Terrestrial Animal Health Code
Stray dog population control
Preamble: The scope of these recommendations is to deal with stray and feral dogs, which pose serious human health, animal health and animal welfare problems and have a socio-economic, environmental, political and religious impact in many countries. Human health, including the prevention of zoonotic diseases, notably rabies, is a priority. Dog population management is an integral part of rabies control programmes. Furthermore, the OIE recognises the importance of controlling dog populations without causing unnecessary animal suffering. Veterinary Services should play a lead role in preventing zoonotic diseases and ensuring animal welfare and should be involved in dog population control, coordinating their activities with other competent public institutions and/or agencies.
The following recommendations are based on those laid down in Chapter 7.1. Some additional principles are relevant to these recommendations:
Because dog ecology is linked with human activities, control of dog populations has to be accompanied by changes in human behaviour to be effective.
Carrying capacity: means the upper limit of the dog population density that could be supported by the habitat based on the availability of resources (food, water, shelter), and human acceptance.
Dog population control programme: means a programme with the aim of reducing a stray dog population to a particular level and/or maintaining it at that level and/or managing it in order to meet a predetermined objective (see Article 7.7.3.).
Person: this can include more than one individual, and could comprise family/household members or an organisation.
Dog population control programme objectives
The objectives of a programme to control the dog population may include the following:
improve health and welfare of owned and stray dog population;
reduce numbers of stray dogs to an acceptable level;
promote responsible ownership;
assist in the creation and maintenance of a rabies immune or rabies free dog population;
manage other risks to human health (e.g. parasites);
prevent harm to the environment and other animals;
prevent illegal trade and trafficking.
Responsibilities and competencies
The Veterinary Authority is responsible for the implementation of animal health and animal welfare legislation, in coordination with other competent government agencies and institutions. Control of endemic zoonotic diseases such as rabies and parasitic infections (e.g. Echinococcus spp.) would require technical advice from the Veterinary Authority, as animal health and some aspects of public health are within this Authority’s competence but organising and/or supervising dog control schemes can be the responsibility of non-governmental organisations and governmental agencies other than the Veterinary Authority.
Other government agencies
The responsibilities of other government agencies will depend on the risk being managed and the objective/nature of the dog population control measures employed.
The ministry or other agency responsible for public health would normally play a leadership role and may have legislative authority in dealing with zoonotic diseases. Control of stray dogs with regard to other human health risks (e.g. stray dogs on roads; dog attacks within communities) may fall within the responsibility of the public health agency but is more likely to be the responsibility of the local government authorities or other agencies for public safety/security operating at the state/provincial or municipal level.
Environment protection agencies may take responsibility for control problems associated with stray dogs when they present a hazard to the environment (e.g. control of feral dogs in national parks; prevention of dog attacks on wildlife or transmission of diseases to wildlife) or where a lack of environmental controls is giving rise to stray dog populations that threaten human health or access to amenities. For example, environmental protection agencies may regulate and enforce measures to prevent dogs from accessing waste or human sewage.
Private sector veterinarians
The private sector veterinarian is responsible for providing advice to dog owners or handlers consulting the veterinarian for advice or treatment of a dog. The private sector veterinarian can play an important role in diseasesurveillance because he/she might be the first to see a dog suffering from a notifiable disease such as rabies. It is necessary that the private sector veterinarian follow the procedure established by the Veterinary Authority for responding to and reporting a suspected rabies case or a dog that is suffering from any other notifiable disease. Private sector veterinarians also play an important role (often in liaison with the police and/or local authorities) in dealing with cases of neglect that can lead to problems with stray and mismanaged dogs.
The private veterinarian has competence and will normally be involved in dog health programmes and population control measures, including health testing, vaccination, identification, kennelling during the absence of the owner, sterilisation and euthanasia. Two-way communication between the private sector veterinarian and Veterinary Authority, often via the medium of a veterinary professional organisation, is very important and the Veterinary Authority is responsible for setting up appropriate mechanisms for this action.
Non-governmental organisations (NGOs) are potentially important partners of the Veterinary Services in contributing to public awareness and understanding and helping to obtain resources to contribute in a practical way to the design and successful implementation of dog control programmes. NGOs can supply local knowledge on dog populations and features of ownership, as well as expertise in handling and kennelling dogs and the implementation of sterilisation programmes. NGOs can also contribute, together with veterinarians and the authorities in educating the public in responsible dog ownership.
