Why is spaying & neutering a critical factor in reducing the homeless pet population

Individuals in the rescue community easily understand the importance of spaying and neutering.  We regularly walk through crowded shelters and witness animals being led away to be euthanized, and we all maintain that it is nothing short of a tragedy that these animals are sentenced to death simply because the population is too high to accommodate and the expense to provide vet services and living accommodations far exceeds the existing funding.  The rescue and shelter community continues to work toward decreasing the overpopulation of homeless animals by charging an increased return fee for un-spayed and un-neutered strays.  Many shelters even include the cost of spay or neuter in an animal’s adoption fee.  Despite these efforts, several Maricopa County kill-shelters are still reporting a euthanasia rate of slightly less than half of their intake (6).  Increasing public education regarding the importance of spaying and neutering is an essential step toward curbing these numbers, the alternative of which is to continue to euthanize nearly 2.7 million cats and dogs each year (12).

Several peer-reviewed studies have concluded that Trap-Neuter-Release (TNR) programs can reduce a feral feline community dramatically in up to five years (3).  These studies support the reasoning that controlling cat and dog reproduction rates can only decrease the number of these animals that end up in shelters and on the euthanization list.  However, not every community has access to grant-funded research resources, and community campaigns or mandatory spay and neuter laws have proven fairly unsuccessful (11).  “The usual natural history of these laws is a year of vigorous enforcement, a year of less enforcement, then enforcement only against people who make someone in the animal control establishment mad. Of course at that point, many otherwise good pet owners are violating the law.” (2)  Education about the significance of humane animal birth control within the homeless pet population, the consequences of ignorance, and the advantages of spaying and neutering for pet owners, could certainly prove to be a more stable foundation on which we build a more responsible pet owner community.

Many individuals outside of the rescue community may not have a clear understanding of the incredible rate of reproduction that un-altered animals possess.  The American Society for the Prevention of Cruelty to Animals (ASPCA) estimates that an average fertile cat can produce 1-2 litters of 4-6 kittens per year, and an average fertile dog can produce 1 litter of 4-6 puppies per year (8).  Based on these numbers, 1 single fertile feral cat will produce up to 40 kittens over the course of 5 years.  Both female and male cats can reach sexual maturity anywhere between 5-12 months (4), so if that first generation produced 1 litter in their first year of life, and 2 litters in each subsequent year within that same 5 year span, they would be responsible for 4,000 kittens.  The ASPCA also reports that only 37% of the cats entering their shelters as strays are adopted, while 41% are euthanized (the remaining 5% are returned to their owners) (8). Even if we reduce the number of 4,000 kittens to 3,000, (25%) due to external influences that may cause early death (e.g. illness, birth defects, etc.), we are still left with approximately 1,770 (41%) kittens produced from that first generation that will inevitably be euthanized.  This number obviously increases exponentially as we add the reproduction rate of the 3rd, 4th, and 5th generations of kittens to the formula, and view the rate of reproduction over an extended span of time.

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This issue of exponential reproduction is not just present within the feral community.  The U.S. Humane Society reports that the majority of the approximately three-million animals being euthanized in U.S. shelters every year “are not the offspring of homeless ‘street’ animals - these are the puppies and kittens of cherished family pets and even purebreds.” (12)  They additionally estimate that 25% of the dogs in reporting shelters are purebred (9).  High School Biology class taught us that the hormones in sexual reproductive organs motivates all animals to search for a mate.  A well-kept dog, or cat, with easy access to the outdoors will seek any opportunity for “sexual roaming” when their reproductive hormones are in full-gear, and male dogs and cats can prove fertile with numerous mates over the course of 24-hours.  Owners of male-strays may never even see the results of their pet’s time on the “outside”, but it is likely that those resulting puppies and kittens will enter a shelter at some point in their lives. And, with only 3-4 million cats and dogs being adopted from shelters each year, it is also likely that those puppies and kittens will end up being a part of the nearly 38% of companion animals euthanized yearly (9).

Setting the issue of reproductive rates aside, we can examine a more qualitative type of negative influence on the homeless animal community, which occurs when the adoption of each new puppy or kitten decreases the likelihood that young or adult aged homeless animals will find a happy ending.  For each kitten or puppy that finds a home, the adoption opportunities decrease for animals already in shelters and rescues.  The American Pet Products Association estimates that 70% of individuals with companion dogs only have one dog in their home, while 46% of owners with companion cats only have one cat (1).  This leaves a 20% chance that a pet-owner with one dog will adopt a second dog, and only a 10% chance that a pet-owner will adopt three or more dogs (1).

