Letter from WHO authorities (2003)
WHO/FAO Collaborating Centre for Research and Training in Veterinary Public Health
Mrs Maria Harbova
Chair of the Ecology Commission
Municipal Council of Sofia
Dear Mrs Harbova,
Thank you for applying to our centre for consultancy regarding the problem of stray dog control in the city of Sofia.
The WHO/FAO Collaborating Centre for Veterinary Public Health has been interested for long in such an issue as well as in other problems concerning Veterinary Urban Hygiene.
On the basis of the World Health Organisation (WHO) surveys and recommendations, and of international and local trials and experiences, it has been shown that the killing (or removal) of stray (including vagrant and feral) dogs alone does not solve the problem.
Indeed, if a fixed quantity of food and water resources exists in a certain place and there are adequate shelters for the dogs, there will be fixed number of them living there, and so called "holding capacity" will be reached in that location. Individual dogs in the group may change but the size of the population will remain roughly constant because it depends upon (and is balanced by) the birth of puppies and the addition of abandoned dogs on the one side and natural death, re-homing, kennelling or euthanasia on the other side. Under such circumstances, if a female produces young but the "holding capacity" does not change, the young will not remain but will either die from disease or will move away when they become independent of the mother. Yet, if an animal is removed from the group, a new young will replace it, and if many animals are removed then more puppies will survive so that the local population will always return to the "holding capacity".
Accordingly, the elimination of the "overflow" (or excess) of dogs by killing removes only the symptom but will not solve the problem and proves also to be very expensive. Another attempt to solve the stray dog problem is to try to catch and kill all stray animals within 2 months, i.e. the lenght of canine pregnancy. Field experiences have shown that this is very hard to attain, and if it is not possible to catch all strays in an area within the breeding time (as it is usually the case), the total canine population will raise again to the "holding capacity".
Interventions made to influence the "holding capacity" are rarely efficacious (dogs may easily find water, and many existing natural or man-made structures may be used as shelters). The only parameter which can be successfully controlled is food supply. Authorities should manage the rubbish problem properly by rendering dumping places and food waste inaccessible to dogs (by fencing, using dog-proof garbage containers, etc.), and especially by educating the public not to leave food refuse in the streets and not to feed freely roaming dogs.
Besides the citizen's education, a successful strategy to manage stray dog problem consists of two main approaches to be applied jointly: 1) Registration and identification and 2) Spay/neuter and return programmes.
1. Registration and identification (e.g. by tattooing or subcutaneous microchip insertion). A system for registration/identification of canine population can help prevent dogs from being abandoned as it allows the owners to be traced and even be fined for the abandoning. Unfortunately, this practice does not avoid the abandoning of puppies nor does not prevent people from depositing unwanted animals in kennels and dog pounds.
2. Spay/neuter and return programmes. As a rule, the main source of stray canine population is the unwanted offspring of pets. Owners quite abandon also the mother and keep a male puppy hoping to thus avoiding the problem of the birth of new unwanted offspring. This common behaviour may be discouraged by offering pet owners free (or low-cost) spaying and neutering followed by the re-homing of the sterilized animals. This type of programme is capable of permanently reducing the total population in that when in a group of sterile animals should one die of any cause there will no young to replace it. A sterilized dog may be returned either to the owner (if accepted) or to its territory of origin as a "neighbourhood dog" where it will be cared of by the citizens. This last solution has the additional advantage of the animal keeping its territory free of other "intruder" dogs.
The strategy of "registering plus sterilization and return" has been studied and practically applied in a number of countries facing serious stray dog problem (including Italy, Great Britain and USA). Field results of these programmes proved invariably to be both effective and money-saving. The chances of success of this policy may be strengthened by properly tailoring the programmes to individual, local conditions. Differences are found in various countries or part of countries as a consequence of differences in approach to animals, economic status, religion, social factors, etc.
We hope that this account will profitably assist you in solving your problem. Of course, our Collaborating Centre keeps at your disposal should you require more details or more extensive information on the issue.
Very truly yours
doct. Agostino Macri
prof. Adriano Mantovani
Rome, June 2003