Local government authorities
Local government authorities are responsible for many services and programmes that relate to health, safety and public good within their jurisdiction. In many countries the legislative framework gives authority to local government agencies in regard to aspects of public health, environmental health/hygiene and inspection/compliance activities.
In many countries local government agencies are responsible for the development and enforcement of legislation relating to dog ownership (e.g. registration, microchipping, vaccination, leash laws, abandonment), the control of stray dogs (e.g. dog catching and shelters) and the alleviation of the problems stray dogs cause in their jurisdiction. This would normally be done with advice from a higher level (national or state/provincial) authority with specialised expertise in regard to public health and animal health. Collaboration with the private sector veterinarians (e.g. in programmes to sterilise and vaccinate stray dogs) and NGOs is a common feature of dog control programmes. Regardless of the legislative basis, it is essential to have the co-operation of local government authorities in the control of stray dogs.
When a person takes on the ownership of a dog, there should be an immediate acceptance of responsibility for that dog, and for any offspring it may produce, for the duration of its life or until a subsequent owner is found. The owner should ensure that the welfare of the dog, including behavioural needs, are respected and the dog is protected, as far as possible, from infectious diseases (e.g. through vaccination and parasite control) and from unwanted reproduction (e.g. through contraception or sterilisation). Owners should ensure that the dog’s ownership is clearly identified (preferably with permanent identification such as a tattoo or microchip) and, where required by legislation, registered on a centralised database. All reasonable steps should be taken to ensure that the dog does not roam out of control in a manner that would pose a problem to the community and/or the environment.
In the development of a dog population control programme it is recommended that the authorities establish an advisory group, which should include veterinarians, experts in dog ecology, dog behaviour and zoonotic diseases, and representatives of relevant stakeholders (local authorities, human health services/authorities, environmental control services/authorities, NGOs and the public). The main purpose of this advisory group would be to analyse and quantify the problem, identify the causes, obtain public opinion on dogs and propose the most effective approaches to use in the short and long term.
Important considerations are as follows:
Identifying the sources of stray dogs
Estimating the existing number, distribution
Practical tools that are available include registers of dogs, population estimates, and surveys of dogs, owners, dog shelters and veterinarians. The important factors relevant to the dog carrying capacity of the environment include food, shelter, water and human attitudes and behaviour.
A methodology could be established to make an estimate of the total dog population. An overview of appropriate methodologies may be found in Article 7.7.8. The same methodology could be used at appropriate intervals to assess population trends.
A regulatory framework that would help authorities establish successful dog control programmes could include the following key elements:
registration and identification of dogs and licensing of dog breeders;
veterinary procedures (e.g. surgical procedures);
control of dog movement (national and international);
control of dangerous dogs;
regulations on the breeding and sale of dogs;
environmental controls (e.g. abattoirs, rubbish dumps, dead stock facilities);
regulations for dog shelters;
animal welfare obligations of owners and authorities.
Resources available to authorities
central-state or province-local partnerships.
The following control measures could be implemented in accordance with the national context and local circumstances. Measures may be used in combination. Euthanasia of dogs, used alone, is not an effective control measure. If used, it should be done humanely (see point 11 of Article 7.7.6.) and in combination with other measures to achieve effective long term control. It is also important that authorities gain an understanding of people’s attitudes towards dog ownership so that they can develop a cooperative approach to the control of dog populations.
Education and legislation for responsible ownership
Encouraging dog owners to be more responsible will reduce the number of dogs allowed to roam, improve the health and welfare of dogs, and minimise the risk that dogs pose to the community. The promotion of responsible dog ownership through legislation and education is a necessary part of a dog population control programme. Collaboration with local government authorities, animal welfare NGOs, kennel clubs, private veterinarians and veterinary organisations will assist Veterinary Authorities in establishing and maintaining programmes.
the importance of proper selection for behaviour and care to ensure the welfare of the dog and any offspring; the latter may include preparing the dog to cope with its environment through attention to socialisation and training;
registration and identification of dogs (see point 2 of Article 7.7.6.);
preventing negative impacts of dogs on the community, via pollution (e.g. faeces and noise), risks to human health through biting or traffic accidents and risks to other dogs, wildlife, livestock and other companion animal species;
control of dog reproduction.
