Health and Happiness: the Canine-Human Connection

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Billy – Healthy & Happy

Many of the advances in human healthcare and science can be attributed to the fact that we are able to try various medical treatments on our canine best friends before applying them to humans. This is because, from a physiological and biological perspective, humans and canines are very similar. In  fact, we routinely utilize canine models in human medical research (e.g., cardiovascular studies, cancer, heart and lung research, orthopedics, neurology).

Does it make any sense then, that you would take a procedure you know to be extremely harmful to humans (and in some cases illegal) and mandate that it be performed on each and every dog – with almost NO exception and without the benefit of any peer- reviewed research establishing its safety?  And, taking it a quantum leap further, would you then promote this procedure as actually being good for dogs? The quintessential example of this would have to be the spay (ovariohysterectomy) of female dogs and the neuter (castration) of male dogs. Contrast these overly invasive and often unsafe sterilization procedures with those we safely perform on humans, i.e., tubal ligations on females and vasectomies on males. This begs the question, why can’t vasectomies and tubal ligations be performed on our canine best friends? The short answer is, “They can!”. According to a 2007 systematic review  83 of more than 50 peer reviewed studies regarding the effects of spay/neuter:

“One thing is clear – much of the spay/neuter information that is available to the public is unbalanced and contains claims that are exaggerated or unsupported by evidence. Rather than helping to educate pet owners, much of it has contributed to common misunderstandings about the health risks and benefits associated of spay/neuter in dogs.”

One oft-repeated aspect of spay/neuter that we must challenge is the assertion that spay/neuter lengthens the lives of our dogs. On our Lifespan page, we discredit a recent study supporting spay/neuter as a procedure which will enhance the lifespan of the family dog. We counter by introducing studies which establish a nexus between the stress and hormonal disruption of spay/neuter and shortened canine lifespans.

With respect to spay (ovariohysterectomy) of female dogs, both the uterus and ovaries are removed to achieve sterilization, with no consideration for hormone replacement. We will utilize current studies/data throughout this website to illustrate spay’s negative medical ramifications for healthy female dogs. In healthy human females, if sterilization is desired, we perform tubal ligation. This leaves the ovaries and uterus intact, thereby preserving hormone balance. Hysterectomy or ovariohysterectomy would only be performed on humans when there is a medical necessity to remove the uterus/ovaries due to disease. In that circumstance, hormone replacement therapy is typically a part of the post-surgical protocol.

With respect to neuter (castration), there is long term evidence regarding the medical ramifications for healthy young human males in previous societies dating back several centuries. The historical information is consistent with data/conclusions from current studies of castration. Due to the long-term medical consequences, we now opt for vasectomy in human males, so as to preserve the testes and the hormones they produce. Surgical castration of human males remains highly controversial, if not illegal, even when performed on convicted sexual predators. A review 81 of the literature on the subject of castration with respect to its medical consequences in previous societies concludes:

Hopefully, it will never again be possible to repeat the studies reviewed in this paper, as in more recent times we have used different means of expressing man’s inhumanity to man”.

The ACLU argues surgical or chemical castration 82 of humans is considered “cruel and unusual punishment”. Why would we inflict this upon our innocent dogs without a second thought?

Billy  (effects of neuter over time)

After spending 13 years battling behavioral and physical problems with our dog Billy, we finally came to the devastating conclusion that all of his suffering was the result of his being neutered as a young dog in a shelter. Once we came to that conclusion, we uncovered a wealth of information/studies/research that supported our position. We were left wondering why no one in the veterinary community ever revealed to us that this was all quite predictable based solely on Billy’s being neutered at a young age.


