Spaying or not spaying your dog: that is the question


There are a number of third-tier issues that occasionally electrify the talkative careless dog owner: Grain or Grain Free? Removal of dew claws, cut off ears and tails or let it go? Raw or cooked? Flat collar or choke, pinch or electronic?

But dog owners who grew up in the decades prior to neutering grew up de riguer are sometimes shocked by the increasingly popular accusation that spaying a dog is tantamount to sentencing him or her to a shorter or more painful life. If you are a reputable dog owner, almost all of your adult life may have been spent judging people with reproductively intact dogs – especially intact mixed breed dogs – as extremely irresponsible. What gives? Why the reverse?

Veterinarians have long wondered what the “best” time in a dog’s life to undergo spay / neuter surgery, and some have theorized that maturation without the benefit of secondary sex hormones could have deleterious effects the health could have. There were even small studies looking for such. However, until a 2013 study (Torres et al.) By the University of California – Davis found a link between neutering and the risk of certain factors, there wasn’t really any meaningful data that led the average dog owner to choose the wisdom from castration to question cancer and joint disease in golden retrievers.

Since then, there have been a steady number of studies (with more on the immediate publication horizon) examining one aspect or another of dog health and the potential effects of spay / neuter – and the effects of that endless drop of evidence torture for many dog ​​owners. We thought we were doing the right thing by sterilizing our dogs!

But it is Really so bad to have dogs neutered? Many of the studies people cite to back up their claims that the practice is unhealthy for dogs are based on statistically tiny samples or dogs of a single breed. Extrapolating the results of very limited studies to suggest spay / neuter is harmful everything Dogs is quite a range.

To help you understand the modern day claims that spay / neuter is bad for dogs, we examined dozens of studies examining some aspects of the potential health effects of gonadectomy – the removal of the dog’s gonads (reproductive organs, testicles in men and the ovaries in women). We’ll describe the evidence and discuss what it all means – but here’s a sneak peek at our conclusions: You still have to decide for yourself what is “best” for you and your dog. And if your dog has already been gonadectomized, that’s fine! The evidence isn’t cut and dried to support any general recommendations for all dogs.

A note on terminology

The term “neuter” can be used for both male and female dogs, although it is more commonly used for the castration process (removal of testicles) in male dogs. Castration is specific to men, as is spay to women.

Spay / neuter generally refers to the removal of the gonads (the male testicles and female ovaries); This is more precisely known as a gonadectomy. It should be noted, however, that while the woman’s uterus and uterine horns are not gonads, they are also removed during spay operations. Confusingly, “spay” is sometimes used to refer to a hysterectomy – removal of only the uterus and uterine horns. The removal of the ovaries (to protect the uterus and uterus horns) is called an ovariectomy.

“Sterilization” is another general term that is used frequently. However, it can refer to a process that induces infertility without a gonadectomy.

“Desexing” is a term that has gained popularity in the research literature. It is defined as spaying or neutering an animal, but the term has strong negative connotations in many people who may fear that it is referring to somehow removing a dog’s biological sex. it doesn’t!

Because alternative methods of preventing reproduction are not yet common in the United States, almost all research has focused on dogs that have undergone spay (removal of all reproductive organs) or neutered. We will use the terms “spay / neuter” and “gonadectomy” interchangeably.

There are other common terms related to the age of the gonadectomy. “Early age” or “prepubertal” spay / neuter indicates dogs that had a gonadectomy before the age of six months. “Pediatric” spay / neuter operations are usually defined as those that occur between 6 and 16 weeks of age.


Before looking at the studies that look at the effects of gonadectomy, it is helpful to understand what functions the gonads perform Next Reproduction.

Normal male and female dogs each have a pair of gonads.

The male gonads – the testes – are located in the scrotum and produce the male reproductive cells (sperm, short sperm) as well as androgen hormones, which promote the male characteristics.

Sperm are formed in the seminiferous tubules in the testes; Between these tubules are groups of endocrine cells called interstitial cells that produce androgens in response to luteinizing hormone (LH, sometimes called interstitial cell-stimulating hormone) [ICSH]) secreted anteriorly from the pituitary gland located in the brain.

The main androgen produced is testosterone, which is responsible for the development of the male reproductive system and secondary male sexual characteristics such as male body shape and sexual behavior. Testosterone is a steroid hormone that has an overall anabolic effect on the body, promoting protein synthesis and tissue growth, promoting the growth of muscle mass and strength, increasing bone density and strength, stimulating linear growth, and helping bone maturation – all this results in a larger size and weight in male dogs compared to female dogs of the same breed.

Testosterone also stimulates the development of the penis during puberty, the function of the prostate (a male accessory sex gland) and the activation of sperm production. Testosterone peaks in male dogs between 6 and 12 months of age and then begins to plateau. As soon as a male is neutered, testosterone production stops.

The ovaries are the female gonads that produce the eggs (reproductive cells) and the female hormones estrogen (a compound term for the estradiol, estriol and estrone) and progestin.

Estrogens are produced by the cells of the ovarian follicles and are responsible for the development of female secondary sexual characteristics, which help in the maturation of the reproductive organs, control of the reproductive system, and the behavioral and physical changes in preparation for breeding.

Progestins and especially progesterone are produced by the corpus luteum, a cell mass that develops from the empty follicle after ovulation. They help prepare the uterus for the implantation of the fertilized egg, maintain the pregnancy, and promote the development of the mammary glands.

