breeds and coat
colours of the dogs entering the shelters. As well, certain data could not be included in the model
as a result of different data keeping practices across the BC SPCA shelters.
Future Directions for Research
This thesis identifies numerous areas for future research. There is an opportunity for further
knowledge synthesis efforts investigating the effectiveness of control practices used to manage
free roaming (owned and unowned) and unwanted companion animals. More specifically, a
systematic review and meta-analysis (SR-MA) focused on TNR, non-surgical reproduction
control (ZP immunocontraception and chemical castration) or poison (for eradication) should be
prioritized. The research on non-surgical reproduction control types were mainly conducted
through controlled trials, thus providing the best opportunity for future SR-MAs. Further
137
knowledge synthesis efforts will aid in determining the efficacy of these control practices and
ultimately contribute to informing the development of successful control programs.
Continued research on other control practices will help determine if they could be used in future
control programs and aid in the development of evidence-based policies surrounding free
roaming and unwanted companion animals. As many of the studies included in the scoping
review recommended increasing public education, more research is needed to determine how
effective education programs can be used to manage free roaming (owned and unowned) and
unwanted companion animals.
A small number of primary research articles used mathematical models to determine the effects a
control practice will have on the free roaming and unwanted companion animal populations.
Development of mathematical models could inform how to best use resources, therefore saving
resources from being invested in unsuccessful control practices. Further research validating
mathematical models for predicting the effectiveness of control practices is needed.
This thesis has shown that animal characteristics play an important role in determining how
quickly a dog in a shelter will get adopted. Further research investigating the impact of dog
behaviour, dog health and dog size have on time to adoption within a shelter or shelter system
will enhance the understanding on which characteristics shelters should target when creating
adoption promotions. Adoption promotions should target characteristics that have been shown to
lead to a longer length of stay prior to adoption. Decreasing time to adoption could aid in
improving the animals’ welfare by decreasing stress and decreasing disease spread, ultimately
improving the animals’ experience in the shelter.
138
Shelters have implemented many different adoption programs in an attempt to increase adoptions
and reduce animals’ time in shelters. Further research investigating the impact of these adoption
programs at the shelter as well as the community-animal level is needed. Shelters have limited
resources, therefore understanding how successful these programs are will inform shelters where
they should apply their resources.
In Canada and the United States, cats enter shelters more frequently than dogs. Therefore, it is
recommend that a similar study investigating factors that affect time to adoption for cats should
be conducted. Understanding factors which influences time to adoption for cats should help
shelters to increase the number of cats adopted.
139
References
Diesel, G., Smith, H., & Pfeiffer, D. U. (2007). Factors affecting time to adoption of dog re-
homed by a charity in the UK. Animal Welfare, 16, 353-360.
DeLeeuw, J. L. (2010). Animal shelter dogs: Factors predicting adoption versus euthanasia
(Doctoral Dissertation). Wichita State University.
Eze, C. A., & Eze, M. C. (2002). Castration, other management practices and socio-economic
implications for dog keeps in Nsukka area, Enugu state, Nigeria. Preventative Veterinary
Medicine, 55, 273-280.
Farnworth, M. J., Blaszak, K., Hiby, E. F., & Waran, N. K. (2012). Incidence of dog bites and
public attitudes towards dog care and management in Samoa. Animal Welfare, 21, 477-486.
Fielding, W. J. (2010a). Dog breeding in New Providence, the Bahamas, and its potential impact
on the roaming dog population I: Planned and accidental. Journal of Applied Animal Welfare
Science, 13, 250-260.
Fielding, W. J. (2010b). Dog breeding New Providence, the Bahamas, and its potential impact on
the roaming dog population II: The fate of puppies. Journal of Applied Animal Welfare Science,
13, 300-313.
Fielding, W. J., & Mather, J. (2001). Dog ownership in the West Indies: A case study form the
Bahamas. Antrhozoos, 14, 72-80.
Finkler, H., & Terkel, J. (2012). The contribution of cat owners’ attitudes and behaviours to the
free-roaming cat overpopulation in Tel Aviv, Israel. Preventive Veterinary Medicine, 104, 125-
135.
Flockhart, D. T. T., Norris, D. R., & Coe, J. B. (2016). Predicting free-roaming cat population
densities in urban areas. Animal Conservation.
Gardner, D. (2008). Managing grief associated with euthanasia.
Gunther, I., & Terkel, J. (2002). Regulation of free-roaming cat (Felis silvestris catus)
populations: A survey of the literature and its application to Israel. Animal Welfare, 11, 171-188.
Hsu, Y., Severinghaus, L. L., & Serpell, J. A. (2003). Dog keeping in Taiwan: Its contribution to
the problem of free-roaming dogs. Journal of Applied Animal Welfare Science, 6, 1-23.
Hurley, K. F. (2005). Feline infectious disease control in shelters. Veterinary Clinics of North
America: Small Animal Practice, 35, 21-37.
Karsten, C. (2014). Calculating your humane capacity [Powerpoint Slides]. Retrieved from
http://www.petpoint.com/summits/past-summits.asp
Lepper, M., Kass, P. H., Hart, L. A. (2002). Prediction of adoption versus euthanasia among
dogs and cats in a California animal shelter. Journal of Applied Animal Welfare Science, 5, 29-
42.
140
Lohr, C. A., & Lepczyk, C. A. (2014). Desires and management preferences of stakeholders
regarding feral cats in the Hawaiian Islands. Conservation Biology, 28, 392-403.
McNicholas, J., Gilbey, A., Rennie, A., Ahmedzai, S., Dono, J., & Ormerod, E. (2005). Pet
ownership and human health: A brief review of evidence and issues. BMJ, 331, 1252-1255.
Newbury, S., Blinn, M. K., Bushby, P. A., Cox, C. B., Dinnage, J. D., Griffin, B., … Spindel, M.
(2010). Guidelines for standards of care in animal shelters.
Ortega-Pacheco, A., Segura-Correa, J. C., Jimenez-Coello, M., & Linde Forsberg, C. (2007).
Reproductive patterns and reproductive pathologies of stray bitches in the tropics.
Theriogenology, 67, 382-390.
Voslářá, E., & Passantino, A. (2012). Stray dog and cat laws and enforcement in Czech Republic
and in Italy. Annali dell’Istituto Superiore di Sanità, 48, 97-104.
Wald, D. (2015). Understanding stakeholder conflict: An analysis of public values, risk
perceptions and attitudes toward outdoor cat management (Doctoral Dissertation). University of
Florida.
White, D. J., & Shawhan, R. (1996). Emotional responses of animal shelter workers to
euthanasia. Journal of the American Veterinary Medical Association, 208, 846-849.
Winter, L. (2004). Trap-neuter-release programs: the reality and the impacts. Journal of the
American Veterinary Medical Association, 225, 1369-1376.
141
APPENDIX A
A Scoping review of published research on the population dynamics and control practices
of companion animals
A.1: Database Specific Search Strategies
A.2: Relevance Screening Form
A.3: Data Extraction and Characterization Form
A.4: Reference List of Included 869 Articles
A.5: Description of Non-English Articles Excluded from the Study
A.6: Description of Articles that were Unable to be Obtained
142
A.1.
Database Specific Search Strategies
CAB Direct
title:(("companion animal" OR dog OR cat OR
pet OR canine OR feline) AND
(overpopulation OR population* OR surplus)
AND (homeless OR abandon* OR stray* OR
unowned OR unwanted OR feral OR free-
roaming OR roaming OR (reproduc* OR
breed* OR fertil* OR "birth rate" OR "puppy
mills") OR ("animal control" OR "animal
management" OR euthan* OR shelter* OR
rescue* OR "animal welfare" OR sterilization
OR spay OR neuter OR castration OR
ovariohysterectomy OR orchiectomy))) OR
ab:(("companion animal" OR dog OR cat OR
pet OR canine OR feline) AND
(overpopulation OR population* OR surplus)
AND (homeless OR abandon* OR stray* OR
unowned OR unwanted OR feral OR free-
roaming OR roaming OR (reproduc* OR
breed* OR fertil* OR "birth rate" OR "puppy
mills") OR ("animal control" OR "animal
management" OR euthan* OR shelter* OR
rescue* OR "animal welfare" OR sterilization
OR spay OR neuter OR castration OR
ovariohysterectomy OR orchiectomy))) OR
subject:(("companion animal" OR dog OR cat
OR pet OR canine OR feline) AND
(overpopulation OR population* OR surplus)
AND (homeless OR abandon* OR stray* OR
unowned OR unwanted OR feral OR free-
roaming OR roaming OR (reproduc* OR
breed* OR fertil* OR "birth rate" OR "puppy
mills") OR ("animal control" OR "animal
management" OR euthan* OR shelter* OR
rescue* OR "animal welfare" OR sterilization
OR spay OR neuter OR castration OR
ovariohysterectomy OR orchiectomy)))
Medline (Pubmed)
("companion animal" OR "companion
animals" OR dog OR dogs OR cat OR cats OR
canine OR feline OR pet OR pets) AND
(overpopulation OR population* OR surplus)
AND ((homeless OR abandon* OR stray* OR
143
unowned OR unwanted OR feral OR free-
roaming OR roaming) OR (reproduc* OR
breed* OR fertil* OR "birth rate" OR "puppy
mills") OR ("animal control" OR "animal
management" OR euthan* OR shelter* OR
rescue* OR animal-welfare OR sterilization
OR spay OR neuter OR castration OR
ovariohysterectomy))
Agricola - ProQuest
("companion animal" OR "companion
animals" OR dog OR cat OR canine OR feline
OR pet) AND (overpopulation OR population*
OR surplus) AND (homeless OR abandon* OR
stray* OR unowned OR unwanted OR feral
OR free-roaming OR roaming OR (reproduc*
OR breed* OR fertil* OR "birth rate" OR
"puppy mills") OR ("animal control" OR
"animal management" OR euthan* OR shelter*
OR rescue* OR "animal welfare" OR
sterilization OR spay OR neuter OR castration
OR ovariohysterectomy))
PsycINFO APA PsycNET
("companion animal" OR "companion
animals" OR dog OR dogs OR cat OR cats OR
canine OR feline OR pet OR pets) AND
(overpopulation OR population* OR surplus)
AND (homeless OR abandon* OR stray* OR
unowned OR unwanted OR feral OR free-
roaming OR roaming OR (reproduc* OR
breed* OR fertil* OR "birth rate" OR "puppy
mills") OR ("animal control" OR "animal
management" OR euthan* OR shelter* OR
rescue* OR "animal welfare" OR sterilization
OR spay OR neuter OR castration OR
ovariohysterectomy))
Scopus
(TITLE-ABS-KEY((cat OR dog OR pet OR
"companion animal" OR feline OR canine))
AND TITLE-ABS-KEY((overpopulation OR
population* OR surplus)) AND TITLE-ABS-
KEY((homeless OR abandonment OR stray*
OR unowned OR unwanted OR feral OR free-
roaming)) OR TITLE-ABS-KEY((cat OR dog
OR pet OR “companion animal” OR feline OR
canine)) AND TITLE-ABS-
KEY((overpopulation OR population* OR
144
surplus)) AND TITLE-ABS-KEY((reproduc*
OR breed* OR fertil* OR (birth W/1 rate) OR
(puppy W/1 mill*))) OR TITLE-ABS-
KEY((cat OR dog OR pet OR "companion
animal" OR feline OR canine)) AND TITLE-
ABS-KEY((overpopulation OR population*
OR surplus)) AND TITLE-ABS-KEY((animal
W/1 control) OR (animal W/1 management)
OR euthan* OR shelter* OR rescue* OR
welfare OR sterilization OR spay OR neuter
OR castration OR ovariohysterectomy OR
orchiectomy))
New search adding terms “growth rate”, lambda, or “carrying capacity”
Agricola
("companion animal" OR "companion
animals" OR dog OR cat OR canine OR feline
OR pet) AND ("growth rate" OR lambda OR
"carrying capacity") AND (homeless OR
abandon* OR stray* OR unowned OR
unwanted OR feral OR free-roaming OR
roaming OR (reproduc* OR breed* OR fertil*
OR "birth rate" OR "puppy mills") OR
("animal control" OR "animal management"
OR euthan* OR shelter* OR rescue* OR
"animal welfare" OR sterilization OR spay OR
neuter OR castration OR ovariohysterectomy))
Medline (PubMed)
(("companion animal" OR "companion
animals" OR dog OR dogs OR cat OR cats OR
canine OR feline OR pet OR pets) AND
(growth-rate OR lambda OR "carrying
capacity") AND ((homeless OR abandon* OR
stray* OR unowned OR unwanted OR feral
OR free-roaming OR roaming) OR (reproduc*
OR breed* OR fertil* OR "birth rate" OR
"puppy mills") OR ("animal control" OR
"animal management" OR euthan* OR shelter*
OR rescue* OR animal-welfare OR
sterilization OR spay OR neuter OR castration
OR ovariohysterectomy)))
PsycINFO
145
("companion animal" OR "companion
animals" OR dog OR dogs OR cat OR cats OR
canine OR feline OR pet OR pets) AND
("growth rate" OR lambda OR "carrying
capacity") AND (homeless OR abandon* OR
stray* OR unowned OR unwanted OR feral
OR free-roaming OR roaming OR (reproduc*
OR breed* OR fertil* OR "birth rate" OR
"puppy mills") OR ("animal control" OR
"animal management" OR euthan* OR shelter*
OR rescue* OR "animal welfare" OR
sterilization OR spay OR neuter OR castration
OR ovariohysterectomy))
CabDirect
(title:(("companion animal" OR dog OR cat
OR pet OR canine OR feline) AND ("growth
rate" OR lambda OR "carrying capacity")
AND (homeless OR abandon* OR stray* OR
unowned OR unwanted OR feral OR free-
roaming OR roaming OR (reproduc* OR
breed* OR fertil* OR "birth rate" OR "puppy
mills") OR ("animal control" OR "animal
management" OR euthan* OR shelter* OR
rescue* OR "animal welfare" OR sterilization
OR spay OR neuter OR castration OR
ovariohysterectomy OR orchiectomy))) OR
ab:(("companion animal" OR dog OR cat OR
pet OR canine OR feline) AND ("growth rate"
OR lambda OR "carrying capacity") AND
(homeless OR abandon* OR stray* OR
unowned OR unwanted OR feral OR free-
roaming OR roaming OR (reproduc* OR
breed* OR fertil* OR "birth rate" OR "puppy
mills") OR ("animal control" OR "animal
management" OR euthan* OR shelter* OR
rescue* OR "animal welfare" OR sterilization
OR spay OR neuter OR castration OR
ovariohysterectomy OR orchiectomy))) OR
subject:(("companion animal" OR dog OR cat
OR pet OR canine OR feline) AND ("growth
rate" OR lambda OR "carrying capacity")
AND (homeless OR abandon* OR stray* OR
unowned OR unwanted OR feral OR free-
roaming OR roaming OR (reproduc* OR
breed* OR fertil* OR "birth rate" OR "puppy
mills") OR ("animal control" OR "animal
146
management" OR euthan* OR shelter* OR
rescue* OR "animal welfare" OR sterilization
OR spay OR neuter OR castration OR
ovariohysterectomy OR orchiectomy))))
Scopus
(TITLE-ABS-KEY((cat OR dog OR pet OR
"companion animal" OR feline OR canine))
AND TITLE-ABS-KEY(("growth rate" OR
lambda OR "carrying capacity")) AND TITLE-
ABS-KEY((homeless OR abandonment OR
stray* OR unowned OR unwanted OR feral
OR free-roaming)) OR TITLE-ABS-KEY((cat
OR dog OR pet OR “companion animal” OR
feline OR canine)) AND TITLE-ABS-
KEY(("growth rate" OR lambda OR "carrying
capacity")) AND TITLE-ABS-
KEY((reproduc* OR breed* OR fertil* OR
(birth W/1 rate) OR (puppy W/1 mill*))) OR
TITLE-ABS-KEY((cat OR dog OR pet OR
"companion animal" OR feline OR canine))
AND TITLE-ABS-KEY(("growth rate" OR
lambda OR "carrying capacity")) AND TITLE-
ABS-KEY(((animal W/1 control) OR (animal
W/1 management) OR euthan* OR shelter*
OR rescue* OR welfare OR sterilization OR
spay OR neuter OR castration OR
ovariohysterectomy OR orchiectomy)))
147
A.2.
Relevance Screening Form
Scoping review: What is the current state of knowledge on approaches to managing companion
animal population dynamics to control the number of owned free-roaming, unowned free-
roaming and unwanted companion animals?
Abstract-level relevance screening form
Question Options Definitions/additional notes
RefID
1. Does the abstract or title
investigate or discuss the
population dynamics or
surveillance or control practices
of free-roaming (owned or
unowned) or unwanted
companion animals?
1) Yes, within the context of
primary research OR
review/commentary.
2) No
Reviewer Decision:
If the reviewer selects option
1) “Yes,” the article will
advance to level 2, where the
full article will be used for
further screening and
appraisal.
If option 2) “No” is selected,
the abstract will be
EXCLUDED.
IMPORTANT: Please use
your best judgement in
deciding whether an abstract
is relevant or not; however, if
you are quite unsure we would
prefer you pass it through as
"yes".
Companion animals are defined
as any animal species kept for
companionship and enjoyment
or a household animal, as
opposed to livestock, laboratory
animals, working animals or
sport animals, which are kept for
economic reasons.
Population Dynamics refers to
any process that affects the size
and or structure of a companion
animal population over time
(e.g. births, deaths, migration).
Surveillance to monitor the
population size.
Control refers to decreasing or
maintaining.
Control Practices examples:
Trap neuter release (TNR)
148
Low cost or early spay and
neuter
Euthanasia
Free-roaming companion
animals are defined as
companion animals that are
living outdoors at least part of
the time, not confined to an
owner’s residence or property at
that time and not under direct
supervision.1,2
Straying is used to describe
companion animals that have a
home and are free-roaming, not
confined to an owner’s
residence or property at that
time and not under direct
supervision.1,2
Owned free-roaming
companion animals are defined
as owned companion animals
that are straying from the
owner’s residence or property.1
Abandoned is used to describe
companion animals that are
discarded or left to fend for
themselves rather than being
formally surrendered to a
facility by their previous owner.6
Feral is used to describe
companion animals that are free-
149
roaming and unsocialized to
humans.2
Unowned free-roaming
companion animals are defined
as unowned companion animals
that are abandoned, or feral. 2, 3, 4
Surrender is defined as when
the owner of a companion
animal which is no longer
wanted takes the animal to an
animal shelter or municipal
pound and legally surrenders all
further claim to ownership of the
companion animal.6
Unwanted companion animals
are defined as companion
animals who are not free-
roaming but are being
surrendered to a shelter, are
being given away, are being
sold, killed, or euthanized by
their owners.5
Stray is used to describe
companion animals that are
socialized unowned and free-
roaming, or feral.2
Primary research is defined as
any original research using
specific quantitative, qualitative
or both methods to investigate
the issue of companion-animal
population dynamics to control
the number of owned free-
150
roaming, unowned free-roaming
and unwanted companion
animals and report new results.6
Review/commentary is defined
as a comprehensive or brief
narrative review or commentary
(from peer-reviewed articles to
lay magazine or newspaper
articles or briefs) describing
and/or discussing the issue of
companion-animal population
dynamics to control the number
of owned free-roaming,
unowned free-roaming and
unwanted companion animals,
with or without mentioning any
case study or contextual
examples. No methods
(qualitative or quantitative) are
reported.6
1Slater, et al., 2008
2Slater, 2004
3Faulkner, 1975
4Feldman & Carding, 1973
5Fielding, 2010
6Coe et al., 2015
References
Coe, J. B., Young, I., Lambert, K., Dysart, L., Nogueira Borden, L., Rajić, A. (2014). A scoping
review of published research on the relinquishment of companion animals. Journal of Applied
Animal Welfare Science, 17, 253-273.
Faulkner, L.C. (1975) Dimensions of the pet population problem. Journal of the American
Veterinary Medical Association, 166, 5, 477-478.
Feldmann, B. M., & Carding, T. H. (1973). Free roaming urban pets. Health Services Report,
88(10), 956-962.
151
Fielding, W.J. (2010). Dog breeding in New Providence, the Bahamas, and its potential impact
on the roaming dog population II: The fate of puppies. Journal of Applied Animal Welfare
Science, 13, 4, 300-313.
Slater, M.R., Di Nardo, A., Pediconi, O., Dalla Villa, P., Candeloro, L., Alessandrini, B., & Del
Papa, S. (2008). Free-roaming dogs and cats in central Italy: Public perceptions of the problem.
Preventive Veterinary Medicine, 84, 27-47.
Slater, M.R. (2004). Understanding issues and solutions for unowned, free-roaming cat
populations. Journal of the American Veterinary Medical Association, 225, 9, 1350-1354
152
A.3.
Data Characterization and Extraction Form
Question Options Definitions/Additional Notes
1. Is this a review,
commentary or primary
research article on the
issue of free roaming
(owned or unowned) or
unwanted companion
animal population
dynamics, control
practices or surveillance?
o Yes, review or
commentary
o Yes, qualitative primary
research
o Yes, quantitative primary
research
o Yes, mixed-methods
research
o None of the above,
specify reason for
exclusion:
- Not Relevant:
- Other:
o Other (1 sentence to 1
paragraph on the topic but
not main focus of the
article)
If “None of the above” is
selected, article will be
Excluded. Please specify the
reason for exclusion and
submit the form without
completing the remaining
questions.
Companion animals are
defined as any animal species
kept for companionship and
enjoyment or a household
animal, as opposed to
livestock, laboratory animals,
working animals or sport
animals, which are kept for
economic reasons.
Owned free-roaming
companion animals are
defined as owned companion
animals that are straying from
the owner’s residence or
property.1
Unowned free-roaming
companion animals are
defined as unowned
companion animals that are
abandoned, or feral. 2, 3, 4
Unwanted companion
animals are defined as
companion animals who are
not free-roaming but are
being surrendered to a shelter,
are being given away, are
being sold, killed, or
euthanized by their owners.5
Population Dynamics refers
to any process that affects the
size and or structure of a
companion animal population
over time (e.g. births, deaths,
migration).
Surveillance to monitor the
population size.
153
Control Practices examples:
Trap neuter release (TNR)
Low cost or early spay and
neuter
Euthanasia
Re-homing
Review or commentary: A
comprehensive or brief
narrative review or
commentary (from peer-
reviewed articles to lay
magazine or newspaper
articles or briefs) describing
and/or discussing the issue of
pet abandonment, with or
without mentioning any case
study or contextual examples.
No methods (qualitative or
quantitative) are reported.
Primary research: Any
original research using
specific quantitative,
qualitative or both methods to
investigate the issue of
unowned or owned free-
roaming or unwanted
companion animals and
report new results.
Qualitative research: Aimed
at understanding social
phenomena, exploring issues,
and answering questions of
“why” and “how”. Examples:
focus groups, interviews.
Quantitative primary
research: Investigator(s)
collected samples or data
themselves for analysis (e.g.,
cross-sectional studies,
surveys, case-control studies)
154
Mixed-method research:
Conduct of qualitative and
quantitative methods in the
same study (e.g., focus
groups and a quantitative
survey/questionnaire)
2. Is the article in English or
Spanish?
o English
o Spanish
o Other: please specify
If “Other” is selected, article
will be Excluded.
3. Author Name(s)
4. What year was the article
published?
5. What is the type of
document?
o Journal Article
o Lay Magazine Article
o Conference Proceeding
o Newspaper Article
o Government or Research
Report
o Thesis or Dissertation
o Book or Book Chapter
o Other, Please Specify
6. Where was the study
conducted? (Country,
State/Province, City – if
given)
o
o Not Reported
Global: One or more
countries on at least 3
continents.
7. Source of Funding o Government
o Industry
o Public Health Agency
o University
o Other: Please Specify
o Not Reported
8. What is the main study
(review) objective as
stated by the authors?
o
o Not Reported
9. What is the study design? o Observational Study
a) Cross Sectional
b) Cohort
-Retrospective
-Prospective
c) Case-Control
-Retrospective
-Prospective
d) Prevalence Survey
Observational study:
Assignment of subjects into a
treated group versus a control
group is outside the control of
the investigator.
Cross-sectional: Observation
of all of a population, or a
representative subset, at a
defined time
155
e) Case or Case
Series
o Experimental Study
a) Controlled Trial
b) Challenge Trial
c) Quasi Experiment
d) Other, please
specify
o Qualitative Study
a) Grounded Theory
b) Ethnography
c) Phenomenology
d) Not Specified
e) Other, please
specify
o Routine monitoring or
surveillance data
collection
o Mathematical modeling
or methodology study
o Other, please specify
o Not applicable, this is not
primary research
Cohort study: A study in
which individuals with
differing exposures to a
suspected factor are observed
over a period of time for
occurrence of an outcome
Case-control study:
Compares exposure in
patients who have a condition
(the 'cases') with subjects who
do not have the condition, but
are otherwise similar (the
'controls').
