To spay, or not to spay? That is the question. Whether 'tis nobler in the mind to suffer The slings and arrows of animal rights activists Or to take arms against a sea of troubles...
(With apologies to The Bard)
We've been told for years the only way to stop pet overpopulation was to spay and neuter all dogs. Hmmm, if that were to actually happen then in one generation there would be NO MORE DOGS.
If there really is a pet overpopulation problem, then why are rescues paying to bring strays from other countries at the rate of a million dogs every year? Hmmm, makes you wonder. (Yes, I acknowledge the humanitarian issues such as the strays in Sochi, Russia that were being killed before the Olympic Games. Another question is why aren't these dogs properly vetted before bringing in diseases such as rabies and brucellosis?)
We've been told that spaying and neutering makes happier and healthier pets. Hmmm. A C-BARQ study found that "spayed female dogs tend to be more aggressive toward their owners and to strangers than intact females" and there wasn't much evidence that neutering would stop aggressive behavior in male dogs. Also that early spay/neuter "was associated with an increased incidence of noise phobias." I don't think that sounds happier.
What about healthier?
Health effects of neutering male dogs are somewhat different than spaying female dogs.
Neutering male dogs has some positives - it eliminates the tiny risk (less than 1%) of dying from testicular cancer and it reduces the risks of non-cancerous prostate disorders and perianal fistulas.
But there are several potential negatives for males:
- early neutering significantly increases the risk of bone cancer (osteosarcoma) which is common in larger dogs and has a poor prognosis
- increases the risks of hypothyroidism, cardiac hemangiosarcoma, geriatric cognitive impairment, obesity, prostate cancer, urinary tract cancers, orthopedic disorders and adverse reactions to vaccines
It's a little different with females, although there are both positives and negatives.
Spaying reduces the risk of mammary tumors (if done before 2-1/2 years old), almost eliminates the risk of pyometra and reduces the risks of perianal fistulas and the very small risks (<0.5%) of uterine, cervical and ovarian tumors.
But spaying also:
- if done early, significantly increases the risk of bone cancer (osteosarcoma) which is common in larger dogs and has a poor prognosis
- increases the risks of splenic and cardiac hemangiosarcomas which are common cancers
- increases the risks of hypothyroidism, obesity, spay incontinence, urinary tract infections, recessed vulva, vaginal dermatitis, vaginitis, urinary tract tumors, orthopedic disorders and adverse reactions to vaccines
Overall the study concluded that "no compelling case can be made for neutering most male dogs to prevent future health problems." But it's a more complex decision with most female dogs. Some risks can be reduced or avoided by waiting until the dog is physically mature. It's well worth your time to read more.
For a little more insight on spaying females, there is a study that concluded shorter lifespan was associated with spaying. They looked at Rottweilers that had an average lifespan of about 9-1/2 years compared with Rotties who lived to at least 13 years old.
Females tend to live longer than males, but it didn't hold true for females that were spayed before 4 years old.
As they dug deeper, their results showed that how long females kept their ovaries affected how long they lived. If they were at least six years old before being spayed they were 4.6 times more likely to live an exceptionally long life. When they excluded all deaths due to cancer, they found "females that kept their ovaries the longest were 9 times more likely to reach exceptional longevity than females with shortest ovary exposure."
Research funded by the AKC Canine Health Foundation studied the incidence of cancer and joint problems based on age at the time of neutering. They determined:
- Risk of developing hip dysplasia DOUBLED with earlier onset for males who were neutered early (less than 12 months old).
- Early spay/neuter increased the risk of canine cruciate ligament injury
- Chance of developing lymphoma was three times greater in males who were neutered early
- Interestingly mast cell tumors in males and females were highest in the late-neuter group (over 12 months) compared to the early neuter and intact groups
- Hemangiosarcoma in females was also highest in the late-neuter group compared to the early neuter and intact groups
- Overall they found "increased likelihood of hemangiosarcoma, lymphoma, mast cell tumors, and canine cruciate ligament (CCL) rupture in neutered dogs"
Another veterinarian summarized numerous research findings and papers. He also found increased orthopedic issues and cancers:
- Some growth plates closed later in bitches spayed at 7 weeks compared to those spayed at 7 months and those spayed at 7 months had growth plates that closed later than intact bitches. This results in significantly longer leg bones in dogs that were spayed/neutered early compared to intact dogs. (Note: other research found when some bones continue to grow after they would normally stop leads to an imbalance with increased strain causing a higher incidence of CCL tears and hip dysplasia.)
- Spayed females had a five time greater risk for cardiac hemangiosarcoma and over two times greater risk of splenic hemangiosarcome compared to intact females.
- Neutered males had 2-4 times greater risk of prostate and bladder cancers compared to intact males.
- Female Labs had more mast cell cancer, hemangiosarcoma, and lymphoma if they were spayed between 2-8 years old.
- Although the risk of mammary cancer in females increases with each heat cycle, the overall risk of getting a mammary tumor was 0.2% compared to the "200 to 400% increased risk of other cancers in spayed females."
- Other risks of early spaying included urinary incontinence, hypothyroidism and pancreatitis compared to intact females. And higher risk of adverse reactions to vaccines for all neutered dogs.
In a nutshell, spay/neuter tends to increase the risks of orthopedic problems and of some types of cancers. It may also reduce lifespan. However the results can be different depending on WHEN they are spayed or neutered with early spay/neuter having higher risks of various problems.
The recommendations are pretty clear for males - don't neuter unless you have to. If your intact dog develops prostate or testicular cancer - the main risks - neutering usually resolves the problem.
It's a little less clear for females. Early spay does seems to cause more problems than waiting until at least maturity, however the longevity study suggests females may live longer if they're not spayed until they're at least 4-6 years old. But each heat cycle increases the chance of pyometra and breast cancer. An alternative to traditional spay is an ovary sparing spay which involves removing the uterus and cervix while leaving one or both ovaries. Unfortunately not all veterinarians know how - and are willing - to do this surgery.
Here in the US spay/neuter is expected unless you will be breeding (which has it's own set of issues), but other countries consider spaying and neutering inhumane and in some countries it's even illegal. In Sweden and Norway nearly all the dogs are intact and you have to get permission for the surgery based on your dog's needs. They believe it is "more responsible to leave a dog intact and guard and train the dog properly rather than have mass spay/neuter campaigns to prevent unwanted pregnancies."
Another thing to consider is that your pet may die due to the surgery. It doesn't happen very often, but it's pretty devastating when it's YOUR pet that dies. I had a beautiful, healthy palomino colt die during a "routine" gelding.
What are other potential downsides of NOT spaying or neutering?
1. A few weeks every year of messiness for females, but they can be taught to wear "shorts" which takes care of most of the problem. However don't leave them clothed and unsupervised as some have been known to eat the material in their efforts at cleanliness.
2. Potentially higher licensing costs which is partially offset by not having to pay for the surgery and can be potentially offset by fewer health issues.
3. Higher HOA fees and even bans on intact animals.
4. Accidents leading to puppies.
5. Criticism from people who believe every pet should be neutered and pressure from veterinarians to neuter, often at a young age.
So do what's right for your dog based on knowledge rather than custom. If you decide to spay or neuter, put it off at least until your dog is mature which is about 18-24 months for a Labrador.
Here are some more resources:
Podcast on early spay and neuter research
More on the Rottweiler longevity study