Why is it “cruel and unusual punishment” to spay/neuter our beloved canine pals? Neuter (castration) removes the testes in the male dog and spay (ovariohysterectomy) removes the ovaries and uterus in the female dog. The testes and ovaries are glands responsible for the production of sex hormones in humans and dogs. They are a part of a group of glands known collectively as the endocrine system. Removal of the ovaries and testes disrupts the production of sex hormones, which, by definition, makes spay/neuter an endocrine disruptor (ED). A disruption in the hormones produced by one gland, or set of glands, can cause other glands to malfunction, resulting in a disruption of the endocrine system as a whole. All this chaos causes unpleasant symptoms, at the very least. In severe situations, these disruptions can lead to a weakened immune system, chronic disorders, and/or disease. The present day study of endocrine disruption of this magnitude in humans is limited by ethical considerations. Castrating healthy young human males or removing the ovaries and uterus of healthy young human females with no intent to provide hormonal replacement would never be permitted.


There are a group of chemicals, both natural and man-made, that exist in our environment and are classified as endocrine disruptors (EDs). These EDs have been studied in humans and wildlife. Most of these EDs do their damage by mimicking or blocking male and female sex hormones. For example, in males, EDs effectively “chemically castrate 70 (i.e., neuter) their victims. The names of some of these EDs might be familiar to you and include DDT, dioxin, BPA, PFOA, atrazine (herbicide), PCBs, and arsenic. The effects on humans of exposure to these EDs is quite similar to the effects of spay/neuter on our young dogs. We will explore this in depth in the Diseases section of this website, where we will refer you to resources from the Hormone Health Network. The Hormone Health Network is the public education affiliate of the 100 year old Endocrine Society – the largest global membership organization representing professionals (medical doctors, scientists, researchers, and educators) from the field of endocrinology.

At a recent European Union (EU) conference on endocrine disruptors,65 R. Thomas Zoeller, PhD, an invited spokesperson for the Endocrine Society, stated:

“It’s important for regulating agencies to understand that hormones control elements of development that are irreversible when disrupted. We are facing a continuing pandemic of chronic disease if we do not act now.”

Spay/neuter is the ultimate ED, and it is never a responsible option for a young, healthy dog. Yes, we said NEVER. The conclusions of Dr. Zoeller (just above), with respect to endocrine disruptors are remarkably similar to the conclusions in a 2013 UC Davis study of the effects of spay/neuter:

“Because [spaying and] neutering can be expected to disrupt the normal physiologic developmental role of gonadal [i.e., sex] hormones on multiple organ systems, one can envision disease syndromes…” 

Once a dog has been spayed or neutered, their endocrine system has been forever altered. There is no going back to optimal health, despite best efforts. In fact, we will illustrate on our Hormones and the Endocrine System page of this website how attempting to remedy an initial hormonal imbalance brought on by spay or neuter, will subsequently cause another different problem, whose remedy will beget yet another problem, and so on. The damage of spay/neuter to the endocrine system of your dog is permanent, and no dog is immune.

We will summarize the multitude of studies revealing the consequences of spay/neuter in the Spay and Neuter sections of this website (note: there are over 100 peer reviewed studies referenced in our Bibliography). We will document the developmental damage of early spay/neuter in the Orthopedic section and the emerging chronic diseases related to spay/neuter in the Diseases section of this website. The Research section explains why it is acceptable to apply the research and studies pertaining to endocrine diseases in humans as a basis for understanding the emerging disease entities in dogs. In our History section, we will discuss at great length how our dog Billy’s health problems led us to our conclusions.

In short, spay/neuter significantly increases the risk of an otherwise young, healthy dog developing:

  1. Orthopedic problems
    • hip dysplasia
    • elbow dysplasia
    • CCL ligament tear in their knees (requires TPLO surgery)
  2. Cancer
    • osteosarcoma
    • hemangiosarcoma
    • Lymphosarcoma
    • mast cell tumor
  3. Diseases of the endocrine (hormone) systems
    • hypothyroidism
    • Cushings and Atypical Cushings
    • Type 2 diabetes
    • Hyperestrinism and Alopecia (hair loss)
    • Allergies (atopic dermatitis)
  4. Behavior problems
    • aggression towards people and other dogs
    • fear and anxiety
    • reactivity to touch or handling
Spay/Neuter – the ultimate endocrine disruptor

We recognize spay/neuter is a means to an admirable goal. However, is it ethical to compromise the right to a healthy and happy life for the individual dog for the perceived “greater good” of controlling dog overpopulation?  A 2012 Texas A&M research paper 99  titled, “Inconvenient Desires: Should We Routinely Neuter Companion Animals?”, explores this very question. Summarizing their conclusions:

Routine neutering of companion animals raises significant ethical questions and from some ethical perspectives, looks highly problematic. In the case of male dogs and the long-term health risks involved, routine neutering is not morally justified.