The adult male dog’s testes continuously produce spermatozoa and hormones. In contrast, adult female canines produce reproductive cells in cycles that occur about every six months.

The oestrus cycle is controlled by follicle-stimulating hormone (FSH) and luteinizing hormone (LH) from the anterior pituitary gland. Simultaneously with this short ovulation period, estrogen levels rise, followed by an increase in progesterone levels. After ovulation, progesterone levels remain high for several weeks, even if the dog has not become pregnant. When a bitch does not have oestrus, her estrogen and progesterone levels are low.

In addition to these reproductive-based tasks, the dog’s hormones act as chemical messengers with far-reaching and diverse roles in the body – and likely include some that have yet to be identified. It should come as no surprise, then, that researchers studying the effects of gonadectomy on dogs keep getting results that need further investigation.

A brief history of spay / neuter

E.In the 20th century in the United States, the majority of dogs never saw a veterinarian. Very few have undergone a procedure that would prevent their reproduction. (If so, spays were often carried out at the age of 3 to 6 months and castration after four weeks!)

M.Until the late 1960s and early 1970s, when the stray dog ​​population grew large enough to cause problems in human society, including dog bites, fear of rabies, and the cost of public animal control, all dogs were allowed to move for better or worse Authorities have had to deal with dogs and dog-related human health hazards.

B.In the early 1970s, animal control agencies confiscated millions of dogs and killed most of them every year. In a 1973 survey of animal shelters, the Humane Society of the United States (HSUS) estimated that 13.5 million dogs and cats were euthanized by animal shelters nationwide. This number of euthanized animals eventually sparked enough outrage for society to try to resolve the problem.

IIt was recognized from the beginning that efforts to prevent dog breeding are an important weapon in the war against pet overpopulation, with spay / neuter surgery being the most common method of sterilization for dogs.

P.Up until that point, in the unusual case of a veterinarian recommending the procedure to a dog owner, it was presented as a convenience – a way to reduce behaviors that many owners found problematic, such as dog grooming. B. Strays – as well as puppies as a way to prevent undesirable behavior. However, from the mid-1970s onwards, dog owners were encouraged to acknowledge promoting the wellbeing of the entire dog population when their dog’s potential to contribute to the homeless dog population was eliminated.

ÖFor the next four decades, the practice of routine spay / neuter surgery became the social norm in this country. An estimated 85% of service dogs in the United States have had an elective gonadectomy. According to the American Veterinary Medical Association (AVMA), there are currently no state or federal laws mandating a gonadectomy of all dogs in the United States, and the AVMA does not endorse any regulations or laws that would spay / neuter dogs that are privately owned and not a shelter are, prescribe and cats. “Some states have proposed mandatory gonadectomy laws, although none have been successful. However, there are cities and other local governments that have proposed and passed ordinances on neutering laws. Many communities are charging higher royalties for intact dogs, sterilization for dogs that are considered malicious or dangerous , as well as gonadectomies for all protection animals before release.

Where are things today? There are no statistics available to show that the rate of spay / neuter compliance is decreasing. However, conversations among dog owners today show an increased awareness of the possible adverse effects of the procedure. No mention of spay / neuter practices can be made online or in print without comment from owners who are convinced by the critical literature (or their personal experiences) that spay / neuter practices are unmistakably and clearly harmful.

We’re not so sure.

Understanding history can guide our decisions today. Nobody wants to return to a world where more than 13 million dogs are killed in animal shelters annually, and we know that not all dog owners are able to prevent their intact dogs from reproducing. As history continues, we look forward to studies that will allow researchers to make more targeted recommendations so that each owner can find information that will prevent them from choosing a course of action that will harm their dog more than will help the entire canine population.


The following is an overview of the main problem areas related to the possible harmful effects of neutering / neutering on dogs and the results of relevant studies. The studies mentioned in the following text (which are fully referenced on page 22) are among the most frequently cited in discussions in the veterinary literature.

life span

Overall, spay / neuter appears to be associated with longer lifespans. Note, however, that most of the studies that came to this conclusion looked only at gonadectomy (as opposed to other sterilization methods) and usually did not consider the age of spay / neuter.

In addition, the appearance of spay / neuter can increase the likelihood of better husbandry and veterinary care, which theoretically has a positive effect on life expectancy.

In the retrospective study by Hoffman et al. (2013) analyzed the records of more than 40,000 spayed and intact domestic dogs listed in the Veterinary Database (a collection of data from veterinary teaching hospitals) for associations between gonadectomy and lifespan and causes of death. It was found that spayed dogs lived an average of 1.5 years longer than intact dogs, and life expectancy increased by 13.8 percent in men and 26.3 percent in women.

Studies have shown that intact dogs are more likely to be abandoned than dogs that have been neutered or neutered.

The study also found that intact dogs were more likely to die from infectious diseases, trauma, vascular disease, and degenerative diseases, and spayed dogs were more likely to die from neoplasia (including an increased likelihood of transitional cell carcinoma, osteosarcoma, lymphoma, and mast cell cancer) and immune-mediated diseases. No causal link was found; Note that gonadectomized dogs live longer and cancer is more common in older dogs.

The data set did not include the age at which a dog was neutered or neutered, or whether a dog had reproduced before the gonadectomy.

