Neutering, from the
Latin (, or , ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through ...
''neuter'' ('of neither sex'), is the removal of an animal's
A sex organ (or reproductive organ) is any part of an animal or plant that is involved in sexual reproduction. The reproductive organs together constitute the reproductive system. In animals, the testis in the male, and the ovary in the female, ...
, either all of it or a considerably large part. The male-specific term is castration, while spaying is usually reserved for female animals. Colloquially, both terms are often referred to as fixing. In male horses, castrating is referred to as '' gelding
''. An animal that has not been neutered is sometimes referred to as ''
Entire may refer to:
* Entire function, a function that is holomorphic on the whole complex plane
* Entire (animal), an indication that an animal is not neutered
* Entire (botany)
This glossary of botanical terms is a list of definitions of ...
'' or ''intact''.
Neutering is the most common method for animal
Sterilization may refer to:
* Sterilization (microbiology), killing or inactivation of micro-organisms
* Soil steam sterilization, a farming technique that sterilizes soil with steam in open fields or greenhouses
* Sterilization (medicine) rende ...
. Humane societies
, animal shelter
An animal rescue group or animal rescue organization is a group dedicated to pet adoption. These groups take unwanted, abandoned, abused, or stray pets and attempt to find suitable homes for them. Many rescue groups are created by and run by ...
s urge pet owners to have their pets neutered to prevent the births of unwanted litters
, which contribute to the overpopulation of unwanted animals in the rescue system
. Many countries require that all adopted cats and dogs be sterilized before going to their new homes.
Methods of sterilization
Spaying is the surgical removal of the ovaries and uterus in female animals. It is commonly performed as a method of birth control and
Behavior modification is an early approach that used respondent and operant conditioning to change behavior. Based on methodological behaviorism, overt behavior was modified with consequences, including positive and negative reinforcement conti ...
In non-human animals, the technical term is an ovo- hysterectomy
or ovariohysterectomy; while in humans, this is called a hystero- oophorectomy
. One form of spaying is to remove only the ovaries (oophorectomy or ovariectomy), which is mainly done in cat
s and young dog
s. Another, less commonly performed method is an "ovary-sparing spay" in which the uterus is removed but one (or both) ovaries are left. A complete ovariohysterectomy may involve removal of the ovaries, uterus, oviduct
s, and uterine horns
The surgery can be performed using a traditional open approach
or by laparoscopic "keyhole" surgery
. Open surgery is more widely available, as laparoscopic surgical equipment costs are expensive. Traditional open surgery is usually performed through a ventral midline incision below the umbilicus
. The incision size varies depending upon the surgeon and the size of the animal. The uterine horns are identified and the ovaries are found by following the horns to their ends.
There is a ligament that attaches the ovaries to the body wall, which may need to be broken down so the ovaries can be identified. The ovarian arteries are then ligated with resorbable suture material
and then the arteries transected. The uterine body (which is very short in litter-bearing species) and related arteries are also tied off just in front of the
The cervix or cervix uteri (Latin, 'neck of the uterus') is the lower part of the uterus (womb) in the human female reproductive system. The cervix is usually 2 to 3 cm long (~1 inch) and roughly cylindrical in shape, which changes during ...
(leaving the cervix as a natural barrier). The entire uterus and ovaries are then removed. The abdomen is checked for bleeding and then closed with a three-layer closure. The linea alba
and then the subcutaneous layer are closed with resorbable suture material. The skin is then stapled, sutured, or glued closed. For suturing the feline linea alba, the most appropriate suture bite and stitch interval size was suggested to be 5 mm.
Laparoscopic surgery is performed using a camera and instruments placed through small incisions (ports) in the body wall. The patient is under anaesthesia and lying on the back. The incisions are between and the number varies according to the equipment and technique used. The surgeon watches on a screen during the operation. The first port is made just behind the umbilicus and the camera is inserted. The abdomen is inflated with carbon dioxide gas to create a space in which to operate. A second port is introduced a few centimeters in front of the navel and a long grasping instrument called a Babcock forceps is inserted. The surgeon finds the ovary with the instrument and uses it to suspend the ovary from a needle placed through the abdominal wall. This lifts the ovary and uterus safely away from other organs. The surgeon then removes the grasping instrument and replaces it with an instrument that cauterizes and cuts tissue. This instrument uses electricity to heat the blood vessels to seal them and to cut them. No sutures are placed inside. The ovary is separated from the uterus and round ligament. The cautery instrument is removed and replaced by the grasping instrument, which is used to pull the ovary out through the small abdominal incision (port). This is repeated on the other side and the small holes are closed with a few sutures. Another method uses ligatures and even the uterus is removed. In female dogs only removing the ovaries and not the uterus is not state of the art because this way the risk of pyometra
The benefits of laparoscopic surgery are less pain, faster recovery, and smaller wounds to heal. A study has shown that patients are 70% more active in the first three days post-surgery compared to open surgery. The reason open surgery is more painful is that larger incisions are required, and the ovary needs to be pulled out of the body, which stretches and tears tissue in the abdomen (it is not uncommon for patients to react under anaesthesia by breathing faster at this point).