We don’t believe any dog should be condemned to a life of pain and illness when viable alternatives which protect your dog’s hormones exist. We would strongly recommend the time and human tested procedures of tubal ligation and vasectomy as safe and ethical alternatives to conventional spay/neuter for our dogs. This solution also prevents pet overpopulation.

According to a 2001 published UC Davis Behavior Service study 55:

“There may be a need to evaluate possible methods for counteracting the effects of loss of sex hormones in gonadectomized [i.e., having had ovaries or testes surgically removed] dogs.” (Dr. Benjamin Hart;  School of  Veterinary Medicine, UC Davis; J Am Vet Med Assoc 2001; 219:51–56)

Further, in 2013 60 and 2014,61 UC Davis published studies linking spay/neuter to three significant orthopedic problems and four aggressive cancers. One might reasonably question why UC Davis has not moved to revamp their curriculum to reflect their own studies. Certainly, if that were the case, they would be promoting tubal ligations and vasectomies as a superior alternative – from both a health and behavioral perspective – for achieving population control for our dogs.

Unfortunately, veterinary institutions are not teaching or even discussing tubal ligation or vasectomy as viable alternatives to spay/neuter. They are still debating the timing of spay/neuter as a means to deal with some of the unintended consequences these studies have revealed.108 It appears that change will only occur as a response to pressure from pet guardians. In fact, the authors of at least one study acknowledge the adverse effects of spay/neuter and encourage veterinarians to discuss the harmful effects of spay/neuter with their canine guardians.109 Therefore, at this time it would seem appropriate to introduce/reacquaint your veterinarian to a concept known in human medicine as “shared decision making63 (SDM).  Sharing decisions, as opposed to clinicians making decisions on behalf of patients, is gaining increasing prominence in health care policy. SDM has been defined as:

“…an approach where clinicians and patients share the best available evidence when faced with the task of making decisions, and where patients are supported to consider options, to achieve informed preferences”.

Pet guardians should be apprised of the option of tubal ligation/vasectomy with the understanding the pet guardian will need to exercise some judgment/restraint of both male and female dogs when a female dog is in heat.

If a significant number of pet guardians demand tubal ligation and vasectomy as a method of population control, the veterinary surgeons will respond accordingly and educate themselves on the intricacies of these surgical procedures. We are told by experts in the field that these procedures are simpler (from a technical perspective), have fewer complications and should ultimately be less costly. This should appeal to shelter managers and other custodians of the bottom line as well. If you have difficulty locating a veterinarian in your area who is capable and willing to perform hormone sparing sterilization alternatives to traditional spay/neuter (e.g., vasectomy, tubal ligation, ovary sparing spay), we recommend that you contact specialty surgical centers in your area or consult the list located on our Facebook page.

Should the veterinary community get on board with our recommendations with respect to hormone sparing sterilization alternatives to traditional spay/neuter, any laws requiring spay/neuter can easily be amended to allow tubal ligation and vasectomy as legally valid options. Please visit our Legal section for information regarding each state’s law and a detailed discussion on how to change your state law if necessary.


If your current dog has already been spayed/neutered, the damage has most likely already been done to a large extent. We will do our best to advise you of offsetting measures that were somewhat successful for our dog and/or that we discovered in our research. We ask that you please work with us to change the status quo for all pets – present and future.

This website is dedicated to Billy.

Disclaimer:   Healthy and Happy Dog is intended to provide information helpful to dog guardians, and hopefully veterinarians, as a public service. We do not accept any advertising nor do we promote any products or services.