Spaying & Neutering – Benefits of Fixing Your Dog or Cat

The surgical altering of animals so that they cannot reproduce (otherwise known as gonadectomy) has been going on for centuries. It seems ironic that despite having spayed and neutered millions of animals, sufficient conclusive research has not been conducted to end the debate about the best age or reproductive stage of life to spay and neuter dogs and cats. Early age spay-neuter is still one of the more hotly debated issues in companion animal medicine today. It is fraught with misinformation, misconceptions, and high emotions. Hopefully, the debate will end as more research shows the procedures to be safe in both the short and long term, and veterinarians will then begin to embrace the concept as readily as they embrace neutering at 6 months of age.

Petfinder: PSA on Spaying and Neutering 3

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Spay/Neuter Glossary of Terms

This term refers to the surgical procedures that render an animal unable to reproduce naturally.

This term refers to the removal of the testicles in a male, eliminating the production of testosterone, the male hormone, and sperm.

It is a faster, simpler surgical procedure than ovariohysterectomy because the testicles are normally located outside the body in the scrotal sac. Entry into the abdominal cavity is unnecessary in the normal male animal, and the duration of anesthesia is very short. During the early developmental stages of life, the testicles are located in the abdomen. They descend through the inguinal canal into the scrotal sac shortly after birth. Castrations become complicated when the testicles are retained in the abdominal cavity or the inguinal canal, necessitating searching for them. These animals are referred to as cryptorchids or monorchids. Testicles that are not found in the scrotal sac usually do not produce viable sperm, rendering the animal sterile anyway, but they still produce testosterone, which results in objectionable behavior and strong cat urine odors. The retained testicles may also become cancerous later in life, so they should be located and removed whenever possible.

Cat castrations are not performed following the strict sterile techniques of other abdominal surgeries. General anesthesia or heavy sedation is used. The typical cat castration is performed by placing the animal on his back or side, shaving or plucking the hair from the scrotum, wiping the area with a surgical scrub or alcohol, making an incision in the underside or end of each scrotal sac, pulling the testicle out and ligating or tying the spermatic cord and vessels. (The spermatic cord may be tied upon itself as an alternative to ligation.) The incision is usually left open to drain. It can be performed in one to two minutes.

Dog castrations are performed under strict sterile techniques and general anesthesia. The dog is placed on his back and a pre-scrotal incision (immediately in front of the scrotum) is most commonly made on the midline and each testicle is pushed forward and removed through that single incision. The spermatic cord containing blood vessels is ligated or tied upon itself. The subcutaneous layer is sutured and the skin incision is either sutured or glued. There are many variations on dog castrations, with some veterinarians performing the procedure the way it is done in cats, but under strict sterile technique. Regardless of the method or age of the patient, castrations in animals with both testicles in their normal position rarely take more than a few minutes.

The most common problems include bleeding, anesthesia-related problems, post-operative swelling of the scrotum (sometimes so severe it may appear that the testicles were not removed), or infection. These complications tend to be annoying but are much less serious than those encountered in spays.

Early Age Spay-Neuter
There are several terms being used for early age spay-neuter. It generally refers to any gonadectomy performed before the animal is 6 months of age. Age and weight restrictions are generally 6 weeks of age or 2 pounds of weight. Some veterinarians are proposing that other terminology be used because the term “early” implies that the procedure is being performed prematurely, (and therefore inappropriately). Some alternatives for early age spay-neuter include:
Juvenile Spay Neuter
Pediatric Spay Neuter
Prepuberal Spay Neuter
Prepubertal Spay Neuter
Prepubescent Spay Neuter

See alter. They can be used interchangeably.

This general term refers to the removal of the sex organs or gonads, so it applies to both males (removal of testicles) and females (removal of ovaries).

This term is commonly used to refer to the surgical alteration of a male to prevent reproduction or castration, but it technically refers to the surgical alteration of either males or females to render the animal “neuter” or genderless.

The same as castration, removal of the testicles

This term refers to the surgical removal of the ovaries AND uterus in a female so she cannot reproduce. This eliminates the production of estrogen and progesterone. The removal of the ovaries alone would also render the animal incapable of natural reproduction, but both organs are most commonly removed.

This is the same as an ovariohysterectomy

Peace of Mind

Did you know that a spayed or neutered (sterilized) animal is better behaved?


Neutered cats and dogs focus their attention on their human families. On the other hand, unsterilized, unsupervised males roam in search of a mate, risking injury in traffic and in fights with other males. They mark territory by spraying strong-smelling urine on surfaces. Neutering eliminates the odor and markedly reduces the incidence of urine spraying. It is most effective when performed before marking starts, but will often work even after the marking has become a habit. Indoors, male dogs may embarrass you by mounting furniture and human legs when stimulated. Don’t confuse aggressiveness with protectiveness; a neutered dog protects his home and family just as well as an unneutered dog, and many aggression problems can be avoided by early neutering.


