Spay And Neuter, Revisited


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For decades now, the value of spaying and neutering our pet cats and dogs has barely been questioned. Beginning in the 1960s, anesthesia and surgery became safer and pets were living longer and becoming a bigger part of our lives. More people were moving into cities as opposed to farms and small towns; it was no longer considered acceptable to drown unwanted puppies and kittens. Thus began a campaign to sterilize— that is, spay and neuter—household pets, mainly dogs and cats.

The movement has been so successful that most pet owners no longer consider the surgery optional. Among middle-class pet owners, spaying and neutering is largely taken for granted and done with little thought. But recent studies have called this practice into question, at least for some dogs. This article will attempt to revisit the benefits and the downsides of routine early sterilization in dogs and cats. (Rabbits and ferrets are also routinely sterilized, but that is beyond the scope of this writer’s expertise!)

So, why do most people spay and neuter their pets?

Convenience. Really, who wants to deal with their female dog going into heat every 5 to 6 months? It’s messy and can lead to unwanted mongrel pups that then need homes. Not to mention the need to keep her away from other dogs for up to a month, twice a year, and the fact that bitches go through pseudocyesis—false pregnancy—with every cycle.

Likewise, neutered males are less likely to urinate in the house, escape the yard, fight with other dogs or impregnate the neighbor’s fancy purebred. Without a sex drive, they are more focused on you, their human. And you won’t have to deal with “testicle shaming” at the dog park.

Legal Considerations. It is technically illegal to own an intact dog over the age of 7 months in Riverside County, according to Ordinance 8.21.010—Spay and neuter. Because California has a law requiring pets to be neutered by the age of 6 months, this is actually somewhat redundant. Both allow exceptions for “a dog (or cat) with a high likelihood of suffering serious bodily harm or death if spayed or neutered, due to age or infirmity. The owner or custodian must obtain written confirmation of this fact from a California licensed veterinarian. If the dog is able to be safely spayed or neutered at a later date, that date must be stated in the written confirmation; should this date be later than 30 days, the owner or custodian must apply for an unaltered dog license.”

In reality, this law is unlikely to be enforced unless the pet is found running loose and impounded. But intact pets are considered more likely to escape their yards and go wandering, endangering themselves, other animals, and even humans, so this seems reasonable. However, licensing laws have been enforced with increasing vigor in recent years, and it costs more to register an intact dog than a sterilized one.

The sweeping acceptance of widespread preventive spay and neuter has gone a long way toward reducing this pet overpopulation nationwide.

While most veterinarians agree with the concept of spaying and neutering for most pets, we have mixed feelings about legislation on the matter. This consternation is bound to increase, as we face more and more information about the potential negative effects of pediatric sterilization, especially in dogs.

Public Health/Population Control. This, of course, is the rationale behind the movement and ultimately the laws regarding spaying and neutering of pets. Every year, thousands of unwanted pets are euthanized—killed—simply because they are not wanted. Many of those, frankly, should never have been born. The sweeping acceptance of widespread preventive spay and neuter has gone a long way toward reducing this pet overpopulation nationwide. Still, according to the ASPCA’s website, each year, approximately 1.5 million shelter animals are euthanized (670,000 dogs and 860,000 cats).

According to, the rate of euthanasia in shelters has declined in the past 50 years—by 90 percent. Obviously, there are other factors involved, such as the movement away from buying purebred dogs and toward adopting shelter dogs. But this is a definite indicator that the main goal behind the movement is working.

The trend in recent years of adopting shelter and rescue animals has further promoted the idea that all pets should be sterilized. Legally structured rescues and shelters in California are required to have pets altered prior to adoption. This may be done as early as 6 weeks of age.

Pet Health. Here’s where we get into some gray areas. A number of health benefits have been cited as reasons to spay and neuter. The policy has absolutely improved the lives of countless dogs who previously would have produced litter after litter until finally being dropped at a shelter or dying from pregnancy-related complications. It has also undoubtedly prevented the needless death of millions of dogs and cats, simply by preventing the birth of millions of puppies and kittens. Aside from the benefit to the animals themselves, the policy has led to improved conditions in shelters and in communities where packs of roving stray dogs were once common.

