When Should I Neuter My Labrador Retriever Puppy?

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You have a new Labrador retriever puppy. Congratulations! Now you’re trying to decide when you should neuter him. 

There are various theories regarding when–and if–he should be neutered

In this article, I’ll explain current scientific data regarding neutering your Labrador retriever puppy. 

I’ll also discuss many theories why people traditionally fixed their dogs and whether they are scientifically valid. 

And I’ll examine other reasons that you should consider when making your decision about spaying or neutering your Labrador retriever.

Yellow Labrador Retriever puppy with head in the grassYellow Labrador Retriever puppy with head in the grass

As a dog trainer and behavior consultant, I’ve trained many Labrador retrievers over the years. Most have been fixed, but many have not. 

Labs are such friendly, intelligent, energetic dogs. I find them to be a pleasure to work with–whether they’re neutered, spayed, or not.

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Reasons People Traditionally Had Their Dogs Neutered or Spayed

In the United States, it’s estimated that between 70 and 85 percent of dogs have been fixed. The technical term is gonadectomy, which is the surgical removal of the testes in males or ovaries in females. 

Neutering is considered to be a simpler, less-invasive surgery than spaying. But both are safe if performed by an experienced, licensed veterinarian.

Traditionally, people have had their puppies fixed for various reasons, some of which are behavioral or medical. Others are for the owner’s convenience. They are as follows:

  • Not to have puppies
  • Not to have a female dog who is in heat 
  • To stop or prevent a male dog from roaming and seeking out a female dog in heat
  • To have a calmer puppy
  • To prevent cancer
  • To ensure that he doesn’t gain weight
  • To prevent joint and other disorders
  • To stop or prevent urine marking
  • To stop or prevent excessive barking
  • To stop or prevent aggression towards people or animals
  • To stop or prevent mounting 
  • To stop or prevent chasing small animals
  • To have a more compliant, trainable dog

Much of the above anecdotal evidence and information passed on through time has been debunked by modern scientific studies. 

Some physical problems have been found in larger numbers in neutered and spayed Labrador retrievers than in intact Labs. 

And numerous behavioral problems have been found to increase in the neutered and spayed population as compared to their intact counterparts.

Current Medical Theories on Neutering or Spaying Labradors

Different dogs mature at various ages. Researchers have discovered that even amongst similar breeds and sizes of dogs, there are very different medical outcomes for some breeds when they are spayed or neutered. 

Researchers Benjamin and Lynette Hart of the University of California, Davis, examined 35 dog breeds and found that vulnerability to certain diseases varies greatly depending upon breed.

Their study was set forth in the Journal Frontiers in Veterinary Science

They learned that there is no one-size-fits-all decision regarding the medical effects of spaying and neutering on various breeds. 

And their data showed very specific findings with regard to the 35 breeds studied, including Labrador retrievers.

In their study of Labrador retrievers, there were 714 intact males, 381 neutered males, 400 intact females, and 438 spayed females. This equals 1,933 Labs in total.

1. Joint Disorders in Labrador Retrievers

A significant increase was found regarding joint disorders in fixed dogs than occurred in intact ones. One or more joint disorders were reported in six percent of intact male and female Labrador retrievers. 

However, the risk of joint disorders increased by about 100 percent in desexed Labs. 

In male Labs neutered before six months old, 13 percent were found to suffer from joint disorders. 

In female Labradors spayed before six months old and between six and 12 months old, the risk of joint disorders was found to be between 11 and 12 percent.

2. Cancers in Labrador Retrievers

As far as cancers were concerned, there was a six percent risk for intact males and an eight percent risk for intact females. 

Neutering was not associated with any evident increased risk of cancer at any age studied. 

However, Mast Cell tumors were found in one percent of intact females and two percent of females who were spayed between two and eight years of age. 

3. Other Physical Concerns in Labrador Retrievers

Two percent of intact female Labs were found to have pyometra as compared to none in their spayed counterparts. 

Urinary incontinence was reported in two to three percent of females who were spayed through one year old. 