Prevalence survey:
Measurement of outcomes in
a defined period of time
but doesn’t measure or
investigate potential
predictors
Case Report or Case-series: A descriptive study of a
single individual (case report)
or small group (case series).
Experimental study: Each
subject is randomly assigned
to a treated group or a control
group before the start of the
treatment
Control trial: An
experimental study in which
people are allocated to
interventions and evaluated
for outcomes. For this
question, RCTs are included.
Challenge trial: An
experiment where subjects are
artificially challenged or
exposed to the disease agent
156
Quasi-experiment: An
experiment in which subjects
are not randomly assigned to
groups (e.g., before-after
comparison)
Qualitative study: Aimed at
understanding social
phenomena, exploring issues,
and answering questions of
“why” and “how”.
NOTE: For qualitative
studies please select the
design/methodology that is
identified by the author, and if
none is identified explicitly,
choose “not specified”
Grounded theory:
Development of a theory that
is grounded in data collected
from the field. Often uses
interviews.
Ethnography: Description
and interpretation of a cultural
or social group. Often uses
interviews, in-depth field
work and observations.
Phenomenology:
Understanding the essence
and meaning of experiences
of a phenomenon. Often uses
long, in-depth interviews.
Not specified: Qualitative
study that is not described as
one of the above
methodologies or another
methodology (e.g., case
study).
Routine monitoring or
surveillance data collection: Primarily cover articles that
157
report on an ongoing and
systematic data collection, or
the analysis and interpretation
of data related to our study
question.
10. What are the companion
animal population
studied?
Please Specify ALL that
Apply
o Dogs
o Cats
o Rabbits
o Other, please specify
o Not Specified
Companion animals are
defined as any animal species
kept for companionship and
enjoyment or a household
animal, as opposed to
livestock, laboratory animals,
working animals or sport
animals, which are kept for
economic reasons.
11. What types of populations
were studied?
Please Specify ALL that
Apply
o Owned free roaming
o Un-owned free roaming
o Unwanted
o Owned uncertain
o Not Reported
Owned free-roaming
companion animals are
defined as owned companion
animals that are straying from
the owner’s residence or
property.1
Unowned free-roaming
companion animals are
defined as unowned
companion animals that are
abandoned, or feral. 2, 3, 4
Unwanted companion
animals are defined as
companion animals who are
not free-roaming but are
being surrendered to a shelter,
are being given away, are
being sold, owners.5
Owned uncertain refers to
companion animals who are
owned but it cannot be
determined if they are free
roaming or solely kept
indoors.
12. What was the research
focus area/theme of
investigation?
Please Specify ALL that
Apply
o Population Dynamics:
o Surveillance
Population Dynamics refers
to any process that affects the
size and or structure of a
companion animal population
158
o Control practices (if yes
go to question 13, if no
skip to question 14 )
o Opinions/Perceptions
o Other, please specify
over time (e.g., births, deaths,
migration).
Surveillance to monitor the
population size.
Control Practices examples:
Trap neuter release (TNR)
Low cost or early spay and
neuter
Euthanasia
Re-homing
13. What type of control
practices were
investigated (or discussed
for review articles)?
Please Check ALL that Apply
o Spay and Neuter
a) Early Spay and Neuter
b) Traditional Spay and
Neuter
c) Low cost or
subsidized Spay and
Neuter
d) Non-Surgical Spay
and Neuter
-Chemical Castration
- GnRH
immunocontraceptive
(GonaConTM)
-Zona pellucida
glycoproteins
immunocontraceptive
-Hormonal Implants
-Other, please specify
-Not specified
e) Trap Neuter Release
f) Trap Neuter Relocate
g) Trap Vasectomy
Hysterectomy Release
h) Trap Vasectomy
Hysterectomy
Relocate
i) Trap
Ovariohysterectomy
Release
j) Trap
Ovariohysterectomy
Relocate
Spay and Neuter refers to
sterilization
Traditionally done via
surgical methods:
a) Spay removal of
ovaries, uterus or both
b) Neuter removal of
testes
Early spay or Early neuter
refers to being spayed or
neutered before the cat or dog
has reached the age of 24
weeks
Non-Surgical Spay and
Neuter refers to treatments
that permanently or
temporally inhibit fertility
Alternative Terms
Spay and Neuter =
Sterilization, sterilized, fix,
fixed, de-sexed, de-sex
castration, gonadectomy,
orchiesctomy,
ovariohysterectomy,
hysterectomy, ovariectomy,
altered, castrate, castrated
Early Spay and Neuter =
prepubertal, paediatric, young
or juvenile spay and neuter
159
k) Shelter Neuter
Release
l) Return-to-Field
m) Other, please specify
n) Not specified
o Euthanasia
a) Poison
b) Intravenous injection
c) Shooting
d) Gas
e) Blunt force trauma
f) Other, please specify
g) Not specified
o Legislations/Regulations
a) Licensing or
Registration
b) Limit the number of
free roaming cats
c) Mandatory Spay and
Neuter
d) Breeding laws
e) Other, please specify
f) Not specified
o Re-homing
o Education
o Vaccination
o Other, please specify
o Not Reported
Trap Neuter Release = Trap
Neuter Return, TNR, catch
neuter release/return
Trap Vasectomy
Hysterectomy Release = Trap
Vasectomy Hysterectomy
Return or TVHR
Trap Ovariohysterectomy
Release = Trap
Ovariohsterectomy Return
Euthanasia = eradication or
culling
Re-homing = adopting
14. Who are the stakeholders
(as specified by the
authors)?
Please Check ALL that Apply
o Veterinarians
o Shelters
o Rescues
o Animal Welfare
Professionals
o Public Health
o Ecologists
o Society/General Public
o Corporations and
Institutions
o Small Businesses
o Pounds
o Animal Control Facilities
o Other, please specify
o Not Reported
Shelters include SPCAs, and
humane societies
Rescues generally on take in
animals of a specific species
but sometimes they focus on
a specific breed or type
Pounds are government run
facilities that take in strays or
surrendered animals
Animals Control are also
government run facilities
where animals can be
surrendered and strays can
brought in. However animal
control facilities can deal
160
with cases of animal abuse or
animal attacks.
15. What were the main
outcomes investigated or
discussed?
Please Check ALL that Apply
o Free-roaming/unwanted
companion animal
population size
o Number of euthanized
free roaming/unwanted
companion animals
o Number of free
roaming/unwanted
companion animals in
shelters
o Number of adoptions
from shelters
o Number of shelter intakes
o Prevalence of disease in
free roaming/unwanted
companion animals
o Cost Benefit (economics)
of a control program for
free roaming/unwanted
companion animals
o Improve methodology of
control practices
o Views/opinions on free
roaming/unwanted
companion animals
o By-laws and legislations
o Non-zoonotic diseases,
specify disease:
a) Feline Leukemia
Virus (FeLV)
b) Canine Distemper
c) Canine Papilloma
Virus (CPV)
d) Feline Papilloma
Virus (FPV)
e) Other, please
specify
o Zoonotic Disease, specify
disease:
a) Rabies
b) Toxoplasma
gondii
Zoonotic diseases refers to
diseases that can spread
among species (specifically
transmission from animals to
humans)
Ectoparasite refers to
parasites that live outside
their host
Alternative Terms
Adoptions = rehoming
161
c) Leishmaniasis
d) Bartonella
e) Brucellosis
f) Other, please
specify
o Ectoparasites (e.g. Fleas,
ticks, mites)
o Other public health/safety
issues (e.g. Animal bites,
sanitation)
o Protect the environment
and other species
a) Birds
b) Reptiles
c) Other mammals,
please specify
d) Biodiversity
e) Other, please
specify
o Other, please specify
16. Was the effectiveness of
control practices
investigated or discussed?
- Yes, for each practice
investigated for
effectiveness, please
specify the following
- For Primary Research
a) Control Practice
b) Population
c) Outcome(s)
d) Effectiveness
(effective or no
effective)
e) Significant, non-
significant, or not
assessed for
statistical
significance
- For Reviews/
Commentaries
a) Control Practice
b) Population
c) Outcome(s)
d) Effectiveness
(effective or no
effective)
e) Significant, non-
significant, or not
162
assessed for
statistical
significance
o Not reported
17. Are raw/unadjusted data
or measures of
association/effect
provided?
Please Check ALL that
Apply
o Yes
a) Prevalence outcome
b) Dichotomous outcome
(2X2 table data)
c) Continuous outcome
d) Measure of
association (OR, RR)
e) Modelling
coefficients/beta
parameters
f) P values
g) Measure of variability
(CI, SE, SD)
h) Spatial analysis
i) Ordinal/Likert scale
j) Other:
o No
a) Graphical
b) Other reason:
o N/A – qualitative study or
review/commentary
Yes, please specify:
Raw results or
measures of
association/effect
unadjusted by
statistical modeling
are provided
Minimum necessary data:
a. Prevalence/frequency:
Following data must
be reported measuring
in at least ONE
microbe in ONE
discrete sample type:
Numerator and
denominator, or
Proportion + EITHER
numerator or
denominator
b. Continuous outcome
Must be provided
with a measure of
variability AND
sample size
c. Measures of
association/effect:
OR/RR/IR/RD/PAF/
AFe reported and its
measure of variability
(SE, SD, CI) or P-value
and sample size (n) is
reported
Spatial analysis or spatial
statistics includes any of the
formal techniques which
study entities using their
topological, geometric, or
geographic properties.
An ordinal measure involves
an ordered series, such as
graded responses to an item
163
on a questionnaire: Response
choices: Strongly agree = 4,
Agree = 3, Neither agree nor
disagree = 2, Disagree = 1,
Strongly disagree = 0.
Likert scale - an item is
presented as a declarative
statement, followed by
response options that indicate
varying degrees of agreement
with or endorsement of the
statement
18. For primary research
studies, what data
collection methods were
used?
o Quantitative questionnaire
or survey, specify details:
o Qualitative interviews,
specify details:
o Observations, specify
details:
o Focus groups, specify
details:
o Analysis of documents,
specify details
o Other, please specify
o Not specified
o N/A – not primary
research
19. Who collected the data? Please check ALL that
apply
o Research
authors/technicians
o Veterinarians
o Shelters
o Public Health
o Ecologists
o Society/General public
o Other, please specify
o Not Reported
o N/A
20. For qualitative research
studies, what were the
main themes
investigated/identified?
o
o Not Applicable
21. Do the authors explicitly
report the strengths of
o Yes, please specify
o No
164
their/this research in
general?
o Not applicable, not
primary research
22. Do the authors explicitly
report the weakness of
their/this research in
general?
o Yes, please specify
o No
o Not applicable, not
primary research
23. What are the overall
recommendations of the
authors?
Please Check ALL that Apply
o Control the number free
roaming/unwanted
companion animals
o Increase Spays and
Neuters
a) Early Spay and Neuter
b) Traditional Spay and
Neuter
c) Low cost or
subsidized Spay and
Neuter
d) Non-Surgical Spay
and Neuter
-Chemical Castration
- GnRH
immunocontraceptive
(GonaConTM)
-Zona pellucida
glycoproteins
immunocontraceptive
-Hormonal Implants
-Other, please specify
-Not specified
e) Trap Neuter Release
f) Trap Neuter Relocate
g) Trap Vasectomy
Hysterectomy Release
h) Trap Vasectomy
Hysterectomy
Relocate
i) Trap
Ovariohysterectomy
Release
j) Trap
Ovariohysterectomy
Relocate
k) Shelter Neuter
Release
l) Return-to-Field
165
m) Other, please specify
n) Not specified
o Increase Euthanasia
a) Poison
b) Intravenous injection
c) Shooting
d) Blunt force trauma
e) Other, please specify
f) Not specified
o Decrease Euthanasia
a) Poison
b) Intravenous injection
c) Shooting
d) Blunt force trauma
e) Other, please specify
f) Not specified
o Enforce new and or
existing
Legislations/Regulations
a) Licensing or
Registration
b) Limit the number of
free roaming
companion animals
c) Mandatory Spay and
Neuter
d) Breeding Laws
e) Other, please specify
f) Not specified
o Increase the number of
free-roaming/unwanted
companion animals re-
homed
o Increase Public Education
o Increase Vaccination
o Control the spread of
disease
o Other, please specify
o None
o Not Specified 1Slater, et al., 2008
2Slater, 2004
3Faulkner, 1975
166
4Feldman & Carding, 1973
5Fielding, 2010
References
Faulkner, L.C. (1975) Dimensions of the pet population problem. Journal of the American
Veterinary Medical Association, 166, 5, 477-478.
Feldmann, B. M., & Carding, T. H. (1973). Free roaming urban pets. Health Services Reports,
88(10), 956-962.
Fielding, W.J. (2010). Dog breeding in New Providence, the Bahamas, and its potential impact
on the roaming dog population II: The fate of puppies. Journal of Applied Animal Welfare
Science, 13, 4, 300-313.
Slater, M.R., Di Nardo, A., Pediconi, O., Dalla Villa, P., Candeloro, L., Alessandrini, B., & Del
Papa, S. (2008). Free-roaming dogs and cats in central Italy: Public perceptions of the problem.
Preventive Veterinary Medicine, 84, 27-47.
Slater, M.R. (2004). Understanding issues and solutions for unowned, free-roaming cat
populations. Journal of the American Veterinary Medical Association, 225, 9, 1350-1354.
168
A.4.
Reference List of Included 869 Articles
Abbas, S. S., Kakkar, M., Rogawski, E. T. (2014). Costs analysis of a population level rabies
control programme in Tamil Nadu, India. PLoS Neglected Tropical Diseases, 8, e2721.
Abbas, S. S., Venkataramanan, V., Pathak, G., & Kakkar, M. (2011). Rabies control initiative in
Tamil Nadu, India: a test case for the ‘One Health’ approach. International Health, 3, 231-239.
Ackermann, D. L. (2010). Thoughts on feral cat control. Journal of the American Veterinary
Medical Association, 237, 26-27.
Acosta-Jamett, G., Cleaveland, S., Cunningham, A. A., & deC Bronsvoort, B. M. (2010).
Demography of domestic dogs in rural and urban areas of the Coquimbo region of Chile and
implications for disease transmission. Preventive Veterinary Medicine, 94, 272-281.
Adkins, B. (2008). Factors associated with the relinquishment of domestic canines to animal
shelters. ProQuest, 69, 676.
Aguilar, G. D., & Farnworth, M. J. (2012). Stray cats in Auckland, New Zealand: discovering
geographic information for exploratory spatial analysis. Applied Geography, 34, 230-238.
Aguilar, G. D., & Farnworth, M. J. (2013). Distribution characteristics of unmanaged cat
colonies over a 20 year period in Auckland, New Zealand. Applied Geography, 37, 160-167.
Aidaros, H. (2005). Global perspectives – the Middle East: Egypt. Scientific and Technical
Review of the Office International des Epizooties, 24, 589-596.
Aiyedun, J. O., & Olugasa, B. O. (2012). Use of aerial photograph to enhance dog population
census in Ilorin, Nigeria. Sokoto Journal of Veterinary Sciences, 10, 22-27.
Akkan, H. A., Genccelep, M., Karaca, M., Ceylan, E., Tutuncu, M., Agaoglu, Z., & Aytekin, I.
(2004). The effects of succinylcholine on some clinical, haematological and biochemical
parameters in dogs. Indian Veterinary Journal, 81, 718.
Alberthsen, C, Rand, J. S., Bennett, P. C., Paterson, M., Lawrie, M., & Morton, J. M. (2013). Cat
admissions to RSPCA shelters in Queensland, Australia: description of cats and risk factors for
euthanasia after entry. Australian Veterinary Journal, 91, 35-42.
Algar, D., Angus, G. J., & Onus, M. L. (2011). Eradication of feral cats on Rottnest Island
Western Australia. Journal of the Royal Society of Western Australia, 94, 439-443.
Algar, D., Angus, G. J., Williams, M. R., & Mellican, A. E. (2007). Influence of bait type,
weather and prey abundance on bait uptake by feral cats (Felis catus) on Peron Peninsula,
Western Australia. Conservation Science Western Australia, 6, 109-149.
Algar, D., & Burbidge, A. (2000). Isle of cats: the scourging of Hermite Island. Landscope: The
Journal of the Western Australian Department of Conservation and Land Management, 15, 18-
22.
169
Algar, D. A., Burbidge, A. A., & Angus, G. J. (2002). Cat eradication on Hermite Island,
Montebello Islands, Western Australia. In C. R. Veitch, & M. N. Clout (eds.), Turning the tide:
the eradication of invasive species (pp. 14-18). IUCN SSC Invasive Species Specialist Group.
Algar, D., & Burrows, N. D. (2004). Feral cat control research: Western Sheild review –
February 2003. Conservation Science Western Australia, 5, 131-163.
Algar, D., Hilmer, S., Nickels, D., & Nickels, A. (2011). Successful domestic cat neutering: first
step towards eradicating cats on Christmas Island for wildlife protection. Ecological
Management & Restoration, 12, 93-101.
Alliance for Contraception in Cats & Dogs. (2013). Contraception and Fertility Control in Dogs
and Cats.
Allen, B. L., Allen, L. R., Engerman, R. M., & Leung, L. K. P. (2013). Intraguild relationships
between sympatric predators exposed to lethal control: predator manipulation experiments.
Frontiers in Zoology, 10.
Allen, B L., Allen, L. R., & Leung, L. K. P. (2015). Interactions between two naturalised
invasive predators in Australia: are feral cats suppressed by dingoes? Biological Invasions, 17,
761-776.
Allen, D. K. (1992). Pet overpopulation. Journal of the American Veterinary Medical
Association, 200, 256.
Amaku, M., Dias, R. A., Ferreira, F. (2010). Dynamics and control of stray dog populations.
Mathematical Population Studies, 17, 69-78.
Amaral, A. C., Ward, M. P., & Freitas, J. da C. (2014). Estimation of roaming dog populations in
Timor Leste. Preventive Veterinary Medicine, 113, 608-613.
American Bird Conservancy (1997). American Bird Conservancy’s resolution on free-roaming
cats.
Amity, R. (1985). Animal in Fairfax County, Virginia. 82-84.
Amyx, C. (2005). Yet another perspective on TNR. Journal of the American Veterinary Medical
Association, 226, 514.
Andersen, M. C., Martin, B. J., Roemer, G. W. (2004). Use of matrix population models to
estimate the efficacy of euthanasia versus trap-neuter-return for management of free-roaming
cats. Journal of the American Veterinary Medical Association, 225, 1871-1876.
Anderson, D. G. (1992). The control of pet overpopulation. Veterinary Technician, 13, 119-123,
128.
Anonymous. (1973). Spay clinics: the other side of the story. Modern Veterinary Practice, 54,
29-34.
*Anonymous. (1974). Proceedings of the National Conference of the Ecology of the Surplus Dog
and Cat Problem, May 21-23, 1974. [Ecology of the surplus and cat problem].
170
Anonymous. (1974). The rising surplus of dogs & cats. Modern Veterinary Practice, 55, 614-
618.
Anonymous. (1976). A report on a workshop on the per population in New York State: held
…24th and 25th of September 1975 at the Sheraton Syracuse Motor Inn, Syracuse New York.
Anonymous. (1987). Purebred overpopulation: “papers” don’t guarantee a home. Advocate, 5,
16-17.
Anonymous. (1989). Dog population control in Latin America. Animals International World
Society for the Protection of Animals, 9, 8-9.
*Anonymous. (1990). Guidelines for Dog Population Management. Geneva: WHO.
Anonymous. (1991). AVMA recommends steps to control pet population. Journal of the
American Veterinary Medical Association, 198, 1113.
*Anonymous. (1991). Pet overpopulation. Journal of the American Veterinary Medical
Association, 198, 1151-1243.
Anonymous. (1993). HSUS calls for end to breeding. Journal of the American Veterinary
Medical Association, 202, 1809.
Anonymous. (2003). Decisions and finding no significant impact management of feral and free-
ranging cat populations to reduce threats to human health and safety and impacts to native
wildlife species in the commonwealth of Puerto Rico. USDA, APHIS, WS.
*Anonymous. (2004). AVMA Animal Welfare Forum. Management of Abandoned and Feral
cats, 7 November 2003, Illinois, USA. In Journal of the American Veterinary Medical
Association (Vol. 225, pp. 1349-1383). Schamburg: American Veterinary Medical Association.
Anonymous. (2011). Farm dog neutering scheme takes off. Veterinary Record, 169, 514.
*Anonymous. (2012). 3rd International conference of Veterinary Medicine of the Collective,
Federal University of Parana, Curitiba, Brazil, 23 to 25 November 2012. In Archives of
veterinary science (Vol. 17, pp. 1-57). Curitiba, Universidade Federal do Paraná, UFPR.
Anonymous. (2012). Campaign aims to ‘make neutering the norm’. Veterinary Record, 171, 417.
Anonymous. (2014). Prepubertal neutering key to tackling ‘cat crisis’, says RSPCA. Veterinary
Record, 174, 417.
Apps, P. (1984). Cat on Dassen Island. Acta Zoologica Fennica, 172, 115-116.
Aréchiga Ceballos, N., Karunaratna, D., & Aguilar Setién, A. (2014). Control of canine rabies in
developing countries: key features and animal welfare implications. Scientific and Technical
Review of the Office International des Epizooties, 33, 311-321.
Arkow, P. (1985). Animal control, birth control, and community education: impacts on the
Colorado Springs pet population, 1970-1984. In A. K. Wilson, & A. N. Rowan (Eds.),
Proceedings of a Workshop on Animal Control (pp. 30-48). Tufts Center for Animals, Boston.
Arkow, P. (1991). Animal control laws and enforcement. Journal of the American Veterinary
Medical Association, 198, 1164-1171.
171
Arkow, P. (1994). A new look at animal “overpopulation”. Anthrozoös, 7, 202-205.
Arnaudova, A., & Varlyakov, I. (2010). Shelter policies in the management of canine aggression.
Agricultural Science and Technology, 2, 64-70.
Artois, M. (1997). Managing problem wildlife in the ‘Old World’: a veterinary perspective.
Reproduction, Fertility and Development, 9, 17-25.
*Ash, S. J. (2001). Ecological and sociological considerations of using the TTVAR (trap, test,
vaccinate, alter, return) method to control free-ranging domestic cat, Felis catus, populations
(Doctoral Dissertation). Texas A&M University.
Ash, S. J., & Adams, C. E. (2003). Public preferences for free-ranging domestic cat (Felis catus)
management options. Wildlife Society Bulletin, 31, 334-339.
Attanasio, E., & Palmas, C. (1984). Cost-effectiveness analysis of echincococcosis-hydatidosis
eradication project in Sardinia. Social Science & Medicine, 19, 1067-1072.
Atuman, Y. J., Ogunkoya, A. B., Adawa, D. A. Y., Nok, A. J., & Biallah, M. B. (2014). Dog
ecology, dog bites and rabies vaccination rates in Bauchi State, Nigeria. International Journal of
Veterinary Science and Medicine, 2, 41-45.
*August, J. R. (2006). Consultations in feline internal medicine.
Aurich, J., & Becher, A. (2013). Educating owners – the key to managing cat populations.
Veterinary Record, 172, 576-577.
Avanzino, R. (1991). Pet overpopulation and humane education in schools and communities.
Journal of the American Veterinary Medical Association, 198, 1237-1240.
Baioni, E., Capello, K., Biggeri, A., Mutinelli, F., & Vascellari, M. (2011). Dog population size
and dynamics: a method for control. Epidémiologie et Santé Animale, 59-60, 30-31.
Bajunid, A. F. I., Salim, N. B., Cheng, N. A. B. Y.., & Hassan, L. (2004). An ecological study of
the free-roaming cat population in the Universiti Putra Malaysia (UPM) campus. In The 11th
International Conference of the Association of Institutions for Tropical Veterinary Medicine (pp.
181-183).
Balcom, S. A. (2000). Legislating a solution to animal shelter euthanasia: a case study of
California’s controversial SB 1785. Society and Animals, 8, 129-150.
Baldwin, C. J., Peter, A. T., Bosu, W. T. K., & Dubielzig, R. R. (1994). The contraceptive effects
of levonorgestrel in the domestic cat. Laboratory Animal Science, 44, 261-269
Barber, M. R., Lee, S. M., Steffens, W. L., Ard, M., & Fayrer-Hosken, R. A. (2001).
Immunolocalization of zona pellucida antigens in the ovarian follicle of dogs, cats, horses and
elephants. Theriogenology, 55, 1705-1717.
Barnett, B. D. (1985). Chemical vasectomy of domestic dogs in the Galapagos Islands.
Theriogenology, 23, 499-509.
Barrows, P. L. (2002). Final letters for now on feral cats. Journal of the American Veterinary
Medical Association, 221, 1547.
172
Barrows, P. L. (2004). Professional, ethical, and legal dilemmas of trap-neuter-release. Journal
of the American Veterinary Medical Association, 225, 1365-1369.
Bartlett, P. C., Bartlett, A., Walshaw, S., & Halstead, S. (2005). Rates of euthanasia and adoption
for dogs in Michigan animal shelters. Journal of Applied Animal Welfare Science, 8, 97-104.