In order to achieve a shift towards responsible ownership, a combination of legislation, public awareness, education, and promotion of these elements will be required. It may also be necessary to improve access to resources supporting responsible ownership, such as veterinary care, identification and registration services and measures for control of zoonotic diseases.
Registration and identification of dogs (licensing)
A core component of dog population control by the Competent Authorities is the registration and identification of owned dogs. This may include granting licences to owners and breeders. Registration and identification may be emphasized as part of responsible dog ownership and are often linked to animal health programmes, for example, mandatory rabies vaccination and traceability.
Registration of animals in a centralised database can be used to support the enforcement of legislation and the reuniting of lost animals with owners. The control of dog reproduction by sterilisation can be encouraged through financial incentives presented by differential licensing fees.
Controlling reproduction in dogs prevents the birth of unwanted puppies and can help address the balance between demand for dogs and the size of the population. It is advisable to focus efforts to control reproduction on those individuals or groups in the dog population identified as the most productive and the most likely to be the sources of unwanted and stray dogs, to ensure best use of resources. Methods of controlling reproduction will require direct veterinary input to individual animals. Involvement of both private and public veterinary sectors may be required to meet demand for services. Subsidisation of sterilisation programmes by government or other organisations may be considered to encourage uptake. The control of reproduction is essentially the responsibility of owners and can be incorporated into education on responsible ownership (see point 1 of Article 7.7.6.). Methods for controlling reproduction in dogs include:
separation of female dogs during oestrus from unsterilised males.
Surgical sterilisation should be carried out by a veterinarian and include appropriate anaesthesia and pain management.
Any chemicals or drugs used in controlling reproduction should be shown to have appropriate safety, quality and efficacy for the function required and used in accordance with the manufacturer’s and Competent Authority’s regulations. In the case of chemical sterilants and contraceptives, research and field trials may need to be completed before use.
Removal and handling
The Competent Authority should collect dogs that are not under direct supervision and verify their ownership. Capture, transport, and holding of the dogs should be done humanely. The Competent Authority should develop and implement appropriate legislation and training to regulate these activities. Capture should be achieved with the minimum force required and equipment should be used that supports humane handling. Uncovered wire loops should not be used for capture.
Capture and return, rehoming or release
Competent Authorities have the responsibility to develop minimum standards for the housing (physical facilities) and care of these dogs. There should be provision for holding the dogs for a reasonable period of time to allow for reunion with the owner and, as appropriate, for rabies observation.
Minimum standards for housing should include the following provisions:
site selection: access to drainage, water and electricity are essential and environmental factors such as noise and pollution should be taken into account;
kennel size, design and occupancy taking exercise into account;
disease control measures including isolation and quarantine facilities.
Management should address:
adequate fresh water and nutritious food;
regular hygiene and cleaning;
routine inspection of the dogs;
monitoring of health and provision of required veterinary treatments;
policies and procedures for rehoming (adoption), sterilisation and euthanasia;
training of staff in safe and appropriate handling of dogs;
record keeping and reporting to authorities.
Dogs that are removed from a community may be reunited with the owner or offered to new owners for rehoming. This provides an opportunity to promote responsible ownership and good animal health care (including rabies vaccination). Prior to rehoming, authorities may consider sterilisation of dogs as a population control measure. The suitability of new owners to adopt dogs should be assessed and owners matched with available animals. The effectiveness of rehoming may be limited due to the suitability and number of dogs.
Dogs that are removed from a community may in some cases be provided with health care (including rabies vaccination), sterilised, and released to their local community at or near the place of capture. This method is more likely to be accepted in the situation where the presence of stray dogs is considered to be inevitable and is well tolerated by the local community.
This method is not applicable in all situations and may be illegal in countries or regions where legislation prohibits the abandonment of dogs. Problems caused by dogs, such as noise, faecal pollution, bite injuries and traffic accidents, would not be alleviated as dogs are returned to the local community and their movements are not restricted. If the local community has owned dogs, and sterilised dogs are released, consideration should be given to the risk that this could encourage abandonment of unwanted dogs. In the situation where many dogs are owned, a population control programme that focuses on neutering and responsible ownership may be more appropriate.
It is recommended that before adopting this approach, a cost-benefit analysis is conducted. Factors such as the monetary costs, impact on culture of ownership and public safety should be assessed as well as the benefits for disease control and animal welfare as well as any societal benefits.
