Although spaying and neutering dogs are standard practices to prevent unwanted litters, these procedures can increase the risk of several long-term health issues, including obesity, urinary incontinence, bladder stones, hypothyroidism, diabetes, hip dysplasia, cruciate ligament tears, and various behavioral changes such as aggression and fear. Additionally, spayed and neutered dogs may face higher risks of cognitive problems and several types of cancer, including leukemia, prostate cancer, bone cancer, skin cancer, splenic cancer, and bladder cancer.

It is estimated that 83% of all dogs in the United States are desexed, either spayed or neutered. Early spay and neutering, before six months and as early as 8-12 weeks, is being advocated by most veterinarians and animal welfare groups as a method of population control. However, in European countries, the attitude toward routine neutering is shifting, with several countries outlawing the surgery without a medical reason.

History of Spay/Neuter of Dogs in the United States

The history of spaying and neutering, or desexing, in the United States, has evolved significantly over the past century, driven by changing attitudes toward pet population control and animal welfare. In the early 20th century, efforts to control the pet population were sporadic and largely unregulated, with euthanasia in animal shelters being the primary method for managing unwanted animals.

During the 1970s, there was a significant increase in public awareness about the problems of pet overpopulation and the humane treatment of animals. Organizations such as the Humane Society of the United States (HSUS) and the American Humane Association (AHA) began advocating for spay/neuter programs to solve the growing number of homeless animals. Cities and states started establishing low-cost spay/neuter programs and mandatory licensing laws for pets, and the movement gained momentum as part of a broader animal rights campaign.

The 1980s and 1990s saw the launch of national campaigns promoting spaying and neutering. One significant milestone was the establishment of "Spay Day USA" by the Doris Day Animal League in 1995, which aimed to reduce the number of animals entering shelters. The veterinary community increasingly supported spaying and neutering as essential for preventing pet overpopulation and improving animal health, with the American Veterinary Medical Association (AVMA) endorsing it as a standard practice for companion animals. 

Bob Barker's dedication to the cause also had a lasting impact on the animal welfare community. His consistent and passionate advocacy helped normalize the conversation around spaying and neutering, encouraging many pet owners to take action. By leveraging his platform and resources, Barker significantly contributed to efforts to reduce the number of homeless and euthanized animals in the United States.

By the early 2000s, spay/neutering had become widely accepted and practiced across the United States, with the percentage of spayed and neutered pets increasing significantly. Many shelters and rescue organizations required sterilization as a condition for adoption. Ongoing public education campaigns continue to emphasize the importance of spaying and neutering to prevent unwanted litters and reduce euthanasia rates in shelters. These efforts have contributed to a significant decline in the number of animals euthanized in shelters—from an estimated 20 million per year in the 1970s to about 1.5 million per year in recent years.

In some countries, including Germany, Norway, and Sweden, it is illegal to desex dogs without medical reasons.  This approach views desexing as a form of mutilation and prioritizes the animal's natural state unless there is a health or behavioral necessity for the procedure. These regulations reflect a broader approach in these countries to maintain the animal's natural state and focus on responsible pet ownership, training, and alternative methods for managing reproductive and behavioral issues in dogs.

Interestingly, in countries like Norway, Sweden, and Germany, where it is illegal to desex dogs without a medical reason, the rates of dog overpopulation and euthanasia are remarkably low. In Sweden, the euthanasia rate for shelter dogs is close to zero despite only about 20% of dogs being neutered. This is significantly lower than in countries like the United States, where a much higher percentage of dogs are neutered, yet shelter euthanasia rates are higher. 

Norway also maintains a low euthanasia rate without routine castration, attributing their success to strict control laws requiring dogs to be under their owner’s control at all times, reducing the number of strays. Germany follows similar practices, with effective population control and minimal stray dog problems. 

Differences Between Desexing and Sterilization 

Desexing and sterilization are terms often used interchangeably when discussing the management of a dog's reproductive capabilities, but they have distinct meanings. 

Desexing refers to the surgical procedures that remove the reproductive organs of an animal to render it unable to reproduce. 