Barnett, B. D., & Rudd, R. L. (1983). Feral dogs of the Galapagos Islands: impact and control.
International Journal for the Study of Animal Problems, 4, 44-58.
Bastian, S. (2006). The debate on feral cats continues. Journal of the American Veterinary
Medical Association, 228, 684-686
Bateman, C. (2005). AIDS fuels ownerless feral dog populations. South African Medical
Journal, 95, 78-79.
Beaver, B. V. (1991). The role of veterinary colleges in addressing the surplus dog and cat
problem. Journal of the American Veterinary Medical Association, 198, 1241-1243.
Beck, A. M. (1973). The ecology of stray dogs: a study of free-ranging urban animals. Purdue
University Press.
Beckman, M., Hill, K. E., Farnworth, M. J., Bolwell, C. F., Bridges, J., & Acke, E. (2014).
Tourists’ perceptions of the free-roaming dog population in Samoa. Animals, 4, 599-611.
Belsare, A. V., & Gompper, M. E. (2015). A model-based approach for investigation and
mitigation of disease spillover risks to wildlife: dogs, foxes and canine distemper in central India.
Ecological Modelling, 296, 102-112.
Bender, S. C., Bergman, D. L., Wenning, K. M., Miller, L. A., Slate, D., Jackson, F. R., &
Rupprecht, C. E. (2009). No adverse effects of simultaneous vaccination with the
immunocontraceptive GonaConTM and a commercial rabies vaccine on rabies virus neutralizing
antibody production in dogs. Vaccine, 27, 7210-7213.
Bengsen, A., Butler, J., & Masters, P. (2011). Estimating and indexing feral cat population
abundances using camera traps. Wildlife Research, 38, 732-739.
Beran, G. W. (1982). Ecology of dogs in the central Philippines in relation to rabies control
efforts. Comparative Immunology, Microbiology & Infectious Diseases, 5, 265-270.
Bernstein, P. (2005). The home-cat relationship. In I. Rochlitz (Ed.), The welfare of cats (pp. 47-
89). Dordrecht: Springer.
Bester, M. N., Bloomer, J. P., Aarde, R. J. Erasmus, B. H., Rensburg, P. J. J., Skinner, J. D., …
Naude, T. W. (2002). A review of the successful eradication of feral cats from sub-Antarctic
Marion Island, southern Indian Ocean. South African Journal of Wildlife Research, 32, 65-73.
Bloomberg, M. S. (1996). Surgical neutering and nonsurgical alternatives. Journal of American
Veterinary Medical Association, 208, 517-519.
Bogel, K. (1984). Guidelines for dog rabies control continued. Geneva: WHO.
173
Bomford, M. (1990). A role for fertility control in wildlife management. Australian Government
Publishing Service.
Bonnaud, E., Zarzoso-Lacoste, D., Bourgeois, K., Ruffino, L., Legrand, J., & Vidal, E. (2010).
Top-predator control on islands boosts endemic prey but not mesopredator. Animal
Conservation, 13, 556-567.
Bradbury, L., & Corletter, S. (2006). Dog health program in Numbulwar, a remote Aboriginal
community in east Arnhem Land. Australian Veterinary Journal, 84, 317-320.
Bradshaw, J. W. D., Casey, R. A., & Brown, S. L. (2012). Hunting and Predation. The behaviour
of the domestic cat (Ed. 2) (pp. 128-141).
Bradshaw, J. W. S., Horsfield, G. F., Allen, J. A., & Robinson, I. H. (1999). Feral cats: their role
in population dynamics of Felis catus. Applied Animal Behaviour Science, 65, 273-283.
Brant, K. (1987). The case for neutering cats & dogs. The Animals’ Agenda, 34.
Brestle, K. (2008). High-volume spay / neuter clinics: what do they mean to a community? In
NAVC Conference (pp. 1478).
Bromwell, D. R. (1976). The problem of enforcing statewide animal control and regulation. In
Proceedings of the National Conference on Dog and Cat Control: February 2-5, 1976, Denver,
Colorado/jointly sponsored by American Humane Association…[et al.](pp. 186-193). Denver,
Co.: American Humane Association.
Brook, L. A., Johnson, C. N., & Ritchie, E. G. (2012). Effects of predator control on behaviour
of an apex predator and indirect consequences for mesopredator suppression. Journal of Applied
Ecology, 49, 1278-1286.
Brooks, R. (1990). Survey of the dog population of Zimbabwe and its level of rabies vaccination.
Veterinary Record, 127, 592-596.
Budke C. M., & Slater, M. R. (2009). Utilization of matrix population models to assess a 3-year
single treatment nonsurgical contraception program versus surgical sterilization feral cat
populations. Journal of Applied Animal Welfare Science, 12, 277-292.
Burke, T. J., & Reynolds, H. A. (1975). Megestrol acetate for estrus postponement in the bitch.
Journal of the American Veterinary Medical Association, 167, 285-287.
Burleigh, A., McMahon, S., & Kiely, S. (2015). Owned dog and cat populations in remote
Indigenous communities in the Northern Territory: a retrospective study. Australian Veterinary
Journal, 93, 145-150.
Bushby, P. (2012). Early-age spay/neuter. NAVC Clinician’s Brief, 71-73.
Butcher, R. (2009). Catch, neuter and release programmes – the pros and cons. In World Small
Animal Veterinary Association World Congress Proceedings.
Butcher, R. (2009). Humane dog population management guidelines. In NAVC Conference (pp.
1475-1477).
174
Byrd, K. (2009). Thoughts on mandatory spay/neuter programs. Journal of the American
Veterinary Medical Association, 235, 145-146.
Caltabiano, J. A. (2002). Readers disturbed about letter on free-roaming cats. Journal of the
American Veterinary Medical Association, 221, 930.
Caltabiano, J. A. (2006). Reports positive results from sterilization of cats in Connecticut.
Journal of the American Veterinary Medical Association, 228, 1337.
Caltabiano, J. A. (2007). Fighting overpopulation with low-cost neutering. Journal of the
American Veterinary Medical Association, 230, 1795.
Calver, M. C., Grayson, J., Lilith, M., & Dickman, C. R. (2011). Applying the precautionary
principle to the issue of impacts by pet cats on urban wildlife. Biological Conservation, 144,
1895-1901.
Caras, R. (1993). One generation away from humanity. Journal of the American Veterinary
Medical Association, 202, 910-912.
Carding, A. H. (1969). The significance and dynamics of stray dog population with special
reference to the U.K. and Japan. Journal of Small Animal Practice, 10, 419-446.
Carroll, M. J., Singer, A., Smith, G. C., Cowan, D. P., & Massei, G. (2010). The use of
immunocontraception to improve rabies eradication in urban dog populations. Wildlife Research,
37, 676-687.
Carter, C. N. (1990). Pet population control: another decade without solutions? Journal of the
American Veterinary Medical Association, 197, 192-195.
Carter, E. (2007). Humane dogs population management guidance. Animal Welfare, 17, 321-322.
Catillo, D. (2001). Population estimates and behavioural analyses of managed cat (Felis catus)
colonies located in Miami-Dade County, Florida, Parks (Doctoral dissertation). Florida
International University.
Castillo, D., & Clarke, A. L. (2003). Trap/Neuter/Release methods ineffective in control
domestic cat “colonies” on public lands. Natural Areas Journal, 23, 247-253.
Cathey, M., & Memon, M. A. (2010). Nonsurgical methods of contraception in dogs and cats:
where are we now? Veterinary Medicine, 105, 12-17.
Caughley, G., Pech, R., & Grice, D. (1992). Effect of fertility control on a population’s
productivity. Wildlife Research, 19, 623-627.
Centonze, L. A., & Levy, J. K. (2002). Characteristics of free-roaming cats and their caretakers.
Journal of the American Veterinary Medical Association, 220, 1627-1633.
CFHS. (2012). Cats in Canada: a comprehensive report on the cat overpopulation crisis.
Retrieved from http://cfhs.ca/athome/cat_overpopulation_crisis/
Chassy, L. M. (2003). Discussions on TNR programs continue. Journal of the American
Veterinary Medical Association, 222, 710, 712.
175
Chatterjee, S. N., & Kar, A. B. (1968). Chemical sterilization of stray dogs. Indian Veterinary
Journal, 45, 649-654.
Chawla, S. K., & Reece, J. F. (2002). Timing of oestrus and reproductive behaviour in Indian
street dogs. Veterinary Record, 150, 450-451.
Cherkassy, L. M. (2008). More on finding solutions for free-roaming cats. Journal of the
American Veterinary Medical Association, 233, 551-552.
Childs, J. E. (1990). Urban cats: their demography, population density, and owner characteristics
in Baltimore, Maryland. Anthrozoös, 3, 234-244.
Childs, J. E., & Ross, L. (1986). Urban cats: characteristics and estimation of mortality due to
motor vehicles. American Journal of Veterinary Research, 47, 1643-1648.
Choudhury, S., Srivastava, N., Narwal, P.S., Rath, A., Jaiswal, S., & Gupta, S. K. (2006).
Feasibility and challenges in the development of immunocontraceptive vaccine based on zona
pellucida glycoproteins. Society of Reproduction and Fertility supplement, 63, 479-493.
Christensen, P., & McDonald, T. (2013). Reintroductions and controlling feral predators:
interview with Per Christensen. Ecological Management & Restoration, 14, 93-100.
Christensen, P. E. S., Ward, B. G., & Sims, C. (2013). Predicting bait uptake by feral cats, Felis
catus, in semi-arid environments. Ecological Management & Restoration, 14, 47-53.
*Christiansen, B. (1998). Save our Strays: How we can End Pet Overpopulation and Stop Killing
Healthy Cates & Dogs. Canine Learning Center
Cistola, A. M., Golder, F. J., Centonze, L. A., McKay, L. W., & Levy, J. K. (2004). Anesthetic
and physiology effects of tiletamine, zolazepam, ketamine, and xylazine combination (TKX) in
feral cat undergoing surgical sterilization, 6, 297-303.
Clancy, E. A., Moore, A. S., & Bertone, E. R. (2003). Evaluation of cat and owners
characteristics and their relationships to outdoor access of owned cats. Journal of the American
Veterinary Medical Association, 222, 1541-1545.
Claridge, A. W., Cunningham, R. B., Catling, P. C., & Reid, A. M. (2010). Trends in the activity
levels of forest-dwelling vertebrate fauna against a background of intensive baiting for foxes.
Forest Ecology and Management, 260, 822-832.
Clark, C. C. A., Gruffydd-Jones, T., & Murray, J. K. (2012). Number of cats and dogs in the UK
welfare organisations. Veterinary Record, 170, 493.
Clark, K. (2012). Neutering: how early is too early? Veterinary Record, 170, 432-433.
Clarke, A. L., & Pacin, T. (2002). Domestic cat “colonies” in natural areas: a growing exotic
species threat. Natural Areas Journal, 22, 154-159.
Clevenger, J., & Kass, P. H. (2003). Determinants of adoption and euthanasia of shelter dogs
spayed or neutered in the University of California veterinary student surgery program compared
to other shelter dogs. Journal of Veterinary Medical Education, 30, 372-378.
176
Clifton, M. (1998). Animal populations may not be out of control. Journal of the American
Veterinary Medical Association, 213, 603.
Cliquet, F., Picard-Meyer, E., & Robardet, E. (2014). Rabies in Europe: what are the risks?
Expert Review of Anti-infective Therapy, 12, 905-908.
Cloud, D. F. (1993). Working with breeders on solutions to pet overpopulation. Journal of the
American Veterinary Medical Association, 202, 912-914.
Coe, J. B., Young, I., Lambert, K., Dysart, L., Nogueira Borden, L., & Rajić, A. (2014). A
scoping review of published research on the relinquishment of companion animals. Journal of
Applied Animal Welfare Science, 17, 253-273.
Coleman, J. S., & Temple, S. A. (1996). On the prowl: in surburban backyards and rural fields,
free-roaming cats are pouncing on songbird populations. Wisconsin Natural Resources, 20, 4-8.
Coleman, J. S., Temple, S. A., & Craven, S. R. (1997). Cats & Wildlife: a conservation dilemma.
University of Wisconsin--Extension.
Collins, T. F. B. (1976). Control of pet animals. South African Medical Journal, 50, 1054-1057.
Coman, B. (1992). Simulated rabies eradication: the lessons from two exercises in Victoria. In
Bureau of Rural Resources Proceedings, (pp. 91-95).
Constable, S., Dixon, R.., & Dixon, R. (2010). For the love of dog: the human-dog bond in rural
and remote Australian indigenous communities. Anthrozoös, 23, 337-349.
Cook, A. J., & McCobb, E. (2012). Quantifying the shelter rabbit population: an analysis of
Massachusetts and Rhode Island animal shelters. Journal of Applied Animal Welfare Science, 15,
297-312.
Corbett, H. (2007). Paediatric desexing. Australian Veterinary Journal, 85, N24.
Courchamp, F., & Cornell, S. J. (2000). Virus-vectored immunocontraception to control feral
cats on islands: a mathematical model. Journal of Applied Ecology, 37, 903-913.
Courchamp, F., & Sugihara, G. (1999). Modeling the biological control of an alien predator cats
to protect island species from extinction. Ecological Applications, 9, 112-123.
Crenshaw, W. E., & Carter, C. N. (1995). Should dogs in animal shelters be neutered early?
Veterinary Medicine, 756-760.
Croft, D. (2007). Controlling vertebrate pets after a drought. Primefact 369.
Cruz, J., Glen, A. S., & Pech, R. P. (2013). Modelling landscape-level numerical responses of
predators to prey: the case of the cats and rabbits. PLoS ONE, 8, e73544.
Dabritz, H. A., Atwill, E. R., Gardner, I. A., Miller, M. A., & Conrad, P. A. (2006). Outdoor
fecal deposition by free-roaming cats and attitudes of cat owners and nonowners toward stray
pets, wildlife and water pollution. Journal of the American Veterinary Medical Association, 229,
74-81.
Dalla Villa, P., Kahn, S., Stuardo, L., Iannetti, L., Di Nardo, A., Serpell, J. A. (2010). Free-
roaming dog control among OIE-member countries. Preventive Veterinary Medicine, 97, 58-63.
177
Dalla Villa, P., Ianneti, L., Vulpiani, M. P., Maitino, A., Trentini, R., & Del Papa, S. (2008). A
management model applied in two ‘no-kill’ dog shelters in central Italy: use of population
medicine for three consecutive years. Veterinaria Italiana, 44, 347-359.
Dalla Villa, P., Messori, S., Possenti, L., Barnard, S., Cianella, M., & Di Francesco, C. (2013).
Pet population management and public health: a web service based tool for the improvement of
dog traceability. Preventive Veterinary Medicine, 109, 349-353.
Daniels, T. J. (1983). The social organization of free-ranging urban dogs: I. Non-estrous social
behavior. Applied Animal Ethology, 10, 341-363.
Daniels, T. J., & Bekoff, M. (1989). Population and social biology of free-ranging dogs, Canis
familiaris. Journal of Mammalogy, 70, 754-762.
Daniels, T. J., & Bekoff, M. (1989). Spatial and temporal resource use by feral and abandoned
dogs. Ethology, 81, 300-312.
Danner, R. M., Farmer, C., Hess, S. C., Stephens, R. M., & Banko, P. C. (2010). Survival of feral
cats, Felis catus (Carnivora: Felidae), on Mauna Kea, Hawaii, based on tooth cementum lines.
Pacific Science, 64, 381-389.
Davis, B. W., Alie, K., Fielding, W. J., Morters, M., & Galindo, F. (2007). Preliminary
observations on the characteristics of the owned dog population in Roseau, Dominica. Journal of
Applied Animal Welfare Science, 10, 141-151.
De Hoff, J. B. (1976). Roaming animals: the health commissioner’s view. Proceedings of the
National Conference on Dog and Cat Control: February 3-5, 1976, Denver, Colorado/jointly
sponsored by American Humane Association...[et al.] (pp. 47-51). Denver, Co.: American
Humane Association.
Delibes-Mateos, M., & Delibes, A. (2013). Pets becoming established in the wild: free-living
Vietnamese potbellied pigs in Spain. Animal Biodiversity and Conservation, 36, 209-215.
Dias, R. A., Guilloux, A. G. A., Borba, M. R., Guarnieri, M. C. de L., Prist, R., Ferreira, F., …
Stevenson, M. (2013). Size and spatial distribution of stray dog population in the Univerity of
São Paulo campus, Brazil. Preventive Veterinary Medicine, 110, 263-273.
Díaz, E., Valencia, J., & de Aluja, A. S. (1981). Esterilidad en el perro inducida por la inyección
de formaldehido en la cola del Epidídimo. Veterinaria México, 12, 73-79.
Dickman, C. R., & Newsom, T. M. (2015). Individual hunting behaviour and prey specialisation
in the house cat Felis catus: implication for conservation and management. Applied Animal
Behaviour Science, 173, 76-87.
Di Nardo, A., Candeloro, L., Budke, C. M., & Slater, M. R. (2007). Modeling the effect of
sterilization rate on owned dog population size in central Italy. Preventive Veterinary Medicine,
82, 308-313.
Dissen, G. A., Lomniczi, A., Boudreau, R. L., Chen, Y. H., Davidson, B. L., & Ojeda, S. R.
(2012). Applying gene silencing technology to contraception. Reproduction in Domestic
Animals, 47, 381-386.
178
Dissen, G. A., Lomniczi, A., Boudreau, R. L., Chen, Y. H., Davidson, B. L., & Ojeda, S. R.
(2012). Targeted gene silencing to induce permanent sterility. Reproduction in Domestic
Animals, 47, 228-232.
Djerassi, C., Israel, A., & Jöchle, W. (1973). Planned parenthood for pets? Bulletin of the Atomic
Scientists, 1, 10-19.
S., Bengsen, A. J., & Davis, R. A. (2014). A critical review of habitat use by feral cats and key
directions for future research and management. Wildlife Research, 41, 435-446.
Dombrosky, J., & Wolverton, S. (2014). TNR and conservation on a university campus: a
political ecological perspective. PeerJ, 2, e312.
Duffy, D. C., & Capece, P. (2012). Biology and impacts of Pacific Island invasive species. 7.
The domestic cat (Felis catus). Pacific Science, 66, 173-212.
Dunton, R. F., & Sargent, G. R. (2009). Addressing feral and wild animal threats during
deployment: the distinction between animal control and rabies control. The Army Medical
Department Journal, 33-39.
Durkin, T. M. (1976). Human relations and public relations as they relate to animal control. In
Proceedings of the National Conference on Dog and Cat Control: February 3-5, 1976, Denver,
Colorado/jointly sponsored by American Humane Association…[et al.] (pp. 157-162). Denver,
Co.: American Humane Association.
Eade, J. A., Roberston, I. D., & James, C. M. (2009). Contraceptive potential of porcine and
feline zona pellucida A, B and C subunits in domestic cats. Reproduction, 137, 913-922.
Eason, C. T., & Frampton, C. M. (1991). Acute toxicity of sodium monofluoroacetate (1080)
baits to feral cats. Wildlife Research, 18, 445-449.
Edmiston, A. (1974). Cost analysis of a sterilization clinic.
Eze, C. A., & Eze, M. C. (2002). Castration, other management practices and socio-economic
implications for dog keeps in Nsukka area, Enugu state, Nigeria. Preventative Veterinary
Medicine, 55, 273-280.
Faleke, O. O. (2003). Studies on dog population its implication for rabies control. Nigerian
Society for Animal Production, 30, 242-245.
Fancourt, B. A. (2014). Rapid decline in detections of the Tasmanian bettong (Bettongia
gaimardi) following local incursion of feral cats (Felis catus). Australian Mammalogy, 36, 247-
253.
Fancourt, B.A., Hawkins, C A., Cameron, E. S., Jones, M. E., & Nicol, S. C. (2015). Devil
declines and catastrophic cascades: is mesopredator release of feral cats inhibiting recovery of
the Eastern Quoll? PLoS ONE, 10, e0119303.
Faria, M. C. F., de Almeida, F. M., Serrão, M. K., Almeida, N. K. de O., & Labarthe, N. (2005).
Use of cyanoacrylate in skin closure for ovariohysterectomy in a population control program.
Journal of Feline Medicine and Surgery, 7, 71-75.
179
Farnworth, M. J., Blaszak, K., Hiby, E. F., & Waran, N. K. (2012). Incidence of dog bites and
public attitudes towards dog care and management in Samoa. Animal Welfare, 21, 477-486.
Farnworth, M. J., Campbell, J., & Adams, N. J. (2010). Public awareness in New Zealand of
animal welfare legislation relating to cats. New Zealand Veterinary Journal, 58, 213-217.
Farnworth, M. J., Campbell, J., & Adams, N. J. (2011). What’s in a name? Perceptions of stray
and feral cat welfare and control in Aotearoa, New Zealand. Journal of Applied Animal Welfare
Science, 14, 59-74.
Farnworth, M. J., Dye, N. G., & Keown, N. (2010). The legal status of cats in New Zealand: a
perspective on the welfare of companion, stray and feral domestic cats (Felis catus). Journal of
Applied Animal Welfare Science, 13, 180-188.
Faulkner, L. C. (1975). An immunologic approach to population control in dogs. Journal of the
American Veterinary Medical Association, 166, 479-480.
Faulkner, L. C. (1975). Dimensions of the pet population problem. Journal of the American
Veterinary Medical Association, 166, 477-478.
Faulkner, L. C. (1976). Alternatives to ovariohysterectomy. In Proceedings of the National
Conference on Dog and cat Control: February 3-5, 1976, Denver Colorado/jointly sponsored by
American Humane Association…[et al.] (pp. 125-130). Denver, Co.: American Humane
Association.
Fayrer-Hosken, R. A., Dookwah, H. D., & Brandon, C. I. (2000). Immunocontrol in dogs.
Animal Reproduction Science, 60-61, 365-373.
Fei, S. Y., Chiang, J. T., Fei, C. Y., Chou, C. H., & Tung, M. C. Estimating stray dog
populations with the regression method versus Beck’s method a comparison. Environmental and
Ecological Statistics, 19, 485-498.
Feldmann, B. M., & Carding T. H. (1973). Free-roaming urban pets. Health Services Reports,
88, 956-962.
Fielding, W. J. (2010). Dog breeding in New Providence, the Bahamas, and its potential impact
on the roaming dog population I: Planned and accidental. Journal of Applied Animal Welfare
Science, 13, 250-260.
Fielding, W. J. (2010). Dog breeding in New Providence, the Bahamas, and its potential impact
on the roaming dog population II: The fate of puppies. Journal of Applied Animal Welfare
Science, 13, 300-313.
Fielding, W. J. Gall, M., Green, G., & Eller, W. S. (2012). Care of dogs and attitude of dog
owners in Port-au-Prince, the Republic of Haiti. Journal of Applied Animal Welfare Science, 15,
236-253.
Fielding, W. J., & Mather, J. (2001). Dog ownership in the West Indies: a case study from the
Bahamas. Antrhozoös, 14, 72-80.
Fielding, W. J., & Plumbridge, S. J. (2005). Characteristics of owned dogs on the island of New
Providence, The Bahamas. Journal of Applied Animal Welfare Science, 8, 245-260.
180
Filipenco, N., & Baraitareanu, S. (2012). Assessment of owner’s perception concerning role of
neutering and spaying in welfare of dogs. Anatomical and Radiological Study of Some
Characteristics of the Pony and the Horse Autopodium, 286-293
Finkler, H., & Terkel, J. (2012). The contribution of cat owners’ attitudes and behaviours to the
free-roaming cat overpopulation in Tel Aviv, Israel. Preventive Veterinary Medicine, 104, 125-
135.
Finkler, H., Hatna, E., & Terkel, J. (2011). The impact of anthropogenic factors on behaviour,
reproduction, management and welfare of urban free-roaming cat populations. Anthrozoös, 24,
31-49.
Finkler, H., Hatna, E., & Terkel, J. (2011). The influence of neighbourhood socio-demographic
factors on densities of free-roaming populations in an urban ecosystem in Israel. Wildlife
Research, 38, 235-243.
Fiore, C. A. (2000). The ecological implications of urban domestic cats (Felis catus) predation
on birds in the city of Wichita, Kansas.
Fisher, P., Algar, D., & Sinagra, J. (1999). Use of Rhodamine B as a systemic bait marker for
feral cats (Felis catus). Wildlife Research, 26, 281-285.
Flis, M. (2013). Synanthropic predators as an environmental heat. Annales Universitatis Mariae
Curie-Skłodowska. Sectio EE Zootechnica, XXXI, 1-9.
Florida Fish and Wildlife Commission. (2001). Impacts of Feral and Free-ranging Domestic
Cats on Wildlife in Florida.
Foley, J. (2002). Readers disturbed about letter on free-roaming cats. Journal of the American
Veterinary Medical Association, 221, 931.
Foley, P., Foley, J. E., Levy, J. K., & Paik, T. (2005). Analysis of the impact of trap-neuter-
return programs on population of feral cats. Journal of the American Veterinary Medical
Association, 227, 1775-1781.