Spaying in female dogs removes the production of progesterone
, which is a natural calming
A hormone (from the Greek participle , "setting in motion") is a class of signaling molecules in multicellular organisms that are sent to distant organs by complex biological processes to regulate physiology and behavior. Hormones are required ...
Serotonin () or 5-hydroxytryptamine (5-HT) is a monoamine neurotransmitter. Its biological function is complex and multifaceted, modulating mood, cognition, reward, learning, memory, and numerous physiological processes such as vomiting and va ...
uplifter. Spaying may therefore escalate any observable aggressive behaviour, either to humans or other dogs.
The risk of infections, bleeding, ruptures, inflammation and reactions to the drugs given to the animal as part of the procedure are all possibilities that should be considered.
In male animals,
Castration is any action, surgical, chemical, or otherwise, by which an individual loses use of the testicles: the male gonad. Surgical castration is bilateral orchiectomy (excision of both testicles), while chemical castration uses pharm ...
involves the removal of the
A testicle or testis (plural testes) is the male reproductive gland or gonad in all bilaterians, including humans. It is homologous to the female ovary. The functions of the testes are to produce both sperm and androgens, primarily testoste ...
(testicles), and is commonly practiced on both household pets (for birth control and behaviour modification) and on livestock (for birth control, as well as to improve commercial value). Often the term ''neuter ng
' is used to specifically mean castration, e.g. in phrases like "spay and neuter".
Surgical alternatives (vasectomy, tubal ligation, "gomerization")
: In a more delicate procedure than castration, the vasa deferentia
– ducts that run from the testes to the
A penis (plural ''penises'' or ''penes'' () is the primary sexual organ that male animals use to inseminate females (or hermaphrodites) during copulation. Such organs occur in many animals, both vertebrate and invertebrate, but males d ...
– are cut then tied or sealed, to prevent
Sperm is the male reproductive cell, or gamete, in anisogamous forms of sexual reproduction (forms in which there is a larger, female reproductive cell and a smaller, male one). Animals produce motile sperm with a tail known as a flagellum, ...
from entering into the
The urethra (from Greek οὐρήθρα – ''ourḗthrā'') is a tube that connects the urinary bladder to the urinary meatus for the removal of urine from the body of both females and males. In human females and other primates, the urethra ...
. Failure rates are insignificantly small.
A breeder is a person who selectively breeds carefully selected mates, normally of the same breed to sexually reproduce offspring with specific, consistently replicable qualities and characteristics. This might be as a farmer, agriculturalist, o ...
routinely have this procedure carried out on male
The ferret (''Mustela furo'') is a small, domesticated species belonging to the family Mustelidae. The ferret is most likely a domesticated form of the wild European polecat (''Mustela putorius''), evidenced by their interfertility. Other mus ...
Sheep or domestic sheep (''Ovis aries'') are domesticated, ruminant mammals typically kept as livestock. Although the term ''sheep'' can apply to other species in the genus '' Ovis'', in everyday usage it almost always refers to domesticate ...
to manipulate the estrus cycles of in-contact females. It is uncommon in other animal species. Because a vasectomy is usually a more expensive procedure, among pet-keepers it is more often performed on show animals
, to cosmetically preserve their appearance (though depending upon the fancier organization
, the procedure may invalidate the animal's candidacy for certain awards, or relegate it to a non-
Pedigree may refer to:
* Pedigree chart, a document to record ancestry, used by genealogists in study of human family lines, and in selective breeding of other animals
** Pedigree, a human genealogy (ancestry chart)
** Pedigree (anim ...
, generic "household pet" competition division, just as with full castration).
