An inconvenient truth

On obesity and sterilization in dogs

If you’re like me, you were raised to think that all dogs should be sterilized. Veterinary school and our lives in practice further reinforced that truism. Dogs, we were reverently informed, require sterilization if they’re to live long, healthy lives. To fail to spay and neuter every pet, goes the mantra, is irresponsible and near tantamount to animal cruelty.

For decades, it only made sense to me, too. Dogs, like humans, experience the probability of diseased reproductive organs. And, of course, animal overpopulation is the inevitable result of an intact reproductive system. Sterilization, therefore, has long been the gospel of modern pet medicine. Praise be!

Enter the 21st century and its newfangled ideas with respect to our dogs’ reproductive tracts. Suddenly it seemed we were hearing more about diseases related specifically to sterilization in dogs.

Hormone-related incontinence in females was the first such culprit, one we immediately glossed over as the inevitable result of sterilization, one that’s a necessary risk, veterinarians lamented. Then we learned about a few studies that identified an increased risk of certain cancers and orthopedic diseases in sterilized dogs. Could it be that canine sterilization was not incontrovertibly benign?

Despite these recent findings, the prevention of reproductive diseases remains a perfectly legitimate reason to spay and neuter. That is what we are taught in veterinary school, and it is widely regarded as the primary reason veterinarians recommend sterilization procedures like spays and neuters.

But as we’re now learning, preventing reproductive disease isn’t necessarily a good enough reason to remove organs; not if those organs offer more benefits than they pose risks. Not if sterilization, should it become necessary, can cure any future disease.

Arguments for not sterilizing

As a probably unnecessary recap, here’s a quick rundown of the risks and benefits of letting our dogs remain intact:

Risks posed by reproductive organs:
These include prostat ic disease, testicular disease, and perineal hernias for boys. Most are highly treatable. For girls, pyometra (uterine infections) and mammary tumors are the biggest risk. All but the most aggressive mammary tumors are treatable, if caught early. Male behaviors like roaming, urine marking, and aggression are more likely.

Benefits of intact reproductive organs:
Normal hormone levels may protect dogs from suffering from certain orthopedic diseases along with some cancers. In females, low sex hormone levels predispose them to hormone-related incontinence. On the behavior side, very recent work indicates that intact male dogs may be more socially adept. They may be less aggressive with other dogs and may experience less fear-based aggression in social interactions.

The big problem

As the 21st century dawned, it became clear that the US had a huge pet obesity problem. Since then, our dogs have continued to become so incredibly fat that we’re unable to even properly understand how they got that way. Sure, we know it’s because we’re feeding them more calories than they expend, but that’s a long way from the heart of it. What, exactly, has changed in recent decades, to account for the boom?

To be sure, it has a lot to do with how we feed ourselves and our families and the “food is love” culture we reside in. It also has a lot to do with the rise of the pet food industry and the proliferation of diets and treats it so effectively markets. But could there be another component we conveniently tend to overlook? After all, everyone knows for sure that spayed and neutered dogs are heavier.

There’s no doubt about it. The inconvenient truth is that dog sterilization leads to fatter dogs. This we know. No one disputes it. Whatever you think about all these new studies on sterilization and certain diseases, the reality of the situation is this: Intact dogs are much more likely to enjoy healthy weights.

This raises several questions:
a) Is spaying and neutering our dogs actually healthier for them?
b) Have we been led astray in our thinking on this issue by our community’s desire to prevent pet overpopulation?
c) Are veterinarians actually recommending what’s best for our individual dogs?
d) Have we researched this issue well enough given our level of sophistication on so many other veterinary issues?

The answers:
a) Don’t know.
b) Absolutely.
c) Probably not.
d) Hell no!

In my opinion, health and overpopulation are two separate issues, and they need to be divorced once and for all. After all, sterilization is not required to achieve normal population levels. In fact, in Europe, for example, where spaying and neutering isn’t common, there is no dog overpopulation problem (and, incidentally, a much reduced incidence of canine obesity compared to US dogs).

Indeed, we have to quit thinking that spaying and neutering is the solution and that overpopulation is inevitable otherwise. I mean, responsible Americans are completely capable of keeping their pets from breeding just like Europeans do. (Aren’t we?) Yet every time I raise the issue I get lambasted by loud-voiced zealots who claim that I’m irresponsibly encouraging pet overpopulation by suggesting there may be alternatives to sterilization.

The way I see it, however, until we do stop talking about overpopulation and sterilization in the same breath, we’ll have to face the inevitable reality:
Our dogs are fat, and they’re destined to get fatter. Perhaps one day we’ll be able to look at this problem more dispassionately, but until then, I expect to continue to see more obesity-related disease in dogs than almost any other
medical condition.

Dr. Patty Khuly owns a small animal practice in Miami and is a passionate blogger at Columnists’ opinions do not necessarily reflect those of Veterinary Practice News.

8 thoughts on “An inconvenient truth

  1. Wow, is this vet for real? A veterinarian who actually believes pets are fat because of spay/neuter? Seriously? Americans (a major majority of whom are NOT responsible people, by the way) overfeed themselves and their dogs, end of story. This isn’t a spay/neuter issue. It’s a cultural issue. And no, pyometra and mammary cancer are almost never caught early (again, a major majority of people aren’t responsible for recognizing the signs) and trying to mop up those problems is never ending. I’m not sure what fairy tale world our Florida doctor lives in, but those of us in the trenches for 30 years is lower income regions could teach her some reality. But don’t preach your wishful thinking garbage here.