If this method is adopted, the following factors should be addressed:
raising awareness of the programme within the local community to ensure understanding and support;
use of humane methods for catching, transporting and holding dogs;
correct surgical technique, anaesthesia and analgesia, followed by post-operative care;
behavioural observation may be used to assess if dogs are suitable for release; if not suitable for release or rehoming, euthanasia should be considered;
permanent marking (e.g. tattoo or microchip) to indicate that the animal has been sterilised; individual identification also allows for tracking of vaccination status and treatment history and identification of a level of ‘ownership’ by the organisation/authority responsible for carrying out this intervention; a visible identification (e.g. collar) may also be used to prevent unnecessary recapture;
the dog should be returned to a place that is as near as possible to the place of capture;
the welfare of dogs after release should be monitored and action taken if required.
Dogs that are removed from a community may be too numerous or may be unsuitable for any rehoming scheme. If euthanasia of these unwanted animals is the only option, the procedure should be conducted in accordance with the regulations of the Competent Authority (see point 11 of Article 7.7.6.).
Steps should be taken to exclude dogs from sources of food (e.g. rubbish dumps and abattoirs, and installing animal-proof rubbish containers).
This should be linked to a reduction in the dog population by other methods, to avoid animal welfare problems.
Control of dog movement – international (export/import)
Chapter 8.13. provides recommendations on the international movement of dogs, with respect to provisions for rabies.
Control of dog movements – within country (e.g. leash laws, roaming restrictions)
Measures for the control of dog movement in a country are generally invoked for the following reasons:
for rabies control when the disease is present in a country;
for public safety reasons;
to protect wildlife and livestock.
It is necessary to have a regulatory framework and a national or local infrastructure comprising organisation, administration, staff and resources to encourage the finders of stray dogs to report to the Competent Authority.
Regulation of commercial dog dealers
Dog breeders and dealers should be encouraged to form or join an appropriate association. Such associations should encourage a commitment to the raising and selling of physically and psychologically healthy dogs, as unhealthy dogs may be more likely to be abandoned to become part of the stray population. They should encourage breeders and dealers to provide advice on proper care to all new owners of dogs. Regulations covering commercial dog breeders and dealers should include specific requirements for accommodation, provision of suitable food, drink and bedding, adequate exercise, veterinary care and disease control and may require breeders and dealers to allow regular inspection, including veterinary inspection.
Reduction in dog bite incidence
The most effective means of reducing prevalence of dog bites are education and placing responsibility on the owner. Dog owners should be educated in principles of responsible dog ownership as described in point 1 of Article 7.7.6. Legal mechanisms that enable the Competent Authorities to impose penalties or otherwise deal with irresponsible owners are necessary. Mandatory registration and identification schemes will facilitate the effective application of such mechanisms. Young children are the group at highest risk for dog bites. Public education programmes focussed on appropriate dog-directed behaviour have been demonstrated to be effective in reducing dog bite prevalence and these programmes should be encouraged. Authorities should seek advice from dog behaviour experts in developing dog safety education programmes.
When euthanasia is practised, the general principles in the Terrestrial Code should be followed, with the emphasis on using the most practical, rapid and humane methods and ensuring operator safety. Regardless of the method used, it is important to minimise distress, anxiety and pain by ensuring that operators are appropriately trained.
Table 1 shows a summary analysis of methods for the euthanasia of dogs.
Comments on methods for the euthanasia of dogs:
When a dog needs to be restrained for any procedure, including euthanasia, this should always be done with full regard for operator security and animal welfare. Some euthanasia methods should be used in association with sedation or anaesthesia in order to be considered humane.
When special equipment is needed to perform euthanasia (e.g. gas chamber), the system should be designed for the purpose and regularly maintained in order to achieve operator security and animal welfare.
The following methods, procedures and practices are unacceptable on animal welfare grounds:
Embutramide +Mebezonium +Tetracaine without sedation or by other than IV injection
Nitrous oxide: may be used with other inhalants to speed the onset of anaesthesia, but alone it does not induce anaesthesia in dogs
Neuromuscular blocking agents (nicotine, magnesium sulphate, potassium chloride, all curariform agents): when used alone, respiratory arrest occurs before loss of consciousness, so the dog may perceive pain
Household products and solvents.
Air embolism on conscious animal
Exsanguination of conscious animal
Decompression: expansion of gas trapped in body cavities may be very painful
Hypothermia, rapid freezing
Electrocution of conscious animal.