For male dogs, this involves neutering or castration, which removes the testicles. While castration eliminates the dog's ability to produce sperm, it also significantly reduces testosterone levels, which can influence certain behaviors and health risks. 

For female dogs, a traditional spay surgery involves the removal of the ovaries and uterus, stopping the production of eggs, and eliminating heat cycles.

Sterilization, on the other hand, is a broader term that refers to any procedure that renders an animal incapable of reproduction. Surgical sterilization encompasses both neutering and spaying, as well as other less standard procedures such as ovary-sparing spay (OSS) in females or vasectomy in males. These latter methods prevent reproduction but do not remove the reproductive organs or significantly alter hormone levels. 

The key differences between these terms lie in the procedures and their hormonal impacts. Desexing involves the removal of reproductive organs, significantly affecting hormone levels and, consequently, the animal's behavior and health. Sterilization includes any method that prevents reproduction, and methods like vasectomy or an OSS do not significantly affect hormone levels.

A vasectomy involves cutting or sealing the vas deferens, the tube that carries sperm from the testicles, thus preventing sperm from being included in the ejaculate. This procedure does not affect the production of hormones such as testosterone.

OSS, also known as partial spay or hysterectomy, involves removing the uterus while leaving one or both ovaries intact. An OSS allows the dog to retain her natural hormone production, preventing health ramifications caused by hormonal imbalances.

The Impact of Desexing on Your Dog’s Body

Spaying a female dog through an ovariohysterectomy, the removal of the ovaries and the uterus leads to significant hormonal changes in her body. Immediately after the surgery, the primary sources of the hormones estrogen and progesterone are gone, causing a sudden drop in these levels. This drop prompts the brain to release more of certain hormones, luteinizing hormone (LH), Gonadotropin hormone-releasing hormone (GnRH), and follicle-stimulating hormone (FSH), but without ovaries; these hormones can't function as they are intended, disrupting the normal hormonal balance.

Over time, the adrenal glands might try to compensate by producing small amounts of hormones that can be converted to estrogen, but this usually isn't enough to restore the original hormone levels. The loss of estrogen affects various body systems. Estrogen is vital for bone health, so decreased levels increase osteoporosis and bone fracture risk. The dog's metabolism may also change, potentially leading to weight gain. The lack of estrogen can also impact the urinary system, possibly causing urinary incontinence since estrogen helps maintain the tone and function of the urinary tract.

Behaviorally, some dogs may become more docile, while others might experience increased anxiety or fearfulness due to the absence of stabilizing sex hormones. The dog's cardiovascular health can also be affected, as changes in hormone levels can influence cholesterol and other aspects of heart health.

Neutering, or gonadectomy, significantly impacts a male dog's body and hormonal system. This procedure alters hormone levels, reducing testosterone, LH, and FSH. These hormonal changes affect various bodily functions, leading to increased levels of LH and FSH receptors in tissues such as the urinary tract. 

Neutering is also linked to an increased risk of certain cancers, like lymphoma and hemangiosarcoma, as well as joint disorders, including hip dysplasia and cranial cruciate ligament tear, especially if performed early. Additionally, neutered dogs often experience weight gain due to metabolic changes, which reduces their energy requirements and necessitates careful dietary management to prevent obesity.

Given these potential changes, dog parents need to consider the timing and necessity of desexing. Discussing these factors with your veterinarian can help you make an informed decision and ensure your dog's best long-term health management.

Several research projects examine the risks associated with spaying and neutering dogs, especially at an early age. Many projects focus on a single breed, but the information can be extrapolated to other breeds. 

A study conducted in 2002 revealed that the risk of prostate cancer in neutered dogs is significantly higher, up to four times higher, compared to their intact counterparts. However, veterinarians and many websites still tout that a benefit of castration is a decreased risk for prostate cancer! 

The University of California-Davis is conducting a Golden Retriever study that demonstrated a 100% increase in the rate of hip dysplasia in male Goldens neutered before 12 months of age. The risk of lymphoma in early neutered males was three times higher, and the risk of hemangiosarcoma in early-spayed females was four times higher.