Folger, W. R., Lovelace, K., Robertson, S., & Rose, C. (2012). Feline focus. Journal of Feline
Medicine and Surgery, 14, 822-825.
Font, E. (1987). Spacing and social organization: urban stray dogs revisited. Applied Animal
Behaviour Science, 17, 319-328.
Fontbonne, A. (2006). Recent advances in canine male reproduction. In Worlds Congress
WSAVA/FECAVA/CSAVA. Retrieved from:
http://www.vin.com/apputil/content/defaultadv1.aspx?meta=Generic&pId=11223&catId=31441
&id=3859256.
Forin-Wiart, M. A., Cotteland, C., Gilot-Fromont, E., & Poulle, M. L. (2014). Assessing the
homogeneity of individual scat detection probability using the bait-marking method on a
monitored free-ranging carnivore population. European Journal of Wildlife Research, 60, 665-
672.
181
Forzám, M. J., Garde, E., Pérez, G. E., & Vanderstichel, R. V. (2013). Necrosuppurative orchitis
and scrotal necrotizing dermatitis following intratesticular administration of zinc gluconate
neutralized with arginine (EsterilSol) in 2 mixed-breed dogs. Veterinary Pathology, 00, 1-4.
Fournier, A., & Geller, E. (2004). Behaviour analysis of companion-animal overpopulation: a
conceptualization of the problem and suggestions for intervention. Behavior and Social Issues,
13, 51-68.
Fox, M. W. (1977). To spay or not to spay? Veterinary medicine small animal clinician, 822-
827.
Fox, M. W. (1990). Pet population control. Journal of the American Veterinary Medical
Association, 197, 682.
Fox, M. W. (2005). Vasectomising stray dogs. Veterinary Record, 153, 96.
Frank, J. (2001). The economics, ethics and ecology of companion animal overpopulation and a
mathematical model for analyzing the effectiveness of policy alternatives (Doctoral Dissertation).
Rensselaer Polytechnic Institute.
Frank, J. (2004). An interactive model of human and companion dynamics: the ecology and
economics of dog overpopulation and the human costs of addressing the problem. Human
Ecology, 32, 107-130.
Frank, J. M., & Carlisle-Frank, P. L. (2007). Analysis of programs to reduce overpopulation of
companion animals: do adoption and low-cost spay/neuter programs merely cause substitution of
sources? Ecological Economics, 62, 740-746.
Franka, R., Smith, T. G., Dyer, J. L., Wu, X., Neizgoda, M., Rupprecht, C. E. (2013). Current
and future tools for global canine rabies elimination. Antiviral Research, 100, 220-225.
Franti, C. E., & Kraus, J. F. (1974). Aspects of pet ownership in Yolo County, California.
Journal of the American Veterinary Medical Association, 164, 166-171.
Fraser, A. F. (2012). Review of well-being. In A. F. Fraser (ed.), Feline behaviour and welfare
(pp. 154-166). Wallingford, CABI.
Fredrickson, L. E. (1975). Solve the pet population crisis with pet planning programs. Modern
Veterinary Practice, 56, 93-95.
Fuh, Y. B., Tung, M. C., Tung, K. C., Chiang, J. T., & Fei, C. Y. (2012). Causes of relinquishing
the dogs adopted from animal shelters in Taiwan. Thai Journal of Veterinary Medicine, 42, 113-
116.
García, C. A. (1996). Programas de prevención y control de la equinococosis/hidatidosis en
España situacióm epidemiológica nacional. Científica Nacional de la Ascoiación Española de
Hiatidología, 19-28.
García-Aguilar, M. C. (2012). Monitoreo de la población de perros ferales en la isla de ceros,
Baja California, y las amenazas a la mastofauna nativa, Acta Zoológica Mexicana, 28, 37-48.
182
García Mitacek, M. C., Stornelli, M. C., Tittarelli, C., Núñez Favre, R. D. L. Á., Williams, S. I.,
de la Sota, R. L., & Stornelli, M. A. (2012). Interrupción de la gestación en la gata doméstica:
actualización bibliográfica. Analecta Veterinaria, 32, 50-56.
Garrett, W. (1984). Animal control in Fulton County.
Gerhold, R. W., & Jessup, D. A. (2013). Zoonotic disease associated with free-roaming cats.
Zoonoses and Public Health, 60, 189-195.
Gerht, S. D., Wilson, E. C., Brown, W. L., Anchor, C. (2013). Population ecology of free-
roaming cats and interference competition by coyotes in urban parks. PLoS ONE, 8, e75718.
Gething, M. (2000). Strategies for urban animal management. Journal of Small Animal Practice,
41, 437.
Gibson, K. L., Keizer, K., Golding, C. (2002). A trap, neuter, and release program for feral cats
on Prince Edward Island. Canadian Veterinary Journal, 43, 695-698.
Glen, A. S., & Dickman, C. R. (2003). Effects of bait-station design on the uptake of baits by
non-target animals during control programmes for foxes and wild dogs. Wildlife Research, 30,
147-149.
Glen, A. S., & Dickman, C. R. (2005). Complex interactions among mammalian carnivores in
Australia, and their implications for wildlife management. Biological Reviews, 80, 387-401.
Gray, M. E., Thain, D. S., Cameron, E. Z., & Miller, L. A. (2010). Multi-year fertility reduction
in free-roaming feral horses with single-injection immunocontraceptive formulations. Wildlife
Research, 37, 475-481.
Greenberg, M., Lawler, D., Zawistowski, S., Jöchle, W. (2013). Low-dose megestrol acetate
revisited: a viable adjunct to surgical sterilization in free roaming cats? The Veterinary Journal,
196, 304-308.
Greenebaum, J. (2009). “I’m not an activist!” Animal rights vs. animal welfare in the purebred
dog rescue movement. Society and Animals, 17, 289-304.
Griffin, B. (2001). Prolific cats: the impact of their fertility of the welfare of the species.
Compendium, 23, 1058-1069.
Griffin, B., Baker, H., Welles, E., Miller L., & Fagerstone, K. (20. 04). Response of dogs to a
GnRH-KLH conjugate contraceptive vaccine adjuvanted with adjuvac. In Proceedings of the
2004 ACCD International Symposium on Nonsurgical Methods for Pet Population Control (pp.
185-186).
Griffin, B., & Levy, J. (2008). The future is not far away: nonsurgical sterilization. In NAVC
Conference 2008 (pp. 1481-1483).
Griffiths, A. O., & Silberg, A. (1975). Stray animals: their impact on a community. Modern
Veterinary Practice, 56, 255-256.
Gobello, C. (2007). New GnRH analogs in canine reproduction. Animal Reproduction Science,
100, 1-13.
183
Goeree, A. (1998). A different approach to controlling the cat population. Canadian Veterinary
Journal, 39, 242-243.
Gonzalez, S., Allen, A. F., Post, K., Mapletoft, R. J., & Murphy, B. D. (1989). Immunological
approaches to contraception in dogs. Journal of Reproduction & Fertility, 39, 189-198.
Gorman, S. P., Levy, J. K., Hampton, A. L., Collante, W. R., Harris, A. L., Brown, R. G. (2002).
Evaluation of a porcine zona pellucida vaccine for the immunocontraception of domestic kittens
(Felis catus). Theriogenology, 58, 135-149.
Gortazar Schmidt, C., Calveteh Margolles, C., Lucientes Curdi, J., & Arriolabengoah Igarza, A.
(1993). Population densities of feral dogs in north-eastern Spain, estimating using two different
methods. Revue Scientifique et Technique – Office International des Epizooties, 12, 189-191
Gosling, L., Stavisky, J., & Dean, R. (2013). What is a feral cat? Variation in definitions may be
associated with different management strategies. Journal of Feline Medicine and Surgery, 15,
759-764.
Gsell, A. S., Knobel, D. L., Cleaveland, S., Kazwala, R. R., Vounatsou, P., & Zinsstag, J. (2012).
Domestic dog demographic structure and dynamics relevant to rabies control planning in urban
areas in Africa: the case of Iringa, Tanzania. BMC Veterinary Research, 8.
Guerra, Y. L., Echagarrúa, Y., Marin, E., Mencho, J., Marin, A., Pascual, T., … Abad, G. (2007).
Factores que conllevan al abandon de perros region de Cuba. REDVET, VIII.
Gunn, A. (1976). Dangers of domestic pets. British Medical Journal, 2, 109.
Gunther, I., Finkler, H., & Terkel, J. (2011). Demographic differences between urban feeding
groups of neutered and sexually intact free-roaming cats following a trap-neuter-return
procedure. Journal of the American Veterinary Medical Association, 238, 1134-1140.
Gunther, I., Raz, T., Berke, O., & Klement, E. (2015). Nuisances and welfare of free-roaming
cats in urban settings and their association with cat reproduction. Preventive Veterinary
Medicine, 119, 203-210.
Gunther, I., & Terkel, J. (2002). Regulation free-roaming cat (Felis Silvestris catus) populations:
a survey of the literature and its application to Israel. Animal Welfare, 11, 171-188.
Gupta, S. K., Gupta, N., Suman, P., Choudhury, S., Prakash, K., Gupta, T., … Srinivasan, V. A.
(2011). Zona pellucida-based contraceptive vaccines for human and animal utility. Journal of
Reproductive Immunology, 88, 240-246.
Gürtler, R. E., Kravetz, F. O., Petersen, R. M., Lauricella, M. A., & Wisnivesky-Colli, C. (1990).
The prevalence of Trpanosoma cruzi and the demography of dog populations after insecticidal
spraying of houses: a predictive model. Annals of Tropical Medicine and Parasitology, 84. 313-
323.
Guttilla, D. A. (2007). Effects of sterilization on movement, home range behavior, and habitat
use of feral cat on Santa Catalina Island, California (Master’s Thesis). California State
University.
184
Haimbodi, F., Mavenyengwa, R., & Noden, B. (2014). Knowledge and practices of residents in
two north Namibian towns with regard to rabies and pet care. South African Journal of Infectious
Diseases, 29, 141-146.
Hambolu, S. E., Dzikwi, A. A., Kwaga, J. K. P., Kazeem, H. M., Umoh, J. U., & Hambolu, D. A.
(2014). Dog ecology and population studies in Lagos State, Nigeria. Global Journal of Health
Science, 6, 209-220.
Hamilton, F. E. (2010). Leading and organizing social change for companion animals.
Anthrozoös, 23, 277-292.
*Hansen, C. M. (2010). Movements and predation activity of feral and domestic cats (Felis
catus) on Banks Peninsula (Master’s Thesis). Lincoln University.
Hansen, H., Hess, S. C., Dole, C., & Banko, P. C. (2007). Using population genetic tools to
develop a control strategy for feral cats (Felis catus) in Hawaii. Wildlife Research, 34, 587-596.
Hanson, C. C., Jolley, W. J., Smith, G., Garcelon, D. K., Keitt, B. S., Little, A. E., & Campbell,
K. J. (2015). Feral cat eradication in the presence of endemic San Nicolas Island foxes.
Biological Invasions, 17, 977-986.
Harper, G. A. (2005). Numerical and functional response of feral cats (Felis catus) to variations
in abundance of primary prey on Stewart Island (Rakiura), New Zealand. Wildlife Research, 32,
597-604.
Hart, L. A., Takayanagi, T., & Yamagucki, C. (1998). Dogs and cats in animal shelters in Japan.
Anthrozoös, 11, 157-163.
Haspel, C., & Calhoon, R. E. (1990). The interdependence of humans and free-ranging cats in
Brooklyn, New York. Anthrozoös, 111, 155-161.
Hatley, P. J. (2003). Feral Cat Colonies in Florida: the Fur and Feather are Flying Gainesville,
FL. University of Florida Conservation Clinic.
Haynes, G. (2007). Compulsory desexing. Australian Veterinary Journal, 85, N26.
Heath, S. E., Kass, P., Hart, L., & Zompolis, G. (1998). Epidemiology study cats and dogs
affected by the 1991 Oakland fire. Journal of the American Veterinary Medical Association, 212,
504-511.
Hemachudha, T. (2005). Rabies and dog population control in Thailand: success or failure?
Journal of the Medical Association of Thailand, 88, 120-123.
Herbert, M., Basha, R., Thangaraj, S. (2012). Community perception regarding rabies prevention
and stray dog control in urban slums in India. Journal of Infection and Public Health, 5, 374-
380.
Herbert, C. A., & Trigg, T. E. (2005). Applications of GnRH in the control and management of
fertility in female animals. Animal Reproduction Science, 88, 141-153.
Hervías, S., Oppel, S., Medina, F. M., Pipa, T., Díez, A., Ramos, J. A., … Nogales, M. (2014).
Journal of Zoology, 292, 39-47.
185
Hetherington, C. A., Algar, D., Mills, H., & Bencini, R. (2007). Increasing the target-specificity
of ERADICAT® for feral cats (Felis catus) control by encapsulating a toxicant. Wildlife
Research, 34, 467-471.
Heussner, J. C., Flowers, A. I., Williams, J. D., & Silvy, N. J. (1978). Estimating dog cand cat
populations in an urban area. Animal Regulation Studies, 1, 203-212.
Heussner, J. C., & Grant, W. E. (1978). Ecological aspects of urban dog management: a
simulation model. Animal Regulation Studies, 1, 355-374.
Hiby, E. (2010). Understanding the need: dog and cat reproduction control around the world. In
4th ACC&D International Symposium on Non-Surgical Contraceptive Methods of Pet Population
Control.
Hiby, E. (2013). Dog population management. In C. N. L. Macpherson, F. X. Meslin, & A. I.
Wandeler (Eds), Dogs, zoonoses and public health (pp. 177-204). CABI.
Hiby, E., Eckman, H., & MacFarlaine, I. (2013). The domestic cat. In D. C. Turner, & P.
Bateson (Eds.), The domestic cat: the biology of its behaviour (pp. 215-230).
Hiby, L. R., Reece, J. F., Wright, R., Jaisinghani, R., Singh, B., & Hiby, E. F. (2011). A mark-
resight survey method to estimate the roaming dog population in three cities in Rajasthan, India.
BMC Veterinary Research, 7.
Hilsenroth, R. (1999). Feral cat colonies: controlling overpopulation and addressing the issue of
parasitology. Feline Practice, 27, 24.
Hines, S. (2007). Thoughts on the root cause of pet overpopulation. Journal of the American
Veterinary Medical Association, 230, 658.
Hodges, B. (2009). Thoughts on mandatory spay/neuter programs. Journal of the American
Veterinary Medical Association, 235, 145.
Høgåsen, H. R., Er, C., Di Nardo, A., Dalla Villa, P. (2013). Free-roaming dog populations: a
cost-benefit model for different management options, applied to Abruzzo, Italy. Preventive
Veterinary Medicine, 112, 401-413.
Holcomb, K. E., Stull, C. L., & Kass, P. H. (2012). Characteristics of relinquishing and adoptive
owners of horses associated with U.S. nonprofit equine rescue organizations. Journal Applied
Animal Welfare Science, 15, 21-31.
Holton, L. (1998). A perspective on controlling cat populations. Journal of the American
Veterinary Medical Association, 212, 1866.
Homes, J. (1984). Comprehensive animal control. 51-54.
Hooper, B. E. (1976). Municipal animal control ordinances. 106-115
Horn, J. A., Mateus-Pinilla, N., Warner, R. E., & Heske, E. J. (2011). Home range, habitat use,
and activity patterns of free-roaming domestic cats. Journal of Wildlife Management, 75, 1177-
1185.
186
Howe, L. M. (2006). Surgical methods of contraception and sterilization. Theriogenology, 66,
500-509.
Howe, L.M., & Slater, M. R. (1999). Assessment of the educational benefits of a prepubertal
gonadectomy program. Journal of Veterinary Medical Education, 26, 21-27.
Howe, L. M., Slater, M. R., Boothe, H. W., Hobson, H. P., Holcom, J. L., & Spann, A. C.
(2001). Long-term outcome of gonadectomy performed at an early age or traditional age in dogs.
Journal of the American Veterinary Medical Association, 218, 217-221.
Howell, P. G. (1984). An evaluation of the biological control of the feral cat Felis catus
(Linnaeus, 1758). Acta Zoologica Fennica, 172, 111-113.
Hsu, Y., Severinghaus, L. L., & Serpell, J. A. (2003). Dog keeping in Taiwan: its contribution to
the problem of free-roaming dogs. Journal of Applied Animal Welfare Science, 6, 1-23.
Hughes, J. E. (1993). Feral cats. Journal of the American Veterinary Medical Association, 203,
1256-1257.
Hughes, J., & Macdonald, D. W. (2013). A review of the interactions between free-roaming
domestic dogs and wildlife. Biological Conservation, 157, 341-351.
Hughes, K. L., & Slater, M. R. (2002). Implementation of feral cat management program on a
university campus. Journal of Applied Animal Welfare Science, 5, 15-28.
Hughes, K. L., Slater, M. R., & Haller, L. (2002). The effects of implementing a feral cat
spay/neuter program in a Florida County animal control service. Journal of Applied Animal
Welfare Science, 5, 285-298.
Hummer, R. L. (1975). Pets in today’s society. American Journal of Public Health, 65, 1095-
1098.
Huntley, B. J. (1999). South Africa’s experience regarding alien species: impacts and controls. In
O. T. Sandland, P. J. Schei, & A. Viken (Eds.), Invasive species and biodiversity management
(pp. 363-375). Netherlands Kluwer Academic Publishers.
Hyndman, R. J. (2007). Underage desexing. Australian Veterinary Journal, 85, N24.
Ibarra, L. M., Cisternas, P. L., Valencia, J. G., & Morales, M. A. (1997). Dog and cat population
indexes and existences of other species in the county El Bosque, metropolitan region, Chile.
Avances en Ciencias Veterinarias, 12, 80-84.
Ibarra, L. M., Espínola, F. Q., Echeverría, M. L. (2006). A survey to the population of existing
dogs in the streets of Santiago City, Chile. Avances en Ciencias Veterinarias, 21, 33-39.
Ibarra, L. M., Espínola, F. Q., Echeverría, M. L. (2006). Factors related to the presence of dogs
in the streets of Santiago city, Chile. Avances en Ciencias Veterinarias, 21, 21-26.
Ibarra, L., Morales, A. M., Acuña, P. (2003). Demographic aspects of dog and cat population in
Santiago City, Chile. Avances en Ciencias Veterinarias, 18, 13-20.
Illinois Department of Public Health. (2006). Animal Population Control Program.
187
Immegart, H. M., & Threlfall, W. R. (2000). Evaluation of intratesticular injection of glycerol for
nonsurgical sterilization of dogs. American Journal of Veterinary Research, 61, 544-549.
Inserro, J. C. (1997). Cooperation key to handling feral cat population. Journal of the American
Veterinary Medical Association, 210, 1399-1400.
Ivanter, E., V. & Sedova, N. A. (2008). Ecological monitoring of urban stray dogs: an example
of the city of Petrozavodsk. Russian Journal of Ecology, 39, 105-110.
Jackman, J., & Rowan, A. (2007). Free-roaming dogs in developing countries: The benefits of
capture, neuter and return programs. State of the animals (pp. 55-78).
Jagoe, J. A., & Serpell, J. A. (1988). Optimum time for neutering. Veterinary Record, 122, 447.
Jana, K., & Samanta, P. K. (2007). Sterilization of male stray dogs with a single intratesticular
injection of calcium chloride: a dose-dependent study. Contraception, 75, 390-400.
Jana, K., & Samanta, P. K. (2011). Clinical evaluation of non-surgical sterilization of male cats
with single intra-testicular injection of calcium chloride. BMC Veterinary Research, 7.
Jayakumar, R. (1997). A pilot survey of the dog population and rabies vaccination in India.
Biomedicine, 17, 25-27.
Jessup, D. A. (2002). Suggests TNR programs follow AVMA policy more closely. Journal of the
American Veterinary Medical Association, 221, 1101.
Jessup, D. A. (2004). Believes feral cat welfare has dark side. Journal of American Veterinary
Medical Association, 224, 1070.
Jessup, D. A. (2004). The welfare of feral cats and wildlife. Journal of American Veterinary
Medical Association, 225, 1377-1383.
Jessup, D. A. (2006). Do the victims of free-roaming cats have rights? Journal of the American
Veterinary Medical Association, 228, 30.
Jessup, D. A. (2006). The debate on feral cats continues [1]. Journal of the American Veterinary
Medical Association, 228, 683.
Jessup, D. A. (2008). Thoughts on study of attitudes toward free-roaming cats. Journal of the
American Veterinary Medical Association, 232, 1796.
Jessup, D. A., Barrows, P. L., Winter, L., & Storts, C. M. (2003). TNR debates still active.
Journal of the American Veterinary Medical Association, 223, 1254-1255.
Jessup, D. A., & Stone, E. (2010). Another perspective on feral cat control. Journal of the
American Veterinary Medical Association, 237, 495.
Jewgenow, K., Klima, F., Blottner, S., Göritz, F., Lengwinat, T., & Schadow, D. (1994). The
characterisation of an antiserum against zona pellucida of domestic cats. Animal Reproduction
Science, 36, 329-341.
Jewgenow, K., Rohleder, M., & Wegner, I. (2000). Differences between antigenic determinants
of pig and cat zona pellucida proteins. Journal of Reproduction and Fertility, 119, 15-23.
188
Jibat, T., Hogeveen, H., & Mourits, M. C. M. (2015). Review on dog rabies vaccination coverage
in Africa: a question of dog accessibility or cost recovery? PLoS Neglected Tropical Disease, 9,
e0003447.
Jöchle, W. (1974). Progress in small animal reproductive physiology, therapy of reproductive
disorders and pet population control. Folia Veterinaria Latina, 4, 706-731.
Jöchle, W. (1976). Dog and cat reproduction control by chemical methods. In Proceedings of the
national conference on dog and cat control: February 3-5, 1976, Denver, Colorado/jointly
sponsored by American Humane Association...[et al.] (pp. 120-123). Denver, Co.: American
Humane Association.
Jöchle, W. (1980). Reproduction in small animals: advances in biology, pet population control
and hormonal therapy. 7-36.
Jöchle, W. (1991). Pet population control in Europe. Journal of the American Veterinary
Medical Association, 198, 1225-1230.
Jöchle, W., & Jöchle, M. (1993). Reproduction in a feral cat population and its control with a
prolactin inhibitor, cabergoline. Journal of Reproduction and Fertility. Supplement, 47, 419-424.
Johnson, K. L., & Cicirelli, J. (2014). 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. Peer J, 2,
e646.
*Johnston, S. D., Root Kustriz, M. V., & Olson, P. N. S. (2001). Canine and Feline
Theriogenology.
Jones, A. L., & Downs, C. T. (2011). Managing feral cats on a university’s campuses: how many
are there and is sterilization having an effect? Journal of Applied Animal Welfare Science, 14,
304-320.
Jones, E. (1977). Ecology of the feral cat, Felis catus (L.), (Carnivora: Felidae) on Macquarie
Island. Australian Wildlife Research, 4, 249-262.
Josa, J. M., & Del Cañizo, P. (1999). Campaña de control poblacional. Med Vet, 16, 583-586.
Joyce, A., & Yates, D. (2011). Help stop teenage pregnancy! Early-age neutering in cats. Journal
of Feline Medicine and Surgery, 13, 3-10.
Kachani, M., & Heath, D. (2014). Dog population management for the control of human
echinococcosis. Acta Tropica, 139, 99-108.
Kaczorkiewicz, A. J. (2008). Perros callejeros. REDVET. Revista Electrónica de Veterinaria, IX.
Kaeuffer, R., Pontier, D., Devillard, S., & Perrin, N. (2004). Effective size of two feral domestic
cat populations (Felis catus L.): effect of the mating system. Molecular Ecology, 13, 483-490.
Kahler, S. (1991). Breeding ban polarizes California community. Journal of the American
Veterinary Medical Association, 198, 1109-1111.
Kahler, S. (1993). “Spay or pay” – is mandatory sterilization the answer to pet overpopulation
problem? Journal of the American Veterinary Medical Association, 202, 842-845.
189
Kahler, S. C. (1995). Spay day USA endorsed by AVMA. Journal of the American Veterinary
Medical Association, 206, 127-128.
Kahler, S. C. (1996). AVMA considers independent Spay Day. Meanwhile, Spay Day USA had
cut into future overpopulation. Journal of the American Veterinary Medical Association, 208,
1600.
Kahler, S. C. (1996). Welfare of cats depends on humankind. Journal of the American
Veterinary Medical Association, 208, 169-171.
Kahn, S., Stuardo, L., & Rahman, S. A. (2008). OIE guidelines on dog population control.
Developments in Biologicals, 131, 511-516
Kass, P. H. (2007). Cat overpopulation in the United States. In I. Rochlitz (Ed.), The welfare of
cats (pp. 119-139). New York: Springer.
Kass, P. H., Johnson, K. L., & Weng, H. Y. (2013). Evaluation of animal control measures on
pet demographics in Santa Clara County, California, 1993-2006. PeerJ, e18.
