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What Is the Best Age to Spay My Dog? (Current Research and FAQs)

Dr. Mark is a veterinarian. He works mostly with dogs and also spends time training and caring for his own canine family.

New research points out that Cocker Spaniels are one breed that should be spayed early.

New research points out that Cocker Spaniels are one breed that should be spayed early.

Why You Should Avoid Spaying Your Dog Early

Some vets will still recommend that you bring your dog in to be spayed at about four months old, as soon as she is finished with her vaccinations. The surgery is fast in a dog that age, safer for the dog since they are anesthetized for a shorter time, and young dogs heal faster than older animals.

Shelter and rescue dogs are often spayed even sooner. Shelters sometimes do not like to adopt a dog before she is spayed because some new owners will never have the surgery done, even if it is included in the cost of the adoption.

Reasons Not To Spay Your Dog Early

Current research teaches us that spaying early is not such a good idea; we learn more every year. (1, 2) There is no definite answer for all dogs, but here are some things to think about:

  • Spaying early does not have much effect on breast cancer.
  • Spaying early does not matter in cases of pyometra.
  • Spaying early may cause a dog to dribble urine.
  • Spaying too early may lead to arthritis (joint diseases).
  • Spaying early may increase cancer rates.
Many Westies develop leaky bladders after being spayed too early.

Many Westies develop leaky bladders after being spayed too early.

Will Spaying Early Really Prevent My Dog From Getting Breast Cancer?

This is often cited as the reason to get dogs spayed early, but it is overemphasized as the numbers do not back it up. Although spaying your dog early will decrease the chances of her developing breast cancer later in life, the number of dogs that get this disease is small and the risk of developing breast cancer is not as significant as the risk of other diseases.

(Urine dribbling, for example, which will need to be treated for the rest of the dogs life.)

Even out of 100,000 dogs, only a few develop mammary cancer if they are spayed later instead of early.

The breed of dog appears to be a lot more important. (3) Dogs with a risk of developing mammary cancer include:

The dog breeds that never developed breast cancer (among more than 7,000 tested), whether or not they were spayed:

  • Miniature Schnauzer
  • Pug
  • West Highland White Terrier
  • Shetland Sheepdog
  • Saint Bernard

Studies indicate that if you have a Cocker, you should spay early, but if you have a Westie, there are other things to worry about. If a neighbor or someone at the vet says: "Get your dog spayed when she is a puppy so that she does not get breast cancer," you can answer with: "Prove it." The facts will not support that argument.

Why Do Some Spayed Dogs Dribble In The House?

There is evidence that spaying a dog before three months old increases the risk of dribbling urine later on in life. Most dogs then develop this problem when they are less than a year old. (5)

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Some of the most commonly affected breeds are:

All of these breeds respond to hormones, and may also respond to keeping their hormones longer (not being spayed too early). This is not a life-threatening condition, but sometimes these dogs end up in a kill shelter because the family is no longer willing or able to deal with this problem.

How Early Should I Have My Dog Spayed To Prevent Pyometra?

Dogs almost never develop pyometra when very young. It usually happens in dogs that are over four years old, so it is easily taken care of by spaying your dog when she is an adult. The only dog breed known to be at high risk when young is the Dogue de Bordeaux (4), but even they only present when adults and only after several heat cycles (the average age to show signs of pyometra was 3.3 years).

Getting your dog spayed as a puppy does not make any difference.

Dogue de Bordeaux may develop pyometra young but do not become ill with this disease as small puppies.

Dogue de Bordeaux may develop pyometra young but do not become ill with this disease as small puppies.

Will My Dog Get Arthritis If I Spay Her Too Early?

In one study of Golden Retrievers, hip dyspasia was twice as common when the dogs were neutered early. (6) Dogs also developed anterior cruciate ruptures much more frequently, and in other studies many other joint diseases were found to be more common.

Dog breeds at special risk of developing joint problems from early spay:

  • Golden Retriever
  • Labrador Retriever
  • Bernese Mountain Dog
  • Rottweiler
  • Saint Bernard

If you have a large breed dog that is mixed with one of these breeds, it may also be better to wait, although this has not been proven. Small dog breeds will probably not develop arthritis if they are spayed early.

