Pet Population Dynamics (Why are there too many euthanasias?)
Promoting the Human-animal Bond in Veterinary Practice
Thomas E. Catanzaro, DVM, MHA, FACHE, Diplomate American College of Healthcare Executives

I remember when I returned from an interdisciplinary Pet Overpopulation Workshop at the University of Minnesota. Everyone with a national interest was represented, from the American Humane Association, Humane Society of the United States, and American Society for the Prevention of Cruelty to Animals, American Kennel Club, Cat Fanciers, to the American Veterinary Medical Association and American Animal Hospital Association. The meeting was also loaded with academic researchers, epidemiologists, population scientists, and others who care about too many animals being killed every year.

Two Decades of Inertia

The main impact on me was the amazing fact that the problem has not changed after twenty years of these types of meetings. Granted, strays have decreased in cities were there are strict leash laws. Veterinarians have experienced this decrease with the low number of "hit by car" patients they are seeing. We are still killing between 5 and 25 million animals a year because they do not have a home (there is no single reporting system, so the guess-i-mates are all over the board). Some of these have to be euthanized, due to their feral nature, non-social behavior, or medical indications, but not millions. Like an iceberg in a shipping lane, the problem has been seen ('elephant in the room' syndrome) but not completely defined. Some have looked at the tip of the iceberg, others have tried to assess the size of the entire iceberg, but to date, no one has really researched the cause of the iceberg.

As a management diagnostician, not an academic researcher, I was asked to be an information resource for the meeting. The first big definition hurdle was to get a handle on "pet overpopulation." There was great discussion, but the consensus settled on the simple statement that "too many animals were being euthanized each year." Then we had to define "too many," so we came up with a simple formula:

births (- medically indicated euthanasias) - natural deaths / number of responsible pet owners (x multi-pets) = 1

Then we started looking at the factors impacting on each element of the formula, and looked at any assumptions we were making that could not be measured. In fact, none of the elements had ever been actually measured with any statistical accuracy. So we looked at clear definitions. The definition of responsible pet owner was one such challenge in clarity. We have never researched the "profile" of a responsible pet owner, or for that matter, an irresponsible pet owner. The Delta Society had a lot of data on the human-animal bond, but this question appeared too subjective for research grant funding (isn't that why we do research?). So we defined irresponsible pet owners as a percentage of the animal-owning public:

(1 - responsible pet owners) x 100 = irresponsible percent

This great exercise in pursuit of the better definition did bring us closer to the real challenge that has caused these decades of inertia. Why haven't the humane groups, local community leaders, or veterinary medical groups been able to solve this problem? In the eighties, the mayors of the United States placed stray (uncontrolled) animals in the top three problems of urban America. Caring people have been addressing the pet overpopulation "assumption" from their own perspective. Do we have too many pets or too few responsible owners; do we see too many births or not enough natural deaths; or is it a population dynamics factor that is not easily defined?

With the guidance of Drs. Glickman and Patronek, pathobiology researchers from Purdue University, we attempted to develop a model of the population dynamics as they appear today, with the basic assumption that this dynamic population (animal or human) constantly seeks a form of equilibrium (supply and demand):

Click on the image to see a larger view.


This model is noteworthy because of the relationships (arrows); we don't know the values (impact) of the various elements. If there was good research, we would know the intensities of demand within a population (perhaps a county). When one population is defined, then the second population could be surveyed and compared, with the variances being validated for "cause and effect" relationships. If we look at current efforts, such as licensure, where does that impact this model? Is taxation a method of controlling pet reproduction, or is it the registration need for returning lost pets. With this model, anyone can see that these issues become very small contributors to the success or failure of any community problem.

If we look at the dynamics with the "pet-owning" segment of the total population, additional relationships become very evident.

Click on an image to see a larger view.




Even with these two models, we don't know the values or intensities which influence the equilibrium. If we compare Europe with the United States, the stray animal problems are different. Why would this be? Why are breed types, ears and tails included, different between the two populations? Why are animals more acceptable in public places in Europe? Which values are different; the animal's reproductive urges, the community mores, the animal owners themselves, or.......? How could a similar set of values be economically introduced into an American population? Would the values cause the same results? How would we measure the changes?

For twenty years we have been picking at this problem from the edge but have never addressed the total causative parameters. Only an interdisciplinary effort can ever hope to address the cause and effect which requires millions of animals to be killed annually at shelters and veterinary facilities across the nation.

The Alternatives

Remember, I am the management diagnostician, not a researcher. I look at what could be done, today, with very little expense, to start getting a handle on the problem. There are about 4500 shelters in the United States (no one knows for sure how many). In heavy "no kill" shelter areas, triage facilities have been established to supply acceptable/adoptable animals to 'no kill' shelters; the triage facilities do not deal with the public, so they fall outside the traditional legal definition of shelters and can euthanize the unadoptable animals. There are about 28,400 companion animal exclusive veterinary practices (no one knows for sure). If the powers in the combined movements (e.g., ASPCA, AHA, HSUS, AVMA, AAHA, etc.) got together and developed a single "values survey" for pet owners, a statistically valid sample could be obtained from a portion of the existing facilities with existing staff resources. This could be compared to existing Delta Society research for human-animal bond relationships.

Are there behavior management courses that could be offered within a community, shelter or veterinary practice which would stem the euthanasia impulse? We know that practices that used the 90-plus pages of behavior programs in the appendices of the first edition of this text actually did effect retention and return rates. Most people do perceive behavior problems in their pets, and responsible pet owners either accept the animal's ways or try to get professional assistance in the resolution of the behavior problem. The shortfall was initially veterinary practices confusing obedience training with behavior management; most practices could do behavior management with their paraprofessional staff and few CD training sessions (e.g., Linda White's Puppy Smarts® , Welcome Home by PetCareTV®, etc.). Irresponsible pet owners ignore the animal's ways or dispose of the animal (release, turn-in, euthanasia, etc.), but they are a small minority when veterinary practices provide proactive behavior management programs. The current research shows about eighty-five percent of the behavior problems are manageable without putting the owner through prolonged obedience training.

A more expensive alternative is the "total county profile." There are methods to statistically survey a population by telephone (but you miss the non-phone households, a statistically important population in some areas of the country). New Zealand has developed a protocol for surveying stray animal populations which could likely be adapted to the United States. Non-pet owners must be profiled to determine if there is a factor that could be used to increase the number of available households (we are aware that housing restrictions are artificially limiting the pet-owning population potentials).

If we don't address this dynamic situation from an interdisciplinary viewpoint, if we don't "release our turf" and share, I don't see any great opportunity for resolution of this situation. No one can do it alone, we have proven that in the past two decades. If we don't change, we will continue to kill too many animals every year.

Speaker Information
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Thomas E. Catanzaro, DVM, MHA, FACHE, Diplomate American College of Healthcare Executives