4. Conclusions Regarding Age To Spay or Neuter for Medical Reasons

The Harts concluded that the guidelines suggested that males should be neutered if at all after they are six months old because of the much higher rate of problems suffered by male Labrador retrievers fixed before that age. 

They found that the guidelines suggest spaying female Labs if at all after one year old because of the increase of joint disorders when spayed prior to 11 months old.

Current Behavioral Theories on Neutering and Spaying Dogs

There have been long-held beliefs that spaying and neutering help prevent or end certain undesirable behaviors such as those in the bulleted list above. 

But many of those anecdotal thoughts have been disproven by current scientific studies.

One of the major behavioral studies on the effect of spaying and neutering on dogs is the Canine Behavioral Assessment and Research Questionnaire (C-BARQ). 

This standardized behavioral evaluation test was developed and validated by Yuying and James Serpell in 2003 at the University of Pennsylvania. 

Since 2005, the public has been able to access the study and fill in numerical scores for 14 different categories of dog behavior. 

The current database contains detailed behavioral evaluations for about 50,000 pet dogs consisting of more than 300 different breeds and cross breeds.

Dr. Parvene Farhoody, Director of Behavior Matters, interpreted the C-BARQ data of 10,839 dogs in her master’s thesis for Hunter College. 

With regard to many of the behavioral studies, generally the earlier that a dog was fixed, the more negative effects were seen regarding behavior.  

In the studies, female dogs who were spayed later in life were less likely to show an increase in aggression than females spayed at a young age. 

And neutered male dogs were found to be more likely to be aggressive toward intact males than other intact males were.

So how are all behaviors affected by neutering or spaying? Here’s what was found:

1. Preventing a Male Dog from Roaming and Seeking out a Female Dog in Heat

Current studies confirm that neutered males are less likely than their intact counterparts to roam and seek female dogs in heat.

2. Having a calmer puppy

Modern studies show that fixed dogs are about eight percent more excitable than intact ones. 

A significant increase in fear and anxiety was seen in neutered dogs regardless of the age of neutering.

3. Stopping or Preventing Urine Marking

The studies showed that neutered dogs are less likely to leave urine marks indoors.

4. Stopping or Preventing Excessive Barking

More anxious and fearful behaviors as well as more excitability were seen in desexed male and female dogs. 

And excessive barking when alarmed or excited was seen more often in neutered dogs. 

However, neutered dogs were found to be less likely to howl when left alone.

5. Stopping or Preventing Aggression

This was one of the most surprising results in the studies. Contrary to popular belief, more aggressive behaviors were seen in fixed dogs than in intact ones. 

Specifically, neutered dogs were more likely show an increase in certain aggressive behaviors when:

  • Delivery workers approached the home
  • Strangers walked past their home
  • Joggers, cyclists, and rollerbladers passed by
  • They were approached directly by an unfamiliar female dog
  • An unfamiliar person approached the owner or another family member or even just visited the home
  • Small animals such as cats or squirrels entered the yard

The significantly higher aggression score seen in neutered males as compared to intact dogs was seen regardless of the age that the dogs were neutered. 

In spayed females, there was a significant increase in aggression scores when they were spayed at 12 months old or earlier as compared with their intact counterparts.

6. Fear-Related Behaviors

Neutered dogs demonstrated more fear-related behaviors than their intact counterparts. 

The younger the dog was neutered, the more severe the fear-related effects were. 

In fact, a 31 percent increase in fearfulness was seen in spayed females and neutered males. These included:

  • Responses to loud noises
  • When they are first exposed to unfamiliar situations
  • When approached directly by an unfamiliar child
  • When barked at or growled at by an unfamiliar dog
  • When approached by an unfamiliar dog who is of similar size or larger
  • When encountering strange or unfamiliar objects on or near the sidewalk
  • When encountering windblown objects
  • When being examined by a veterinarian
  • When having nails clipped

7. The Trainability of the Puppy

Whereas it has been believed that a desexed puppy is more trainable, current research has demonstrated that this is not the case.

In fact, the evidence showed that spayed and neutered dogs are less trainable and less responsive to cues overall. 