The results of the Hoffman study were supported by the 2013 Banfield State of Pet Health 2013 report, which examined data from Banfield facilities across the country and included 2.2 million dogs.

Orthopedic concerns

The literature review by Houlihan (2017) deals with research into diseases of the musculoskeletal system and possible associations with spay / neuter. Several studies have shown that gonadectomy is a risk factor for developing cruciate ligament disease (CLD) and hip dysplasia (HD) in both male and female dogs.

Huntington’s disease has a high genetic component but is recognized as a multifactorial disease. The incidence of CLD tends to occur in young, active large breed dogs for degenerative or traumatic reasons, but has also been linked to aging, conformational disorders, and immune-mediated joint problems.

One focus of recent research is assessing the tibial plateau angle (TPA) – the slope at the top of the tibia. The steeper the TPA, the more stress is placed on the ligament, leading to an increased risk of CLD. Studies have shown that the TPA is steeper in dogs that undergo a gonadectomy before the tibial growth plates are closed. However, the risk may have a racial predisposition: Hart et al. (2014) found that the risk of CLD increased in golden retrievers gonadectomized between 6 and 11 months of age, but the risk for Labrador Retrievers did not increase when they underwent gonadectomy of the same age.

In a study of 759 customer-owned Golden Retrievers, Torres et al. (2013) The Effects of Spay / Neuter on Joint Disease and Cancer. The authors note, “An important point is that the results of this study, which are breed specific for the effects of early and late neutering, cannot be extrapolated to other breeds or dogs in general.”

It is well documented that both testosterone and estrogen play important roles in the growth and maturation of bones. Decreases in bone density in castrated beagles have been reported in one study, but these results have yet to be reproduced in subsequent studies.

An increased concern is whether gonadectomy affects the closure of growth plates (physes). Salmeri et al. (1991) found that overall spay / neuter growth rates did not appear to be affected, although prepubertal gonadectomy was associated with delayed closure, resulting in lengthening of the associated limb bones. Although this may be statistically relevant, it is not readily apparent or is classified as clinically relevant.

The age at which the growth plates close depends on race, genetic factors and disorders, physiological conditions, diseases, and nutritional conditions (unbalanced or incomplete diets can lead to stunted growth). Certain categories of breeds, such as working, herding, and sporting breeds, are generally more prone to orthopedic disorders. Dogs with a large stature or large substance, in particular, have a higher risk of hip and elbow dysplasia (Oberbauer et al., 2019).

Spain et al. (2004) found no specific correlation between age at spay / neuter and the incidence rate of arthritis or long fractures, including physical fractures. This retrospective study at the SPCA in Erie County, New York looked at 1,842 dogs who had undergone spay or neuter surgery between the ages of 6 weeks and 12 months. Dogs that had the procedure before 5.5 months of age had a higher incidence (6.7%) of hip dysplasia and were diagnosed at an earlier age than dogs that underwent the procedure at old age of 5.5 months or older (4.7%). .

Dogs that had spay / neuter surgery older than 5.5 months were three times more likely to be euthanized for hip dysplasia than dogs that had surgery when they were younger. This suggests that early gonadectomy may be linked to a less severe form of Huntington’s disease.

Estrogen has a number of metabolic functions and its effects on muscles, tendons and ligaments has become the focus of further research. Chidi-Ogbolu and Baar (2019) found that while estrogen improves muscle mass and strength and increases the collagen content of connective tissue, it reduces the stiffness of tendons and ligaments, which can have a direct impact on performance and injury rate. (Risk of cruciate ligament of the skull [CCL]injury appears to be increasing with the spay / neuter in both the general dog population and the individual breeds studied.)

Kustriz (2007) found no studies at this point in time that implied changes in physical closure with subsequent asynchrony of long bone growth and abnormalities in joint formation as the cause of CCL ruptures in dogs.

Study considerations

When you read (or read about In any study that contains information about the benefits or dangers of spay / neuter, it is important to identify and keep an eye on the limitations of the study. Not all study results are relevant to everything Dogs.

Most research on the health effects of spay / neuter is retrospective. Researchers examine past and current medical records for a specific dog population and look for patterns and trends to develop hypotheses. These retrospective studies can only reveal associations; Some can be confusing while others are educational and meaningful.

It is difficult to assess the effects of spay / neuter and the resulting loss of hormones on dog health. The multifactorial nature of many diseases can affect the ultimate determination of the cause. In humans, for example, areas of study related to the development of cancer include factors such as age, gender, ethnicity, diet, occupation and environment, creating a complex set of potential health effects. Rarely are such factors considered in veterinary studies, but research is beginning to expand to include these considerations.

As you look at the conclusions of a study, remember to assess the overall incidence rates for diseases of concern. When an overall rate is rare or low and a study shows the likelihood of spay / neuter increases, the overall risk remains rare or low. Kustritz (2007) categorized 11 different dog conditions based on their incidence rates of rare, low, medium, or high. These high-rated conditions (breast neoplasia, pyometra, benign prostatic hypertrophy) as well as one in the moderate category (testicular tumors) all showed a decrease in impact when gonadectomized. Conditions classified as rare (transitional cell carcinoma), low (prostate tumors, osteosarcoma, hemangiosarcoma, cruciate ligament disease, hypothyroidism), and moderate (urinary incontinence) have been shown to increase with the spay / neuter, but even with an increase, the overall risk remains low.