: Snipping and tying of
The fallopian tubes, also known as uterine tubes, oviducts or salpinges (singular salpinx), are paired tubes in the human female that stretch from the uterus to the ovaries. The fallopian tubes are part of the female reproductive system. In o ...
s as a sterilization measure can be performed on female cats, dogs, and other species; it is essentially the female equivalent of vasectomy, but a more invasive procedure. Risk of unwanted pregnancies is insignificantly small. Only a few veterinarians perform the procedure.
Like other forms of neutering, vasectomy and tubal ligation eliminate the ability to produce offspring. They differ from neutering in that they leave the animal's levels and patterns of
Sex hormones, also known as sex steroids, gonadocorticoids and gonadal steroids, are steroid hormones that interact with vertebrate steroid hormone receptors. The sex hormones include the androgens, estrogens, and progestogens. Their effect ...
unchanged. Both sexes will retain their normal reproductive behavior, and other than birth control, none of the advantages and disadvantages listed above apply. This method is favored by some people who seek minimal infringement on the natural state of companion animals to achieve the desired reduction of unwanted births of cats and dogs.
"" is breeders' informal term for surgical techniques by which male livestock, such as bulls, retain their full libido
(and related effects like sex pheromones
that would be lost through castration), but are rendered incapable of
Sexual intercourse (or coitus or copulation) is a sexual activity typically involving the insertion and thrusting of the penis into the vagina for sexual pleasure or reproduction.Sexual intercourse most commonly means penile–vaginal penetra ...
. This is done to stimulate and identify estrous
females without the risk of transmitting
Sexually transmitted infections (STIs), also referred to as sexually transmitted diseases (STDs) and the older term venereal diseases, are infections that are spread by sexual activity, especially vaginal intercourse, anal sex, and oral ...
or causing a pregnancy by a male other than the one intended for
Selective breeding (also called artificial selection) is the process by which humans use animal breeding and plant breeding to selectively develop particular phenotypic traits (characteristics) by choosing which typically animal or plant ...
. Animals altered for this purpose are referred to as teasers (teaser bulls, etc.), or gomers. Several methods are used. Penile translocation surgically alters the penis to point far enough away from its normal direction that it cannot manage
In mammals, the vagina is the elastic, muscular part of the female genital tract. In humans, it extends from the vestibule to the cervix. The outer vaginal opening is normally partly covered by a thin layer of mucosal tissue called the hymen ...
l penetration. Penile fixation permanently attaches the penis to the abdomen so that it cannot be lowered for penetration. Penectomy
is the partial or complete removal of the
A penis (plural ''penises'' or ''penes'' () is the primary sexual organ that male animals use to inseminate females (or hermaphrodites) during copulation. Such organs occur in many animals, both vertebrate and invertebrate, but males d ...
* Male dogs – Two intratesticular injectable formulations are known to sterilize male dogs. Zeuterin was approved by the United States
Food and Drug Administration
The United States Food and Drug Administration (FDA or US FDA) is a federal agency of the Department of Health and Human Services. The FDA is responsible for protecting and promoting public health through the control and supervision of food ...
(FDA) for permanent sterilization of male dogs ages three months and older by causing necrosis
of the testicle. It is not currently available commercially. Calcium chloride dissolved in a variety of diluents have also been studied, with the majority of research and most promising results using calcium chloride dissolved in ethyl alcohol. Calcium chloride formulations can be purchased for use in animals from compounding pharmacies, but the use of calcium chloride for sterilization of males is not approved by the FDA or any other international regulatory agency.
* Male cats – Calcium chloride formulations have also been studied in male cats.
* Male rats – Adjudin
of indazole-carboxylic acid), induces reversible germ cell loss from the seminiferous epithelium
by disrupting cell adhesion function between nurse cells
and immature sperm cells
, preventing maturation
* Male mice – injection of a solution of the JQ1 molecule to bind to a pocket of BRDT necessary for chromatin remodeling, which gives the proteins that regulate how genes act access to the genetic material
* Male sheep and pigs – Wireless Microvalve. A proposed non-chemical, reversible sterilization method using a piezoelectric
A polymer (; Greek '' poly-'', "many" + '' -mer'', "part")
is a substance or material consisting of very large molecules called macromolecules, composed of many repeating subunits. Due to their broad spectrum of properties, both synthetic a ...
that will deform when exposed to a specific electric field broadcast from an emitter. The valve will then open or close, preventing the passage of sperm, but not
Semen, also known as seminal fluid, is an organic bodily fluid created to contain spermatozoa. It is secreted by the gonads (sexual glands) and other sexual organs of male or hermaphroditic animals and can fertilize the female ovum. Semen is ...