While their cycles vary greatly, most female cats exhibit the following signs when in heat. For four or five days, every three weeks during the breeding season, they yowl and urinate more frequently sometimes all over the house advertising for mates. Often, they attract unneutered males who spray urine around the female's homes. Female dogs also attract males from great distances. Female dogs generally have a bloody discharge for about a week and can conceive for another week or so.

Good Medicine

Did you know that a spayed or neutered animal will live a longer, healthier life?

Spaying a female (removing the ovaries and uterus) or neutering a male (removing the testicles) are veterinary procedures performed under general anesthesia. Both surgeries usually require minimal hospitalization. The ASPCA strongly recommends spaying or neutering your pet as early as possible. Besides preventing unwanted breeding, neutering a male cat or dog before six months of age prevents testicular cancer and prostate disease. Spaying a female cat or dog helps prevent pyometra (a pus-filled uterus) and breast cancer; having this done before the first heat offers the best protection from these diseases. Treatment of pyometra requires hospitalization, intravenous (IV) fluids, antibiotics, and spaying. Breast cancer can be fatal in about 50 percent of female dogs and 90 percent of female cats. For an older, seriously ill animal, anesthesia and surgery are complicated and costly. Neutering markedly also reduces the incidence of benign hyperplasia of the prostate gland, prostatitis, and perineal hernias in dogs.

Responsible Care

Did you know that you can help prevent the suffering and death of millions of animals?

Almost everyone loves puppies and kittens, but some people lose interest when these animals grow up. As a result, millions of cats and dogs of all ages and breeds are euthanized annually or suffer as strays. Many of these are the result of unwanted, unplanned litters that could have been prevented by spaying or neutering. Rarely surviving for more than a few years on their own, strays die painfully by starvation, disease, freezing, or being hit by cars.

Concerns About Pediatric Neutering

The following concerns are usually cited about pediatric neutering:

  • Lack of sufficient scientific data about long-term consequences
  • Obesity
  • Stunted growth
  • Perivulvular dermatitis
  • Behavioral problems
  • Lower urinary tract disease
  • Secondary sex characteristics
  • Urinary Incontinence
  • Preputial adhesions
  • Anesthesia
  • Surgery
  • Infectious disease
  • Income Loss

Several of the more common concerns about pediatric neutering will be discussed here.

Special Pointers for Pediatric Surgical Patients

The following pointers highlight the main considerations when performing a pediatric procedure:


The handling of pediatric patients before surgery should be minimized to prevent excitement before sedation for surgery. The staff should be urged to resist the temptation to play with them. Excited animals will resist being restrained and they become more difficult to sedate.

It may be easier to use intramuscular injections for initial sedation, as less restraint is needed.

Animals should not be fasted for more than 3-4 hours before the procedure to avoid hypoglycemia.

Hypothermia can be a problem for these patients. A small area of hair at the surgical site should be clipped and a warm surgical scrub used. The use of alcohol should be avoided or minimized because of its cooling effects on the skin.

There are many different protocols in the literature for pediatric anesthesia. The most successful protocols are usually already in use by the veterinarian with adjustments for the weight difference. The use of inhalation anesthesia mitigates many of the concerns about the biotransformation of anesthetic drugs in the liver and kidneys of pediatric patients.

Good monitoring of the patient for safety is no different from the protocols used for any other patient, ie, observing the heart and respiratory rate, depth of anesthesia, the color of the patient’s mucus membranes, etc.


A supplemental source of heat should be used to prevent hypothermia. Warm water heating pads covered by a blanket or towel on the surgical table work fine.

Some surgeons recommend that the surgical incision for female puppies should be 2-3 cm caudal to the umbilicus for easier exposure to the uterus. Its location remains the same in kittens as it is for adult cats.

Tissues must be handled gently and close attention paid to hemostasis, but this is true in any surgical procedure. The truth is, in most cases, bleeding in these animals is minimal.

Pediatric animals tend to have a lot of clear abdominal fluid, but this is normal.

The animals should be tattooed in the inguinal region or tattoo ink applied to the incision to identify them as having already been neutered. This is more critical for female animals than males, but it might spare male animals from exploratory surgery if it was assumed the animal had bilaterally retained testicles.

Post-Surgical Considerations

Heating lamps are fine to use to prevent hypothermia. These patients should be monitored closely during recovery, and if there are problems, their temperature and blood glucose should be checked.

A small meal should be offered within an hour after anesthetic recovery to minimize the chance of developing hypoglycemia. If there are signs of hypoglycemia, treat quickly and accordingly.