Biases can affect the value of a research study, even if it is unintentional. Recall bias may occur in studies where owners are asked to provide information; The veracity of owners’ reports about their dogs can be very problematic. Choice bias occurs when selection of a group for the study does not achieve proper randomization. Many studies are affected by this bias because the data sets often come from records in veterinary teaching / referral hospitals. This leaves out a percentage of dogs in the general population whose diseases have not been reported to veterinarians (which also skews disease incidence rates because they are not reported). Additionally, dogs treated in these hospitals are usually from higher- and middle-income owners and tend to have conditions that are treatable to some degree.

After all, studies often only cover one breed of dog, which leads to a Racial bias; Studies of this type cannot be extrapolated to all breeds, but they sometimes provide useful information.


Behavior is the result of a complex interaction between genetics and the environment. It has been found that spay / neuter can mitigate some behaviors – and that’s about as far as the data can take you. The few effects that were studied and found to be statistically relevant were generally positive.

Studies generally report that spay / neuter reduces libido and associated reproductive behavior. Castrated females tend not to engage in the behaviors associated with oestrus and therefore do not seek breeding opportunities.

Castrated men tend to show decreases in roaming, intermal aggression, montage and urine marking behavior. There is consistent evidence that the frequency of urine marking does so Not depend on age at gonadectomy.

Kustritz (2007) reported that neither the reproductive status nor the age at the time of castration impair the training ability of working dogs.

According to Duffy and Serpell (2006), changes in behavior are difficult to measure; The parameters with which they are measured are too subjective. Race, gender, and individual differences must be considered when examining the manifestation of behavior change after spay / neuter. As a result, there is no clear consensus on the real impact.

Furthermore, the interpretation of the literature on behavior change is further complicated by different definitions of aggression (Houlihan, 2017); As a result, evidence of the influence of gonadectomy on aggressive behavior is inconsistent and sometimes contradicting.

Kustritz (2007) reported that several studies in female dogs showed increased reactivity towards humans after Spay. It is believed that this may be due to a decrease in levels of estrogen and oxytocin. Additionally, testosterone has been shown to increase confidence; This can be useful for shy dogs, but not for cocky dogs.

Reproductive system

Spay surgery has been shown to have beneficial effects on life-limiting diseases in bitches. Not only does it eliminate the risk of pyometra, uterine and ovarian cancer, but it also reduces the risk of breast cancer.

Research into the impact of spaying on breast cancer is extensive. Dorn et al. (1968) found that there is strong evidence that ovarian hormones are essential for the development of most breast cancer cases, so removal of the ovaries reduces this risk. Subsequent studies have continued to support the protective effects of early spay.

The greatest benefit is obtained if the spay occurs before the first oestrus; The rates given are 0.05% before oestrus, 8% after the first oestrus, and increase to 26% after the second oestrus cycle (Schneider et al., 1969). The rate of breast cancer in dogs increases sharply with age. Purebred dogs have been shown to have twice the rate of breast cancer compared to mixed breed dogs of the same age. The incidence rate of breast neoplasia is estimated to be about 3.4%, with about 50% being benign fibroadenomas and 50% being malignant adenocarcinomas.

Castration removes the risk of testicular cancer (if the testicles are removed) in men. Castration also reduces the risk of age-related prostate problems, benign prostatic hyperplasia (common but not generally life-limiting), and perianal adenomas.

Several studies showing that testicular neoplasms are common in older (mean age 10 years) intact male dogs; However, metastases are rare and castration at diagnosis is curative. Benign prostatic hypertrophy is common in intact male dogs as well (63.4% in one study). It tends to manifest itself in 50% of dogs by the age of 2-3 years and in 75-80% by the age of 6 years. Castration leads to a reduction in prostate size, which leads to a reduction in clinical symptoms (Kustritz, 2007).


The literature review by Urfer and Kaeberlein (2019) reports that there are many studies that provide evidence of an increase in cancer risk in dogs of both sexes who have undergone gonadectomy. Smith (2014) summarized that after castration, male dogs were at increased risk of developing cardiac tumors, osteosarcomas, prostate tumors, transitional cell carcinomas and lymphomas, while the risk of testicular cancer decreased.

Female dogs were at increased risk of cardiac tumors, cardiac and splenic hemangiosarcoma, osteosarcoma, mast cell tumors and lymphoma after Spay, while the risk of ovarian, uterine and breast cancer decreased.

Many of the studies did not consider age – which is arguably the most important factor in tumor development. However, taking age into account, it was found that increased age is a higher risk factor than spay / neuter.

Es wurde gesagt, dass Krebs letztendlich das Ergebnis einer fehlgeschlagenen Immunüberwachung ist. Es wird vermutet, aber noch nicht bewiesen, dass krebsjagende Immunzellen in gewissem Maße von Signalen der Sexualhormone abhängen, um diese Überwachung durchzuführen. Forscher haben spekuliert, dass die krebsjagenden Immunzellen bei dieser Aufgabe bei gonadektomierten Hunden aufgrund des Mangels an hormonellen Signalen möglicherweise weniger wirksam sind.