. Located in a section of the vas deferens
that occurs just after the epididymis
, the implantation can be carried out by use of a hypodermic needle.
* Female mammals – Vaccine of antigens (derived from purified porcine zona pellucida
) encapsulated in liposomes (cholesterol and lecithin) with an adjuvant, latest US patenRE37,224
(as of 2006-06-06), CA paten2137263
(issued 1999-06-15). Product commercially known as SpayVac, a single injection causes a treated female mammal to produce antibodies that bind to
Zona pellucida sperm-binding protein 3, also known as zona pellucida glycoprotein 3 (Zp-3) or the sperm receptor, is a ZP module-containing protein that in humans is encoded by the ''ZP3'' gene. ZP3 is the receptor in the zona pellucida which bi ...
on the surface of her ovum, blocking sperm from fertilizing it for periods from 22 months up to 7 years (depending on the animal). This will not prevent the animal from going into heat (ovulating) and other than birth control, none of the above-mentioned advantages or disadvantages apply.
* Male mice – reversible regulation of the KATNAL1 gene in the Sertoli cell microtubule dynamics of the testes.
* Female mammals – orally administered phosphodiesterase 3 inhibitor ORG 9935 daily before and during ovulation, which blocks the resumption of meiosis resulting in ovulation of a non-fertilizable, immature oocyte without rupturing the follicle.
Early-age neutering, also known as pediatric spaying
or prepubertal gonadectomy, is the removal of the ovaries or testes before the onset of
Puberty is the process of physical changes through which a child's body matures into an adult body capable of sexual reproduction. It is initiated by hormonal signals from the brain to the gonads: the ovaries in a girl, the testes in a ...
. It is used mainly in animal sheltering and rescue where puppies and kittens can be neutered before being adopted out, eliminating non-compliance with sterilization agreement, which is typically above 40%.
American Veterinary Medical Association
The American Veterinary Medical Association (AVMA), founded in 1863, is a not-for-profit association representing more than 99,500 veterinarians in the US.
The AVMA provides information resources, continuing education opportunities, publicati ...
, American Animal Hospital Association
Canadian Veterinary Medical Association
The Canadian Veterinary Medical Association (CVMA) (french: Association canadienne des médecins vétérinaires, ACMV), founded in 1876, provides leadership on national veterinary issues, advocates for animal welfare, and works to encourage life ba ...
support the procedure for population control, provided that the veterinarian uses their best knowledge when making the decision about the age at neutering.
[Dog and Cat Spay/Castration](_blank)
A task force recommends that cats are spayed–neutered prior to 5 months of age.
While the age-unrelated risks and benefits cited above also apply to early-age neutering, various studies have indicated that the procedure is safe and not associated with increased mortality or serious health and behavioral problems when compared to conventional age neutering.
Anesthesia recovery in young animals is usually more rapid and there are fewer complications.
One study found that in female dogs there is an increasing risk of urinary incontinence the earlier the procedure is carried out; the study recommended that female dogs be spayed no earlier than 3 to 4 months of age.
A later study comparing female dogs spayed between 4 and 6 months and after 6 months showed no increased risk.
One study showed the incidence of hip dysplasia increased to 6.7% for dogs neutered before 5.5 months compared to 4.7% for dogs neutered after 5.5 months, although the cases associated with early age neutering seems to be of a less severe form. There was no association between age of neutering and arthritis or long-bone fractures.
Another study showed no correlation between age of neutering and musculoskeletal problems.
A study of large breed dogs with cranial cruciate ligament
rupture associated early-age neutering with the development of an excessive tibial plateau angle.
Of particular note are two recent studies from Lynette Hart's lab at UC Davis. The first study from 2013, published in a well-known interdisciplinary peer-reviewed journal demonstrated "no cases of CCL (cruciate ligament tear) diagnosed in intact males or females, but in early-neutered males and females the occurrences were 5 percent and 8 percent, respectively. Almost 10 percent of early-neutered males were diagnosed with LSA (lymphosarcoma), 3 times more than intact males. The percentage of HSA (hemangiosarcoma) cases in late-neutered females (about 8 percent) was 4 times more than intact and early-neutered females. There were no cases of MCT (mast cell tumor) in intact females, but the occurrence was nearly 6 percent in late-neutered females".