Because neonatal animals and adults with impaired breathing or low blood pressure are resistant to hypoxia, methods that depend upon achieving a hypoxic state (e.g. CO2, CO, N2, Ar) should not be used. These methods should not be used in animals aged less than two months, except to produce loss of consciousness and should be followed by another method to cause death. Concussion and cervical dislocation may be used in very small neonatal dogs and only in cases of emergency.
Operators should be well trained in the use of physical techniques to ensure that they are correctly and humanely carried out. The dog should be exsanguinated immediately after concussion or cervical dislocation.
Confirmation of death
Carcasses should be disposed of in a manner that complies with legislation. Attention should be paid to the risk of residues occurring in the carcass. Incineration is generally the safest way of carcass disposal.
Table 1.Summary analysis of methods for the euthanasia of dogs
|Barbiturates||Correct restraint is needed.|
IP is slow and may be irritant.
IC injection is a painful procedure.
|Recommend to use IV injection.|
When using IP injection, the solution may be diluted or local anaesthetic agent used in conjunction.
IC should only be performed on unconscious animal and by skilled operator.
|Correct restraint is needed.|
Administered under veterinary supervision and requires trained personnel.
|Speed of action generally depends
on the dose, concentration, route and rate of injection.|
Barbiturates induce euthanasia smoothly, with minimal discomfort to the animal. Barbiturates are less expensive than many other euthanasia agents.
|These drugs persist in the carcass and may cause sedation or death in animals that consume the cadaver.|
|Embutramide +Mebezonium +Tetracaine||Muscle paralysis may occur before loss of consciousness if injection given rapidly.||Use slow IV injection with sedation to permit slow rate of injection.||Correct restraint is needed.|
To be administered under veterinary supervision and by trained personnel.
|Quite low cost.||Unavailable/
unlicensed in some countries.
|Anaesthetic agent overdose (thiopentone or propofenol)||Underdosing may lead to recovery.||IV injection of a sufficient dose.||Correct restraint is needed.|
To be administered under veterinary supervision and by trained personnel.
|Generally quick action and minimal discomfort to animal.||Large volume required (cost implications).|
|Potassium chloride (KCl)||K+ is cardiotoxic and very painful if used without anaesthetic agent.||Only use on anaesthetised animals, IV injection.||Requires trained personnel.||Readily available without veterinary control.||Prior need for anaesthetic (cost and availability implications).|
|Mechanical||Free bullet||Can be inhumane if shot is inaccurate and dog is only wounded; dog may also escape.||Skilled operator essential.||Risk of injury to operators and spectators.||Not necessary to handle or capture dog.||Brain tissue may be unavailable for rabies diagnosis. Risk of injury to bystanders. Legal constraints on use of firearms.|
|Penetrating captive bolt followed by pithing where necessary to ensure death||Can be inhumane if shot is inaccurate and dog is only wounded.||Skilled operator essential.||Animal should be restrained. Skilled operator essential.||No risk to operator (see free bullet) unless risk of dog infected with rabies, due to potential contact with brain tissue.||Brain tissue may be unavailable for rabies diagnosis. Legal constraints on use of firearms. May raise aesthetic objections.|
|Exsanguination||Onset of hypovolaemia may cause dog to become anxious.||Only use on unconscious animal.||Danger to operator through use of sharp instrument.||Material requirements minimal.||Need to render animal unconscious. Aesthetically objectionable.|
|Gaseous||Carbon monoxide (CO)||Inadequate concentration of CO is not lethal and can cause suffering. Signs of distress (convulsions, vocalization and agitation) may occur.||Compressed CO in cylinders should be used to achieve and maintain adequate concentration, which should be monitored. Note: fumes from gasoline engines are an irritant and this source of CO is not recommended.||Very hazardous for operator - gas is odourless and causes toxicity at both acute high levels and chronic low levels.||Dog dies quite rapidly if concentration
of 4 to 6% used.|
No odour (therefore no aversive effect).
Gas is not flammable or explosive except at a concentration greater than 10%.
|Carbon dioxide (CO2)||Gas is aversive. Inadequate concentration of CO2 is not lethal and can cause suffering. CO2 is heavier than air, so when incomplete filling of the chamber occurs, dogs may raise their head and avoid exposure. Few studies on adequate concentration and animal welfare.||Compressed CO2 gas chamber is the only acceptable method because the concentration can be monitored and regulated.||Minimal hazard to operator when properly designed equipment used.||Gas is not flammable or explosive
and causes quite rapid anaesthesia when correct concentrations used.