In der rassenspezifischen retrospektiven Studie von Kent et al. (2018) war das Timing von Spay / Neutrum für die meisten Golden Retriever nicht verfügbar. Während in der Studie Krebs als Todesursache bewertet wurde, konnte der Zusammenhang zwischen hormoneller Exposition über die Lebensspanne oder dem Risiko des Todes durch Krebs weder bewertet werden, noch war er Teil der Bewertung des Krebsentwicklungsrisikos. Da bekannt ist, dass Golden Retriever ein hohes Krebsrisiko haben, können diese Ergebnisse nicht auf andere Rassen übertragen werden.

Die Studie von Cooley et al. (2002) ergab, dass Rottweiler beiderlei Geschlechts, die sich einem frühen Spay / Neutrum unterzogen hatten, im Vergleich zu Rottweilern, die während ihres gesamten Lebens intakt waren, ein höheres Risiko für ein Knochensarkom hatten (1 zu 4). Die Studie bestätigt jedoch, dass nicht bekannt ist, wie Hormone die Entwicklung eines Osteosarkoms beeinflussen. Makielski et al. (2019) veröffentlichten eine vergleichende Übersicht über Osteosarkom-Risikofaktoren bei Hunden und Menschen und schlossen diesen Kommentar zu aktuellen aktuellen Hormonstudien ein:

„… Die Assoziationen zwischen dem Fortpflanzungsstatus und der Entwicklung eines Osteosarkoms waren inkonsistent. Obwohl mehrere Berichte darauf hinweisen, dass kastrierte und / oder kastrierte Hunde häufiger an bestimmten Krebsarten leiden, einschließlich Osteosarkom, kann die Beziehung zwischen dem Fortpflanzungsstatus und dem Krebsrisiko durch andere Variablen wie die dokumentierte Tendenz zu erhöhter Adipositas und Körperzustand bei gonadektomierten Hunden verwechselt werden . ”


Bei Hunden wird Fettleibigkeit durch Ernährung, Rasse, Aktivitätsniveau und Alter beeinflusst. Es wurde jedoch auch berichtet, dass Spay / Neutrum ein häufiger prädisponierender Risikofaktor für ein erhöhtes Körpergewicht ist. Es gibt widersprüchliche Informationen darüber, ob die Gonadektomie den Stoffwechsel verändert (Reichler, 2009). Es wird spekuliert, dass gonadektomierte Hunde im Allgemeinen niedrigere Stoffwechselraten haben (es wurde geschätzt, dass sie bis zu 30% weniger Kalorien benötigen) und tendenziell mehr an Gewicht zunehmen als intakte Hunde, jedoch ist die Ursache-Wirkungs-Beziehung nicht genau definiert .

Hunde, die kastriert oder kastriert wurden, haben häufig niedrigere Stoffwechselraten und sind möglicherweise für Fettleibigkeit prädisponiert.

Spain et al. (2004) führten eine Bevölkerungsstudie durch, die ergab, dass die Gonadektomie von Hunden vor dem 6. Lebensmonat mit einer geringeren Prävalenz von Fettleibigkeit verbunden ist als bei Hunden, die sich nach dem 6. Lebensmonat einer Gonadektomie unterziehen.

Im Jahr 2019 veröffentlichten Bjørnvad et al. Eine Studie über hunde- und besitzerbezogene Risikofaktoren für Fettleibigkeit bei dänischen Begleithunden. Die Forschung ergab, dass kastrierte männliche Hunde ein erhöhtes Risiko für Fettleibigkeit hatten; Es wird vermutet, dass dies auf eine Verringerung des Testosterons und eine anschließende Senkung des Grundumsatzes zurückzuführen ist. Es wurde festgestellt, dass Hündinnen unabhängig vom Fortpflanzungsstatus einem Risiko ausgesetzt sind. Sie fanden auch heraus, dass es einen komplexen Zusammenhang zwischen dem Gewicht des Besitzers, dem Gewicht des Hundes und den Ernährungsgewohnheiten gab.


In Studien liegt die Inzidenz von Harninkontinenz bei kastrierten Hündinnen bei 4% bis 20%, verglichen mit einer Rate von 0,4% bis 8% bei intakten Frauen. Kastrierte Hunde können innerhalb von Tagen nach der Operation oder häufiger Jahre später Inkontinenz entwickeln. es wird typischerweise mit der Behandlung kontrolliert. Große und riesige Rassen scheinen ein höheres Risiko zu haben. Andere Faktoren, die zur Erkrankung beitragen können und einer weiteren Bewertung bedürfen, sind die Harnröhrenlänge, die Ruheposition der Harnblase, die Rasse, der Schilddrüsenspiegel, Allergien und der Grad der Fettleibigkeit.

Studien sind widersprüchlich, wenn es darum geht, eine Korrelation zwischen dem Alter zum Zeitpunkt der Spay und der Wahrscheinlichkeit einer Inkontinenz zu bestimmen. Spain et al. (2004) und Thrusfield et al. (1998) berichteten über einen Anstieg der Harninkontinenz bei Frauen, die in einem frühen Alter kastriert wurden. Andere Studien haben diese Schlussfolgerung jedoch nicht bestätigt. Weitere Forschung ist erforderlich, aber in diesen Studien, dass tat Finden Sie eine Korrelation, es war nur mit pädiatrischer (6-12 Wochen) Gonadektomie assoziiert. Es wurde auch berichtet, dass Frauen, die in einem frühen Alter kastriert wurden, eine etwas höhere Inzidenz von Blaseninfektionen hatten, aber diese Infektionen waren leicht zu behandeln und wurden nicht chronisch.