The second study from 2014 highlighted significant difference in closely related breeds (retrievers), suggesting that inter-breed variability is quite high and that sweeping legal measures and surgical mandates are not the best solutions to canine welfare and health. Specifically the study states: "In Labrador Retrievers, where about 5 percent of gonadally intact males and females had one or more joint disorders, neutering at 6 months doubled the incidence of one or more joint disorders in both sexes. In male and female Golden Retrievers, with the same 5 percent rate of joint disorders in intact dogs, neutering at 6 months increased the incidence of a joint disorder to 4–5 times that of intact dogs. The incidence of one or more cancers in female Labrador Retrievers increased slightly above the 3 percent level of intact females with neutering. In contrast, in female Golden Retrievers, with the same 3 percent rate of one or more cancers in intact females, neutering at all periods through 8 years of age increased the rate of at least one of the cancers by 3–4 times. In male Golden and Labrador Retrievers neutering had relatively minor effects in increasing the occurrence of cancers."
In terms of behavior in dogs, separation anxiety, aggression, escape behavior and inappropriate elimination are reduced while noise phobia and sexual behavior was increased. In males with aggression issues, earlier neutering may increase barking.
Asthma is a long-term inflammatory disease of the airways of the lungs. It is characterized by variable and recurring symptoms, reversible airflow obstruction, and easily triggered bronchospasms. Symptoms include episodes of wheezing, co ...
, gingivitis, and hyperactivity were decreased, while shyness was increased. In male cats, occurrence of abscesses, aggression toward veterinarians, sexual behaviors, and urine spraying
was decreased, while hiding was increased.
Health and behavioral effects
Besides being a birth control method, and being convenient to many owners, castrating/spaying has the following health benefits:
* Sexually dimorphic
behaviors such as mounting
and urine spraying
are reduced due to the decrease in hormone levels brought about by neutering. In species other than dogs, certain forms of male
Aggression is overt or covert, often harmful, social interaction with the intention of inflicting damage or other harm upon another individual; although it can be channeled into creative and practical outlets for some. It may occur either reacti ...
are also reduced. Sexual behavior in cats seems to make them especially undesirable to pet owners.
* Early spaying significantly reduces the risk of development of mammary tumours in female dogs. The incidence of mammary tumours in un-spayed female dogs is 71% (of which approximately 50% will be malignant and 50% will be benign), but if a dog is spayed before its first heat cycle, the risk of developing a mammary tumour is reduced to 0.35%—a 99.5% reduction. The positive effects of spaying on reduction of later mammary tumours decreases with each heat the dog has (backing up the contention that the greatest benefit to reduce future mammary tumour development is to spay before the first heat), and there is no added benefit to spaying to reduce recurrence of a mammary tumour once it has been diagnosed.
* Neutering increases life expectancy in cats: one study found castrated male cats live twice as long as intact males, while spayed female cats live 62% longer than intact females. Non-neutered cats in the U.S. are three times more likely to require treatment for an animal bite. Having a cat neutered confers health benefits, because castrated males cannot develop testicular cancer, spayed females cannot develop uterine, cervical or ovarian cancer, and both have a reduced risk of mammary cancer.
* Without the ability to reproduce, a female necessarily has zero risk of pregnancy complications, such as spotting
and false pregnancy
, the latter of which can occur in more than 50% of unspayed female dogs.
, uterine cancer
Ovarian cancer is a cancerous tumor of an ovary. It may originate from the ovary itself or more commonly from communicating nearby structures such as fallopian tubes or the inner lining of the abdomen. The ovary is made up of three different ...
Testicular cancer is cancer that develops in the testicles, a part of the male reproductive system. Symptoms may include a lump in the testicle, or swelling or pain in the scrotum. Treatment may result in infertility.
Risk factors include a ...
are prevented, as the susceptible organs are removed, though stump pyometra
may still occur in spayed females.
