To Spay or Not To Spay? That is the Question

I get asked this question A LOT, and I tell them "it's complicated."

For starters, there is a lot of information online. It can be daunting to go through, and not all of it is correct, or some of it is fuzzy. It also depends on where the information comes from. I focus on behavior and training - so most of my point of reference for suggesting a spay or neuter comes from a training perspective. My vet friends will give advice based on the latest scientific information and the health of your pet. Rescue and Shelter groups don't want ANY more homeless pets. Breeders want your dog to look just the right way and to keep the breed pure. Researchers want to discover important and interesting things. It's not too hard to see that information extracted from one expert will differ from another expert. That being said, I've compiled from a variety of sources a list that should help you make the decision to spay or neuter...or not. My best advice is to talk with your vet, and if you are having behavior problems, consult with your trainer, and weigh out what is going to be best for you and your dog specifically.

It's important to say I am not a veterinarian, and am not an expert in the medical field. If you are a vet and have points to add, please feel free to add them in the comments section. I strive to make this blog as informative as possible, and to help the dog owners that read this blog.

My dog will become fat and lazy if altered too early:
  I hate to be the bearer of bad news, but your dog will be just as energetic post surgery than before the surgery. Case in point: my friend Matt and his neutered Frisbee dog, One Eyed Jack.. Not only does he not have his balls, but he also is missing an eye, and as you can see in the video, he's not slowing down for anyone!
If spaying or neutering calmed dogs down and made them lazy, Border Collies and Jack Russell Terriers would be WAY more popular in urban environments. I'd also probably have a Viszla to sit at home, fatten it up, and just watch football on weekends instead of the requisite 12 mile hikes the un-neutered ones need.

My female dog HAS to have a litter/heat cycle before she's spayed: 
 The theory behind this is "it calms the dog down" or "she becomes more mature". This is especially frustrating to hear when it's in regards to a bitch having a littler of puppies. First of all, on average, a female dog will have her first cycle between 6 and 15 months old. By the time the dog has her first litter, she'd be more mature regardless of if she has a litter or not because she got older, not necessarily because she had a litter.
 Additionally, the spay surgery for female dogs is less complex if they don't go  through a heat cycle. The tissue is more veinous, and therefore, more of  a challenge (and more expensive!) to remove.
 Lastly, and perhaps the most important: you won't be accidentally or intentionally, contributing to the pet  overpopulation problem. As much as you think your dog would be a "great  mom", "a wonderful stud", or the puppies would be oh, so very cute, a few quick statistics should bring you right back to reality. Between 4-6 MILLION pets are euthanized each year  because they are homeless. According to The  Humane Society, these aren't just street dogs that are  reproducing. These stats factor in the loved pets and even pure bred  dogs that find themselves in shelters all across the United States. One animal is killed in a shelter every single second.  For all the people who love the animals that are in your home, let me applaud you - because only one pet in 10 finds a permanent, lifetime home. Don't  add to the population problem, no matter how cute the puppies would be -  there are far too many cute puppies that need help immediately.

Now, go give your dog (or cat) a big hug. I just did.

Our kids should witness the miracle of birth:
 That's all fine and dandy, but that's no reason to have your dog go through the stress of pregnancy and mating (the male and female get "stuck" or "tied" together during sex, which is really difficult to explain to young children). Some bitches will kill and eat the young that are sick and unhealthy. That's not exactly "witnessing the miracle of life" - it's nature at it's rawest, and it's really hard to explain why there were 5 puppies, and now 4.
 Most people think breeders make a ton of money on a litter. That's not the case. Most break even, at best.
Details on breeding a litter, and the cost breakdown. It's staggeringly expensive, and you're lucky if you break even. You have to do it out of love, not for any dues you owe your dog or your kids.

You'd be better off renting Porky's and explaining The Birds and the Bees that way.

Other Really Good Reasons To Consider Spay/Neuter: 
 -According to Dr. Nicholas Dodman, neutering a dog can reduce his tendency to roam by 90%. Translation: If he has no junk, he has no reason to look for hotties, and therefore, won't be as likely to be hit by a car in search of a nice piece of tail (which, he WILL dig under fences and jump off of 3 story balconies for. I witnessed the latter. Romeo, eat your heart out).
 -Altering significantly reduces the chance of embarrassing leg-humping of your guests, especially if he is neutered before he reaches sexual maturity.
 -Reduces "fixation" in dog/dog situations (where a dog gets fixated on one dog to the point of obsession), like at the dog park.
 -Marking inappropriately is less likely when the dog is neutered (and proper house-training techniques are applied).