Do Spayed Dogs Get Cancer More Often?

There are several types of cancer that are diagnosed most often in spayed or neutered dogs:

  • Osteosarcoma
  • Lymphoma
  • Hemangiosarcoma
  • Transitional Cell Carcimona
  • Mastocytoma

For many of the cancers, we are not sure whether the dogs were spayed very early or later. Mast cell tumors, which were twice as common in early spayed dogs (compared to dogs spayed older), was an exception. (7) Hemangiosarcoma, a tumor usually found in the spleen or heart, is found a lot more frequently in spayed dogs.

There are several studies that show that cancer is more common in neutered dogs (compared to intact dogs), especially lymphosarcoma, which was three times as common in dogs neutered early. No cases were found in dogs that were neutered later.

This information is especially important if you have one of the dog breeds that are prone to cancer:

  • Labrador Retriever
  • Golden Retriever
  • Rottweiler
  • Boxer
  • German Shepherd Dog
  • Bernese Mountain Dog
  • Great Dane
  • Bouvier des Flandres
  • Doberman
Cancer and joint problems are concerns for all Golden owners and should influence when you decide to spay your dog.

Cancer and joint problems are concerns for all Golden owners and should influence when you decide to spay your dog.

Other Questions About When To Spay My Dog

Should I Let My Dog Go Into Heat Before Spaying?

Yes, there are now many good reasons to allow a dog to go through a heat cycle before spaying. Her urinary tract has time to mature so she is less likely to dribble urine when she is older, her bones are fully formed when she is old enough to go through at least one heat cycle, and statistically she has less chance of developing some types of cancer.

Not spaying before that first heat is a little more trouble. By not spaying early you will have to keep her locked up when she is attracting males and might want to purchase "doggy diapers" so she does not drip blood around the house.

How Long Should You Wait After Heat To Spay A Dog?

It is a good idea to wait at least six weeks, even though many veterinarians will be able to perform the surgery earlier without complications, even when a dog is in heat. Dogs in heat do bleed more than dogs that are not in heat, so some blood will be lost if you get it done too early.

The best thing for the dog is to wait about three months. Her blood vessels will not be large after the last heat cycle and her new blood vessels for the next heat have not started to develop.

Should I Let My Dog Have Puppies Before Getting Her Spayed?

There are no benefits to letting your dog have puppies before she is spayed. Besides having to find homes for the puppies, you will also need to worry about the extra expenses of more food, more veterinary visits, deworming costs, and the first vaccines for the new puppies.

Will My Dog Get Fat After She Is Spayed?

There are several reasons that dogs become obese after they are spayed. The metabolic rate goes down and dogs no longer have their appetite suppressed by estrogen. (8)

Since fat dogs live shorter lives and have more health problems than thin dogs, the best way to keep them thin is by feeding less and using a high fiber diet after they are spayed. Exercise helps a lot, and if you need more tips on the best exercise plan for your dog be sure to read this article.

Do Female Dogs Behave Better After Being Spayed?

Although some dogs that are spayed too early will develop aggressive or fearful behaviors (9), the usual consensus is that spaying your dog as an adult will not change her personality.

She is going to run around just like before, and if she had behavior problems before the surgery, she will probably still have them after. If someone suggests to you that your dog will stop growling at you after she is spayed, they are incorrect.

At What Age Is It Too Late To Spay My Dog?

If you decide not to spay your dog early, you may get used to taking care of her every six months when she is in heat and only decide you want to go through with the surgery when she is a few years old.

Is your dog now too old?

No, it is never too late to spay your dog. The big benefit of getting your dog spayed, even at a late age, is that older dogs are more likely to develop pyometra and this can be avoided by having the surgery done. If your dog does develop this disease and it has to be taken care of with an emergency surgery, it is going to cost you several thousand dollars.

If she is a senior, the veterinarian will be more careful before anesthesia and probably require a blood work up that includes testing for infection as well as tests to examine the health of the liver, kidneys, and other internal organs.