* Pyometra (or a pus filled womb) ('Pyo' = pus; 'metra' = uterus or womb) is a life-threatening condition that requires emergency veterinary treatment. The risk of a non-spayed female dog developing pyometra by age 10 is 25% across all breeds, but can be as high as 54% in some breeds. The treatment of choice for a closed-pyometra (where the cervix is closed and the pus cannot drain) is admission to hospital, commencement on intravenous fluids and appropriate antibiotics and, once stable enough for the anaesthetic and surgery, emergency removal of the infected pus-filled uterus. Medical management can be attempted if the animal's condition allows (for example in the case of an 'open' pyometra where the pus drains per-vaginum from the uterus via the open cervix) or dictates (where the animal is too old or otherwise unwell to withstand surgery), if the owner wishes to keep the dog entire to breed or if the owner is unable to afford the veterinary fees associated with surgery. Emergency removal of the infected uterus carries a much higher degree of risk of death than a routine 'spay' operation. The risk of death from in dogs undergoing surgical treatment for pyometra is up to 17%. Thus the risk of death in entire female dogs from a pyometra, even if given correct veterinary attention can be up to 9% by 10 years of age (17% of 54%). This risk is reduced to virtually zero if spayed.
* As with any surgical procedure, immediate complications of neutering include the usual anesthetic
complications, such as bleeding, infection, and death. These risks are relatively low in routine neutering; however, they may be increased for some animals due to other pre-existing health factors. In one study the risk of anesthetic-related death (not limited to neutering procedures) was estimated at 0.05% for healthy dogs and 0.11% for healthy cats. The risks for sick animals were 1.33% for dogs and 1.40% for cats.
* Spaying and castrating cats and dogs may increase the risk of
Obesity is a medical condition, sometimes considered a disease, in which excess body fat has accumulated to such an extent that it may negatively affect health. People are classified as obese when their body mass index (BMI)—a person's ...
if nutritional intake is not reduced to reflect the lower metabolic requirements of neutered animals.
In cats, a decrease in sex hormone levels seems to be associated with an increase in food intake.
In dogs, the effects of neutering as a risk factor for obesity vary among breeds.
* Neutered dogs of both sexes are at a twofold excess risk to develop osteosarcoma
(bone cancer) as compared to intact dogs. The risk of osteosarcoma increases with increasing breed size and especially height.
* Studies of cardiac tumors in dogs showed that there was a 5 times greater risk of hemangiosarcoma
(cancer of blood vessel lining), one of the three most common cancers in dogs, in spayed females than intact females and a 2.4 times greater risk of hemangiosarcoma in castrated dogs as compared to intact males.
* Spaying and castrating is associated with an increase in urinary tract cancers in dogs, however the risk is still less than 1%.
* Neutered dogs of both sexes have a 27% to 38% increased risk of adverse reactions to vaccinations. However, the incidence of adverse reactions for neutered and intact dogs combined is only 0.32%.
* Neutered dogs have also been known to develop hormone-responsive alopecia
* A 2004 study found that neutered dogs had a higher incidence of cranial cruciate ligament (CCL) rupture, a form of anterior cruciate ligament (ACL) injury.
* A study of
The Golden Retriever is a Scottish breed of retriever dog of medium size. It is characterised by a gentle and affectionate nature and a striking golden coat. It is commonly kept as a pet and is among the most frequently registered breeds i ...
found that castrated males were 3 times more likely than intact males to be diagnosed with
Lymphoma is a group of blood and lymph tumors that develop from lymphocytes (a type of white blood cell). In current usage the name usually refers to just the cancerous versions rather than all such tumours. Signs and symptoms may include en ...
and 2 times more likely to have hip dysplasia
* Castration and spaying can also increase the risk of geriatric cognitive impairment, as noted in Laura J. Sanborn's meta-analysis.
* About 2% of castrated male dogs
eventually develop prostate cancer
, compared to less than 0.6% of intact males.
The evidence is most conclusive for Bouviers
* In a study of 29 intact male dogs and 47 castrated males aged 11–14, the neutered males were significantly more likely to progress from one geriatric cognitive impairment condition (out of the four conditions – disorientation in the house or outdoors, changes in social interactions with human family members, loss of house training, and changes in the sleep-wake cycle) to two or more conditions. Testosterone in intact males is thought to slow the progression of cognitive impairment, at least in dogs that already have mild impairment.
* As compared to intact males, castrated cats are at an increased risk for certain problems associated with feline lower urinary tract disease. They are much more likely to suffer from feline cystitis which can escalate into a life-threatening urethral blockage.
* Neutering also has been associated with an increased likelihood of urethral sphincter incontinence in male dogs.
* There is evidence that spaying can increase the risk of urinary incontinence in dogs, especially when done before the age of three months. Up until 12 months of age, the risk decreases as the age at spaying increases.] Urinary incontinence can affect up to one out of five spayed female dogs, and develops an average of 2.9 years after the dog has been spayed.