Another study with Vizslas showed that the earlier the dog is neutered, the younger they tend to be when diagnosed with mast cell cancer, other cancers, hemangiosarcoma, lymphoma, all cancers combined, behavioral disorders, or fear of storms compared to dogs that remain intact. Additionally, dogs neutered at six months old or younger are significantly more likely to develop behavioral disorders. 

One study showed no cranial cruciate ligament (CrCL) rupture cases in intact males, intact females, or females spayed after one year. However, the incidence of CrCL rupture was higher in dogs neutered before one year, with 5% in males and 8% in females, compared to intact dogs and those neutered after one year.

Many more studies enlighten veterinarians and dog parents about the dangers of desexing dogs. The simplest answer is to change the standard of care for sterilization rather than desexing dogs. Veterinary schools must adapt their teaching principles to reflect the information from these studies and teach future veterinarians the surgical techniques for vasectomies and ovary-sparing spays. 

Veterinary schools need to be informed that dog parents want alternatives to the traditional spay and neuter surgeries for their dogs. Of the 33 veterinary schools in the United States, only four currently teach alternative surgical sterilization techniques for dogs.

The University of California, Davis School of Veterinary Medicine is known for its comprehensive veterinary training. It has been involved in research and education about alternative sterilization techniques, including OSS and vasectomy​.

The University of Florida College of Veterinary Medicine has incorporated discussions and some practical training on alternative sterilization methods. Their programs emphasize the importance of understanding all available options to make informed recommendations to dog parents.

Purdue University College of Veterinary Medicine includes training on various sterilization techniques, including less conventional methods like OSS and vasectomy, particularly in the context of their shelter medicine program, which provides students with experience in high-volume spay and neuter clinics.

Colorado State University College of Veterinary Medicine and Biomedical Sciences veterinary program is another leading institution that explores alternative sterilization methods. The focus here is on the benefits of hormone preservation for long-term health.

In addition to formal veterinary school curricula, many veterinarians learn these techniques through continuing education workshops and seminars. Organizations such as the Humane Alliance and the ASPCA offer specialized training programs and resources for veterinarians interested in learning these alternative procedures.

The Parsmus Foundation  non-profit organization is an amazing resource for dog parents to learn more about the benefits of OSS and vasectomies. The site includes a directory of qualified veterinarians  to perform OSS and vasectomies.

Nutritional Support of the Spayed and Neutered Dog

If your dog was adopted from an animal shelter or rescue group, she would likely have been desexed before coming into your home. The choice of keeping your dog intact has been removed from you. But there are ways to support your dog’s body to counter the negative impact of gonad removal. 

The removal of the reproductive organs creates havoc on your dog’s endocrine system. When the gonads are removed, the remaining endocrine glands must work harder to maintain hormonal balance. Essential sex hormones, crucial for healthy biological functions throughout life, must then be produced by the adrenal glands. The additional strain on the adrenal glands can lead to various issues, including bone growth and development changes, ligament and hip problems, urinary issues, immune system imbalances, cancer, and even a shorter lifespan.

A species-appropriate diet is the first level of support for your spayed or neutered dog. The most commonly used fresh feeding models for adult dogs are the Biologically Appropriate Raw Food Diet (BARF), Prey Model Raw Diet (PMR), Real Ancestral (6X) DietTM , and a combination of these three. 

While all three diet models include raw meaty bones, muscle meat, and secreting organs, the Real Ancestral Diet also includes fish as a source of omega-3 fatty acids and fur or low glycemic fruits and vegetables as a source of fiber. Fatty fish like sardines, mackerel, and salmon are excellent sources of omega-3 fatty acids, which are vital for reducing inflammation and supporting hormone production.

Additional whole foods that offer support to the endocrine system include: 

Eggs: Rich in high-quality protein and essential fatty acids, eggs support overall health and hormone production.

Bone Broth: Packed with minerals and amino acids, bone broth supports joint health and provides essential nutrients for the endocrine system.