 -Cryptorchid dogs (dogs whose testicles haven't descended) tend to have a higher rate of tumor growth in the undescended testicles. It's recommended that these dogs get neutered.
  -Spaying a female dog eliminates uterine cancer, ovarian cancer, and cervical cancer.
  -Additionally, spaying nearly eliminates all chances of pyometra, a nasty uterine infection that requires surgery to eliminate. I've seen some pretty nasty pyometras back in the days of working at the animal hospital. It's incredibly sad, and very serious, and can be fatal.
 -Spayed females have a drastically reduced chance of developing mammary (breast) cancer.
 -Spayed females won't bleed all over your house for 10 days straight twice a year. 
 -Cheaper pet licensing fees when you go to the city hall annually to update your dogs license.

Keep in mind that not all of our canine problems are solved easily with a snip. If your dog has tendency to mark in the house, getting him neutered is not going to solve the problem for you, but it may help you get the behavior under control in combination with training. I know many male dogs that were neutered before sexual maturity that still hump and mount dogs at the park - but many of them have figured out that it's a quick way to get another dog to engage in play. "I mount, they chase me - yay playtime!" Not all of the testosterone will be gone from your dogs system (and the later they are neutered, the longer it takes for the bulk of the Testosterone to get out of your dogs system: vets say up to 30 days post surgery for best effect), so your dog may still engage in the behaviors you dislike. You still will have to train your dog to get the behaviors you dislike under control - but for some challenging things (like inappropriate humping, roaming and sexually linked behaviors), it gives you a leg up for training.

Risks To Spay/Neuter:
 - As with any surgical procedure, there are risks related to adverse reactions to anesthesia, infection, and other complications; however for spays and neuters, the instances of serious complications are extremely low.
 - Dogs neutered before adolescence tend to have longer legs, flatter chests, and a rounder face. By holding on to the testosterone longer, the growth plates (specifically, in the legs) close sooner, produce more muscle mass, and a more angular head. These are mostly aesthetic issues, though there are some scientific studies in the works that are addressing if there is any concern other than aesthetic value.
 - Bladder incontinence in females, though the increased risk of incontenence tends to be for females spayed REALLY early: it's call pediatric spay, any spay procedure occuring prior to 24 weeks of age. This procedure tends to only happen in shelters to make sure that the dogs leaving the shelter won't come back to the shelter with 6 puppies later on.
 - Joint problems (due to the hormones responsible for closing growth plates being absent or minimized), which is more of a concern for sport dogs and large breed dogs. Either way - make SURE your dog is on an appropriate diet for large breed puppies - this will help with the joint issues cited in some of these studies.
 - Increased risk of cardiac hemangiosarcomas (which, again, tends to occur in larger dogs anyway, regardless of spay or neuter status, between 6 and 13 years of age)

Two Biggies: Bone Cancer and Hypothyroidism
 - According to one study, osteosarcoma (bone cancer) is higher in dogs that are spayed or neutered. However, the study is more complex than a simple statement. What the study says is "the risk of osteosarcoma rose with increasing age, increasing body  weight, increasing standard weight and increasing standard height...The highest risk of  osteosarcomas was found for large and giant breeds, while small breeds  had reduced risks. A twofold excess risk was observed among neutered  dogs. {The study} showed a stronger and more consistent  association of osteosarcoma with increasing height than increasing  weight." So there is an increase in bone cancers in dogs that are neutered, but taking the whole picture into account, there is a greater likelihood of osteosarcoma in taller, bigger dogs - which, we've known for years are the dogs that have always been more prone to this type of cancer, and being neutered increases this already higher risk in larger dogs specifically.

