Spay or neuter surgery

Spay or neuter surgery: Myths, facts, and drawbacks

Twenty years and more ago, pet sterilization was hailed as the only way to keep unwanted litters from clogging shelters and ultimately dying there to make room for even more unwanted litters. In the past decade the tide has turned: shelters have instituted their own sterilization policies and animal welfare advocates have conducted highly successful campaigns to decrease the number of unplanned and unwanted litters.

As a result of rescue and shelter sterilization policies, education about the practical aspects of the surgery, and an aggressive campaign by responsible breeders, veterinarians, and welfare groups, about 75 percent of dogs have been spayed or castrated(1) and canine populations in shelters have dropped. However, this decrease is not enough for radical groups that oppose all pet breeding. Some of these groups insist that responsible owners do not keep intact dogs, and they blame breeders for the number of dogs in shelters(2). Not content to depend on education campaigns to convince the remaining 25 percent of owners to capitulate, they promote severely restrictive laws that require spay and neuter of all dogs unless owners buy permission to keep their animals intact and pay yet again to produce a litter. Lawmakers in several states and cities have introduced mandatory sterilization bills on behalf of these extremists.

However, canine spay and neuter surgery is not a cut and dried issue. While the surgery certainly prevents pregnancies, it is not without drawbacks, both in potential health consequences and, if mandated by law, infringement on the constitutional rights of dog owners.

Some research indicates that the health benefits of sterilization may be offset by the drawbacks and that owners should be aware of potential problems that can occur as a direct result of the surgery. For example, although spaying reduces the incidence of reproductive system cancers and uterine infections, spayed bitches have a higher risk of developing other types of cancer, joint problems, and thyroid disease.(3)

Many dog owners consider a spay and neuter requirement to be an infringement of their rights. They take responsibility for their dogs and for any litters that might be produced, and they resent government codification of a radical anti-breeding agenda.

Some owners think that sterilization is cruel, and many join welfare advocates who complain that the cost of surgery is too high. Some owners project their own feelings about loss of reproductive capacity on their pets, and many men have a difficult time dealing with neutering of their male pets.

Myths and facts

There are many myths about canine reproductive needs. Chiefly among these are the suspicion that neutering turns a male into a sissy and spaying causes a female to get fat and to lament her lost capacity.

The truth is that male dogs, especially those with a submissive personality, are usually better pets if they are neutered. They may have less desire to roam, to mark territory (including furniture), and, if neutered before sexual maturity, they may be less likely to exert dominance over family members. They may also be healthier pets: no testicles means no testicular cancer.

A word of caution, however. Neutering a dog reduces production of testosterone but does not eliminate this hormone. Thus a neutered dog, especially if he has a dominant character, may also retain his desire to roam and an assertive or even aggressive personality. Owners who depend on neutering to resolve behavior problems run a high risk of being disappointed unless they also train the pet to have good manners at home and in public.

Females also tend to be better pets if they do not experience oestrus every six-to-nine months. Heat cycles bring hormonal changes that can lead to personality changes, and oestrus females must be confined to prevent unwanted pregnancies. Repeated heat cycles may subject the reproductive system to uterine and mammary cancers as they age. Some bitches experience false pregnancies that can be a bother to deal with and uterine infections that can be fatal.

While the hormone changes caused by sterilization can contribute to overweight, dogs and bitches do not generally get fat simply as a result of spay or neuter surgery. Like other mammals, they gain weight if they eat too much and exercise too little or are genetically programmed to be hefty. Weight gain that follows sterilization surgery may be linked to those hormone changes but will be aggravated by continuing to feed a high energy diet to a dog that is reducing the need for energy as he reaches his adult size. Excess energy in the food becomes excess fat on the body.

As far as we know, dogs do not lament their lost capability to reproduce. This is a different species than ours; they reproduce to ensure survival of their kind, not to nurture a pup for 18 years, watch it go off to college, marry, establish a career, and produce grandchildren. Bitches nurse their pups for a few weeks, teach them to behave like dogs, and go on. Males know nothing of fatherhood; they do not recognize pups as their own.

Surgery costs: are they too high?

Many animal population control proponents say that veterinarians should reduce the cost of spay-neuter surgery or should offer it for free so that dog owners will sterilize their pets.

In the attempt to increase the numbers of dogs that are sterilized, some folks on all sides of the discussion have cultivated the perception that an ovariohysterectomy (removal of the ovaries and uterus) is quick and easy surgery that can be done on an assembly line, especially since a surgical protocol for puppies has been perfected. In recent years, some national organizations and local shelters have held marathon sterilization clinics, often at low cost, and issued press releases about the number of pets that underwent the surgery in a 24- or 48-hour period. Actually, however, most veterinarians consider the surgery to be major: although it can be quick and easy on young bitches, it can be difficult and time-consuming on bitches that have had several heats or have been bred.

The spay protocol should include a pre-surgical exam (including blood tests for older dogs) followed by injections of a muscle-relaxer and a short-acting barbiturate to allow insertion of a tube into the dog's airway for air and anesthesia.

A technician may prepare the dog while the veterinarian dresses and scrubs for the surgery. The technician cleans and rinses the dog's belly, and the veterinarian uses a sterile scrub pack and scrubs his hands and arms just as a surgeon does before an operation.

The surgical team places the anesthetized dog on her back on the operating table or in a tray that is placed on the table. The tray keeps the dog from sliding and gives the doctor clearer access to the abdomen. The needle used to inject the barbiturate is left in the vein in case more drug is needed.