* Spayed female dogs are at an increased risk of hypothyroidism
Hypothyroidism (also called ''underactive thyroid'', ''low thyroid'' or ''hypothyreosis'') is a disorder of the endocrine system in which the thyroid gland does not produce enough thyroid hormone. It can cause a number of symptoms, such as ....
Various studies of the effects neutering has overall on male and female dog aggression have been unable to arrive at a consensus. A possible reason for this according to two studies is changes to other factors have more of an effect than neutering.
One study reported results of aggression towards familiar and strange people and other dogs reduced between 10 and 60 percent of cases, while other studies reported increases in possessive aggression and aggression towards familiar and strange people, and more studies reported there was no significant difference in aggression risk between neutered and non-neutered males. For females with existing aggression, many studies reported increases in aggressive behavior and some found increased separation anxiety behavior. A report from the American Kennel Club Canine Health Foundation reported significantly more behavioral problems in castrated dogs. The most commonly observed behavioral problem in spayed females was fearful behavior and the most common problem in males was aggression. Early age gonadectomy is associated with an increased incidence of noise phobias and .
Terminology for neutered animals
A specialized vocabulary is used in animal husbandry and animal fancy for neutered (castrated) animals:
There are differing views in
Islam (; ar, ۘالِإسلَام, , ) is an Abrahamic monotheistic religion centred primarily around the Quran, a religious text considered by Muslims to be the direct word of God (or '' Allah'') as it was revealed to Muhammad, the ... with regard to neutering animals, with some Islamic associations stating that when done to maintain the health and welfare of both the animals and the community, neutering is allowed on the basis of being in the interest of ' maslaha
Maslaha or maslahah ( ar, مصلحة, lit=public interest) is a concept in shari'ah ( Islamic divine law) regarded as a basis of law.I. Doi, Abdul Rahman. (1995). "Mașlahah". In John L. Esposito. ''The Oxford Encyclopedia of the Modern Islamic W ...' (general good) or "choosing the lesser of two evils".
Orthodox Judaism is the collective term for the traditionalist and theologically conservative branches of contemporary Judaism. Theologically, it is chiefly defined by regarding the Torah, both Written and Oral, as revealed by God to Moses o ... forbids the castration of both humans and non-human animals by Jews, except in lifesaving situations. In 2007, the Sephardic
Sephardic (or Sephardi) Jews (, ; lad, Djudíos Sefardíes), also ''Sepharadim'' , Modern Hebrew: ''Sfaradim'', Tiberian: Səp̄āraddîm, also , ''Ye'hude Sepharad'', lit. "The Jews of Spain", es, Judíos sefardíes (or ), pt, Judeus sefa ... Chief Rabbi
Chief Rabbi ( he, רב ראשי ''Rav Rashi'') is a title given in several countries to the recognized religious leader of that country's Jewish community, or to a rabbinic leader appointed by the local secular authorities. Since 1911, through a ... of Israel
Israel (; he, יִשְׂרָאֵל, ; ar, إِسْرَائِيل, ), officially the State of Israel ( he, מְדִינַת יִשְׂרָאֵל, label=none, translit=Medīnat Yīsrāʾēl; ), is a country in Western Asia. It is situated ... Rabbi Shlomo Amar issued a ruling stating that it is permissible to have companion animals neutered on the basis of the Jewish mandate to prevent cruelty to animals.
Animal population control
Population control is the practice of artificially maintaining the size of any population. It simply refers to the act of limiting the size of an animal population so that it remains manageable, as opposed to the act of protecting a species from ...
* Animal shelter
* Cruelty to animals
* Overpopulation in companion animals
* Wildlife contraceptive
Wildlife contraceptives are contraceptives used to regulate the fertility of wild animals. They are used to control population growth of certain wild animals.
White-tailed deer may be controlled with contraceptives in suburban areas, wh ...
* World Spay Day World Spay Day advocates spaying, or neutering, advocating it "as a proven means of saving the lives of companion animals, community (feral and stray) cats, and street dogs who might otherwise be put down in a shelter or killed on the street." It is ...
DVM Article on health effects of spay/neuter: Long-Term Health Risks and Benefits Associated with Spay / Neuter in Dogs
Determining the optimal age for gonadectomy of dogs and cats, AVMA (pdf)
Canine Spay Photos and Description
Surgical removal procedures