Just The Facts, Please

Myth: A female cat or dog should have a litter before she is spayed.
Fact: The sooner you spay your female, the better her health will be in the future. As long as a kitten or puppy weighs more than 2 pounds and is 2 months old, he or she can be neutered or spayed. Many veterinarians practice perfectly safe early sterilization. The longer a female goes unspayed, the greater the likelihood of developing mammary tumors or uterine infections. In fact, a female spayed before her first heat (6 to 9 months of age) has one-seventh the risk of developing mammary cancer as an intact female.

Myth: Spaying or neutering (sterilization) will alter my pets personality.
Fact: Any slight changes will be positive. Regardless of the age when spayed or neutered, your pet will remain a caring, loving and protective companion. Neutering will reduce the need to breed, and that has a calming effect on many animals. Both neutered male canines and felines tend to stop roaming and fighting, and they also lose the desire to mark their territory with urine.

Myth: Companion animals will become fat and lazy if they are neutered.
Fact: Absolutely not! Lack of exercise and overfeeding make pets fat and lazynot neutering. Your pet will not gain weight if you provide exercise and monitor food intake. Neutering is good for your pet, since sterilized pets tend to live an average of two to three years longer than unsterilized pets.

Myth: Sterilization is a dangerous and painful surgery for my pet.
Fact: Spaying and neutering are the most common surgeries performed on animals. With a minimal amount of home care, your pet will resume normal behavior in a couple of days.

Myth: Children should witness the miracle of birth.
Fact: Countless books and videos are available to teach your children about birth in a responsible manner. Letting your pet produce offspring that you have no intention of keeping is teaching your children irresponsibility. Anyone who has seen an animal euthanized in a shelter for lack of a home knows the truth behind this dangerous myth.

Many states and counties have established low-cost spay/neuter programs that make the surgery affordable. Many cities also offer reduced licensing fees for owners of spayed and neutered pets. To find a low-cost program near you, call your local humane society or shelter, or call toll-free (800) 248-SPAY.

Lack of studies about the long-term effects

The results of studies of the long-term outcome of gonadectomy performed at an early age or traditional age in cats and dogs were published in JAVMA in the December 1, 2000 and January 15, 2001 issues respectively. The studies were performed at the Texas A&M Veterinary College on 269 dogs and 263 cats from animal shelters. The conclusion for dogs was that “with the exception of infectious diseases, prepubertal gonadectomy may be safely performed in dogs without concern for the increased incidence of physical or behavioral problems during at least a 4 year period after gonadectomy.” Shelters that held puppies long-term encountered problems with parvo. Shelters that held puppies short-term did not encounter similar disease problems. The conclusion for cats was that ” prepubertal gonadectomy may be performed safely in cats without concern for the increased incidence of physical or behavioral problems for at least a 3-year period after gonadectomy”


Obesity is influenced by a number of factors but spayed and neutered animals do have a tendency to weigh more than intact animals, regardless of whether the surgery was performed prepubertally or at the conventional age of six months. Dietary indiscretions and lack of activity are the real culprits in this case.


Many veterinarians believe that pediatric neutering will stunt the growth of animals, but the exact opposite is true. The removal of hormonal influences on the growth plates of the long bones results in delayed closure, resulting in bones that are actually a little longer. However, there is no clinical significance to this difference in size.

Perivulvular dermatitis

Refer to secondary sexual characteristics


The effects of pediatric spaying and neutering on behavior remain largely unknown. Neutering at any age reduces the urge of male animals to spray urine to mark territory, roam and fight with other male animals. There is some early evidence that animals that are gonadectomized at 7 weeks or 7 months of age are more active and excitable, and that male and female cats may be more affectionate than those left intact, but this is a fairly subjective observation that requires more research to substantiate.

Lower urinary tract disease

Pediatric neutering has not been found to contribute to a higher rate of urinary tract obstructions in male cats. Studies have been conducted on male cats to study the incidence of urinary tract obstructions in all populations. It was found that the diameter of the penile urethra did not vary between animals neutered at 7 weeks or 7 months of age or from intact male cats. It was originally thought that castrated cats had a higher incidence of urinary tract blockages, but this is not the case. The diameter of the penis in male dogs castrated at 7 weeks of age is smaller as is the os penis, and preputial development is juvenile in comparison with animals castrated at 7 months of age or left intact, but there has been no clinical significance attached to those differences

Secondary sexual characteristics

The vulva of females is smaller than that of intact bitches, but there is no evidence that there is any clinical significance to this size difference. Perivulvular dermatitis occurs in intact as well as spayed females and is more largely related to obesity rather than sexual status. Mammary glands and nipples are also smaller. The penis and prepuce of male animals will retain a juvenile appearance, but again, there is no evidence of any clinical significance in animals that are not sexually active. There is a reduction in the male cat’s ability to extrude the penis from the prepuce, but there is no knowledge of any clinical problems associated with this, and it can occur whether the surgery is performed at 7 weeks or 7 months of age.