Kato, M., Yamamoto, H., Inukai, Y., & Kira, S. (2003). Survey of the stray dog population and
the health education program on the prevention of dog bites and dog-acquired infections:
comparative study in Nepal and Okayama Prefecture, Japan. Acta Medica Okayama, 57, 261-
266.
Kays, R. W., & DeWan, A. A. (2004). Ecological impact of inside/outside house cats around a
suburban nature preserve. Animal Conservation, 7, 273-283.
Kelly, T. E. (1980). An effective urban rabies/animal control program. Journal of the American
Veterinary Medical Association, 177, 1231-1234.
Kennedy, M., Phillips, B. L., Legge, S., Murphy, S A., & Faulkner, R. A. (2012). Do dingoes
suppress the activity of feral cats in northern Australia? Austral Ecology, 37, 134-139.
Keyes, M. (2010). Additional views on the costs of feral cat control. Journal of the American
Veterinary Medical Association, 237, 257.
Kikillus, K. H., Hare, K. M., & Hartley, S. (2012). Online trading tools as a method of estimating
propagule pressure via the pet-release pathway. Biological Invasions, 14, 2657-2664.
Killian, G., Thain, G., Diehl, N. K., Rhyan, J., & Miller, L. (2008). Four-year contraception rates
of mares treated with single-inection porcine zona pellucida and GnRH vaccines and intrauterine
devices. Wildlife Research, 35, 531-539.
King, M. (1991). Throwaway animals. Animal’s Agenda, 11, 12-20.
Kirkpatrick, J. F., Liu, I. K. M., & Turner, J. W. (1990). Remotely-delivered
immunocontraception in feral horses. Wildlife Society Bulletin, 18, 326-330.
Kitala, P., McDermott, J., Kyule, M., Gathuma, J., Perry, B., & Wandeler, A. (2001). Dog
ecology and demography of information to support the planning of rabies control in Machakos
District, Kenya. Acta Tropica, 78, 217-230.
190
Knobel, D. L., Laurenson, M. K., Kazwala, R. R., Boden, L. A., & Cleaveland, S. (2008). A
cross-section study of factors associated with dog ownership in Tanzania, BMC Veterinary
Research, 4.
Koch, K., Algar, D., Schwenk, K. (2014). Population structure and management of invasive cats
on an Australian Island. The Journal of Wildlife Management, 78, 968-975.
Koltveit, A. J. (1973). Toward more responsible pet ownership. Journal of the American
Veterinary Medical Association, 162, 434-436.
König, J. (1979). Surplus dogs and cats in Europe. In R. D. Allen, & W. H. Westbrook (Eds.),
The handbook of animal welfare (pp. 81-92). New York, Garland STPM Press.
Kuehn, B. M. (2002). Pros, cons of feral and free-ranging cat management debated. Journal of
American Veterinary Medical Association, 221, 759-762.
Kuehn, B. M., & Kahler, S. C. (2004). The cat debate. Journal of the American Veterinary
Medical Association, 224, 169-173.
Kullberg, J. F. (1985). New York City animal control: an overview. 59-67.
Kuruvita, V. T., Chandratilleke, D., Perera, B. M. O. A., & Aturaliya, D. S. (1987). The use of
vaccination, stray dog population control and sterilization to control rabies in the Kandy
municipal area. Sri Lanka Veterinary Journal, 33, 47.
Kustritz, M. V. R. (2012). Current and proposed research in canine and feline non-surgical
sterilization. Clinical Theriogenology, 4, 225-231.
Kustritz, M. V. R. (2012). Effects of surgical sterilization on canine and feline health and on
society. Reproduction in Domestic Animals, 47, 214-222.
Kustritz, M. V. R. (2014). Pros, cons and techniques of pediatric neutering. Veterinary Clinics of
North America: Small Animal, 44, 221-233.
Kutty, C. I. (2000). An alternative approach for birth control in stray dogs. Intas Polivet, 1, 132-
134.
Kutzler, M. A. (2010). Non-surgical alternative for practitioners to control reproduction in dogs
and cats. Clinical Theriogenology, 2, 215-221.
Kutzler, M., & Wood, A. (2006). Non-surgical methods of contraception and sterilization.
Theriogenology, 66, 514-525.
LaCroix, C. E. (2005). Evaluation of a single intratesticular injection of zinc gluconate
neutralized by arginine (Neutersol®) as a chemical sterilant in sexually mature, male dogs. In
Proceedings of the third symposium on non-surgical contraceptive methods for pet population
control.
Lambert, K., Coe, J., Niel, L., Dewey, C., & Sargeant, J. M. A systematic review and meta-
analysis of the proportion of dogs surrendered for dog-related and owner-related reason.
Preventive Veterinary Medicine, 118, 148-160.
191
Lampe, R., & Witte, T. H. (2014). Speed of dog adoption: impact of online photo traits. Journal
of Applied Animal Welfare Science, 1-12.
Lane, D. M. (1998). Solution to pet overpopulation may involve change in perspective. Journal
of the American Veterinary Medical Association, 213, 26.
Lapiz, S. M., Miranda, M. E., Garcia, R., Daguro, L., Parman, M., Madrinan, F., … Briggs, D.
(2011). A ‘showcase model’ canine rabies prevention and elimination programme: the Bohol
rabies prevention and elimination program. In Rabies control – towards sustainable prevention
at the source. Compendium of the OIE global conference on rabies control (pp. 205-213).
Larrieu, E., Alvarez, T., Cavaglon, L., & Herrastl, A. (1992). Dinamica de la poblacion canina de
general pico, Argentina en la periodo 1986/1990. Veterinaria Argentina, IX, 536-542.
Lauber, T. B., Knuth, B. A., Tantillo, J. A., & Curtis, P. D. (2007). The role of ethical
judgements related to wildlife fertility control. Society and Natural Resources, 20, 119-133.
Lazenby, B. T., Mooney, N. J., & Dickman, C. R. (2014). Effects of low-level culling of feral
cats in open populations: a case from the forests of southern Tasmania. Wildlife Research, 41,
407-420.
Le Corre, M. (2008). Cats, rats and seabirds. Nature, 451, 134-135.
Lefebvre, S. E. (2010). Seasonal variation in the number of dogs and cats entering four animal
shelters in Mississippi and the characteristics influencing their adoption (Doctoral Dissertation).
Mississippi State University.
Leoci, R., Aiudi, G., Silvestre, F., Lissner, E. A., & Lacalandra, G. M. (2014). Alcohol diluent
provides the optimum formulation for calcium chloride non-surgical sterilization in dogs. Acta
Veterinaria Scandinavica, 56, 62.
Leoci, R., Aiudi, G., Silvestre, F., Lissner, E. A., Marino, F., & Lacalandra, G. M. (2014). A
dose-finding, long-term study on the use of calcium chloride in saline solution as a method of
nonsurgical sterilization in dogs: evaluation of the most effective concentration with the lowest
risk. Acta Veterinaria Scandinavica, 56, 63.
Lepczyk, C. A., Dauphine, N., Bird, D. M., Conant, C., Cooper, R. J., Duffy, D. C., … Temple,
S. A. (2010). What conservation biologists can do to counter trap-neuter-return: response to
Longcore et al. Conservation Biology, 24, 627-629.
Lepczyk, C. A., Mertig, A. G., & Liu, J. (2003). Landowners and cat predation across rural-to-
urban landscapes. Biological Conservation, 115, 191-201.
Lessa, I. C. M., & Bergallo, H. G. (2012). Modelling the population control of the domestic cat:
an example from an island in Brazil. Brazilian Journal of Biology, 72, 445-452.
Levy, J. K. (2002). Feral cats: controversies and controls. In the North American Veterinary
Conference – 2002 Proceedings (pp. 419-420).
192
Levy, J. K. (2002). Final letters for now on feral cats. Journal of the American Veterinary
Medical Association, 221, 1547-1548.
Levy, J. K. (2003). Discussions on TNR programs continue. Journal of the American Veterinary
Medical Association, 222, 712.
Levy, J. K. (2009). Non-surgical methods of sterilization: what’s new? In World Small Animal
Veterinary Association World Congress Proceedings.
Levy, J. K. (2011). Contraceptive vaccines for the human control of community cat populations.
American Journal of Reproductive Immunology, 66, 63-70.
Levy, J. K., & Crawford, P. C. (2004). Humane strategies for controlling feral cat populations.
Journal of the American Veterinary Medical Association, 225, 1354-1360.
Levy, J. K., Crawford, P. C., Appel, L. D., & Clifford, E. L. (2008). Comparison of
intratesticular injection of zinc gluconate versus surgical castration to sterilize male dogs.
American Journal of Veterinary Research, 69, 140-143.
Levy, J. K., Foley, J. E., Foley, P., & Paik, T. (2006). The debate on feral cats continues. Journal
of the American Veterinary Medical Association, 228, 683.
Levy, J. K., Friary, J. A., Miller, L. A., Tucker, S. J., & Fagerstone, K. A. (2011). Long-term
fertility control in female cats with GonaConTM, a GnRH immunocontraceptive. Theriogenology,
76, 1517-1525.
Levy, J. K., Gale, D. W., & Gale, L. A. (2003). Evaluation of the effect of a long-term trap-
neuter-return and adoption program on a free-roaming cat population. Journal of the American
Veterinary Medical Association, 222, 42-46.
Levy, J. K., Isaza, N. M., & Scott, K C. (2014). Effect of high-impact targeted trap-neuter-return
and adoption of community cats on cat intake to as shelter. The Veterinary Journal, 201, 269-
274.
Levy, J. K., Miller, L. A., Crawford, P. C., Ritchey, J. W., Ross, M. K., & Fagerstone, K. A.
(2004). GnRH immunocontraception of male cats. Theriogenology, 62, 1116-1130.
Levy, J. K., Mansour, M., Crawford, P. C., Pohajdak, B., & Brown, R. G. (2005). Survey of zona
pellucida antigens for immunocontraception of cats. Theriogenology, 63, 1334-1341.
Levy, J. K., Woods, J. E., Turick, S. L., & Etheridge, D. L. (2003). Number of unowned free-
roaming cats in a college community in the southern United States and characteristics of
community residents who feed them. Journal of the American Veterinary Medical Association,
223, 202-205.
Li, W. Q., Sun, C. Y., Wang, F., Wang, T. C., Zhai, Y. W., Liang, M., … Sun, F. (2013).
Achieving a new controllable male contraception by the photothermal effect of gold nanorods.
Nano Letters, 13, 2477-2484.
Liberg, O. (1980). Spacing patterns in a population of rural free roaming domestic cats. Oikos,
35, 336-349.
193
Liberg, O., Sandell, M., Pontier, D., & Natoli, E. (2000). Density, spatial organisation and
reproductive tactics in the domestic cat and other felids. The domestic cat: the biology of its
behaviour (pp. 119-147). Cambridge University Press, Cambridge, United Kingdom.
Lilich, R. K. (2000). More on ear cropping and neutering. Journal of the American Veterinary
Medical Association, 216, 174-175.
Lilith, M., Calver, M., Styles, I., & Garkaklis, M. (2006). Protecting wildlife from predation by
owned domestic cats: application of precautionary approach to acceptability of proposed cat
regulations. Austral Ecology, 31, 176-189.
Litster, A. (2014). Operation Catnip: working together to reduce free-roaming cat population
ethically and effectively. The Veterinary Journal, 201, 239-240.
*Little, S. (2012). The cat. Bytown Cat Hospital: Ottawa, ON, Canada.
Liu, I. K. M. (2011). A synopsis on contraception in wildlife and feral animals. Revista
Brasileira de Reproduçã Animal, 35, 77-79.
Liu, I. K. M., Turner, J. W., Van Leeuwen, E. M. G., Flanagan, D. R., Hendrick, J. L., Murata,
K., … Morales-Levy, M. P. (2005). Persistence of anti-zonae pellucidae antibodies following a
single inoculation of porcine zonae pellucidae in the domestic equine. Reproduction, 129, 181-
190.
Loew, F. M., & Fraser, A. F. (1977). The anti-social behaviour of urban dogs. Applied Animal
Ethology, 3, 101-104.
Lofflin, J. (2007). Promote and perform early spaying and neutering. Veterinary Medicine, 674-
676.
Lofflin, J. (2007). The euthanasia problem: how practitioners can help. Veterinary Medicine,
667.
Lohr, C. A., Cox, L. J., & Lepczyk, C. A. (2013). Cost and benefits of trap-neuter-release and
euthanasia for removal of urban cats in Oahu, Hawaii. Conservation Biology, 27, 64-73.
Lohr, C. A., & Lepczyk, C. A. (2014). Desires and management preferences of stakeholders
regarding feral cats in the Hawaiian Islands. Conservation Biology, 28, 392-403.
Longcore, T., Rich, C., & Sullivan, L. M. (2009). Critical assessment of claims regarding
management of feral cats by trap-neuter-return. Conservation Biology, 23, 887-894.
Lord, L. K. (2008). Attitudes toward and perceptions of free-roaming cats among individuals
living in Ohio. Journal of American Veterinary Medical Association, 232, 1159-1167.
Lord, L. K., Wittum, T. E., Ferketich, A. K., Funk, J. A., & Rajala-Schultz, P. (2007). Search and
identification methods that owners use to find a lost dog. Journal of the American Veterinary
Medical Association, 230, 211-216.
Lord, L. K., Wittum, T. E., Ferketich, A. K., Funk, J. A., & Rajala-Schultz, P. (2007). Search
methods that people use to find owners of lost pets. Journal of the American Veterinary Medical
Association, 230, 1835-1840.
194
Lord, L. K., Wittum, T. E., Ferketich, A. K., Funk, J. A., Rajala-Schultz, P., & Kauffman, R. M.
(2006). Demographics trends for animal care and control agencies in Ohio from 1996 to 2004.
Journal of the American Veterinary Medical Association, 229, 48-54.
Lord, L. K., Wittum, T. E., Neer, C. A., & Gordon, J. C. (1998). Demographic and needs
assessment survey of animal care and control agencies. Journal of the American Veterinary
Medical Association, 213, 483-487.
Lord, L. K., Wittum, T. E., & Scarlett, J. M. (2007). Use of group-randomized trials in pet
population research, Preventative Veterinary Medicine, 82, 167-175.
Lowe, S. E., & Bradshaw, J. W. S. (2001). Effects of socialisation on the behaviour of feral
kittens. In Proceedings of the third international congress on veterinary behavioural medicine
(pp 28-29).
Loyd, K. A. T., & DeVore, J. L. (2010). An evaluation of feral cat management options using a
decision analysis network. Ecology and Society, 15, 262-273.
Loyd, K. A. T., & Hernandez, S. M. (2012). Public perceptions of domestic cats and preferences
for feral cat management in the southeastern United States. Anthrozoös, 25, 337-351.
Loyd, K. A. T. & Miller, C. A. (2010). An evaluation of feral cat management options using a
decisions analysis network. Ecology and Society, 15, 262-273.
Loyd, K. A. & Miller, C. A. (2010). Factors related to preferences for trap-neuter-release
management of feral cats among Illinois homeowners. Journal of Wildlife Management, 74, 160-
165.
Lynn, A. (2007). The cat conundrum. Compendium.
Lund, H. S., Eggertsson, S., Grøndahl, A. M., Eggerstsdóttir. (2010). Views on euthanasia and
the rehoming of dogs in Norway and Iceland. Veterinary Record, 166, 749-752.
Lunney, M., Jones, A., Stiles, E., & Waltner-Toews, D. (2011). Assessing human-dog conflicts
in Todos Santos, Guatemala: bite incidences and public perception. Preventive Veterinary
Medicine, 102, 315-320.
MacKay, C. A. (1993). Veterinary practitioners’ role in pet overpopulation. Journal of the
American Veterinary Medical Association, 202, 918-921.
MacMahom, K. (1993). Mandatory Sterilization of dogs and cats. Journal of the American
Veterinary Medical Association, 203, 498.
*Macpherson, C. N. L., Meslin, F. X., & Wandeler, A. I. (2013). Dogs, Zoonoses and Public
Health. Wallingford: CABI.
Maehoudt, C., Santos, N. R., & Fontbonne, A. (2014). Suppression of fertility in adult dogs.
Reproduction in Domestic Animals, 49, 58-63.
Mahlow, J. C. (1999). Estimation of the proportions of dogs and cats that are surgically
sterilized. Journal of the American Veterinary Medical Association, 215, 640-643.
195
Mahlow, J. C., & Slater, M. R. (1996). Current issues in the control of stray and feral cats.
Journal of the American Veterinary Medical Association, 209, 2016-2020.
Manning, A. M., & Rowan, A. N. (1992). Companion animal demographics and sterilization
status results from a survey in four Massachusetts towns. Anthrozoös, 5, 192-201.
Manor, R., & Saltz, D. (2004). The impact of free-roaming dogs on gazelle kid/female ration in a
fragmented area. Biological Conservation, 119, 231-236.
Margawani, K. R., & Roberston, I. D. (1995). A survey of urban pet ownership in Bali.
Veterinary Record, 137, 486-488.
Markova, K., & Lutzkanova, O. (2013). Association for German-Bulgarian animal help (Rousse
Branch). Ecological Aspects. Journal of Balkan Ecology, 16, 125-128.
Martin, B. (2010). Additional views on the costs of feral cat control. Journal of the American
Veterinary Medical Association, 237, 257.
Marston, L. C., & Bennett, P. C. (2009). Admissions of cats to animal welfare shelters in
Melbourne, Australia. Journal of Applied Animal Welfare Science, 12, 189-213.
Marston, L. C., Bennett, P. C., & Coleman, G. J. (2004). What happens to shelter dogs? An
analysis of data for 1 year from three Australian shelters. Journal of Applied Animal Welfare
Science, 7, 27-47.
Marston, L. C., Bennett, P. C., & Coleman, G. J. (2005). What happens to shelter dogs? Part 2.
Comparing three Melbourne welfare shelters for nonhuman animals. Journal of Applied Animal
Welfare Science, 8, 24-45.
Marwah, K., & Kamble, M. (2007). The utility of TNR method in ABC surgeries on massive
population of stray dogs. The Royal Veterinary Journal of India, 3, 100-103.
Massachusetts Department of Public Health. (1974). Canis familiaris. New England Journal of
Medicine, 290, 1378-1379.
Massei, G. (2012). Catch, inject and release: immunocontraception as an alternative to culling
and surgical sterilisation to control rabies in free-roaming dogs. In A. R. Fooks, & T. Muller
(eds.), Compendium of the office international epizooties global conference on rabies control
(pp. 181-187).
Massei, G., Fico, R., & Miller, L. (2008). Immuno-contraception to control roaming dog
populations. In 2nd OIE global conference on animal welfare: putting the OIE standard to work
(pp. 16).
Massei, G., & Miller, L. A. (2013). Nonsurgical fertility control for managing free-roaming dog
populations: a review of products and criteria for field applications. Theriogenology, 80, 829-
838.
Matibag, G. C., Ohbayashi, Y., Kanda, K., Yamashina, H., Kumara, W. B., Perera, I. N. G., …
Tamashiro, H. (2009). A pilot study on the usefulness of information and education campaign
materials in enhancing the knowledge, attitude and practice on rabies in rural Sri Lanka. The
Journal of Infection Developing Countires, 3, 55-64.
196
Matter, H. C., Wandeler, A. I., Neuenschwander, B. E., Harischandra, L. P. A., Meslin, F. X.
(2000). Study of the dog population and the rabies control activities in the Mirigama area of Sir
Lanka. Acta Tropica, 75, 95-108.
McCarthy, R. J., Levine, S. H., & Reed, J. M. (2013). Estimation of effectiveness of three
methods of feral cat population control by use of a simulation model. Journal of the American
Veterinary Medical Association, 243, 502-511.
McChesney, G. J., & Tershy, B. R. (1998). History and status of introduced mammals and
impacts to breeding seabirds on the California Channel and northwestern Baja California Islands.
Colonial Waterbirds, 21, 335-347.
McCrindle, C. M. E., Cornelius, S. T., & Schoeman, H. S. (1997). A survey of animal welfare
needs in Soweto. Journal of the South African Veterinary Association, 68, 137-139.
McDonald, M. (1980). Population control of feral cats using megestrol acetate. Veterinary
Record, 106, 129.
McDonald, M. (1980). Contraceptives for feral cats. Veterinary Record, 106, 418.
McDowell, B., Burns, P., & Lepczyk, C. A. (2011). Trends in sheltering and welfare at the
Hawaiian humane society, Oahu, Hawaii. Journal of Applied Animal Welfare Science, 14, 321-
339.
McGregor, H. W., Legge, S., Jones, M. E., Johnson, C. N. (2014). Landscape management of
fire and grazing regimes alters the fine-scale habitat utilisation by feral cats. PLoS ONE, 9,
e109097.
McHarg, M., Baldock, C., Heady, B., & Robinson, A. (1995). National people and pet survey.
Australia, Urban Animal Management Coalition.
*McIlroy, J. C. (1981). The sensitivity of Australian animals to 1080 poison. I. Intraspecific
variation and factors affecting acute toxicity. II. Marsupial and eutherian carnivores. Australian
Wildlife Research, 8, 369-399.
McKay, S. A., Fanrworth, M. J., & Waran, N. K. (2009). Current attitudes toward, and incidence
of, sterilization of cats and dogs by caregivers (owners) in Auckland, New Zealand. Journal of
Applied Animal Welfare Science, 12, 331-344.
Mechler, E. (2006). Overview: Overcoming pet population—Past, present and future challenges
in the USA. In The Proceedings of the Inaugural Summit to End Pet Overpopulation (pp. 8–13).
Gold Coast, Australia: National Desexing Network.
Meltzer, M. I., & Rupprecht, C. E. (1998). A review of the economics of the prevention and
control of rabies. Pharmacoeconomics, 14, 481-498.
Mendes-de-Almeida, F., Faria, M. C. F., Remy, G. L., Branco, A. S., Barata, P., Chame, M., …
Labarthe, N. (2006). The impact of hysterectomy in an urban colony of domestic cats (Felis
catus Linnaeus, 1758). International Journal of Applied Research in Veterinary Medicine, 4,
134-141.
197
Mendes-de-Almeida, F., Remy, G. L., Gershony, L. C., Rodrigues, D. P., Chame, M., &
Labarthe, N. V. (2011). Reproduction of feral cat (Felis catus Linnaeus 1758) colony size
following hysterectomy of adult female cats. Journal of Feline Medicine and Surgery, 13, 436-
440.
Meng-Chih, T., Chang-Young, F., Jeng-Tung, C., Chung-His, C., Lih-Sen, Y., Chen-yuan, L., …
Kwong-Chung, T. (2010). Surveys of dog populations in Taiwan from 1999-2009. Journal of
Chinese Society of Animal Science, 39, 175-188.
Menzies, B. (2006). Populate and perish. Australian Veterinary Journal, 84, N26.
Metsers, E. M., Seddon, P. J., & van Heezik, Y. M. (2010). Cat-exclusion zones in rural and
urban-fringe landscapes: how large would they have to be? Wildlife Research, 37, 47-56.
Milani, M. (2007). Encourages discussion on spay and neuter of dogs and cats. Journal of the
American Veterinary Medical Association, 232, 194.
Miller, G. S., Slater, M. R., Weiss, E. (2014). Effects of geographically-targeted intervention and
creative outreach to reduce shelter intake in Portland, Oregon. Open Journal of Animal Sciences,
4, 165-174.
Miller, L. A., Fagerstone, K. A., & Eckery, D. C. (2013). Twenty years of immunocontraceptive
research: lessons learned. Journal of Zoo and Wildlife Medicine, 44, S84-S96.
*Miller, L., & Zawistowski, S. (Eds.). (2013). Shelter medicine for veterinarians and staff.
Miller, P. S., Boone, J. D., Briggs, J. R., Lawler, D. F., Levy, J. K., Nutter, F. B., …
Zawistowski, S. (2014). Simulating free-roaming cat population management options in open
demographic environments. PLoS ONE, 9, e113553.
Miller, R. M. (1971). The pet population explosion: where do we stand? Veterinary Medicine &
Small Animal Clinician, 66, 1152-1154.
Miller, R. M. (1972). Solving the pet population problem. Veterinary Medicine & Small Animal
Clinician, 67, 474, 478.
Miranda, E. (2014). Has the management of stray dog populations and rabies control improved
since 2008? In Proceedings of the third OIE global conference on animal welfare, implementing
the OIE standards-addressing regional expectations. Kuala Lumpur, Malaysia, 6-8 November
2012. (pp. 41-43). OIE (World Organisation for Animal Health).
Mohan-Gibbons, H., Weiss, E., Garrison, L., & Allison, M. (2014). Evaluation of a novel dog
adoption program in two US communities. PLoS ONE, 9, e91959.
Molento, C. F. M. (2004). Vasectomising stray dogs. Veterinary Record, 155, 648.
Molento, C. F. M. (2014). Public Health and Animal Welfare. Wallingford: CABI.
Moore, D. (1985). Report of the Palm Beach county animal regulation division. 68-74.