Gas anesthesia such as Isoflourane is used for the duration of the surgery. Gas anesthesia can easily be increased or decreased if necessary to lighten or deepen the dog's anesthetized state. Injectable anesthesias can be stopped but cannot be reversed; if the dog gets in trouble on the operating table with an injectable anesthesia, she can die.

Many clinics use a heart monitor during the procedure.

The surgery starts when the veterinarian clamps the skin to stretch it taut and begins the incision with a scalpel. The incision must be done carefully to minimize muscle damage.

The dog's uterus is a Y-shaped organ with two horns and a body. In a complete ovariohysterectomy, the veterinarian removes the uterine body and horns, the ovaries, and the tubes connecting the ovaries to the horns. The doctor uses dissolvable sutures for the cuts at the ovaries and the cervix, checks for any abnormalities, bleeders, etc., and closes the incision with layers of stitches.

Time elapsed from start of surgery to the last stitch that closes the incision is about 25 minutes on bitches that have never come into oestrus. Bitches that have had one or more seasons or one or more litters and bitches that carry a lot of abdominal fat can take much longer. Add to this the time for pre-surgical exam and preparation, post-surgical observation, a post-surgical exam if necessary, and removal of stitches, and the cost to safely spay a beloved pet to prevent unwanted litters, reproductive cancers, and uterine infections is a bargain.

Many veterinarians charge more for spays on mature bitches, for the surgery takes longer. Many charge by the weight of the bitch, for more anesthesia is needed to keep a 90-pound bitch safely asleep than is needed for a 25-pound bitch. Generally, a spay surgery for a bitch that weighs less than 100 pounds may be less than $150.

Laser surgery

Many veterinary clinics now offer laser surgery as an alternative to the traditional surgical method. A laser is an intense beam of light that replaces the scalpel as a surgical instrument. The laser seals nerve endings as it cuts so that the pet has less pain during recovery. The laser also speeds surgery by minimizing bleeding, does not crush tissue so reduces post-surgical swelling, and vaporizes bacteria and viruses that may be in the surgical area.

Veterinarians must attend training in the safe and effective use of the laser equipment to use the technique to its full advantage, avoid potential electrical and fire hazards, and protect the patient and the surgical staff from accidental reflection of the beam.

Laser surgery is not perfect. There is some clinical evidence that tissue may not heal as quickly as with traditional surgery, a situation that can require both veterinarians and pet owners to be vigilant during the recovery period. A dog that feels little pain or discomfort may attempt to resume her regular activities even though the tissue at the surgical site may not be completely healed.

Laser surgery is generally more expensive than traditional surgery. Cost of the equipment is $20,000-$30,000, leading veterinarians to charge at least a bit more for this procedure. Many veterinarians try to keep spay costs reasonable so the increase may be minimal.

For more information about laser surgery, see" Lasers Lead Surgery to the Cutting Edge" at

Drawbacks of sterilization

Any surgery has drawbacks. Dogs can react badly to anesthesia in spite of precautions or can experience complications during recovery. Some dogs react negatively to the suture material used, and incisions do not heal properly.

Concurrent with the increase in laws and regulations regarding pet sterilization, research since 1990 has shown that spay and neuter surgeries may have specific drawbacks as well as benefits. Dogs neutered before puberty tend to have longer legs, flatter chests, and narrower skulls that intact dogs of their breeds because the hormones that regulate sexual activity also interact with hormones that guide growth of muscles, bones, and tendons. These physical differences can place more stress on joints and can cause problems for active dogs, especially those in training for agility and those that work in physically stressful jobs.

Additional drawbacks specific to spay surgery include increased incidence of bladder incontinence, triple the frequency of thyroid disease, and higher risk of some cancers, joint problems, and obesity and adverse reactions to vaccinations.

For more information, see "The Long-Term Health Effects of Spay/Neuter in Dogs," by Laura J. Sanborn
March 27, 2007, and "Early Spay-Neuter Considerations for the Canine Athlete: One Veterinarian's Opinion," © 2005 Chris Zink DVM, PhD, DACV,; and pages 48-50 of the 2005 American Kennel Club Canine Health Foundation National Parent Club Canine Health Conference

Questions you may want to ask your vet

Those pet owners who consider using a clinic that charges $40 or $50 or thereabouts for spays should ask some questions before making an appointment for Fluffy.


Pet owners who decide not to spay their bitches and neuter their dogs have the right to make that decision. However, they bear a responsibility to prevent their intact pets from adding to the population of pets that wind up in animal shelters. So, if there is a pregnancy, owners must be prepared to

Obviously, unless a pet owner is also a dedicated breeder, it's cheaper, healthier, and far more practical to spay the bitch.


(1) 2007-08 pet ownership survey of the American Association of Pet Product Manufacturers.

(2) The Humane Society of the US is one of several organizations promoting anti-breeding laws. On its website, HSUS ( claims "Every day in the United States, thousands upon thousands of puppies and kittens are born because of the uncontrolled breeding of pets" (May 2007) and "The solution is this: only by implementing widespread sterilization programs, only by spaying and neutering all companion animals, will we get a handle on pet overpopulation." (September 2007) However, Bob Christiansen of Save Our Strays ( notes that breeding is done by only three-to-four percent of dog-owning households and that increasing spay-neuter programs that help poor families afford the surgery is necessary to reduce the numbers of unintended litters.

(3) "The Long-Term Health Effects of Spay/Neuter in Dogs" by Laura J. Sanborn, March 27, 2007 (

Norma Bennett Woolf

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