Leafy Greens: Vegetables like spinach, kale, and Swiss chard are high in vitamins and minerals that support overall health and hormone balance.

Berries: Blueberries, strawberries, and raspberries are rich in antioxidants, which help protect the endocrine system from oxidative stress.

Pumpkin: Pumpkin is high in fiber and beta-carotene, supporting digestive health and providing antioxidants.

Sweet Potatoes: A great source of complex carbohydrates and beta-carotene, sweet potatoes help maintain stable blood sugar levels and support adrenal health.

Fermented Foods: Foods like kefir and fermented vegetables provide probiotics that support gut health, which is closely linked to the endocrine system.

Organ Meats: Liver, kidneys, and heart are nutrient-dense foods that provide essential vitamins and minerals for overall health and hormone production.

Coconut Oil: A healthy fat that provides medium-chain triglycerides (MCTs), which support metabolism and thyroid function.

It is estimated that 83% of all dogs in the United States are desexed, either spayed or neutered. Most veterinarians and animal welfare groups advocate early spay and neutering before six months and as early as 8-12 weeks as a method of population control. However, in European countries, the attitude toward routine neutering is shifting, with several countries outlawing the surgery without a medical reason.

The history of spaying and neutering, or desexing, in the United States has evolved significantly over the past century, driven by changing attitudes toward pet population control and animal welfare. In the early 20th century, efforts to control the pet population were sporadic and largely unregulated, with euthanasia in animal shelters being the primary method for managing unwanted animals.

During the 1970s, public awareness increased significantly about pet overpopulation and the humane treatment of animals. Organizations such as the Humane Society of the United States (HSUS) and the American Humane Association (AHA) began advocating for spay/neuter programs to solve the growing number of homeless animals. Cities and states started establishing low-cost spay/neuter programs and mandatory licensing laws for pets, and the movement gained momentum as part of a broader animal rights campaign.

National campaigns promoting spaying and neutering were launched in the 1980s and 1990s. One significant milestone was the establishment of "Spay Day USA" by the Doris Day Animal League in 1995, which aimed to reduce the number of animals entering shelters. The veterinary community increasingly supported spaying and neutering as essential for preventing pet overpopulation and improving animal health, with the American Veterinary Medical Association (AVMA) endorsing it as a standard practice for companion animals.&nbsp;

In some countries, including Germany, Norway, and Sweden, it is illegal to desex dogs without medical reasons. This approach views desexing as a form of mutilation and prioritizes the animal's natural state unless there is a health or behavioral necessity for the procedure. These regulations reflect a broader approach in these countries to maintain the animal's natural state and focus on responsible pet ownership, training, and alternative methods for managing reproductive and behavioral issues in dogs.

Interestingly, in countries like Norway, Sweden, and Germany, where it is illegal to desex dogs without a medical reason, the rates of dog overpopulation and euthanasia are remarkably low. In Sweden, the euthanasia rate for shelter dogs is close to zero despite only about 20% of dogs being neutered. This is significantly lower than in countries like the United States, where a much higher percentage of dogs are neutered, yet shelter euthanasia rates are higher.&nbsp;

Norway also maintains a low euthanasia rate without routine castration, attributing their success to strict control laws requiring dogs to be under their owner’s control at all times, reducing the number of strays. Germany follows similar practices, with effective population control and minimal stray dog problems.&nbsp;

Desexing and sterilization are terms often used interchangeably when discussing the management of a dog's reproductive capabilities, but they have distinct meanings.&nbsp;

Desexing refers to the surgical procedures that remove the reproductive organs of an animal to render it unable to reproduce.&nbsp;

For male dogs, this involves neutering or castration, which removes the testicles. While castration eliminates the dog's ability to produce sperm, it also significantly reduces testosterone levels, which can influence certain behaviors and health risks.&nbsp;

For female dogs, traditional spay surgery involves removing the ovaries and uterus, stopping egg production, and eliminating heat cycles.