Morales, M. A. M., Urcelay, S. V., Núñez, F. S., Cabello, C. P. (1992). Demographic
characteristics of a rural dog population in the northeastern of the Metropolitan region, Chile.
Avances en Ciencias Veterinarias, 7, 45-50.
198
Morales, M. A. M., Urcelay, S. V., Núñez, F. S., Villalobos, A. S. (1993). Characterization of the
canine population and their changes in Santiago County. Avances en Ciencias Veterinarias, 8,
29-32.
Morales, M. A., Varas, C., & Ibarra, L. (2009). Demographic characterization of the dog
population in Viña del Marr, Chile. Archivos de Medicina Veterinaria, 41, 89-95.
Morris, K. N., Wolf, J. L., & Gies, D. L. (2011). Trend in intake and outcome data for animal
shelters in Colorado, 2000 to 2007. Journal of the American Veterinary Medical Assocation,
238, 329-336.
Morters, M. K., Bharadwaj, S., Whay, H. R., Cleaveland, S., Damriyasa I. Md. Wood, J. L. N.
(2014). Participatory methods for the assessment of the ownership status of free-roaming dogs in
Bali, Indonesia, for disease control and animal welfare. Preventive Veterinary Medicine, 116,
203-208.
Morters, M. K., McKinley, T. J., Restif, O., Conlan, A. J. K., Cleaveland, S., Hampson, K., …
Wood, J. L. N. (2014). The demography of free-roaming dog population and applications to
disease and population control. Journal of Applied Animal Ecology, 51, 1096-1106.
Morters, M. K., Restif, O., Hampson, K., Cleaveland, S., Wood, J. L. N., & Conlan, A. J. K.
(2013). Evidence-based control of canine rabies: a critical review of population density
reduction. Journal of Animal Ecology, 82, 6-14.
Mosier, J. E., & Nassar, R. (1985). Pet population dynamics and programs planning for animal
control and animal welfare. Community Animal Control, 12-13, 24-25.
Moulton, C., Wright, P., & Rindy, K. (1991). The role of animal shelters in controlling pet
overpopulation. Journal of the American Veterinary Medical Association, 198, 1172-1176.
Munks, M. W. (2012). Progress in development of immunocontraceptive vaccines for permanent
non-surgical sterilization of cats and dogs. Reproduction in Domestic Animals, 47, 223-227.
Muñoz Alcázar, F. A., Roldán, M. A., Martínez Cepa, M., Santamaría Alvarez, J., & Ariza
Cantero, J. (1996). Programas de prevención y control de la equinococosis-hidatidosis en la
comunidad autónoma de castilla-la mancha. 57-78.
Munson, L. (2006). Contraception in felids. Theriogenology, 66, 126-134.
Munson, L., Bauman, J. E., Asa, C. S., Jöchle, A., & Trigg, T. E. (2001). Efficacy of the GnRH
analogue deslorelin for suppression of oestrus cycles in cats. Journal of Reproduction and
Fertility, 57, 269-273.
Murray, R. W. (1992). A new perspective on the problem of unwanted pets. Australian
Veterinary Practitioner Journal, 22, 88-92.
Murray, R. W. (1992). Unwanted pets and subsidised pet neuter schemes. Australian Veterinary
Practitioner Journal, 22, 12-18.
Murray, R. W., & Speare, R. (1995). Unwanted pets: disposal of dogs and cats in a provincial
Australian city. Australian Veterinary Practitioner, 25, 68-72.
199
Mustiana, A., Toribio, J. A., Abdurrahman, M., Suadnya, I. W., Hernandez-Jover, M. Putra, A.
A. G., & Ward, M. P. (2015). Owned and unowned dog population estimation, dog management
and dog bites to inform rabies prevention and response on Lombok Island, Indonesia. PLoS
ONE, 10, e0124092.
Narayanan, M. K., Rajankutty, K., & John Martin, K. D. (2012). End stray dog menace
permanently by END (Early Neutering in Dogs). Journal of Indian Veterinary Association, 10,
65-66.
Nassar, R., & Fluke, J. (1991). Pet population dynamics and community planning for animal
welfare and animal control. Journal of the American Veterinary Medical Association, 198, 1160-
1164.
Nassar, R., & Mosier, J. E. (1980). Canine population dynamics: a study of the Manhattan,
Kansas, canine population. American Journal of Veterinary Research, 41, 1798-1803.
Nassar, R., & Mosier, J. E. (1982). Feline population dynamics: a study of the Manhattan,
Kansas, feline population. American Journal of Veterinary Research, 43, 167-170.
Nassar, R., & Mosier, J. E. (1986). Understanding the dynamics of your community’s pet
population. Veterinary Medicine, 1120-1126.
Nassar, R., Mosier, J. E., & Williams, L. W. (1984). Study of the feline and canine populations
in the Greater Las Vegas area. American Journal of Veterinary Research, 45, 282-287.
Natoli, E. (1994). Urban feral cats (Felis catus L.): perspectives for a demographic control
respecting the psycho-biological welfare of the species. Annali dell’Istituto Superiore di Sanitá,
30, 223-227.
Natoli, E., Ferrari, M., Bolletti, E., & Pontier, D. (1999). Relationships between cat lovers and
feral cats in Rome. Anthrozoös, 12, 16-23.
Natoli, E., Maragliano, L., Cariola, G., Faini, A., Bonanni, R., Cafazzo, S., Fantini, C. (2006).
Management of feral domestic cats in the urban environment of Rome (Italy). Preventive
Veterinary Medicine, 77, 180-185.
*Naz, R. K. (2011). Special issue: contraceptive vaccines. American Journal of Reproductive
Immunology, 66, 1-70.
Naz, R. K., Gupta, S. K., Gupta, J. C., Vyas, H. K., & Talwar, G. P. (2005). Recent advances in
contraceptive vaccine development: a mini-review. Human Reproduction, 20, 3271-3283
Neidhart, L., & Boyd, R. (2002). Companion animal adoption study. Journal of Applied Animal
Welfare Science, 5, 175-192.
Němcová, D., & Novák, P. (2003). Adoption of dogs in the Czech Republic. Acta Veterinaria
Brno, 72, 421-427.
Neville, P. F. (1989). Feral cats: management of urban populations and pest problems by
neutering. Mammals as pests (pp. 261-268). Kluwer, London.
Neville, P. F., & Remfry, J. (1984). Effect of neutering on two groups of feral cats. Veterinary
Record, 114, 447-450.
200
New, J. C., Kelch, W. J., Hutchison, J. M., Salman, M. D., King, M., Scarlett, J. M., & Kass, P.
H. (2004). Birth and death rate estimates of cat and dogs in U.S. households and related factors.
Journal of Applied Animal Welfare Science, 7, 229-241.
Nogales, M., Martín, A., Tershy, B. R., Donlan, C. J., Veitch, D., Puerta, N., … Alonso, J.
(2004). A review of feral cat eradication on islands. Conservation Biology, 18, 310-319.
Nogales, M., Vidal, E., Medina, F. M., Bonnaud, E., Tershy, B. R., Campbell, K. J., & Zavaleta,
E. S. (2013). Feral cats and biodiversity conservation: the urgent prioritization of island
management. BioScience, 63, 804-810.
Nolen, R. S. (2007). Nonsurgical alternatives explored as possible answer to dog and cat
overpopulation. Journal of the American Veterinary Medical Association, 230, 169-170.
Nolen, R. S. (2013). JAVMA news: assumptions about a mainstay of companion animal practice
are called into question. Journal of the American Veterinary Medical Association, 243, 1218-
1237.
Nolen, R. S. (2013). JAVMA news: high volume neuter clinic a ray of hope on American Indian
reservation. Journal of the American Veterinary Medical Association, 243, 1647-1651.
Norman, S. T., & Collop, T. M. (). Male animal contraception. In P. J. Chenoweth, & S. P.
Lorton (eds.), Animal andrology. Theories and applications (pp. 474-508). CABI.
Novy, L. L. (2006). The debate on feral cats continues. Journal of the American Veterinary
Medical Association, 228, 686-687.
Novy, L. (2007). The cat conundrum. Compendium.
Nuñez, C. M. V., Adelman, J. S., & Rubenstein, D. I. (2010). Immunocontraception in Wild
Horses (Equus caballus) extends reproductive cycling beyond the normal breeding season. PLoS
ONE, 5, e13635.
*Nutter, F. B. (2005). Evaluation of a trap-neuter-return management program for feral cat
colonies: population dynamics, home ranges, and potentially zoonotic diseases (Doctoral
Thesis). North Carolina State Univeristy.
Nutter, F. B., Levine, J. F., & Stoskopf, M. K. (2004). Reproductive capacity of free-roaming
domestic cats and kitten survival rate. Journal of the American Veterinary Medical Association,
225, 1399-1402.
Nutter, F. B., Stoskopf, M. K., & Levine, J. F. (2004). Time and financial costs of programs for
live trapping feral cats. Journal of the American Veterinary Medical Association, 225, 1403-
1405.
Oboegbulem, S. I., & Nwakonobi, I. E. (1989). Population density and ecology of dogs in
Nigeria: a pilot study. Scientific and Technical Review of the Office International des Epizooties,
8, 733-745.
201
Ochoa, Y. A., Falcón, N. P., Zuazo, J. R., & Guevara, B. P. (2014). Estimated population of stray
dogs in the district of Los Olivos, Lima, Peru. Revista de Investigciones Veterinarias del Perú,
25, 366-373.
OIE. (2009). Stray dog population control. In Terrestrial Animal Code.
Okoh, A. E. J. (1988). Dog population census in Jos, Plateau State, Nigeria. Tropical
Veterinarian, 6, 89-94.
Oliveira, É. C. S., Muller, P. M., Silva, F. L. M., Moura, M. R., de Sá, M. J. C., & Marques, A.
de P. (2010). Chemical castration of male dogs… Myth or reality? Acta Scientiae Veterinariae,
38 (Supl 2), s373-s389.
Oliveira, N. M., & Hilker, F. M. (2010). Modelling disease introduction as biological control of
invasive predators to preserve endangered prey. Bulleting of Mathematical Biology, 72, 444-468.
Olson, P. N. (2000). Controlling pet overpopulation: new studies shed new light; new sterilants
being developed. In TNAVC 2000 Proceedings (pp. 656).
Olson, P. N., Johnston, S. D. (1993). New development in small animal population control.
Journal of the American Veterinary Medical Association, 202, 904-909.
Olson, P. N., Johnston, S. D., Root, M. V., & Hegstad, R. L. (1992). Terminating pregnancy in
dogs and cats. Animal Reproduction Science, 28, 399-406.
Olson, P. N., & Moutlon, C. (1993). Pet (dog and cat) overpopulation in the United States.
Journal of Reproduction and Fertility, 47, 433-438.
Olson, P. N., Nett, T. M., Bowen, R. A., Amann, R. P., Sawyer, H. R., Gorell, T. A., …
Phemister, R. D. (1986). A need for sterilization, contraceptives and abortifacients: abandoned
and unwanted pets. I. Current methods of sterilizing pets. The Compendium on Continuing
Education for the Practicing Veterinarian, 8, 87-90, 92.
Oppel, S. Burns, F., Vickery, J., George, K., Ellick, G., Leo, D., Hillman, J. C. (2014). Habitat-
specific effectiveness of feral cat control for the conservation of an endemic ground-nesting bird
species. Journal of Applied Ecology, 51, 12464-1254.
Orihuela, T. A., & Solano, V. J. (1995). Demographics of owned dog population in Miacatlan,
Mor. Mexico. Anthrozoös, 8, 171-175.
Ortega-Pacheco, A., Rodriguez-Buenfil, J., Bolio-Gonzalez, M., Sauri-Arceo, C., Jimenez-
Coello, M., & Forsberg, C. L. (2007). A survey of dog population in urban and rural areas in
Yucatan, Mexico. Anthrozoös, 20, 261-274.
O’Sullivan, E. N., & Hanlon, A. J. (2012). A review of official data obtained from dog control
records generated by the dog control service of country cork, Ireland during 2007. Irish
Veterinary Journal, 65, 10.
Otolorin, G. R., Umoh, J. U., & Dzikwi, A. A. (2014). Demographic and ecological survey of
dog population in Aba, Abia State, Nigeria. ISRN Veternary Science, 2014, 1-5.
202
Page, R. J. C., Ross, J., & Bennett, D. H. (1993). Home ranges of feral cats at Avonmouth Docks
(United Kingdom). Scientific and Technical Review of the Office International des Epizooties,
12, 23-26.
Pal, S.K. (2001). Population ecology of free-ranging urban dogs in west Bengal, India. Acta
Theriologica, 46, 69-78.
Palmer, C. (2014). Value conflicts in feral cat management: trap-neuter-return or trap-euthanize?
(pp. 148-168).
Panda, A. K., Thakur, S. D., & Katoch, R. C. (2008). Rabies: control strategies for Himalayan
States of the Indian subcontinent. Journal of Communicable Disease, 40, 169-175.
Patronek, G. J. (1998). Free-roaming and feral cats – their impact on wildlife and human beings.
Journal of the American Veterinary Medical Association, 212, 218-226.
Patronek, G. J. (2010). Use of geospatial neighborhood control locations for epidemiological
analysis of community-level pet adoption patterns. American Journal of Veterinary Research,
71, 1321-1330.
Patronek, G. J., Beck, A. M., & Glickman, L. T. (1997). Dynamics of dog and cat population in a
community. Journal of the American Veterinary Medical Association, 210, 637-642.
Patronek, G. J., Glickman, L. T., & Moyer, M. R. (1995). Population dynamics and the risk of
euthanasia for dogs in an animal shelter. Anthrozoös, 8, 31-43.
Patronek, G. J., & Rowan, A. N. (1995). Determining dog and cat numbers and population
dynamic. Anthrozoös, VIII, 199-205.
Peek, L. (2002). Readers disturbed about letter on free-roaming cats. Journal of the American
Veterinary Medical Association, 221, 930.
Perez-Rivero, J. J., Martinez-Maya, J. J., Perez-Martinez, M., Aguilar-Setien, A., & Serrano, H.
(2009). Effect of coumestrol on sperm production and smell exploratory behavior in dogs
stimulated with vaginal mucus. Veterinaria México, 40, 9-16.
Perez-Rivero, J. J., Martinez-Maya, J. J., Perez-Martinez, M., Aguilar-Setien, A., Garcia-Suarez,
M. D., & Serrano, H. (2009). Phytoestrogen treatment induces testis alternations in dogs.
Potential use in population control. Veterinary Research Communications, 33, 87-95.
Pernestål, K., & Axnér, E. (2012). An internet survey of breeders’ and cat rescue organizations’
opinions about early castration of cats. Journal of Feline Medicine and Surgery, 14, 849-856.
Perry, B. D. (1993). Dog ecology in eastern and southern Africa: implications for rabies control.
Onderstepoort Journal of Veterinary Research, 60, 429.
Peterson, M. N., Hartis, B., Rodriguez, S., Green, M., & Lepczyk, C. A. (2012). Opinions from
the front lines of cat colony management conflict. PLoS ONE, 7, e44616.
203
Peterson, N. (2002). Helping clients bond with their pets for life. Veterinary Technician, 287-
290.
Peterson, N. (2006). HSUS responds to latest letter about feral cats. Journal of the American
Veterinary Medical Association, 228, 1490.
Pickerell, G. A., O’Donnell, C. F. J., Wilson, D. J., & Seddon, P. J. (2014). How can we detect
introduced mammalian predators in non-forest habitats? A comparison of techniques. New
Zealand Journal of Ecology, 38, 86-102.
Pineda, M. H., & Dooley, M. P. (1984). Surgical and chemical vasectomy in the cat. American
Journal of Veterinary Research, 45, 291-300.
Pineda, M. H., & Helper, C. I. (1981). Chemical vasectomy in dogs. Long-term study.
Theriogenology, 16, 1-11.
Plumb, L. R. (1991). Pet overpopulation. Journal of the American Veterinary Medical
Association, 198, 1848.
Polo, G., Acosta, C. M., Ferreira, F., & Dias, R. A. (2015). Location-allocation and accessibility
models improving the spatial planning of public health services. PLoS ONE, 10, e0119190.
Polydorou, K. (1971). Hydatid disease in Cyprus. Bulletin – Office International des Épizooties,
76, 611-619.
Polydorou, K. (1983). Stray-dog control in Cyprus: primitive and humane methods. International
Journal for the Study of Animal Problems, 4, 146-151.
Ponglowhapan, S. (2011). Clinical application of GnRH agonist deslorelin in dogs and cats. Thai
Journal of Veterinary Medicine, 41, 59-63.
Porters, N., de Rooster, H., Verschueren, K., Polis, I., & Moons, C. P. H. (2014). Development
of behavior in adopted shelter kittens after gonadectomy performed at an early age or at a
traditional age. Journal of Veterinary Behaviour, 9, 196-206.
Porters, N., Polis, I., Moons, C. P. H., Duchateau, L., Goethals, K., Huyghe, S., & de Rooster, H.
(2014). Prepubertal gonadectomy in cats: Different surgical techniques and comparison with
gonadectomy at traditional age. Veterinary Record, 175, 223-227.
Porters, N., Polis, I., Moons, C. P. H., Van de Maele, I., Ducatelle, R., Goethals, K., … de
Rooster, H. (2015). Relationship between age at gonadectomy and health problems in kittens
adopted from shelters. Veterinary Record, 176, 572.
Posage, J. M., Bartlett, P. C., Thomas, D. K. (1998). Determining factors for successful adoption
of dogs from an animal shelter. Journal of the American Veterinary Medical Association, 218,
478-482.
204
Poss, J. E., & Bader, J. O. (2007). Attitudes toward companion animals among Hispanic
residents of a Texas border community. Journal of Applied Animal Welfare Science, 10, 243-
253.
Poss, J. E., & Bader, J. O. (2008). Results of a free spay/neuter program in a Hispanic Colonia
on the Texas-Mexico Border. Journal of Applied Animal Welfare Science, 11, 346-351.
Poss, J. E., & Everett, M. (2006). Impact of a bilingual mobile spay/neuter clinic in a
U.S./Mexico border city. Journal of Applied Animal Welfare Science, 9, 71-77.
Prosperi, S., Giovanni, A., Ostanello, F., & Rossi, T. (1992). Evaluation of the size of stray dog
population and of related problems in Emilia-Romagna. Annali dell’Istituto Superiore di Sanità,
28, 485-491.
Pulczer, A. S., Jones-Bitton, A., Waltner-Toews, D., & Dewey, C. E. (2013). Owned dog
demography in Todos Santos Cuchumatán, Guatemala. Preventive Veterinary Medicine, 108,
209-217.
Punjabi, G. A., Athreya, V., & Linnell, J. D. C. (2012). Using natural marks to estimate free-
ranging dog Canis familiaris abundance in a MARK-RESIGHT framework in suburban
Mumbai, India. Tropical Conservation Science, 5, 510-520.
Purswell, B. J., & Kolster, K. A. (2006). Immunocontraception in companion animals.
Theriogenology, 66, 510-513.
Quisenberry, D. (1985). Charlotte-Mecklenburg animal control program. 15-29.
Ramsey, D. S. L., Parkes, J. P., Will, D., Hanson, C. C., & Campbell, K. J. (2011). Quantifying
the success of feral cat eradication, San Nicolas, California. New Zealand Journal of Ecology,
35, 163-173.
Rangel, M. C. F., Lara, J. C., & de Aluja, A. S. (1981). The canine population of Mexico City: an
estimative study. Animal Regulation Studies, 3, 281-290.
*Ransom, J. I. (2012). Population ecology of feral horses in an era of fertility control
management (Doctoral Dissertation). Colorado State University.
Ratcliffe, N., Bell, M., Pelembe, T., Boyle, D., White, R. D. R., Godley, B., … Sanders, S.
(2010). The eradication of feral cats from Ascension Island and its subsequent recolonization by
seabirds. Oryx, 44, 20-29.
Ratsitorahina, M., Rasambainarivo, J. H., Raharimanana, S., Rakotonandrasana, H.,
Andriamiarisoa, M. O., Rakalomanana, F. A., & Richard, V. (2009). Dog ecology and
demography in Antananarivo, 2007. BMC Veterinary Research, 5.
Raymond, T. N., Roland, M. E., Françoise, K. M. M., Francis, Z., Livo, E. F., & Clovis, S. T. H.
(2015). Do open garbage dumps play a role in canine rabies transmission in Biyem-Assi health
district in Cameroon? Infection Ecology and Epidemiology, 5, 26055.
Read, J., & Bowen, Z. (2001). Population dynamics, diet and aspects of the biology of feral cats
and foxes in arid South Australia. Wildlife Research, 28, 195-203.
205
Read, J., & Eldridge, S. (2010). An optimised rapid detection technique for simultaneously
monitoring activity of rabbits, cats, foxes and dingoes in rangelands. The Rangeland Journal, 32,
389-394.
Reading, A. S., Scarlett, J. W., Berliner, E. A. (2014). A novel approach to identify and map
kitten clusters using geographic information systems (GIS): a case study from Tompkins
Country, NY. Journal of Applied Animal Welfare Science, 17, 295-307.
Reay, C. (2014). Are vets doing enough to help the nation’s pets? Veterinary Times.
Recio, M. R., Mathieu, R., Virgós, E., Seddon, P. J. (2014). Quantifying fine-scale resource
selection by introduced feral cats to complement management decision making in ecologically
sensitive areas. Biological Invasions, 16, 1915-1927.
Recio, M. R., & Seddon, P. J. (2013). Understanding determinants of home range behaviour of
feral cats as introduced apex predators in insular ecosystems: a spatial approach. Behavioral
Ecology and Sociobiology, 67, 1971-1981.
Reddiex, B., & Forsyth, D. M. (2006). Control of pest mammals for biodiversity protection in
Australia. II. Reliability of knowledge. Wildlife Research, 33, 711-717.
Reece, J. F. (2007). Rabies in India: an ABC approach to combating the disease in street dogs.
Veterinary Record, 161, 292-293.
Reece, J. F., & Chawla S. K. (2006). Control of rabies in Jaipur, India, by the sterilisation and
vaccination of neighbourhood dogs. Veterinary Record, 159, 379-383.
Reece, J. F., Chawla, S. K., & Hiby, A. R. (2013). Decline in human dog-bite cases during a
street dog sterilisation programme in Jaipur, India. Veterinary Record, 172.
Reece, J. F., Chawla, S. K., Hiby, E. F., & Hiby, L. R. (2008). Fecundity and longevity of
roaming dogs in Jaipur, India. BMC Veterinary Research, 4.
Reed, D. (1986). Pet overpopulation: more spay/neuter efforts underway. Shelter Sense, 9, 11-15.
Reed, D. (1986). Pet overpopulation: spay/neuter efforts continue to reduce animal births. Shelter
Sense, 9.
Remfry, J. (1978). Control of feral cat population by long-term administration of megestrol
actetate. Veterinary Record, 103, 403-404.
Remfry, J. (1996). Feral cats in the United Kingdom. Journal of the American Veterinary
Medical Association, 208, 520-523.
Rhodes, L., & Jöchle, W. (2007). Additional options for nonsurgical contraception. Journal of
the American Veterinary Medical Association, 230, 806.
Richards, J. R. (2004). The 2004 American Association of Feline Practitioners position statement
on free-roaming abandoned and feral cats. Journal of Feline Medicine and Surgery, 6, vii-ix.
Rimbaud, E., Rivera, G., Morales, X., Soto, J. L., Caballero, P., & Zepeda, N. (2006). Jornadas
de asistencia veterinaria gratuita en comunidades en condiciones de pobreza extrema. REDVET:
Revista Electrónica de Veterinaria, VII, 1-4.
206
Rinzin, K., Stevenson, M. A., Probert, D. W., Bird, R. G., Jackson, R., French, N. P., & Weir, J.
A. (2008). Free-roaming and surrendered dogs and cats submitted to a humane shelter in
Wellington, New Zealand, 1996-2006. New Zealand Veterinary Journal, 56, 297-303.
Risbey, D. A., Calver, M., & Short, J. (1997). Control of feral cats for nature conservation. I.
Field test of four baiting methods. Wildlife Research, 24, 319-326.
Risbey, D. A., Calver, M. C., Short, J., Bradley, J. S., & Wright, I. W. (2000). The impact of cats
and foxes on the small vertebrate fauna of Heirisson Prong, Western Australia. II. A field
experiment. Wildlife Research, 27, 223-235.
Rivero, O. (2005). Analysis of the impact of the free spay and neuter program on the pet
overpopulation and the program’s cost benefit. (Doctoral Dissertation). Argosy
University/Sarasota.
Robbins, S. C., Jelinski, M. D., & Stotish, R. L. (2004). Assessment of the immunological and
biological efficacy of two different doses of a recombinant GnRH vaccine in domestic male and
female cats (Felis catus). Journal of Reproductive Immunology, 64, 107-119.
Robertson, S. A. (2008). A review of feral cat control. Journal of Feline Medicine and Surgery,
10, 366-375.