Readily available as compressed gas.
|Unconsciousness can occur in minutes, but death may take some time. Likelihood of suffering before unconsciousness.|
|Inert gas (nitrogen, N2; argon, Ar)||Loss of consciousness is preceded
by hypoxemia and ventilatory stimulation, which may be distressing
to the dog.|
Re-establishing a low concentration of O2 (i.e. greater than or equal to 6%) in the chamber before death will allow immediate recovery.
|Concentration above 98% should be achieved rapidly and maintained. Properly designed equipment should be used.||Minimal hazard to operator when properly designed equipment used.||Gas is not flammable or explosive
and is odourless.|
Readily available as compressed gas.
Little data on animal welfare implications in dogs.
|Anaesthetic gas overdose (halothane or enflurane)||Animal may struggle and become anxious during induction. Vapours may be irritating and can induce excitement.||Supplementationwith air or O2 required to avoid hypoxemia during induction phase.||Some gases may be hazardous, especially for pregnant women. General recommendation: avoid human exposure to greater than or equal to 2 ppm to avoid narcosis.||Gas is not flammable or explosive.|
Valuable for use with small animals (<7 kgs) and animals that are already anesthetised with gas.
|High cost. Anaesthetic and euthanasia properties of the gas used should be known. Isoflurane has a pungent odour. Methoxyflurane's action is slow and dog may become agitated.|
|Electrical||Electrocution||Cardiac fibrillation occurs before
onset of unconscious-|
ness, causing severe pain if dog is conscious. Pain can also be caused by violent extension of the limbs, head and neck.
Method may not be effective if insufficient current applied.
|Only use on unconscious dogs.
This can be accomplished by electrical stunning (current through
the brain to produce an instantaneous stun) or anaesthesia. Electrodes should
span the brain in order that the current passed through the brain
in order to achieve an effective stun.|
Death would result from current passed through the heart of an unconscious animal.
Proper equipment and trained operator is essential.
|May be hazardous for operator, who should use protective equipment (boots and gloves).||Low cost.||Need to render animal unconscious.
May raise aesthetic objections.
|KEY to abbreviations used in Table 1:|
Monitoring and evaluation of dog population
Monitoring and evaluation allows for comparison of important indicators against the baselines measured during initial assessment (see Article 7.7.5.). The three main reasons for carrying out monitoring and evaluation are:
to help improve performance, by highlighting both problems and successful elements of interventions;
for accountability, to demonstrate that the
programme is achieving its aims;
assuming methods are standardised, to compare
the success of strategies used in different locations and situations.
Monitoring is a continuous process that aims to check the programme progress against targets and allows for regular adjustments. Evaluation is a periodic assessment, usually carried out at particular milestones to check the programme is having the desired and stated impact. These procedures involve the measurement of ‘indicators’ that are chosen because they reflect important components of the programme at different stages. Selection of suitable indicators requires clear planning of what the programme is aiming to achieve, the best selection of indicators will be one that reflects the interest of all relevant stakeholders. Standardised methodology will facilitate comparison of data from subsequent evaluations and performance between different projects. Indicators can be direct measurements of an area targeted to change (e.g. population of free roaming dogs on public property) or indirect measures that reflect change in a targeted area.
Elements that should generally be monitored and evaluated include:
dog population size, separated into sub-populations in accordance with ownership and restriction of movement (i.e. roaming unrestricted or restricted by an owner);
dog welfare, in the target population (e.g. body condition score, skin conditions and injuries or lameness) and as a result of the programme (if interventions involve direct handling of dogs, the welfare of the dogs as result of this handling should be monitored);
prevalence of zoonotic diseases, such as rabies, in both the animal and human population;
responsible animal ownership, including measures of attitudes and understanding of responsible ownership and evidence that this is translating into responsible behaviour.
There are many sources of information for monitoring and evaluation purposes, including:
feedback from the local community (e.g. through the use of structured questionnaires, focus groups or ‘open format’ consultation processes);
records and opinions obtained from relevant professionals (e.g. veterinarians, medical doctors, law enforcement agencies, educators);
animal based measurements (e.g. direct observation surveys of population size and welfare status).