It has been theorized that it is the lack of estrogen that causes incontinence in spayed females, but this is controversial and not fully supported by research. Increased rates of incontinence are not reported in pregnant females even though they have extremely low estrogen levels during pregnancy.

Palm and Reichler (2012) report that incontinence in spayed dogs has been successfully treated with use of gonadotropin-releasing hormone (GNRH) superagonist implants. The implants work by suppressing the release of gonadotropins.

In contrast, surgical gonadectomy increases the release of gonadotropins. This suggests that an increased risk for incontinence is not caused by the lack of sex hormones, but rather by the increased levels of gonadotropins induced by removal of the ovaries.

Male dogs who have been castrated prepubertally tend to have a smaller penis and prepuce, but their urethral diameter and function are the same as dogs neutered later and no clinical significance or condition has been associated with this difference (Salmeri et al, 1991).

Immune System

Findings from Sundberg et al (2016) suggest that spay/neuter is associated with an increased risk for certain autoimmune disorders. Six of the 11 immune diseases evaluated (atopic dermatitis, autoimmune hemolytic anemia, Addison’s disease, hypothyroidism, immune-mediated thrombocytopenia, and inflammatory bowel disease) showed an increased prevalence in gonadectomized dogs.

The study notes that even though the dataset included more than 90,000 dogs and expression of the diseases were statistically relevant, the actual incidence rate was not high and it declined over the 15-year evaluation.

Given that this was a retrospective study limited to dogs seen at a referral veterinary hospital, it may not reflect incidence rates within the population at large but rather may be biased to complex or more severe cases.

Cognitive Function

There has been limited research conducted on the risk that cognitive function may be altered as a result of spay/neuter. A comparison of the progression of cognitive dysfunction in intact and castrated male dogs was performed in the Hart study (2001) with a small sample size (6 dogs); it revealed a slowing of progression in the intact dogs.

In contrast, a 2000 study by Waters et al found that intact Beagles showed DNA damage to the neurons in the brain when compared to castrated Beagles (again, sample size was small, with only four dogs in each group). This is an area of research that is just beginning to be explored. Much more research is needed to understand the processes that influence cognitive function and how they may be changed by spay/neuter.


Statistically, puppies are less likely to die under anesthesia and recover faster from gonadectomy than their adult counterparts. Complications arising from the procedure are uncommon and the rates are consistent across ages.

Doing what you think is right

Parker, handsome and sound at two

In 2018, my five-month-old, intact Border Collie began to display an abnormal outward turn to his left front leg. Parker’s orthopedic surgeon diagnosed him with an early closure of the ulnar growth plate, probably as a result of inury. The ulna ceased growing while the radius continued to lengthen. The radius began to bow as it was restricted by the nongrowing ulna, resulting in the outward splay of the leg. Ultimately, his leg was repaired within a few degrees of normal through a series of surgeries as he grew.

Knowing that my young pup faced multiple surgeries, I did not want to have to put him through an additional anesthetic for neuter surgery within the next year and opted to have his gonadectomy done during one of his orthopedic procedures.

Parker’s intact male littermate, Hero.

Some friends questioned my decision when they heard that I was going to have my young dog neutered, citing unnamed “studies” alleging that early spay/neuter can have a disastrous effect on the bones and growth plates. I researched all the studies I could find – and concluded that they were limited in scope. But I ebenfalls consulted with his orthopedic surgeon (one who treats a great number of canine athletes). He related that he had not seen any negative effect of early spay/neuter in the animals he treated. I was aware that this was anecdotal evidence, but if the person working on the bones of agility dogs wasn’t seeing anything he could relate to early spay/neuter, that was good enough for me.

Two years later my boy is happy, healthy, and active with no residual orthopedic concerns. His appearance is similar to his dad (intact), mom (recently spayed), and sister (intact) from another litter, but not so much like one of his intact male littermates. Is this a result of the lack of testosterone? Or due to his own individual genetic structure and environment? Did neutering him “early” (at 6 months of age) predispose him to cancer and other health concerns? While I may wonder about these issues, I am confident that I made the best decision I could for me and my dog at that time.

Parker’s dam, Honey, was recently spayed.
Parker most resembles his intact full sister, Wynnie.
Parker’s sire, Flash, was intact throughout his lifetime.


Even a minimal survey of the research regarding the effects of spay/neuter reveals that the situation is extremely complex and, at times, ambiguous. There is evidence to support correlations for both beneficial and adverse effects, but even more important is that it demonstrates how much we still don’t understand about reproductive hormones and the consequences of spay/neuter.

When the time comes for you to make spay/neuter decisions for a dog that you do not want to reproduce, remember: There is no single course of action that is “best” for all dogs and all owners, and don’t let anyone make you feel bad for your decision, whatever it is – that is, as long as it doesn’t end with an accidental breeding and unwanted puppies.

Here’s the one time that we feel it makes the most sense for an owner to give more weight to published research than their own preferences: when the person owns a purebred dog of a breed that has been the subject of large, well-respected studies of the effects of spay/neuter on dogs of that specific breed, and the study found clear and significant statistical advantages to a certain course of action. In that case, we would strongly recommend reading the conclusion of those studies and discussing them with your veterinarian. Oberbauer et al (2019) determined that many canine health disorders reflect the dogs’ genetic heritage. Within breeds, there may be shared genetic susceptibility that increases risk for certain diseases within breeds and this risk may be enhanced with neutering.