In addition, the well-known and oftcited advantage of preventing mammary (breast) cancer in females is a big consideration. There is also no chance of developing uterine or ovarian cancer if those organs have been removed. (These are extremely rare in dogs, but may well go undiagnosed if they do occur.) Spayed bitches have a near-zero risk of pyometra, a life-threatening infection of the uterus that requires an emergency hysterectomy to resolve.

So, what’s the problem? Until recently, few stopped to consider the actual health implications of early gonad removal in dogs.

It should be noted that we still have no compelling reason not to spay or neuter cats at an early age, and the challenges of living with unsterilized adult cats make it unlikely that most people would choose not to do so. So the rest of this article will refer to dogs only.

Are there reasons NOT to spay or neuter?

In recent years, studies have been completed in at least Golden Retrievers, Labrador Retrievers (specifically comparing them to Golden Retrievers), Vizslas, German Shepherds, and Rottweillers. Each study looked at specific medical conditions that are common in the breed, comparing dogs that were neutered at a young age with those left intact or neutered later in life.

There seem to be real differences in the incidence of numerous conditions between intact and sterilized dogs.

Like many issues relating to pets, there is a lot of information out there and a lot of it is heavily opinionated. It can be hard to sort the science from the agenda. But there seem to be real differences in the incidence of numerous conditions between intact and sterilized dogs.

Orthopedic Factors. A comparison of, say, a Golden Retriever that was neutered at 6 months of age versus one left intact show that the neutered one has longer, thinner legs, a narrower chest, and a narrower, taller head. This is because sex hormones are involved in telling the bones when to stop growing. Studies appear to show that a Golden neutered young has a significantly greater risk of hip dysplasia and a heightened risk for cranial cruciate ligament rupture, compared to an intact, mature Golden. But that risk means that roughly 5 percent of neutered dogs will, in fact, tear a cruciate ligament. The other 95 percent will not. In the study cited, zero intact Golden Retrievers had cruciate ruptures, but it’s not clear how many unneutered dogs were included in the study.

Another study concluded that early neutering increased the incidence of hip dysplasia by about 50 percent compared to keeping them intact. However, genetic and nutritional factors play a larger role.

Cancer. This may turn out to be the most compelling argument. Historically, it has been argued that neutering prevents testicular cancer and certain other testosteronedependent tumors, as well as prostate disease. However, each of those can be cured by castration at the time of diagnosis, so this argument is somewhat moot.

A study in male Rottweilers conclusively showed that the incidence of bone cancer is higher in neutered versus intact dogs. Osteosarcoma is very common in the breed, enough so that meaningful statistics could be compiled. But critics point out that the study was flawed, because unneutered dogs are less likely to be brought to the vet for diagnosis. Still, later studies seem to bear out at least a slim advantage in keeping these dogs intact, for reducing their risk of bone cancer.

Other studies seem to show that intact large-breed dogs are less likely to develop some of the most common cancers seen in these breeds—hemangiosarcoma, mast cell tumor, and lymphosarcoma. Wouldn’t it be wonderful if we could prevent cancer simply by leaving in a body part? Unfortunately, interpretation of these studies is usually done by people with a strong bias in one direction or the other, so it’s hard to know how valid the results really are. Still, there is no valid health basis for early neutering and all the available evidence points to health advantages for the intact dog, especially for males.

Urinary Incontinence. It has long been recognized that intact females are much less likely to have urinary incontinence issues than are spayed females. Most vets feel that this risk is highest when the spay is done before the first heat.

Obesity. Sterilized pets are more prone to gain excess weight. This isn’t a great argument, however, because diet, genetics, and lifestyle are much more significant factors.

Behavior. It has long been accepted that neutered dogs were calmer and less likely to exhibit unwanted behaviors such as marking, fighting, and “humping” other dogs or objects. Certainly, in some cases, neutering— especially males—has improved such behaviors, seemingly overnight. However, many neutered males and even females may exhibit any of these behaviors. A few studies seem to indicate a higher incidence of anxiety-related behaviors in early-neutered dogs. These studies are somewhat flawed, in that early neutering is more commonly done in shelter or rescue situations, and these dogs have other issues in their lives that might be expected to lead to anxiety. But I mention this for the sake of provoking thought.

So what do I do, Doc?

So, you ask, what’s the bottom line? To spay or not to spay? Unfortunately, there is no strong consensus. Each decision should be made after discussion between the dog’s owner and their veterinarian.