The output of activities against budget should be carefully recorded in order to evaluate the effort (or cost) against the outcomes and impact (or benefit) that are reflected in the results of monitoring and evaluation.
An overview of appropriate methods for estimating the size of dog populations
Population estimates are necessary for making realistic plans for dog population management and zoonosis control, and for monitoring the success of such interventions. However, for designing effective management plans, data on population sizes alone are insufficient. Additional information is required, such as degrees of supervision of owned dogs, the origin of ownerless dogs, accessibility, etc.
The term ‘owned’ may be restricted to a dog that
is registered with licensing authorities, or it may be expanded
to unregistered animals that are somewhat supervised and receive
shelter and some form of care in individual households. Owned dogs may
be well supervised and restrained at all times, or they may be left
without control for various time periods and activities. Dogs without
owners that claim responsibility may still be accepted or tolerated
in the neighbourhood, and individuals may provide food and protection.
Such animals are sometimes called ‘community owned dogs’
or ‘neighbourhood dogs’. For an observer it is frequently impossible
to decide if a free roaming dog belongs to someone or not.
The choice of methods for assessing the size of a dog population depends on the ratio of owned versus ownerless dogs, which may not always be easy to judge. For populations with a large proportion of owned dogs it may be sufficient to consult dog registration records or to conduct household surveys. These surveys should establish the number of owned dogs and the dog to human ratio in the area. In addition, questions on dog reproduction and demographics, care provided, zoonosis prevention, dog bite incidence, etc. may be asked. Standard polling principles should be applied.
If the proportion of ownerless dogs is high or
difficult to assess, then one should resort to more experimental
approaches. Methods borrowed from wildlife biology
can be applied. Being generally diurnal and tolerant to human proximity,
dogs lend themselves to direct observation and the application of
mark-recapture techniques. Nevertheless, a number of caveats and
limitations have to be taken into account. Firstly, the risk of
zoonotic disease transmission
is increased through close physical contact. Also, the methods are
relatively labour intensive, they require some understanding of statistics
and population biology, and most importantly, they are difficult
to apply to very large areas. One should take into account that
dog distribution is non-random, that their populations are not static,
and that individual dogs are fairly mobile.
Counting of dogs visible in a defined area is the simplest approach to getting information on population size. One has to take into account that the visibility of dogs depends on the physical environment, but also on dog and human activity patterns. The visibility of animals changes with the time of the day and with seasons as a function of food availability, shelter (shade), disturbance, etc. Repeated standardized counting of dogs visible within defined geographical localities (e.g. wards) and specific times will provide indications of population trends. Direct counting is most reliable if it is applied to small and relatively confined dog populations, e.g. in villages, where it might be possible to recognize individual dogs based on their physical appearance.
Methods using mark-recapture procedures are often considered more reliable. However, they also produce trustworthy results only when a number of preconditions are met. Mortality, emigration and recruitment into the population should be minimal during the census period. One may be able to incorporate corrective factors into the calculations.
It is therefore important that the recommended census procedures are applied at times of low dispersal and that one selects study plots of shape and size that minimize the effect of dog movements in and out of the observation area. Census surveys should be completed within a few days to a maximum of two weeks in order to reduce demographic changes. In addition, all individuals in the population should have an equal chance of being counted. This is a highly improbable condition for dogs, whose visibility depends on ownership status and degrees of supervision. It is therefore recommended that the investigator determines what fraction of the total population he/she might cover with an observational method and how much this part overlaps with the owned dog segment that he/she assesses with household surveys.
There are essentially two ways to obtain a population estimate if it is possible, in a defined area and within a few days, to tag a large number of dogs with a visible mark, e.g. a distinctive collar or a paint smudge. The first method requires that the capture (marking) effort remains reasonably constant for the whole length of the study. By plotting the daily number of dogs marked against the accumulated total of marked dogs for each day one can extrapolate the value representing the total number of dogs in the area. More commonly used in wildlife studies are mark recapture methods. Dogs are marked (tagged) and released back into the population. The population is subsequently sampled by direct observation. The number of marked and unmarked dogs is recorded. One multiplies the number of dogs that were initially marked and released by the number of subsequently observed dogs divided by the number of dogs seen as marked during the re-observation to obtain a total population estimate.
Since the dog populations of entire countries, states, provinces or even cities are much too large for complete assessment, it is necessary to apply the methods summarized above to sample areas. These should be selected (using common sense) so that results can be extrapolated to larger areas.
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