  - Hypothyroidism had been documented in ONE case study as being higher in cases where the animal was sexually altered. There are two things to keep in mind about this statistic: The study that is frequently cited regarding this was conducted in 1994. That's not to negate the study, but the study was conducted 16 years ago and there have been few studies since that I could easily find. It turns out, the reason I couldn't find any studies is because there aren't any! Dr. Laurie Siperstein-Cook at the SPCA in Sacramento CA explains that the reason I couldn't find other studies is because they don't exist. Recent spay/neuter discussions rarely talk about this at all, and the fact that it still comes up from time to time is unfortunate.

The dogs that had the highest risk of hypothyroidism post-neuter in this (now bunk) study were Golden Retrievers and Doberman Pinschers, but they are also two breeds that have higher rates of hypothyroidism regardless of if they are sexually altered. So, regardless of getting the snip, these dogs are already at higher risk, which means this is a concern among these breeds, not these breeds who are spayed/neutered.

In Conclusion: To Alter, or Not?
I can say, with certainty, that our 80 pound greyhound who was neutered at 3 years old, was always at a higher risk of developing bone cancer, than our 40 pound Border collie, who was spayed at 4 months old in a shelter. Even though he was neutered really late, he wasn’t safe from a cancer that has killed at least 6 greyhounds that I knew personally in the last 10 years, including him. Regardless if Zeppelin was neutered, the chances he would succumb to osteosarcoma were so high, that I had to talk with my husband about it prior to adopting the dog. I can say, with relative confidence, that his testicles, present or absent, would not have changed the outcome. He still statistically would have likely had cancer, and died as a result of it, not because he was neutered, but because he was a greyhound.
The rescue group had him neutered before he came to us, but if it were up to me, I'd still go ahead and have the surgery. Behavior is worth it to me, and I feel that he lived a happier life not dealing with behavioral issues that were curbed with a routine procedure. I was happier knowing my boy wasn't planning his escape to knock up the intact pitbull down the street twice a year. Besides, I’ve actually met a pit-greyhound mix - it was very odd. Yours maybe a different decision entirely, but make sure that the decision you make is informed and that you are asking the right, reputable professionals.
Any study you read, think critically about it. Just like with human studies, one day coffee is bad for you, the next day it will add 75 years to your life. You have to ask yourself what is the study trying to prove? How old is the study? What does your vet say, who is hopefully up to date on the latest scientific data? What issues are you having with your dog, and what is your dogs personality? What breed is your dog, and what health issues are related to that particular breed? Are you in an area where your dog can knock up the neighbors prize winning poodle, creating the ill advised ”sharpoodle”? Is your dog the bitch that brings all the boys to the yard, leaving you with a huge vet bill and 8 puppies you can't home? Is the obsessive leg humping worth not neutering your mastiff so he can have a big blocky head, and can you deal with a 200 pound dog with an embarrassing humping problem that you can't reverse?

Make your own list of pros and cons, and figure out what will be best for your family, and ultimately for your dog. And for Dog sake, talk with your veterinarian!


  1. Did you see this one? Apparently you can have just the ovaries removed.. or just the uterus, which will make all the scientific literature even more complicated!!


    :) I personally would spay/neuter because of the overpopulation issue (and the being responsible for any puppies resulting issue) but I think that timing and type of surgery is up for debate as more research comes out.

  2. Jess, I couldn't agree with you more :)

  3. Melissa, thanks for this thoughtful post about spaying and neutering (especially as most articles on the subject aren't as objective).

    Question that may or may not be stupid: Is a vasectomy a reasonable option for male dogs to control overpopulation? (Obviously, I understand that this wouldn't mitigate the behavioral issues that neutering solves.) I never see anyone talk about this, despite some of the health risks of neutering.

    We're not ready to have a dog yet, but this is definitely a lot of food for thought.

  4. Hey Joe!

    The pros (from what I could find - I've never explored this before now, so thanks for the question!):
    -quicker recovery time/less invasive
    -people who advocate for keeping animal hormones of the dog get to keep the hormones.
    -hypothetically can get the procedure done at a much earlier time since the sex hormones are still in place (so no waiting until 6 months of age).

    The cons:
    -The dog will still be driven to mate, which means will still mount a female in heat, and some of those "bullheaded sperm" might still get through.
    -the risks of hormone linked cancers will occur at the same rate as an unaltered animal.

    It's definitely something to think about as spay/neuter is becoming less of a "one size fits all" procedure. There is also chemical sterilization, just to toss another option out there!