    Urinary Incontinence

    Urinary incontinence, or the inability to control urination, may be observed in female dogs whether they are spayed or intact, and regardless of the age when spayed. Older, intact female dogs may experience incontinence naturally as a result of the decrease in circulating estrogen, which has an effect on the external urethral sphincter. In spayed dogs, incontinence may be seen soon after the surgery has been performed, years later or not at all. It bears repeating that there has been no indication that it occurs at a higher rate in animals spayed prepubertally.

    Infectious Disease

    It is true that some shelters find an increased incidence of infectious disease, (in particular, upper respiratory infections (URI) in cats and parvo in dogs), in animals that are neutered prepubertally, but the stress of anesthesia and surgery affects adult animals as well, not just kittens and puppies. One study showed that surgery and anesthesia have little effect on the dog’s ability to mount a humoral antibody response to distemper vaccination. Many of these shelter animals might have developed URI anyway, because of the presence of these infectious agents in shelters. Good screening of surgical candidates, a good veterinary health care program that includes deworming, and good post-operative care can minimize the impact of this problem. Shelters that neuter animals only after they have been selected for adoption and send them home after the surgery to recuperate seem to have fewer problems with URI. It was also noted in a study at Texas A&M’s Veterinary College that an increased incidence of parvo was seen more at shelters that had longer holding periods than the ones with short holding periods. This should not be a problem in the private practice clinical setting.

    Income Loss

    Many veterinarians find that they already subsidize the cost of adult spays with other procedures. Pediatric spays and neuters are less costly in labor and materials, more procedures can be performed safely in the same amount of time as on adults, and they can be discharged the same day. Adult animals are frequently held overnight or longer, adding to the cost. Veterinarians should find that it costs less to perform pediatric procedures.

      Advantages To Pediatric Neutering Or Spaying

      One of the main reasons why many veterinarians do not perform pediatric spay-neuter is that they are most comfortable performing surgery on animals that are 6 months of age and they believe there are no compelling reasons to change the current protocols in their private practices.

      However, there are actually many benefits of neutering to pediatric neutering or spaying.

      • Veterinarians who are familiar with the surgery insist that it is much less physiologically stressful on younger patients.
      • Animals should be fasted for only an hour or two rather than overnight to prevent hypoglycemia, so owners who forget to fast them overnight can still have the surgery performed the same day.
      • Animals are awake and ambulatory usually within an hour of completion of the surgery, so they can be fed a small meal and then sent home the same day.
      • The surgery is much faster, so it is less stressful for both the patient and the surgeon.
      • The surgery is much cheaper because of the use of fewer materials, and because less staff time is needed for surgery and postoperative monitoring.
      • If the procedure is performed when the last vaccination is given at 3 to 4 months of age, the veterinarian does not have to worry about the client forgetting to return, or shopping around and going elsewhere for the surgery. It can be included as part of a puppy care package of vaccinations, deworming, and neutering. The delay in neutering pets is often responsible for the production of accidental litters that end up at shelters.
      • Neutered animals are not sexually frustrated! Intact animals become sexually frustrated when responsible pet owners do not permit them to mate and satisfy those hormonally driven urges. Without testosterone, these urges are not present and the animals are more likely to focus their attention on their human family rather than on reproduction.
      • Female dogs in heat may attract male dogs from great distances. This is more than just a nuisance. It can result in unwanted pregnancies and present a dangerous situation, especially if several male dogs approach a female at one time. Spaying eliminates this problem.
      • Spaying eliminates the bloody discharge of female dogs in heat. (Cats typically do not exhibit a bloody discharge)
      • Spaying eliminates the objectionable behavior exhibited by female cats in heat who yowl, cry as if in pain, and may urinate in the house as they seek a male to mate with. (They attract males who will also mark by spraying urine.)
      • Spaying before the first heat virtually eliminates the development of breast cancer later in life for both dogs and cats. (If the surgery is performed when the animal is older, this benefit will be lost.)
      • Spaying virtually eliminates the development of pyometras in dogs and cats. Pyometras are infections of the uterus that can also be expensive, life-threatening medical emergencies. (If all ovarian tissue is not removed, a pyometra can still occur in the stump of the uterus that is left behind. This is commonly known as a stump pyometra.)
      • Spayed animals are not sexually frustrated! Intact animals become sexually frustrated when responsible pet owners do not permit them to mate and satisfy those hormonally driven urges. Without estrogen, these urges are not present and the animals are more likely to focus their attention on their human family rather than on reproduction.