The only positive behavior noted with regard to obedience was that desexed dogs were more likely to return to their owners when off-leash and more likely to reliably retrieve tossed items.

8. Separation and Attention-Seeking Behavior

Neutered and spayed dogs were found to have more separation-related behaviors.

And they also had more attachment and attention-seeking behavior than their intact counterparts.

9. Touch Sensitivity

A 33 percent increase in touch sensitivity was seen in spayed and neutered dogs. This can potentially affect how receptive a dog is to grooming.

10. Other Behavioral Problems Seen in Neutered Dogs

Additional unwanted behaviors were also seen more often in neutered dogs than in intact ones. These include:

  • Eating their own or another animal’s feces
  • Rolling in droppings or other smelly substances
  • Stealing food
  • Obsessively licking themselves

Other Theories Regarding Whether (and When) To Spay or Neuter Your Labrador Retriever Puppy

Additional factors should also be considered when deciding whether–and when–to fix your Labrador retriever puppy in addition to the medical and behavioral findings in the studies. 

Many of us don’t want to contribute to the overpopulation problem. Or to deal with a female dog in heat. Or to find homes for a litter of puppies.

In the 1970s, the animal overpopulation problem led to the regular spaying and neutering of puppies, often around six months of age. 

Over time, many shelters and rescue groups performed surgeries to fix dogs at an even earlier age, such as eight weeks old.

1. Spaying Not To Have a Dog in Heat

Spaying a female ensures that she won’t have hormonal changes in which she may become nervous or agitated. And you won’t have to deal with bloody discharge.

Female dogs go into heat approximately every six months for about 18 days each time. 

Personally, all of my dogs have been spayed or neutered. The rescues came to me fixed, and I chose to desex the others. 

One of my dogs was a Belgian tervuren named Jenny who I purchased from a breeder. It was many years ago, and I wanted to show a dog in conformation competition.

The American Kennel Club doesn’t permit dogs in those competitions to be fixed. The theory is that the best representatives of each breed should continue to reproduce to protect its heritage.

Having an unspayed dog wasn’t fun. 

Even though my male dogs were fixed, they all were attracted to her when she was in heat. 

So I had to carefully monitor all of them and manage the situation so that there were no disputes. When she wasn’t in heat, they got along fine. 

I also had to watch her at all times outside so that a male dog wouldn’t find her when she was in heat. 

And she wore a doggy panty with a disposable pad when she was in heat.

After she obtained her Championship, I had her spayed. I chose not to breed her because there were too many dogs in the world without homes. 

Life was much calmer and easier after Jenny was spayed.

2. Neutering In Order To Not Have a Male Dog Who Roams

Neutering does help prevent a male dog from seeking out female dogs who are in heat. Of course, this can also help reduce the risk of having unwanted puppies. 

And it helps keep your male Lab puppy safe because a dog who escapes can become lost or injured.

3. Not Contributing to the Pet Overpopulation Problem

According to the Association for the Prevention of Cruelty for Animals (ASPCA), current data shows that approximately 670,000 dogs are killed in shelters every year

This led to the organization supporting early-age sterilization in order to prevent the accidental breeding of young cats and dogs. 

The ASPCA advocates pediatric spay/neuter even as soon as the animal is at least two months old and two pounds.

So many people–myself included–don’t want to contribute to the pet overpopulation problem. 

There are too many puppies and dogs who need homes. And not enough loving homes.

4. Not Spaying and Neutering so that Your Labrador Puppy Doesn’t Become Overweight

Anecdotal evidence was that spayed and neutered dogs would definitely gain weight. However, this long-held belief has been disproven. 

Spayed and neutered dogs aren’t more likely than their intact counterparts to gain weight

Although there may be slight hormonal and metabolic changes, if your pup is fed the correct amount and receives a sufficient amount of exercise, he shouldn’t gain weight after being fixed.

5. Spaying and Neutering for Reduced Overall Costs

Although neutering or spaying your beloved Labrador retriever has initial costs, the amount is miniscule in comparison to properly raising a litter of puppies. 