Pros and Cons Of Getting My Dog Spayed

Pros:

  • Easier on the dog when done early (less blood loss and faster healing)
  • No bloody discharge to worry about
  • No attracting males around the house
  • Dogs live longer
  • No ovarian or uterine cancers
  • No other uterine diseases like polyps
  • No chance of coming down with pyometra

Cons:

  • Increase in some cancer risks
  • Spayed dogs need fewer calories and may eat more, so will get fat unless you control their food
  • Spayed dogs may only live longer because they get better health care than intact dogs
  • Hormonal changes might be responsible for more diabetes, hypothyroidism, and some kinds of cancer in spayed dogs

Based on the most current research, your vet will most likely tell you to wait until your dog is older. AAHA, however, still recommends small dogs be spayed at about five months of age, and veterinarians that follow those suggestions will still recommend early spay.

If the veterinarian recommends that you spay early, you should call around and get other opinions. If you have your dog spayed through a shelter, however, they are going to want to spay early and you may not have any say in the matter.

Recommendations will change with new research.

This veterinarian is recommending a spay that leaves the ovaries. The dog still has behavioral changes when in heat, but also has the hormone feedbacks that may be important to maintain her health.

There are some negatives, like a longer incision and more surgery time to remove the cervix, which is left during a normal spay. (The ovaries cause the cervix to swell when a dog is in heat and there can be problems if it still there.)

If you decide to have your dog spayed in this way, you will need to discuss this with your regular veterinarian, as not all vets will do this surgery.

Sources

(1) Howe LM. Current perspectives on the optimal age to spay/castrate dogs and cats. Vet Med (Auckl). 2015 May 8;6:171-180. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6070019/

(2) Kustritz MV. Determining the optimal age for gonadectomy of dogs and cats. J Am Vet Med Assoc. 2007 Dec 1;231(11):1665-75. https://pubmed.ncbi.nlm.nih.gov/18052800/

(3) Hart BL, Hart LA, Thigpen AP, Willits NH. Assisting Decision-Making on Age of Neutering for 35 Breeds of Dogs: Associated Joint Disorders, Cancers, and Urinary Incontinence. Front Vet Sci. 2020 Jul 7;7:388. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7359819/

(4) Gibson A, Dean R, Yates D, Stavisky J. A retrospective study of pyometra at five RSPCA hospitals in the UK: 1728 cases from 2006 to 2011. Vet Rec. 2013 Oct 26;173(16):396. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3812855/

(5) Stöcklin-Gautschi NM, Hässig M, Reichler IM, Hubler M, Arnold S. The relationship of urinary incontinence to early spaying in bitches. J Reprod Fertil Suppl. 2001;57:233-6. https://pubmed.ncbi.nlm.nih.gov/11787155/

(6)Torres de la Riva G, Hart BL, Farver TB, Oberbauer AM, Messam LL, Willits N, Hart LA. Neutering dogs: effects on joint disorders and cancers in golden retrievers. PLoS One. 2013;8(2):e55937. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3572183/

(7) Kent MS, Burton JH, Dank G, Bannasch DL, Rebhun RB. Association of cancer-related mortality, age and gonadectomy in golden retriever dogs at a veterinary academic center (1989-2016). PLoS One. 2018 Feb 6;13(2):e0192578. https://pubmed.ncbi.nlm.nih.gov/29408871/

(8) Phungviwatnikul T, Valentine H, de Godoy MRC, Swanson KS. Effects of diet on body weight, body composition, metabolic status, and physical activity levels of adult female dogs after spay surgery. J Anim Sci. 2020 Mar 1;98(3):skaa057. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7070154/

(9) Starling M, Fawcett A, Wilson B, Serpell J, McGreevy P. Behavioural risks in female dogs with minimal lifetime exposure to gonadal hormones. PLoS One. 2019 Dec 5;14(12):e0223709. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6894801/

(10) Palestrini C, Mazzola SM, Caione B, Groppetti D, Pecile AM, Minero M, Cannas S. Influence of Gonadectomy on Canine Behavior. Animals (Basel). 2021 Feb 20;11(2):553. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7923786/

This article is not meant to substitute for diagnosis, prognosis, treatment, prescription, or formal and individualized advice from your veterinarian. Animals exhibiting signs and symptoms of distress should be seen by a veterinarian immediately.

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