If you follow the “Adopt, don’t shop!” mandate, this question will be taken out of your hands. The success in population control makes it highly unlikely that shelters will change their policy of spaying and neutering before adopting.

Interestingly, all the studies I could find have been done in large purebred dogs—usually popular breeds, because they are easier to study and fewer variables are at play. Likewise, negative results tend not to be published, which may be a factor in the lack of data for, say, Yorkshire Terriers and Shih Tzus. But it’s also true that the health problems cited are far more common in large-breed dogs and may have different causes when they occur in smaller dogs.

Based on a recent discussion and poll on the Veterinary Information Network, many vets are now adjusting their recommendations as to when pets should be spayed or neutered.

Cats: Male and female, between 5 and 6 months. This has not changed.

Small dogs, female: Around 6 months of age for most, preferably before the first heat cycle. Why only small dogs? They seem to have a higher risk of mammary cancer if unspayed and a much lower risk of the other tumors that have been looked at. They are also far more likely to have difficulty delivering puppies if they become pregnant.

Large dogs, female: Discuss this with your veterinarian. The surgery is easier on both the dog and the surgeon if done at a young age. Most dog owners do not want to deal with a bitch going into heat. There are, however, definite advantages to going through a single heat cycle in terms of genital anatomy, bone shape and strength, and other factors. And once the first heat is over, you have about 4 to 5 months before the next one, which means more time for the bones to mature and for her to develop a more breed-typical physical stature. This may reduce her chances of orthopedic problems later in life.

Large or small dogs, male: This is where the most controversy rests. There are exactly zero compelling health reasons for early castration in dogs of any size. Virtually every health issue that neutering prevents, can be cured by neutering at the time of diagnosis. The surgery doesn’t get much harder with age, and recovery from surgery doesn’t take longer.

There are exceptions. Testicles that don’t descend—that is, that are retained inside the abdomen—should definitely be removed. One statistic reports that as many as one in four of these develops malignant cancer, and it’s almost impossible to know about it before serious complications occur. Dogs over the age of 10 have a higher incidence of testicular cancer, and by then there’s no continued advantage of remaining intact. So there’s a reasonable argument in favor of castrating males as adults—although the exact age is up for discussion.

However, male dogs can be hard to live with in some cases. While many are delightful companions, some are incorrigible— they mark, they hump anything that holds still, and they pick fights with other male dogs. They injure themselves trying to escape their yards, or they escape their yards and then injure themselves. For these reasons, few vets would refuse to neuter one at any age.

But increasingly, we won’t push you to do so.

What Happens in the OR?

Spay is a slang term that has become the accepted word for surgical sterilization of female dogs. In most cases, it refers to a total hysterectomy—the removal of both ovaries and most of the uterus. In Europe, and occasionally in the US, some veterinarians prefer to remove only the ovaries, touting surgical simplicity and reduced complications. Others counter that the whole procedure typically takes less than 30 minutes, even in large dogs, and the uterus serves no benefit with the ovaries gone.

In most cases, a small incision is made about halfway between the umbilicus and the pelvis. A small hook is inserted to lift one side of the uterus out. The uterus of a dog or cat is shaped like a long “Y,” so one “horn” is retracted to gently pull the rest of the structure through the incision. Each side is clamped and a piece of suture tied around the blood vessels under the clamp before it’s cut. Then clamps are placed over the stump of the uterus, and it is sutured closed and cut. These tissues are discarded and the incision stitched closed.

A spayed bitch still has a vagina, still urinates the same way, and if she was in heat at the time of surgery, is still sexually attractive to males for up to a few weeks after surgery. However, being “mounted” during this recovery time could seriously hurt her, so it’s important to keep this from happening.

While the term neuter is technically non-gender-specific, it is generally accepted to mean surgical castration of a male animal, mainly dogs and cats. This is a remarkably simple operation, involving a single small incision just in front of the scrotum. Each testicle is pushed through the incision, clamped, tied off, and removed. The incision is then stitched closed. In most cases, it takes five to ten minutes, “from cut to close.” Most dogs are up and walking within a few hours, as soon as they recover from anesthesia. A little-known fact: A freshlyneutered dog can still impregnate a female for up to a month after surgery! This is because sperm is still present in the tubes leading from the testicles to the urethra.

Lillian Roberts, DVM, is the owner of Country Club Animal Clinic, which is located at 36869 Cook Street in Palm Desert. (760) 776-7555


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