Vet care for a litter of puppies and for the pregnant mother is very expensive. And feeding and caring for them is costly too!

Many shelters and rescue groups have low-cost or free spay and neuter clinics.

6. Having a Litter To Sell the Puppies

Having a litter of healthy Labradors to sell the puppies isn’t as easy as it sounds. 

First of all, the breeding parents should have many different health clearances. 

Breeding without the required tests is irresponsible. And potentially dangerous to both the breeding female and to the offspring. 

Keep in mind too that the tests, vet care, food, puppy raising, and other necessities cost money and take a lot of time. 

Good breeders don’t get rich from breeding. 

7. Spaying and Neutering To Be Socially Conscious

In addition to helping prevent the overpopulation problem, spaying or neutering your Labrador retriever puppy will often be better for your community. 

Dogs from unwanted litters are often abandoned, thereafter suffering from illness and untimely death. 

They can also pose a danger to other dogs by spreading diseases. 

And, because they may not be properly trained and socialized, they may become aggressive to people and dogs. Abandoned dogs may also pose risks of accidents and destruction to property.

8. Having Children Experience the Miracle of Birth Through Puppies

The idea that a dog should have puppies for children to experience “the miracle of birth” has been held by some people. 

However, the stress that pregnancy and labor place on a female dog don’t justify putting your female Lab through the process. 

And children wouldn’t be able to help with the actual labor process, which requires knowledgeable adults for your Lab’s safety when bearing puppies. 

Instead, you can teach your child through books or videos about childbirth.


Are spayed or neutered dogs more likely to become overweight than unfixed dogs?

No! Dogs who are overfed and under-exercised gain weight.

Does spaying or neutering prevent or stop a dog from becoming aggressive?

No. Scientific data actually shows that spaying or neutering may increase aggression towards people and other dogs.

Should I spay or neuter my Labrador retriever puppy?

It’s a personal decision to be made in consultation with your veterinarian.

There are certain benefits to fixing your dog such as not dealing with a female dog in heat or a male dog who tends to roam seeking female dogs in heat.

You also won’t be contributing to the pet overpopulation problem if you fix your pup.

Summary of Information

Behavioral data shows an increase in many unwanted behaviors in neutered and spayed dogs, including aggression, fearfulness, less trainability, excitability, excessive barking, separation-related issues, and touch sensitivity. 

The age that male Labs were neutered didn’t change regarding if they were aggressive, whereas spaying female Labs at a young age saw an increase in aggression. 

And male Labs neutered prior to six months old and female Labs spayed before a year old tended to have more joint disorders.

So as far as joint issues and aggression considerations are concerned, the data suggests that a male Labrador retriever shouldn’t be neutered before he’s six months old and a female not spayed before she’s a year old.

Of course, these are just two factors of many to consider when deciding whether–and, if so, when–to fix your Labrador retriever.

Spaying or neutering your Labrador retriever wasn’t found to increase or decrease his likelihood of having cancer. 

Neutering does help prevent male dogs from roaming and from urine marking. 

Spaying avoids having to deal with a female Labrador retriever who’s in heat and keeping her safe from potential male suitors. 

It’s also important to keep in mind that puppies are a lot of work and expensive to raise properly! 

And it’s socially responsible to not add to the animal overpopulation problem.

Final Thoughts

So, should you spay or neuter your Labrador retriever puppy and, if so, when? 

It’s really a decision that you should make in consultation with your vet. Health, behavior, and other considerations need to be analyzed.

I’ve trained many Labs over the years of all ages, many of whom were spayed and neutered at various ages. 

Personally, I’ve found that a well-bred, well-socialized Labrador retriever who is trained using positive reinforcement and who receives an appropriate amount of exercise can be a great companion when spayed or neutered.

Have you spayed or neutered your Labrador retriever puppy? At what age?

Have you seen any changes in your puppy’s health or behavior after being fixed?

What determined your decision?

Please tell us about it in the comments.

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When Should I Neuter My Lab Puppy? - Yellow lab puppy lying with head in the grass.When Should I Neuter My Lab Puppy? - Yellow lab puppy lying with head in the grass.

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