Robinson, C. J., Smyth, D., & Whitehead, P. J. (2005). Bush tucker, bush pets, and bush threats:
cooperative management of feral animals in Australia’s Kakadu National Park. Conservation
Biology, 19, 1385-1391.
Robinson, S. A., & Copson, G. R. (2014). Eradication of cat (Felis catus) from subantarctic
Macquarie Island. Ecological Management & Restoration, 15, 34-40.
Rochlitz, I. (2013). The domestic cat. In D. C. Turner, & P. Bateson (Eds). The Domestic Cat:
The Biology of its Behaviour. Cambridge: Cambridge University Press.
Rock, M. J., Adams, C. L., Degeling, C., Massolo, A., & McCormack, G. R. (2015). Policies on
pets for healthy cities: a conceptual framework. Health Promotion International, 30, 976-986.
Rödl, P. (1999). Regulating populations of synanthropic vertebrates in Czech Republic. In
Proceedings of the 3rd international conference on urban pets (pp. 515-518).
Roebling, A. D., Johnson, D., Blanton, J. D., Levin, M., Slate, D., Fenwick, G., & Rupprecht, C.
E. (2014). Rabies prevention and management of cats in the context of trap-neuter-vaccinate-
release programmes. Zoonoses and Public Health, 61, 290-296.
Roen, D. T. (1998). Controlling cat populations. Journal of the American Veterinary Medical
Association, 212, 798.
Rollin, B. E. (1997). An ethicist’s commentary on the case of the veterinarian who wished to
improve rural euthanasia. Canadian Veterinary Journal, 38, 334-335.
Romagnoli, S. (2006). Control of reproduction in dogs and cats: use and misuse of hormones. In
World Congress WSAVA/FECA/CSAVA (pp. 701-706).
Romero-Lopez, J. A., Jaramillo-Arango, C. J., Martinez-Maya, J. J., Peralta, E. A., & Terrones,
C. A. (2008). Journal of Animal and Veterinary Advances, 7, 1352-1357.
207
Ross, L. H. (1985). Human demographics, animal demographics, human-animal interaction and
the animal control program of Baltimore city. 75-81.
Rottenberg, J. (2010). More on the economics behind feral cat control. Journal of the American
Veterinary Medical Association, 237, 899.
Rowan, A. N. (1984). Animal control, animal welfare, and proposals for an effective program.
37-45.
Rowan, A. N. (1991). What we need to learn from epidemiologic surveys pertaining to pet
overpopulation. Journal of the American Veterinary Medical Association, 198, 1231-1236.
Rowan, A. N. (1992). Shelters and pet overpopulation: a statistical black hole. Anthrozoös, 5,
140-143.
Rowan, A. N. & Williams, J. (1987). The success of companion animal management programs: a
review. Anthrozoös, 1, 110-122.
Rowan, A. N., & Wilson, A. K. (1985). The success of companion animal management
programs- a historical and statistical review. 1-12.
RSPCA. (2010). Improving dog ownership: the economic case for dog licensing.
RSPCA. (2014). Tackling the cat crisis. A collaborative approach to neutering.
Ruch-Gallie R., Salman, M. D., & Southwell, C. M. (2000). Pet population dynamics in United
States animal shelters. In Proceedings of the 9th international symposium on veterinary
epidemiology and economics.
Ruff, A. J. (1985). Animal control in Pima County and Tucson, Arizona. 85-91.
Ruiz-García, M., Álvarez, D., & Kajon, A. (1999). Spatial autocorrelation analysis of cat
colonies at microgeographic level in the three cities: Barcelona, Palma de Mallorca (Spain) and
Buenos Aires (Argentina). Boletín de la Real Sociedad Española de Historia Natural, 95, 193-
211.
Ruiz-Izaguirre, E. (2013). A village dog is not a stray: human-dog interactions in coastal Mexico
(Doctoral Dissertation). Utrecht University.
Ruiz-Izaguirre, E., & Eilers, K. C. H. A. M. (2012). Perceptions of village dogs by villagers and
tourists in the coastal region of rural Oaxaca, Mexico. Anthrozoös, 25, 75-91.
Ruiz-Izaguirre, E., Eilers, K. C. H. A. M., Bokker, E. A. M., Ortolani, A., Ortega-Pacheco, A.,
de Boer, I. J. M. (2014). Human-dog interactions and behavioural responses of village dogs in
coastal villages in Michoacán, Mexico. Applied Animal Behaviour Science, 154, 57-65.
Rupprecht, C. E., Wu, X., Franka, R., Smith, T., & Slate, D. (2012). Immunocontraception as a
tool for rabies and canine population management. In Rabies tontrol – Towards sustainable
prevention at the source. Compendium of the OIE global conference on rabies control (pp. 95-
107).
Rush, R. I. (1984). City of Los Angeles animal care and control. 55-58.
208
Saiz Moreno, L. (1984). Wild (feral) dogs as an important epidemiological factor. Revista de
Sanidad e Higiene Pública, 58, 535-542.
Salamanca, C. A., Polo, L. J., Vargas, J. (2011). Sobrepoblación canina y felinia: tendencias y
nuevas perspectivas. Revista de la Facultad de Medicina Veterinaria y de Zootecnia, 58, 45-53.
Salman, M., New, J., Scarlett, J., Kass, P., & Ruch-Gallie, R. (1997). Characterization of dog and
cat surplus in USA: an epidemiological approach. Epidémiologie et Santé Animale, 31-32.
Salmeri, K. R., Bloomberg, S., Sruggs, S. L., & Shille, V. (1991). Gonadectomy in immature
dogs: effects on skeletal, physical and behavioural development. Journal of the American
Veterinary Medical Association, 198, 1193-1203.
Salo, A. L., Stone, E. (2014). A survey of the views of the US veterinary teaching faculty to
owned cat housing practices. Journal of Feline Medicine and Surgery, 1-4.
Samoylov, A., Cox, N., Cochram, A., Wolfe, K., Donovan, C., Kutzler, … Samoylova, T.
Generation and characterization of phage-GnRH chemical conjugates for potential use in cat and
dog immunocontraception. Reproduction in Domestic Animals, 47, 406-411.
Samuelson, M. L. (1973). Clinics and pet population control. Journal of the American Veterinary
Medical Association, 162, 1061-1064.
Say, L., & Pontier, D. (2004). Spacing pattern in a social group of stray cats; effects on male
reproductive success. Animal Behaviour, 68, 175-180.
Scarlett, J., & Johnston, N. (2012). Impact of a subsidized spay neuter clinic on impoundments
and euthanasia in a community shelter and on service and complaint calls to animal control.
Journal of Applied Animal Welfare Science, 15, 53-69.
Scarlett, J. M., Salman, M. D., New, J. G., & Kass, P. H. (2002). The role of veterinary
practitioners in reducing dog and cat relinquishments and euthanasias. Journal of the American
Veterinary Medical Association, 220, 306-311.
Schäfer-Somi, S., Kaya, D., Gültiken, N., & Aslan, S. (2014). Suppression of fertility in pre-
pubertal dogs and cats. Reproduction in Domestic Animals, 49, 21-27.
Scheidegger, J. (2014). Study: TNR reduce feline euthanasia, overpopulation. DVM 360.
Schmidt, P. M., Lopez, R. R., & Collier, B. A. (2007). Survival, fecundity, and movements of
free-roaming cats. Journal of Wildlife Management, 71, 915-919.
Schmidt, P. M., Swannack, T. M., Lopez, R. R., & Slater, M. R. (2009). Evaluation of euthanasia
and trap-neuter-return (TNR) programs in managing free-roaming cat populations. Wildlife
Research, 36, 117-125.
Schneider, R. (1975). Observations on overpopulation of dogs and cats. Journal of the American
Veteri0nary Medical Association, 167, 281-284.
*Schneider, R., Burke, T. J., & Faulkner, L. C. (1980). Population control in urban pets. I.
Demographic aspects. II. Pharmacological control. III. Immunological control. 667-678.
209
Schneider, R., & Vaida, M. L. (1975). Survey of canine and feline population: Alameda and
Contra Costa Counties, California, 1970. Journal of the American Veterinary Medical
Association, 166, 481-486.
Schurer, J. M., Phipps, K., Okemow, C., Beatch, H., & Jenkins, E. (2014). Stabilizing dog
population and improving animal and public health through a participatory approach in
Indigenous communities. Zoonoses and Public Health, 62, 445-455.
Scott, K. C., Levy, J. K., & Crawford, P. C. (2002). Characteristics of free-roaming cats
evaluated in trap-neuter-return program. Journal of the American Veterinary Medical
Association, 221, 1136-1138.
Selby, L. A., Rhoades, J. D., Hewett, J. E., & Irvin, J. A. (1979). A survey of attitudes toward
responsible pet ownership. Public Health Reports, 94, 380-386.
Seimenis, A., & Tabbaa, D. (2014). Stray animal population and public health in the South
Mediterranean and the Middle East regions. Veterinaria Italiana, 50, 131-136.
Sepúlveda, M .A., Singer, R. S., Silva-Rodriguez, E., Stowhas, P., & Pelican, K. (2014).
Domestic dogs in rural communities around protected areas: conservation problem or conflict
solution? PLoS ONE, 9, e86152.
Serrano, H., & Garciá-Suárez. (2001). Alteraciones en ovaries de perras por inmunizacion active
con proteínas de ovocitos de cerdo. Veternaria Mexico¸ 32, 221-224.
Shafik. A. (1994). Prolactin injection, a new contraceptive method: experimental study.
Contraception, 50, 191-199.
Shah, N. J. (2001). Eradication of alien predators in the Seychelles: an example of conservation
action on tropical islands. Biodiversity and Conservation, 10, 1219-1220.
Shore, E. R., & Girrens, K. (2001). Characteristics of animals entering an animal control or
humane society shelter in a midwestern city. Journal of Applied Animal Welfare Science, 4, 105-
115.
Short, J., Turner, B., Risbey, D. A., & Carnamah, R. (1997). Control of feral cats for nature
conservation. II. Population reduction by poisoning. Wildlife Research, 24, 703-714.
Shrestha, A., Srichandan, S., Minhas, V., Panda, A. K., & Gupta, S. K. (2015). Canine zona
pellucida glycoprotein-3: up-scaled production, immunization strategy and its outcome on
fertility. Vaccine, 22, 133-140.
Singh, B. B., Ghatak, S., Banga, H. S., Gill, J. P. S., & Singh, B. (2013). Veterinary urban
hygiene: a challenge for India. Scientific and Technical Review of the Office International des
Epizooties, 32, 645-656.
Sirivaidyapong, S., Mehl, N. S., Trigg, T. E. (2012). Delay of puberty and reproductive
performance in male dogs following the implantation of 4.7 and 9.4 mg GnRH-agonist deslorelin
at an early pre-pubertal age. Reproduction in Domestic Animals, 47, 400-402.
Slater, M. R. (2000). Feral cat epidemiology in the United States: current status and future
directions. In ISVEE 9: Proceedings of the 9th symposium of the International Society for
210
Veterinary Epidemiology and Economics, Breckenridge, Colorage, USA, Pet population issues
session (pp. 397).
*Slater, M. R. (2002). Community Approaches to Feral Cat Problems Alternatives and
Recommendations. Humane Society Press.
Slater, M. R. (2004). Understanding issues and solutions for unowned, free-roaming cat
populations. Journal of the American Veterinary Medical Association, 225, 1350-1354.
Slater, M. R. (2005). The welfare of feral cats. In The welfare of feral cats (pp. 141-175).
Springer Netherlands.
Slater, M. R., Di Nardo, A., Pediconi, O., Dalla Villa., P., Candeloro, L., Alessandrini, B., & Del
Papa, S. (2008). Cat and dog ownership and management patterns in central Italy. Preventive
Veterinary Medicine, 85, 267-294.
Slater, M. R., Di Nardo, A., Pediconi, O., Dalla Villa., P., Candeloro, L., Alessandrini, B., & Del
Papa, S. (2008). Free-roaming dogs and cats in central Italy: public perceptions of the problem.
Preventive Veterinary Medicine, 84, 27-47.
Slater, M., Hughers, K., Fadkin, D., Adams, C., Ash, S., Howe, L., … Zoran, D. (1998). A
Management Program and Study of the Population Characteristics and Dynamics of Feral Cats
on the Texas A&M University Campus. Retrieved from
http://vetmed.tamu.edu/afcat.resources/first-year-report
Sleeman, J. M. (2003). Additional input on feral cat debate. Journal of the American Veterinary
Medical Association, 223, 1729-1730.
Smith, R. E., & Shane, S. M. (1986). The potential for the control of feral cat population by
neutering. Feline Practice, 16, 21-23.
Smucker, T. D., Lindsey, G. D., & Mosher, S. M. (2000). Home range and diet of feral cats in
Hawaii forests. Pacific Conservation Biology, 6, 229-237.
Sorich, T. J. (1976). Reduced cost for surgical-neutering programs. In Proceedings of the
National Conference on Dog and Cat Control: February 3-5, 1976, Denver, Colorado/jointly
sponsored by American Humane Association...[et al.] (pp. 204-219). Denver, Co.: American
Humane Association.
Soto, C. A., & Palomares, F. (2015). Human-related factors regulate the presence of domestic
dogs in protected areas. Oryx, 49, 254-560.
Soto, F. R. M., Viana, W. G., Sousa, A. J., Pinheiro, S. R., Mucciolo, G. B., Hosomi, F. Y. M.,
… Dias, R. A. (2007). Evaluation of zin gluconate, either associated or not to dimethyl sulfoxide,
as contraceptive method for male dogs. Animal Reproduction Science, 4, 119-124.
Spain, V. C., Scarlett, J. M. & Cully, S. M. (2002). When to neuter dogs and cats: survey of New
York State veterinarians’ practice and beliefs. Journal of the American Animal Hospital
Association, 38, 482-488.
Sparkes, A. (2011). Neutering cats – assessing attitudes and challenging conventions. Journal of
Feline Medicine and Surgery, 13, 1-2.
211
Sparkes, A. H., Bessant, C., Cope, K., Ellis, S. L, Finka, L., Halls, V., … Yeates, J. (2013).
ISFM guidelines on population management and welfare of unowned domestic cats (Felis catus).
Journal of Feline Medicine and Surgery, 15, 811-817.
Sparkes, J., Fleming, P. J.S., Ballard, G., Scott-Orr, H., Durr, S., & Ward, M. P. (2015). Canine
rabies in Australia: a review of preparedness and research needs. Zoonoses and Public Health,
62, 237-253.
Sparkes, J., Körtner, G., Ballard, G., Fleming, P. J. S., & Brown, W. Y. (2014). Effects of sex
and reproductive state on interactions between free-roaming domestic dogs. PLoS ONE, 9,
e116053.
Srinivasan, K. (2013). The biopolitics of animal being and welfare: dog control and care in the
UK and India. Transactions of the Institute of British Geographers, 38, 106-119.
Srivastava, N., Santhanam, R., Sheea, P., Mukund, S., Thakral, S. S., Malik, B. S., & Gupta, S.
K. (2002). Evaluation of the immunocontraception potential of Escherichia coli-expressed
recombinant dog ZP2 and ZP3 in a homologous animal model. Reproduction, 123, 847-857.
Stavisky, J. (2014). Too many cats: how owner beliefs contribute to overpopulation. Veterinary
Record, 174, 116-117.
Stavisky, J., Brennan, M. L., Downes, M., & Dean, R. (2012). Demographics and economic
burden of un-owned cats and dogs in the UK: results of a 2010 census. BMC Veterinary
Research, 8, 163-171.
Sticco, M., Trentini, R., & Lucidi, P. (2011). Qualified “in shelter” dogs’ evaluation and training
to promote successful dog-human relationships. Open Journal of Animal Sciences, 1, 135-144.
Stockner, P. K. (1991). The economics of spaying and neutering: market forces and owners’
values affecting pet population control. Journal of the American Veterinary Medical Association,
198, 1180-1182.
Storts, C. M. (2003). Discussions on TNR programs continue. Journal of the American
Veterinary Medical Association, 222, 710, 712.
Stoskopf, M. K., & Nutter, F. B. (2004). Analyzing approached to feral cat management – one
size doesn’t fit all. Journal of the American Veterinary Medical Association, 225, 1361-1364.
Strand, P. L. (1996). The pet owner and breeder’s perspective on overpopulation. Journal of the
American Veterinary Medical Association, 202, 921-928.
Struthers, R. S. (2012). Gonadotropin-releasing hormone targeting for gonadotroph ablation: an
approach to non-surgical sterilization. Reproduction in Domestic Animals, 47, 233-238.
Stubbs, W. P., & Bloomberg, M. S. (1995). Implications of early neutering in the dog and cat.
Seminars in Veterinary Medicine and Surgery (Small Animal), 10, 8-12.
Stubbs, W. P., Salmeri, K. R., & Bloomberg, M. S. (1995). Early neutering of the dog and cat. In
J. Bonagura, & R. Kirk (eds.), Kirk’s current veterinary therapy XII small animal practice (pp.
1037-1040). Philadelphia W. B. Saunders.
212
Stull, C. L., & Holocomb, K. E. (2014). Role of the U.S. animal control agencies in equine
neglect, cruelty, and abandonment investigations. Journal of Animal Science, 92, 2342-2349.
Sturla, K. (1990). Local spay/neuter laws would help slow pet overpopulation. Animal Welfare
Institute Quarterly, 40, 12.
Sturla, K. (1993). Role of breeding regulation laws in solving the dog and cat overpopulation
problem. Journal of the American Veterinary Medical Association, 202, 928-932.
*Subacz, K. B. (2008). Impact assessment of a trap-neuter-return program on selected features
of Auburn, Alabama feral cat colonies (Master Thesis). Auburn University.
Sudarshan, M. K., Mahedra, B. J., & Ashwath Narayan, D. H. (2001). A community survey of
dog bits, anti-rabies treatment, rabies and dog population management in Bangalore City.
Journal of Communicable Diseases, 33, 245-251.
Tabor, R. (1983). The Wildlife of the Domestic Cat. London: Arrow Books.
Tabor, R. (1989). The changing life of feral cats (Felis catus L.) at home and abroad. Zoological
Journal of the Linnean Society, 95, 151-161.
Taggart, J. B. (2008). Management of feral horses at the North Carolina national estuarine
research reserve. Natural Areas Journal, 28, 187-195.
Tennent, J., & Downs, C. T. (2008). Abundance and home ranges of feral cats in an urban
conservancy where there is supplemental feeding: a case study from South Africa. African
Zoology, 43, 218-229.
Tennet, J. K., Downs, C. T., & Bodasing, M. (2009). Management recommendations for feral cat
(Felis catus) populations within an urban conservancy in KwaZulu-Natal, South Africa. South
African Journal of Wildlife Research, 39, 137-142.
Tennent, J. K., Downs, C. T., Wald, D. M., & Watson, H. K. (2010). Public perceptions of feral
cats within an urban conservancy on a campus of the University of KwaZulu-Natal. South
African Journal of Wildlife Research, 40, 16-26.
Tenzin, T., Ahmed, R., Debnath, N. C., Ahmed, G., Yamage, M. (2015). Free-roaming dog
population estimation and status of the dog population management and rabies control program
in Dhaka City, Bangladesh. PLoS Neglected Tropical Diseases, 9, e0003784.
Tenzin, T., McKenzie, J. S., Vanderstichel, R., Rai, B. D., Rinzin, K., Tshering, Y., …Ward, M.
P. (2015). Comparison of mark-resight methods to estimate abundance and rabies vaccination
coverage of free-roaming dogs in two urban areas of south Bhutan. Preventive Veterinary
Medicine, 118, 436-448.
Tenzing, P., Tshering, N. (1991). Stray dog population control in Punakha Dzongkhag. 80.
Tepsumethanon, V., Wilde, H., & Hemachudha, T. (2005). Intratesticular injection of balanced
zinc solution for permanent sterilization of dogs. Journal of the Medical Association of Thailand,
88, 686-689.
Thelander, T. (2005). Subsidised pet desexing. Australian Veterinary Journal, 83, 728.
213
Theran, P. (1993). Early-age neutering of dogs and cats. Journal of the American Veterinary
Medical Association, 202, 914-917.
Thomas, R. L., Fellowes, M. D. E., & Baker, P. J. (2012). Spatio-temporal variation in predation
by urban domestic cats (Felis catus) and the acceptability of possible management actions in the
UK. PLoS ONE, 7, e49369.
Thompson, B. (2007). The cat conundrum. Compendium.
Thornley, M. (2005). Members making a difference. Australian Veterinary Journal, 83, 248.
Thornton, G. W. (1991). Veterinarians as members of the humane community. Journal of the
American Veterinary Medical Association, 198, 1352-1354.
Thornton, G. W. (1992). The welfare of excess animals: status and needs. Journal of the
American Veterinary Medical Association, 200, 660-6620
Thrusfield, M. (2011). The dilemma of when to neuter. Veterinary Journal, 187, 12-13.
Torres López, L. D. (2008). La percepción de la ciudadanía en torno a Los Perros realengos y el
impacto en sus comunidades. (Doctoral Dissertation). Universidad de Puerto Rico.
*Totton, S. C. (2009). Stray dog population health and demographics in Jodhpur, India
following a spay/neuter/rabies vaccination program (Doctoral Thesis). University of Guelph.
Totton, S. C., Wandeler, A. I., Gartley, C. J., Kachhawaha, S., Suman, M., Ribble, C. S., …
McEwen, S. A. (2010). Assessing reproductive patterns and disorders in free-ranging dogs in
Jodhpur, India to optimize a population control program. Theriogenology, 74, 1115-1120.
Totton, S. C., Wandeler, A. I., Zinsstag, J., Bauch, C. T., Ribble, C. S., Rosatte, R. C., McEwen,
S. A. (2010). Stray dog population demographics in Jodhpur, India following a population
control/rabies vaccination program. Preventive Veterinary Medicine, 97, 51-57.
Toukhsati, S. R., Bennett, P. C., & Coleman, G. J. (2007). Behaviours and attitudes towards
semi-owned cats. Anthrozoös, 20, 131-142.
Toukhsati, S. R., Phillips, C. J.C., Podberscek, A. L., & Coleman, G. J. (2012). Semi-ownership
and sterilisation of cats and dogs in Thailand. Animals, 2, 611-627.
Toukhsati, S. R., Young, E., Bennett, P. C., & Coleman, G. J. (2012). Wandering cats: attitudes
and behaviors towards cat containment in Australia. Antrhozoös, 25, 61-74.
Townsend, C. (1995). A street dog’s desire. Animal International: World Soceity for the
Protection of Animals, 51, 26-28.
Trigg, T. E., Wright, P. J., Armour, A. F., Williamson, P. E., Junaidi, A., Martin, G. B., Doyle,
A. G. & Walsh, J. (2001). Long term reversible desexing of male dogs and oestrus
postponements of bitches, using a GnRH analogue implant. Journal of Reproduction & Fertility,
Supplement, 57, 255-261.
Turner, D. C., & Bateson, P. (1988). The domestic cat: the biology of its behaviour. Cambridge
University Press.
214
Turner, A., & Kirkpatrick, J. F. (2002). Effects of immunocontraception on population, longevity
and body condition in wild mares (Equus caballus). Reproduction Supplement, 60, 187-195.
Twigg, L. E., Lowe, T. J., Martin, G. R., Wheeler, A. G., Gray, G. S., Griffin, S. L., … Hubach,
P. H. (2000). Effects of surgically imposed sterility on free-ranging rabbit populations. Journal
of Applied Ecology, 37, 16-39.
Twyford, K. L., Humphrey, P. G., Nunn, R. P. Willoughby, L. (2000). Eradication of feral cats
(Felis catus) from Gabo Island south-east Victoria. Ecological Management and Restoration, 1,
42-49.
Uetake, K., Yamada, S., Yano, M., & Tanaka, T. (2014). A survey of attitudes of local citizens
of a residential area toward urban stray cats in Japan. Journal of Applied Animal Welfare
Science, 17, 172-177.
Valiente, C., Corraga, Y., de la Sota, P. E., Galassi Gerez, P., & Gobello, C. (2007). Effect on the
GnRH antagonist, acyline, on canine testicular characteristics. Theriogenology, 68, 687-692.
van Aarde, R. J. (1978). Reproduction and population ecology in the feral house cat, Felis catus,
on Marion Island. Carnivore Genetics Newsletter, 3, 288-316.
van Aarde, R. J. (1984). Population biology and the control of feral cats on Marion Island. Acta
Zoologica Fennica, 172, 107-110.
Van de Merghel, G. (2005). Encourages communities not to dismiss TNR too quickly. Journal of
the American Veterinary Medical Association, 226, 31.
Van Rensburg, P. J. J., Skinner, J. D., & van Aarde, R. J. (1987). Effects of feline
panleucopaenia on the population characteristics of feral cats on Marion Island. Journal of
Applied Ecology, 24, 63-73.
Vanak, A. T., & Gompper, M. E. (2010). Interference competition at the landscape level: the
effect of free-ranging dogs on a native mesocarnivore. Journal of Applied Ecology, 47, 1225-
1232.