Many people argue that ‘cost’ is a valid reason for resistance to spaying and neutering, yet don’t consider the cost, and time, of safely delivering and re-homing a litter.  It is true that the number of homeless animals has significantly decreased in the past 40 years, and the growing attention being paid to the necessity of spaying and neutering could certainly be a contributor (9).  “There is much more awareness of appropriate pet ownership nowadays,” says a representative from the Human Society (5).  More communities are finding that the homeless pet population and euthanasia rates are less acceptable, which has influenced many veterinary organizations to lower their costs of sterilization services, while many non-profit organizations have amplified the number, and consistency, of free and discount spay and neuter campaigns.  Additionally, this culture shift towards an increased awareness of what “euthanization” means for shelter animals has influenced the increase of no-kill sanctuary and rehabilitation organizations, similar to the Best Friends Animal Society in Utah, which is currently home to more than 1,500 dogs, cats, rabbits, horses, and other wildlife (10).

Ultimately, the decision to spay or neuter your own animals will directly contribute to the increase or decrease of your area’s homeless pet population.  It is a community’s moral responsibility to maintain a population of homed and healthy companion animals, and the only solution for the problem of an overpopulation of homeless animals is to control the population through humane birth control.  Euthanasia is not a solution to overpopulation of these homeless animals, but rather an unfortunate necessity present in many shelters (7).  The homeless animal population will take a positive turn if we can continue to convince pet-owners of the many advantages to spaying and neutering.  I encourage you to follow the links provided in my citation list to learn more about the influence of spaying and neutering on the homeless pet population.  The information is out there, and sharing that information, and creating a community of supportive pet-owners, are steps in the right direction.

I invite you to visit the websites that I have cited in this post.  Additionally, here are some great resources that are definitely worth checking out if you are interested in learning more about spaying and neutering:

"Myths and Facts About Spaying and Neutering" - The Humane Society of the United States

"Why You Should Spay/Neuter Your Pet" - The Humane Society of the United States

"You Can Afford to Have Your Pet Spayed or Neutered" - The Humane Society of the United States

"Are You Having Trouble Affording Your Pet?" - The Humane Society of the United States

"ASPCA Mobile Spay/Neuter Clinic" - The ASPCA


(1) 2013-2014 APPA National Pet Owners Survey. The American Pet Products Association. N.p., Web. 11 April 2015. <http://www.americanpetproducts.org/pubs_survey.asp>

(2) Hutchens, Walt. “An Approach to High Shelter Euthanasia Rates.” Pet-Law. N.p., 2010. Web. 11 April 2015. <http://www.pet-law.com/articles/36>

(3) "Key Scientific Studies on Trap-Neuter-Return." Alley Cat Allies. N.p., 2015. Web. 11 April 2015. <http://www.alleycat.org/page.aspx?pid=668>

(4) Khuly, Patty. "What's the right time to spay and neuter your dog?". petMD. N.p., 30 July 2009. Web. 11 April 2015. <http://www.petmd.com/blogs/dailyvet/2009/July/30-4478>

(5) Mach, Andrew. "Behind the big drop in euthanasia for America's dogs and cats." The Christian Science Monitor: Progress Watch. N.p., 10 February 2012. Web. 11 April 2015. <http://www.csmonitor.com/USA/Society/2012/0210/Behind-the-big-drop-in-euthanasia-for-America-s-dogs-and-cats>

(6) Maddies Fund Comparative Database. Maddies Fund. N.p., 2015. Web. 11 April 2015. <http://www.maddiesfund.org/comparative-db.htm>

(7) Newkirk, Ingrid. People For the Ethical Treatment of Animals. N.p., 21 March 2013. Web. 11 April 2015. <http://www.peta.org/blog/euthanize/>

(8) "Pet Statistics." The American Society for the Prevention of Cruelty to Animals. N.p., 2015. Web. 11 April 2015. <https://www.aspca.org/about-us/faq/pet-statistics>

(9) "Pets by the Numbers." The Humane Society of the United States. N.p., 30 January 2014. Web. 11 April 2015. <http://www.humanesociety.org/issues/pet_overpopulation/facts/pet_ownership_statistics.html?credit=web_id80910746>

(10) "Pet euthanasia in shelters unpopular." CBS News. The Associated Press. 5 January 2012. Web. 11 April 2015. <http://www.cbsnews.com/news/pet-euthanasia-in-shelters-unpopular/>

(11) "Trap-Neuter-Return Effectively Stabilized and Reduces Feral Cat Populations." Alley Cat Allies. N.p., Web. 11 April 2015. <http://www.alleycat.org/page.aspx?pid=1612>

(12) "Why You Should Spay/Neuter Your Pet." The Humane Society of the United States. N.p., 24 August 2014. Web. 11 April 2015. <http://www.humanesociety.org/issues/pet_overpopulation/facts/why_spay_neuter.html?credit=web_id80910746>