However, you have to take single-breed studies with a grain of salt if your dog does not share any of the subject breed’s genes. Some of these studies are widely cited by people who think the studies should inform the decisions of alles dog owners, but the findings often are contradicted when applied to another breed.

Some people strongly believe that it’s unethical to spay or neuter dogs, because the procedure irretrieveably alters the dog’s physiology and might might cause an adverse side effect, perhaps years in the future. As we have described, however, intact dogs are ebenfalls prone to adverse health conditions; there simply isn’t a choice that doesn’t have consequences!


As we’ve stated elsewhere in this article, it has become sort of politically correct today to maintain a dog in his or her intact state. But this isn’t something that everyone can manage in a responsible fashion! If there is a single weak link in a household, whether it’s a forgetful child, a distracted adult, or a less-than-super-secure fence, accidents can and will happen.

We know owners who swear their female dogs never left their sides and had zero contact with another dog, and yet – poof, a virgin pregnancy? Doubtful, and irresponsible, too.

And while some people will try to make you feel bad about it, it’s okay to admit that you do not enjoy living with an intact dog of either sex! If you have grown up in a time and place where literally all the dogs you’ve ever known were neutered, you might be quite alarmed at the personality change exhibited by your female dog when she comes into heat. You may not feel comfortable with some of the more strongly masculine attributes of an intact male dog, which may include more competitive urine-marking, humping, or overzealous sexual interest in female dogs.

Also, there are many people who are strongly committed to adopting only from shelters or rescue organizations, where spay/neuter is not only mandated but might also have been performed on very young puppies. Not only is prepubertal gonadectomy an important tool against pet overpopulation, it is likely to improve the odds that dogs will be retained by their owners. Studies have found that intact dogs are more likely to be relinquished than those that have undergone spay or neuter.

For intact dogs with homes, veterinarians and owners are challenged with making the best decision for that specific dog. An informed decision requires an evaluation reflective of our dogs and our risk tolerances. Every dog is an individual, including how they respond to gonadectomy or remaining intact. We always recommend consulting with your veterinarian to determine the best strategy for your dog based on age, body condition, breed, genetics, lifestyle, behavior, temperament, and reproduction management – and then taking responsibility for your choice.

Spay/Neuter Study References

If you’ve gotten this far, we applaud you! It’s a lot of information! But if you want to delve even more deeply into the research on the possible health effects of spay/neuter, this list is a great resource. It’s impossible to mention every study on the subject, but this list includes all the studies referenced in the foregoing article as well as other frequently cited works.

Banfield Applied Research and Knowledge Team. “Banfield Pet Hospital State of Pet Health 2013 Report, Trends of Life Spans for Dogs and Cats.”

Bentley A, Thalheim L. “Controversies in spaying and neutering: Effects on cancer and other conditions.” Cornell University Veterinary Specialists, Stamford, CT.

Bjørnvad CR, Gloor S, Johansen SS, et al. “Neutering increases the risk of obesity in male dogs but not in bitches: A cross-sectional study of dog- and owner-related risk factors for obesity in Danish companion dogs.” Prev Vet Med 2019; 170:104730.

Chidi-Ogbolu N, Baar K. “Effect of estrogen on musculoskeletal performance and injury risk.” Front Physiol 2019; Jan 15; 9:1834.

Cooley DM, Beranek BC, Schlittler DL, et al. “Endogenous gonadal hormone exposure and bone sarcoma risk.” Cancer Epidemiol Biomarkers Prev 2002; 11: 1434–1440.

Dorn CR, Taylor D, Schneider R, et al. “Survey of animal neoplasms in Alameda and Contra Costa Counties, California.” J Natl Cancer Inst 1968; 40:307-318.

Duffy DL, Serpell JA, Hsu Y. “Breed differences in canine aggression.” Appl Anim Behav Sci 2008; 114:441–460.

Duffy DL, Serpell JA. “Non-reproductive effects of spaying and neutering on behavior in dogs. Presentation from proceedings of the 3rd International Symposium on Non-Surgical Contraceptive Methods for Pet Population Control, 2006.” Alliance for Contraception in Cats & Dogs.

Duval JM, Budsberg SC, Flo GL. “Breed, sex, and body weight as risk factors for rupture of the cranial cruciate ligament in young dogs.” J. Am Vet Med Assoc 1999; 215: 811–814.

Farhoody P, Mallawaarachchi I, Tarwater PM, et al. “Aggression toward familiar people, strangers, and conspecifics in gonadectomized and intact dogs.” Frontiers in Veterinary Science 2018; 5:18.

Grumbach M. “Estrogen, bone growth and sex: a sea of change in conventional wisdom.” J Ped Endocrinol Metab 2000; 13: 1439–1455.

Hart BL, Eckstein RA. “The role of gonadal hormones in the occurrence of objectionable behaviors in dogs and cats.” Appl Anim Behav Sci 1997; 52: 331–344.

Hart BL, Hart LA, Thigpen AP, et al. “Neutering of German Shepherd Dogs: Associated joint disorders, cancers and urinary incontinence.” Vet Med Sci 2016; 2: 191–199.

Hart BL, Hart LA, Thigpen AP, Willits NH. “Long-term health effects of neutering dogs: comparison of Labrador Retrievers with Golden Retrievers.” PLoS ONE 2014; 9: e102241.