Vanderstichel, R., Forzán, M. J., Pérez, G. E., Serpell, J. A., Garde, E. (2015). Changes in blood
testosterone concentrations after surgical and chemical sterilization of male free-roaming dogs in
southern Chile. Theriogenology, 83, 1021-1027.
Vargas, G. R., & Cárdenas, L. J. (1996). Epidemiologia de la rabia: situacion actual en mexico.
Ciencia Veterinaria, 7, 331-360
Vargas-Pino, F., Gutiérrez-Cedillo, V., Canales-Vargas, E. J., Gress-Ortega, L. R., Miller, L. A.,
Rupprecht, C. E., …Slate, D. (2013). Concomitant administration of GonaConTM and rabies
vaccine in female dogs (Canis familiaris) in Mexico. Vaccine, 31, 4442-4447.
Villiers, M. S., Mecenero, S., Sherley, R. B., Heinze, E., Kieser, J., Leshoro, T.M., … Peter, H.
U. (2010). Introduced European rabbits (Oryctolagus cuniculus) and domestic cats (Felis catus)
on Robben Island: population trends and management recommendations. South African Journal
of Wildlife Research, 40, 139-148.
215
Voith, V. L. (2009). The impact of companion animal problems on society and the role of
veterinarians. Veterinary Clinics of North America: Small Animal, 39, 327-5.34
Voslářá, E., & Passantino, A. (2012). Stray dog and cat laws and enforcement in Czech Republic
and in Italy. Annali dell’Istituto Superiore di Sanità, 48, 97-104.
Vučinić, M., Djordjevic, M., Teodorović, R., Janković, L., Radenković-Damnjanović, B., &
Radisavljević, K. (2009). Reason for relinquishment of owned dogs in a municipal shelter in
Belgrade. Acta Veterinaria (Beograd), 59, 309-317.
*Wald, D. M. (2012). Understanding stakeholder conflict: an analysis of public values, risk
perceptions and attitudes toward outdoor cat management (Doctoral Dissertation). University of
Florida.
Wald, D. M., & Jacobson, S. K. (2013). Factors affecting student tolerance for free-roaming cats.
Human Dimension of Wildlife: An International Journal, 18, 263-278.
Wallace, G., & Ellis, J. (2003). Team FCCI Issue Assessment: Impacts of Feral and Free-
ranging Domestic Cats on Wildlife in Florida, Tallahassee. Florida Fish and Wildlife
Conservation Commission.
Wallace, J. L., & Levy, J. K. (2006). Population characteristics of feral cats admitted to seven
trap-neuter-return programs in the United States. Journal of Feline Medicine and Surgery, 8,
279-284.
Walters, H. (2013). A VN’s contribution to the Dogs Trust neutering workshop. Veterinary
Nursing Journal, 28, 298-300.
Wandeler, A. I., Budde, A., Capt, S., Kappeler, A., & Matter H. (1988). Dog ecology and dog
rabies control. Reviews of Infectious Diseases, 10, S684-S688.
Webb, C. (1995). Management of unowned cat colonies. In The Proceedings of the 4th National
Urban Animal Management Conference (pp. 37-48).
Weedon, J. R. (2009). Neutersol: a clinical perspective. In NAVC Conference (pp. 1508-1510).
Weedon, G. R. (2010). Nonsurgical animal sterilization: the potential to control pet
overpopulation – and save human lives. Veterinary Medicine, 105, 8.
Weiss, E., & Gramann, S. (2009). A comparison of attachment levels of adopters of cats: fee-
based adoptions versus free adoptions. Journal of Applied Animal Welfare Science, 12, 360-370.
Weiss, E., Patronek, G., Slater, M., Garrison, L., & Medicus, K. (2013). Community partnering
as a tool for improving live release rate in animal shelters in the United States. Journal of
Applied Animal Welfare Science, 16, 221-238.
Weiss, E., Slater, M. R., Lord, L. K. (2011). Retention of provided identification for dogs and
cats seen in veterinary clinics and adopted from shelter in Oklahoma City, OK, USA. Preventive
Veterinary Medicine, 101, 265-269.
Wells, R. M. (1999). Policies to control pet overpopulation: a case analysis in Waco, Texas
(Master’s Thesis). Baylor University.
216
Welsh, C. P., Gruffydd-Jones, T. J., Roberts, M. A., Murray, J. K. (2014). Poor owner
knowledge of feline reproduction contributes to the high proportion of accidental litters born to
UK pet cats. Veterinary Record, 174, 118-123.
Weng, H. Y., & Hart, L. A. (2012). Impact of the economic recession on companion animal
relinquishment, adoption and euthanasia: a Chicago animal shelter’s experience. Journal of
Applied Animal Welfare Science, 15, 80-90.
Weng, H. Y., Kass, P. H., Chomel, B. B., & Hart, L. A. (2006). Educational intervention on dog
sterilization and retention in Taiwan. Preventive Veterinary Medicine, 76, 196-210.
Weng, H. Y., Kass, P. H., Hart, L. A., Chomel, B. B. (2006). Animal protection measures in
Taiwan: Taiwanese attitudes toward the animal protection law and animal shelters. Journal of
Applied Animal Welfare Science, 9, 315-326.
Weng, H. Y., Kass, P. H., Hart, L. A., Chomel, B. B. (2006). Risk factors for unsuccessful dog
ownership: an epidemiologic study in Taiwan. Preventive Veterinary Medicine, 77, 82-95.
Wenstrup, J., & Dowidchuk, A. (1999). Pet overpopulation: data and measurement issues in
shelters. Journal of Applied Animal Welfare Science, 2, 303-319.
White, S. C., Jefferson, E., & Levy, J. K. (2010). Impact of publicly sponsored neutering
programs on animal population dynamics at animal shelters: the New Hampshire and Austin
experiences. Journal of Applied Animal Welfare Science, 13, 191-212
WHO. (1992). WHO Expert Committee on Rabies [meeting held in Geneva from 24 to 30
September 1991]: eight report.
Wilbur, R. H. (1976). Pets, pet ownership and animal control: social and psychological attitudes,
1975. In Proceedings of the National Conference on Dog and Cat Control: February 3-5, 1976,
Denver, Colorado/jointly sponsored by American Humane Association...[et al.] (pp. 21-34).
Denver, Co.: American Humane Association.
Wilford, C. L. (2004). More on feral cat welfare. Journal of the American Veterinary Medical
Association, 224, 1749, 1752.
Wilford, C. L. (2008). Feral cats 101: let’s get wild. In NAVC Conference 2008 (1491-1493).
Wilford, C. L., & Jessup, D. A. (2004). More on feral cat welfare [2] (multiple letters). Journal
of the American Veterinary Medical Association, 224.
*Willis, M., Thorne, C., Lockwood, R., MacDonald, D. W, Carr, G. M., & Boitani, L (Eds.).
(1995). The domestic dog: its evolution, behaviour, and interactions with people. Cambridge
University Press.
Wikler, M., Pearson, L. K., Campbell, A. J., & Tibary, A. (2014). Non-surgical methods of
contraception and sterilization elect domestic and wildlife species. Clinical Theriogenology, 6,
93-104.
Wilken, R. L. M. (2012). Feral cat management: perceptions and preferences (a case study)
(Master’s Thesis). San José State University.
217
Wilkins, D. B. (1982). Low cost neutering. Veterinary Record, 110, 89.
Williams, B. A. (2002). Final letters for now on feral cats. Journal of the American Veterinary
Medical Association, 221, 1548.
Williams, J. L. (1988). Successful spay and neuter programs across the U. S.. Shelter Sense, 11¸
7-9.
Williams, L. S., Levy, J. K., Robertson, S. A., Cistola, A. M., & Centonze, L. A. (2002). Use of
anesthetic combination of tiletamine, zolazepam, ketamine and xylazine for neutering feral cats.
Journal of the American Veterinary Medical Association, 220, 1491-1495.
Williams, M., Spain, C. V., Scarlett, J. M., & Houpt, K. A. (2004). More on early-age
gonadectomy [3] (multiple letters). Journal of the American Veterinary Medical Association,
224, 1070-1071.
Willis, P. Heusner, G. L., Warren, R. J, Kessler, D., & Fayrer-Hosken, A. (1994). Equine
immunocontraception using porcine zona pellucida: a new method for remote delivery and
characterization of the immune response. Journal of Equine Veterinary Science, 14, 364-370.
Winter, L. (2004). Trap-neuter-release programs: the reality and the impacts. Journal of the
American Veterinary Medical Association, 225, 1369-1376.
Winter, L., & Jessup, D. A. (2005). Encourages communities not to dismiss TNR too quickly
(multiple letters). Journal of the American Veterinary Medical Association, 226, 31-32.
Wodzicki, J. A. (1950). Introduced Mammals of New Zealand. An Ecological and Economic
Survey.
Wolff, E. E. (2002). Final letters for now on feral cats. Journal of the American Veterinary
Medical Association, 221, 1548.
Woodruff, K. A. (2013). Scrotal castration as a safe and effective means of male canine
sterilization (Master’s Thesis). Mississippi State University.
WSPA. (2008). Surveying roaming dog populations: guidelines on methodology. Retrieved from
http://www.icam-coalition.org/downloads/Surveying%20roaming%20dog%20populations%20-
%20guidelines%20on%20methodology.pdf
Wu, X., Franka, R., Svoboda, P., Pohl, J., & Rupprecht, C. E. (2009). Development of combined
vaccines for rabies and immunocontraception. Vaccine, 27, 7202-7209.
Wu, X., Smith T. G., Franka, R., Wang, M., Carson, W. C., Rupprecht, C. E. (2014). The
feasibility of rabies virus-vectored immunocontraception in a mouse model. Trials in
Vaccinology, 3, 11-18.
Wulff, R. (2003). Free-roaming cats becoming bigger issue. Journal of the American Veterinary
Medical Association, 223, 607.
Wulff, R. (2003). TNR debate still active. Journal of the American Veterinary Medical
Association, 223, 1254-1256
218
Wulff, R. (2004). Feral cat welfare debate continues. Journal of the American Veterinary
Medical Association, 225, 199.
Wulff, R. (2005). Comments on welfare of feral cats and wildlife. Journal of the American
Veterinary Medical Association, 226, 30.
Wulff, R. (2006). The debate on feral cats continues. Journal of the American Veterinary
Medical Association, 228, 686.
Wulff, R., & Jessup, D. A. (2004). Feral cat welfare debate continues [3] (multiple letters).
Journal of the American Veterinary Medical Association, 225, 199-200.
Yasmuth, C., Rowe, T. O., Deoge, T. C. & Bangxang, H. N. (1970). Ovarian suppressants in
dogs. Pilot study of an approach to rabies control. The Lancet, 295, 1312-1315.
Yates, D., & Yeates, J. (2014). Prepubertal neutering of cats: three key points. Veterinary
Record, 175, 221-222.
Yates D., Yeates, J., & Roberts, M. (2013). Optimum age for neutering cats. Veterinary Record,
172, 53-54.
Yen, I. F., Lin, H. I., LAN, D. J., Chang, T. W., Pan, K., & Fei, C. Y. (2013). Statistical study of
the association between shelter canine intakes and euthanasia from 2001-2011 in Taiwan. Thai
Journal of Veterinary Medicine, 43, 137-141.
Yen, I. F., Peng, S. J. L., Ryan, W., Chung-Huai, C., Tung, K. C., & Fei, C. Y. (2014). Low
sterilization of pets causes shelter overpopulation. Journal of Animal and Veterinary Advances,
13, 1022-1026.
Yip, S. J. S., Rich, M. A., Dickman, C. R. (2015). Diet of the feral cat, Felis catus, in central
Australian grassland habitats during population cycles of its principal prey. Mammal Research,
60, 39-50.
Yoak, A. J., Reece, J. F., Gehrt, S. D., & Hamilton, I. M. (2014). Disease control through fertility
control: secondary benefits of animal birth control in Indian street dogs. Preventive Veterinary
Medicine, 113, 152-156.
Yoffe, B. (1991). Encourages support of pet overpopulation ordinance. Journal of the American
Veterinary Medical Association, 199, 674.
Young, J. K., Olson, K. A., Reading, R. O., Amgalanbaatar, S., & Berger, J. (2011). Is wildlife
going to the dogs? Impacts of feral and free-roaming dogs on wildlife populations. BioScience,
61, 125-132.
Young, W. A. (1980). The surplus animal problem can be solved. Modern Veterinary Practice,
61, 485-487.
Zanowski, G. M. (2012). A fresh look at spay/neuter legislation: the journey to a middle ground.
Journal of Public Health Management Practice, 18, E24-E33.
Zasloff, R. L., & Hart, L. A. (1995). Attitudes and care practices of cat caretakers in Hawaii.
Anthrozoös, 11, 242-248.
219
Zaunbrecher, K. I., & Smith, R. E. (1993). Neutering of feral cats as an alternative to eradication
programs. Journal of the American Veterinary Medical Association, 203, 449-452.
Zawistowski, S., Morris, J., Salman, M. D., & Ruch-Gallie, R. (1998). Population dynamics,
overpopulation and the welfare of companion animals: new insights on old and new data.
Journal of Applied Animal Welfare Science, 1, 193-206.
Zimbelman, R. G., Sokolowski, J. H., & Jochle, W. (1975). Comments on chemical birth control.
Canine Practice, 4, 7-8.
Zrelli, M., & Seghaier, C. (2008). Practical experience Stray dog population control measures. In
Second OIE Global Conference on Animal Welfare: ‘Putting the OIE standards to work’ (pp.
144).
Zumpano, R., Tortosa, A., & Degregorio, O. J. (2011). Estimating the impact of sterilization on
the canine growth index. Revista de Investigaciones Veterinarias del Perú, 22, 336-341.
*refers to articles that have more than once instance (or not every chapter or article were
included)
220
A.5.
Description of Non-English Articles Excluded from the Study
Author(s) Year of Publication Language
K. Kaliski 2012 Polish
B. D. Canatto, E. A. Silva, F.
Bernadi, et al.
2012 Portuguese
R. Lignieres 1982 French
V. J. Unshelm and A. C.
Mack
1997 German
A. G. A. Guilloux 2011 Portuguese
A. E. da Silva Rodrigues, C.
C. S. de Melo, R. P. Ramo, et
al.
2014 Portuguese
V. D. Novak 1980 German
A. J. Akakpo, A. L. Ndiaye,
and Saluzzo, J. F.
1984 French
B. Balázs, S. Orsolya. and R.
Jenő
2003 Hungarian
A. M. Andrade, L H.
Queiroz, S. H. V. Perri, and
C. M. Nunez
2008 Portuguese
L. Kishida 2002 French
M. Amaku, R. A. Dias, and F.
Ferreira
2009 Portuguese
J. Bouw 1972 Dutch
F. R. M. Soto 2010 Portuguese
F. Mendes-de-Almeida 2008 Portuguese
A. M. L. Vieira 2008 Portuguese
R. de Cassia Garcia 2005 Portuguese
M. R. Q. Sousa, and F. B. S.
Silva
2012 Portuguese
J. P. Dedet, K. Addadi, and
B. Lannuzel
1977 French
N. Petersen 1996 Danish
N. L. de Souza Araúja, R. S.
Carneiro, P. I. da Nóbrega
Neto, and A. L. de Araúja
2012 Portuguese
K. Lúszló 1986 Hungarian
L. Joubert 1980 French
G. A. Corrêa, H. A. Scherer,
I. Breitsameter, et al.
1998 Portuguese
F. Mendes-de-Almeida 2008 Portuguese
221
D. C. Catapan, E. D. da
Costa, G. R. da Cunha, and C.
T. Pimpão
2014 Portuguese
C. F. M. Molento, A. P. Inoe,
M. I. C. Rego, et al.,
2005 Portuguese
E. Kodrnja 1959 Croatian
R. de C. M. Garcia 2009 Portuguese
P. M. L. Germano, S. A.
Vasconcellos, and M. M.
Ishizuka
1987 Portuguese
J. Verschure 2011 Dutch
A. Poyarkov, et al. 2011 Russian
S. I. Ouattara, H. Cissé, P.
Kolia-Diafoulsa, et al.
2012 French
C. Boucher, P. Beragamo, H.
Milla, et al.
2014 French
A. C. R. Silva, L. E.
Nogueira, H. J. Á. Neto, et al.
2009 Portuguese
M. F. de Almeida e Souza 1998? Portuguese
A. W. C. da Silva 2012 Portuguese
B. Zhong, L. Chen, Y. Liu, et
al.
2013 Chinese
A. Saghafipour, M Noroozei,
S. Phalevani, and Z. Akbari
2014 Persian
S. M. Freire, K. M. de
Araújo, M. de Moraes Costa,
et al.
2010 Portuguese
B.L. Cherkasskii and A. V.
Pavlov
1981 Russian
H. Langoni, M. Z.
Troncarelli, E. C. Rodrigues,
et al.
2011 Portuguese
I. M. Reichler 2010 German
E. C. T. de M. Peixoto, W. R.
R. Vicente, M. I. A. Santos,
et al.
20002 Portuguese
V. Melchers 2012 German
D. C. D. D. Coordenadoria 2009 Potuguese
V. P. Sergiev 2007 Russian
M. Baś, and A. Cywlńska 2006 Polish
J. A. de Faria, C. D. da Silva,
E. F. N. Filho, et al.
2013 Portuguese
P. Desnoyers 1979 French
L. Baldi, V. Mizzoni, A.
Guarino
2004 Italian
222
C. Ethiek 2009 Dutch
Mariuseen 1993 Danish
J. M. da Costa Neto, E. M.
Teixeira, E. M. Ferreira
Filho, et al.
2009 Portuguese
J. Remfry and S. Glówka 1995 Polish
M. Hesselholt, N. Ockens, E.
Christensen, et al.
1992 Danish
P. Giraud, J. Ranque, and H.
Cabassu
1950 French
R.. E. Chobanov, R. O.
Gulieva, A. A. Slekhov, et al.
1990 Russian
R. Strikwerda 2007 Dutch
M. Maroli, and C. Khoury 2004 Italian
J. J. Wei, X. J. Wang, R.Q.
Ma, and Y. G. Li
2010 Chinese
L. Chevrier 1959 French
S. Samol 1967 Polish
L. Joubert, D. Lavorel, and L.
Lery
1982 French
J. Nieuwland 2013 Dutch
A. F. D. Nava 2008 Portuguese
Y. Watari, Y. Nagai, F.
Yamada, et al.
2007 Japanese
J. L. da Silva Leitão 1947 Portuguese
C. F. M. Molento, E. Lago,
and G. B. Bond
2007 Portuguese
G. F. de Queiroz, V. V. de
Paula, R. K. dos Reis, and I.
M. Tabosa
2001 Portuguese
T. Süveges and A. Ványi 1961 Hungarian
G. P. Alivisatos 1926 German
D. Levi, and G. Colombo 1991 Italian
J. Riedler, E. Eber, T.
Frischer, et al.
2008 German
L. Gallo, P Carnier, G.
Bittante, and A. Palese
1997 Italian
F. A. Voorwald, C. de Faria
Tiosso, and G. H. Toniollo
2013 Portuguese
C. R. Bittencourt, N. T. F. e
Souza, K. F. Braga, et al.
2013 Portuguese
A. I. J. Christiansen 1990 Danish
J. Dousek, S. Ninčáková, and
E. Voslářová
2013 Czech
E. Virginia 2007 Dutch
223
O. Viaro, M. B. dos Santos,
S. A. Vasconcellos, and S. R.
Pinheiro
2010 Portuguese
J. Žák, V. Večerek, E.
Voslářová, and I. Bedáñová
2014 Czech
E. C. S. Oliveira, A. P.
Marques Júnior, and M. M.
Neves
2003 Portuguese
M. Kržanović 2010 Bosnian
F. F. B. Moutinho, E. R. do
Nascimento, R. L. Paixao
2015 Portuguese
J.P. Sylvain 1970 French
Å. Hedhammar, A. Egenvall,
P. Olson, et al.
1999 Swedish
A. Giacometti, O. Cirioni, M.
Fortuna, et al.
1999 Italian
B. Kalz, K. M. Scheibe, I.
Wegner, and J. Priemer
2000 German
W. Rietschel 1989 German
A. Mantovani, and Z. Matyas 1984 Italian
A. M. Gerbers, V. H.
Barnabe, H. Fuchs
2002 Portuguese
M. Röken 2002 Swedish
F. X. Soesilo 1990 Indonesian
S. Posière 2005 French
F. Dieffenbacher 2006 German
T. Alogninouwa, B. Kamara,
Y. Kaboret, and R. Parent
1992 French
J. B. Neto 2000 Portuguese
H.J. Wormuth 1993 German
B. D. Canatto, E. A. Silva, F.
Bernardi, et al.
2012 Portuguese
A. W. C. da Silvia 2014 Portuguese
F. R. M. Soto, H. J.
Shimozako, A. J. de Sousa,
and F. Bernardi
2007 Portuguese
S. Miccichè, and A. Steiger 2008 German
C. L. Ackermann, E.
Trevisol, and M. D. Lopes
2011 Portuguese
G. S. Ferreira, M. J. Luz, F.
A. Atallah, et al.
2013 Portuguese
E. S. de Almeida, S. D.
Babboni, C. R. Padovani, et
al.
2014 Portuguese
F. Hecke 1943 German
224
A. Virga, and F. Viola 1993 Italian
R. Mindekem, U. Kayali, N.
Yemadji, et al.
2005 French
A. Leventhal, and D.
Gandacu
2001 Hebrew
Y. Poursines, P. Soulie, and
T. Scandarani
1935 French
A. P. da S. M. Alves, F. A. da
S. Coêlho, and M. D. G.
Coêlho
2014 Portuguese
N. Porters, C. P. H. Moons, I.
Polis, et al.
2014 Dutch
R. de C. M. Garcia, N. A. C.
Maldonado, and A. Lombardi
2008 Portuguese
R. de C. M. Garcia, N.
Calderón, and F. Ferreira
2012 Portuguese
L. R. Domingues, J. A. Cesar,
A. G. Fassa, and M. R.
Domingues
2015 Portuguese
H. M. Lu, K Gu., W. H.
Chen, et al.
2009 Chinese
J. C. Pei 2004 Chinese
J. M. Lai, T. M. Wu, and S.
C. Jhang
2011 Chinese
L. H. Gomes, M. F. de
Almeida, N. T. Paranhos, et
al.
2003 Portuguese
G. R. Martins, R. Poletto, F.
A. Blanc, et al.
2003 Portuguese
B. Kalz, and K. M. Schiebe 2001 German
S. Rodaski, R. R. Weiss, S.
D. Guérios, et al.
2001 Portuguese
K. M. de Oliveira, L. A. L.
Muzzi, B. B. J. Torres, et al.
2010 Portuguese
A. Benitez, G. G. Rodrigues,
D. D. Gonçalves, et al.
2010 Portuguese
A. F. M. Lima, S. P. L. Luna,
M. M. P. Rogrigues & G.
Quitzan
2010 Portuguese
M. R. Matos, M. C. G. P.
Alves, M. Reichmann, & M.
H. S. Dominguez
2002 Portuguese
Anonymous 2001 Norwegian
S. Gholami, A. Darani, M.
Sharif, et al.
2011 Persian
225
F. R. M. Soto, F. Ferreira, S.
R. Pinheiro, et al.
2006 Portuguese
R. B. Tamanho, N.
Oleskovicz, A. N. Moraes, et
al.
2010 Portuguese
C. S. Brunckhorst, L. Vuono,
& R. C. Barnabe
2000 Portuguese
M. H. S. Silva, J. A. Silva, D.
F. Magalhães, et al.
2010 Portuguese
F. L. Silva, C. R. A. Silva, &
A. P. R. Costa
2011 Portuguese
E. C. S. Oliveira, F. L. M.
Silva, P. M. Muller, et al.
2011 Portuguese
C. M. Hansen 1994 Russian
Anonymous 2001 German
Anonymous 2010 Thai
I. A. Sadykhov 1976 Russian
A. Bousrih 1983 French
J. Müller 1964 Danish
Anonymous 2012 Portuguese
227
A.6.
Description of Articles Unable to Obtained Excluded from the Study
Authors Year
H. Matter, R. Fico, & B. E.
Neuenschwander
1998
Z. K. Afridi, I. Ahmad, Q.
Habibullah, & S. Efroz
2005
Universities Federation for
Animal Welfare
1981
W. W. Henderson 1940
P. Maheshwari 2012
J. Castro, J. Molina, P.
Anderson, et al
1996
H. H. Brassey-Edwards 1934
J. Okeww-Acai, R. Omara, J.
S. Onyait, et al.
2013
D. A. Georgieva, A. I.
Ivanov, & P. N. Prelesov
1999
H. Brassey-Edwards 1933
Anonymous 2014
J. E. R. Roe 1958
A. Cecchini 1933
Anonymous 1988
D. E. Faulkner 1954
D. Otranto & C. Cantacessi 2007
B. J. Coman 1992
Anonymous 1974
A. O. Miranda, G. Marder, &
A. M. Hojder.
1998
D. J. Evans 1999