    1. This^^^This^^^and This!!!Obesity is a feeding issue, not a spay/neuter issue! In the few intact dogs we see, obesity is still a problem not to mention they have had a mixed litter every 6 months!!! GET REAL!!!

  2. Rebeka M – in all due respect to years in the trenches, Patty seems to be current on the literature here. She asks “Are veterinarians actually recommending what’s best for our individual dogs?” . Clearly in a scenario where you know a cohort of owners won’t be responsible and their bitches will whelp unwanted puppies twice a year, you should recommend blanket neutering. On an individual animal level however, it is unfair to recommend that when study after study in the last two decades keep revealing negative side effects of neutering including increased incidence of multiple neoplasias (outside of mammary and testicular ;-)) as well as increased incidence of other pathologies such 3-fold increased risk of ACL tear (the most common canine ortho ‘disease’). Overall, neutered pet animals have decreased lifespans compared to those neutered before puberty similar to woman who lose their ovaries prior to age 50. While it is convenient to blame obesity on american culture and out lack of self control objectively physiology is surely connected. Cats tend to be fed free choice the neutered pet cats routinely are overweight compared to not neutered. Women who suffer from hypothyroidism seem to suffer from weight gain despite supplementation and those with hyperthyroidism can eat what they like and don’t put weight on. Those are pathological states but illustrate that weight is not all about self control.

  3. I am not a neuter fanatic. I even wrote a convincing letter to a rescue organization one time arguing against neutering of a dog they placed because it was not medically in the best interest of the dog, and he recently died at 11 with his testicles. He had heart disease and two kinds of testicular cancer and inflammatory bowel disease, though it was the heart disease that killed him. I had a complete necropsy performed on this dog because I wanted to find out if the disease I research affected his heart. More complete necropsies would much better inform this relationship between health and reproductive status, though I fully realize such a study is logistically and financially impossible, unless they can necropsy every dog that dies in the lifetime Golden Retriever study that is currently underway.

    I have owned 14 dogs since I was 18 years old. They have been overwhelmingly female, mixed breed and purebreed, and neutered anywhere from 5 months (obtained that way) to 5 years of age. I bred one deliberate litter and have never had an accidental litter. In this very limited population of dogs, not a single one has been overweight, before or afer neuter. Their diseases of old age and age at death did not seem to be associated with age at neuter. All the dogs have been in the 30-45 lb range. I train with food and do dog sports, and my dogs are still not overweight, in spite of being neutered. So obesity may be a “lifestyle” problem more than a neuter problem, even though it undoubtedly easier to keep an intact animal an appropriate body weight. People don’t pay attention to what they feed their dogs and if you read dog food bags, because most of my clients want to feed their dogs good food, the caloric content just keeps going up. Clients buy a “good, high quality food”, and it has 400 calories per cup and they feed what is recommended on the bag. Even an unneutered dog can get fat on that if its primary job is sitting on the couch all day long with a 1 mile slow walk once or twice daily. Do the math.

    I am no longer in day practice and see a specialized group of ill dogs only, so I refrain from commenting on the pet overpopulation issue, except that our animal shelter in my city seems to be just as full of puppies, kittens, and unneutered dogs and cats all the time, even though 95% of the animals I see are neutered, and 100% of cats. Most people cannot live with an intact male or female cat in a house because of behavior, and the ongoing arguments and trying to come up with solutions to feral cat populations underscores the rapidity of cat reproduction when not controlled with sterilization.

    Personally, I neuter my own dogs out of a preference not to have to live with the behavioral characteristcs of an intact male, and because estrus interferes with entering sporting events, at least until such time as AKC changes the rules regarding participating by intact females. My motivation would decrease considerably, and I understand this is being considered by AKC. Unfortunately, I am of the snobbish category of person that really thinks that all crossbred dogs should be neutered to prevent future mixed breed puppies, but I suppose that is its own form of “brainwashing” I have been brought up with culturally. I would never have dreamed of breeding my mixed breed dogs, though I enjoyed them as pets just as much as my purebred dogs and have nothing at all against them.

    In an argument against spaying, I think my dogs have experienced a high amount of estrogen related incontinence. In the arguments for neutering in general, information was omitted on the fact that neutered animals are retained in homes better than unneutered ones (I think this was published in VPN by Karen Overall a few years ago) and that this, too, is a consideration in health and longevity of pets. I do agree that the neutering issue is not a “one size fits all problem,” and I have lots of responsible “dog friends” who have no issues with unwanted litters and live with both genders of intact dogs because they want to breed them, or because they do not mind dealing with the behaviors that are normal for intact dogs. I don’t have the data, but I do think the average, pet-owning American household lacks both the motivation and the education to keep intact pets from reproducing.

  4. When I had my girl spayed at age 12, the vet asked me to check her age. He thought she was about 3. She was a champion showdog
    So remained intact. She had a couple of carefully planned litters that Included champions.
    But I spayed her for my convenience. She’s 16 now. I agree that intact dogs stay in better shape. It helps know longevity too. But people too lazy to control dogs probably ought to neuter them.

  5. Question: why is there not available the veterinary equivalents of tubal ligation and vasectomy? Wouldn’t these procedures provide that hormonal benefits enjoyed by intact dogs, while at the same time address population control concerns?

  6. M. – I’m a couple months late on this article and your response, but your attitude toward Dr. Khuly and apparently anyone who is thinking more carefully about auto spays/neuters for every dog on U.S. soil is unproductive, not to mention just plain nasty. There are other worlds out here beyond the one you occupy, and while your anger may be warranted, it shouldn’t be aimed at veterinarians who are looking more closing at the health problems brought on by removing all the sex hormones in young dogs. Take a chill pill, open your mind, and pry that heart of yours back open.

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