Hoffman JM, Creevy KE, Promislow DE. “Reproductive capability is associated with lifespan and cause of death in companion dogs.” PLoS ONE 2013; 8: e61082.

Houlihan KE. “A literature review on the welfare implications of gonadectomy of dogs.” J Am Vet Med Assoc 2017; 250(10):1155–1166.

Howe LM, Slater MR, Boothe HW, et al. “Long-term outcome of gonadectomy performed at an early age or traditional age in dogs.” J Am Vet Med Assoc 2001; 218: 217–221.

Howe LM. “Current perspectives on the optimal age to spay/castrate dogs and cats.” Vet Med (Auckl). 2015 May 8;6:171-180.

Howe LM. “Prepubertal gonadectomy in dogs and cats, part I.” Compend Contin Educ Pract Vet 1999; 21: 103–110.

Howe LM. Rebuttal to “Early Spay Neuter Considerations for the Canine Athlete,” 2007.“-Early- spay/neuter-Considerations-for-Howe/f9c144ef90d398772af99856d6ec2518ae1a47a8Semantic Scholar.

Kent M, Burton J, Rebhun R. “Association of cancer-related mortality, age and gonadectomy in Golden Retriever dogs at a veterinary academic center.” (1989-2016). PLoS One 2018; 13(2): e0192578.

Kustritz MV. “Determining the optimal age for gonadectomy of dogs and cats.” J Am Vet Med Assoc 2007; 231: 1665–1675.

Kustritz MV. “Pros, cons, and techniques of pediatric neutering.” Vet Clin North Am Small Anim Pract 2014; 44: 221–223.

Makielski, K., Mill, L., Sarver, A., et al. “Risk factors for development of canine and human osteosarcoma: A comparative review.” Vet. Sci 2019, 6(2), 48.

Oberbauer A, Keller G, Fanukla T. “Long-term genetic selection reduced prevalence of hip and elbow dysplasia in 60 dog breeds.” PLoS ONE 2017 12:e0172918.

Oberbauer, AM, Belanger, JM, & Famula, TR. “A review of the impact of neuter status on expression of inherited conditions in dogs.” Frontiers in Veterinary Science 2019; 6:397

Palm J, Reichler IM. “The use of deslorelin acetate (Suprelorin®) in companion animal medicine.” Schweiz Arch Tierheilkde 2012, 154, 7-12.

Reichler IM, Hubler M, Jöchle W, et al. “The effect of GnRH analogs on urinary incontinence after ablation of the ovaries in dogs.” Theriogenology 2003; 60(7):1207–1216.

Reichler IM. “Gonadectomy in cats and dogs: a review of risks and benefits.” Reprod Domest Anim 2009; 44: 29–35.

Salmeri KR, Bloomberg MS, Scruggs SL, et al. “Gonadectomy in immature dogs: effects on skeletal, physical, and behavioral development.” J Am Vet Med Assoc 1991; 198: 1193–1203.

Salmeri KR, Olson PN, Bloomberg MS. “Elective gonadectomy in dogs: A review.” J Am Vet Med Assoc 1991; 198: 1183-1192.

Schneider R, Dorn CR, Taylor DO. “Factors influencing canine mammary cancer development and postsurgical survival.” J Natl Cancer Inst 1969; 43: 1249–1261.

Serpell J, Hsu Y. “Effects of breed, sex, and neuter status on trainability in dogs.” Anthrozoos: A Multidisciplinary Journal of The Interactions of People & Animals 2005; 18: 196-207.

Smith AN. “The role of neutering in cancer development.” Vet Clin North Am Small Anim Pract 2014; 44: 965–975.

Spain CV, Scarlett JM, Houpt KA. “Long-term risks and benefits of early-age gonadectomy in dogs.” J Am Vet Med Assoc 2004; 244: 380–387.

Sundburg CR, Belanger JM, Bannasch DL, et al. “Gonadectomy effects on the risk of immune disorders in the dog: A retrospective study.” BMC Vet Res 2016; 12: 278.

Torres de la Riva G, Hart BL, Farver TB, et al. “Neutering dogs: Effects on joint disorders and cancers in Golden Retrievers.” PLoS ONE 2013; 8: e55937.

Urfer SR, Kaeberlein, M. “Desexing Dogs: A Review of the Current Literature.” Tiere 2019; 9(12):1086.

Von Pfeil DJ, DeCamp CE, Abood SK. “The epiphyseal plate: Nutritional and hormonal influences; hereditary and other disorders.” Compend Contin Educ Vet 2009; 31(8):E1–E14.

Waters DJ, Kengeri SS, Clever B, et al. “Exploring mechanisms of sex differences in longevity: Lifetime ovary exposure and exceptional longevity in dogs.” Aging Cell 2009; 8: 752–755.

Waters DJ, Shen S, Glickman LT. “Life expectancy, antagonistic pleiotropy, and the testis of dogs and men.” Prostate 2000; 43: 272–277

Zink MC, Farhoody P, Elser SE, et al. “Evaluation of the risk and age of onset of cancer and behavioral disorders in gonadectomized Vizslas.” J Am Vet Med Assoc 2014; 244: 309–319.

Barbara Dobbins, a former dog trainer, writes about dogs and studies canine ethology. She lives in the San Francisco Bay area with her dogs, Tico and Parker.

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