Sterilization, on the other hand, is a broader term that refers to any procedure that renders an animal incapable of reproduction. Surgical sterilization encompasses both neutering and spaying, as well as other less standard procedures such as ovary-sparing spay (OSS) in females or vasectomy in males. These latter methods prevent reproduction but do not remove the reproductive organs or significantly alter hormone levels.&nbsp;

Some dogs may become more docile behaviorally, while others might experience increased anxiety or fearfulness due to the absence of stabilizing sex hormones. Changes in hormone levels can also affect the dog's cardiovascular health, influencing cholesterol and other aspects of heart health.

Neutering, or gonadectomy, significantly impacts a male dog's body and hormonal system. This procedure alters hormone levels, reducing testosterone, LH, and FSH. These hormonal changes affect various bodily functions, leading to increased levels of LH and FSH receptors in tissues such as the urinary tract.&nbsp;

Several research projects examine the risks associated with spaying and neutering dogs, especially at an early age. Many projects focus on a single breed, but the information can be extrapolated to other breeds.&nbsp;

A study conducted in 2002 revealed that the risk of prostate cancer in neutered dogs is significantly higher, up to four times higher, compared to their intact counterparts. However, veterinarians and many websites still tout that a benefit of castration is a decreased risk for prostate cancer!&nbsp;

Another study with Vizslas showed that the earlier the dog is neutered, the younger they tend to be when diagnosed with mast cell cancer, other cancers, hemangiosarcoma, lymphoma, all cancers combined, behavioral disorders, or fear of storms compared to dogs that remain intact. Additionally, dogs neutered at six months old or younger are significantly more likely to develop behavioral disorders.&nbsp;

Many more studies enlighten veterinarians and dog parents about the dangers of desexing dogs. The most straightforward answer is to change the standard of care for sterilization rather than desexing dogs. Veterinary schools must adapt their teaching principles to reflect the information from these studies and teach future veterinarians the surgical techniques for vasectomies and ovary-sparing spays.&nbsp;

In light of compelling new findings, the World Small Animal Veterinary Association (WSAVA) has made a groundbreaking policy change. As of May 2024, the WSAVA no longer endorses conventional spay and neuter procedures, signaling a significant evolution in veterinary medicine. This shift reflects a growing body of research suggesting alternative reproductive management approaches may better support companion animals' long-term health and well-being.

The University of California, Davis School of Veterinary Medicine is known for its comprehensive veterinary training. It has been involved in research and education about alternative sterilization techniques, including OSS and vasectomy.

Many veterinarians learn these techniques in addition to formal veterinary school curricula through continuing education workshops and seminars. Organizations such as the Humane Alliance and the ASPCA offer specialized training programs and resources for veterinarians interested in learning these alternative procedures.

The <a href="https://www.parsemus.org/">Parsmus Foundation</a>, a non-profit organization, is an amazing resource for dog parents who want to learn more about the benefits of OSS and vasectomies. The site includes a <a href="https://www.parsemus.org/pethealth/veterinarian-directory/">directory of qualified veterinarians</a> who perform these procedures.

If your dog was adopted from an animal shelter or rescue group, she would likely have been desexed before coming into your home. The choice of keeping your dog intact has been removed from you. But there are ways to support your dog’s body to counter the negative impact of gonad removal.&nbsp;

A species-appropriate diet is the first level of support for your spayed or neutered dog. The most commonly used fresh feeding models for adult dogs are the Biologically Appropriate Raw Food Diet (BARF), Prey Model Raw Diet (PMR), <a href="https://www.feedreal.com/articles/introduction-to-real-ancestral-6x-diet">Real Ancestral (6X) DietTM</a>, and a combination of these three.&nbsp;

As more research studies become available on the dangers of early desexing, there will need to be a paradigm shift among all veterinary professionals about automatically spaying and neutering all pet dogs. Veterinary schools must adjust their teaching protocols to include OSS and vasectomy surgical training. Dog parents must pressure the veterinary community to make these changes.

Desexing vs. Sterilization: Essential Insights for Dog Parents on Spay and Neuter Procedures

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