Until a few years ago, I’d always nodded in agreement with the recommendation to neuter dogs (particularly females) not intended for breeding purposes between six months and one year of age. Spaying and castrating within this age window reduces the risk of accidental pregnancies, behavioral issues (primarily in male dogs), and breast cancer later in life. While I don’t dispute the validity of these cause and effect assessments, a growing body of evidence has caused me (and plenty of other veterinarians) to seriously rethink neutering recommendations.
Evidence in Rottweilers
A 2002 study in Cancer Epidemiology, Biomarkers & Prevention documented that Rottweilers neutered before one year of age were far more likely to develop osteosarcoma (a life ending form of bone cancer) than Rotties who remained sexually intact.
A 2009 study in Aging Cell found that female Rottweilers neutered after the age of six were 4.6 times as likely to live to age 13 compared to those spayed at a younger age.
Evidence in Golden Retrievers
And now we have a Golden Retriever study that demonstrates a higher incidence of the following maladies amongst neutered dogs compared to those left sexually intact:
- Hip dysplasia: Instability and subsequent development of arthritis within the hip joints
- Cruciate ligament disease: Tearing of the major ligament that provides stability to the knee joint
- Lymphosarcoma: A cancerous disease arising from a type of white blood cell called lymphocytes (lymphosarcoma has a particularly high occurrence rate in Golden Retrievers)
- Hemangiosarcoma: A cancerous disease arising from cells that line blood vessels
- Mast cell tumors: A cancerous disease arising from mast cells which are a normal component of a healthy immune system and are responsible for allergic reactions in the body
The rates of occurrence for all of these diseases were significantly higher in both males and females who were neutered either early on or later in life, compared to dogs remaining sexually intact. Neutering before one year of age was associated with increased risk for hip dysplasia, cruciate ligament tear, and lymphosarcoma in male dogs, and increased risk for cruciate ligament tear in female dogs. Neutering after one year of age was associated with increased occurrence of mast cell tumors and hemangiosarcoma in female Goldens.
This Golden Retriever study was conducted at the University of California, Davis. Researchers focused on this breed because of their popularity (both in private homes and as service dogs) as well as the breed’s clear vulnerability to joint maladies and cancer.
Neutering recommendations for your dog
The obvious question now arises- when should you have your dog neutered, if at all? My response for the time being remains rather murky. Based on the known body of evidence for and against neutering, I cannot give a set recommendation that applies to all dogs in all environments. What I do recommend is that you engage your veterinarian in conversation about the risks and benefits as they pertain to your individual dog. Factors to consider should include your dog’s size and breed, behavior, and your ability to prevent unwanted pregnancies.
It is clear is that a great deal more research is needed pertaining tot the timing and consequences of neutering our canine companions. The health implications may play out differently in virtually every dog breed. I will continue to provide updates as more information becomes available.
Have your thoughts changed about neutering your dog?
Nancy Kay, DVM
Diplomate, American College of Veterinary Internal Medicine
Author of Speaking for Spot: Be the Advocate Your Dog Needs to Live a Happy, Healthy, Longer Life
Author of Your Dog’s Best Health: A Dozen Reasonable Things to Expect From Your Vet
Recipient, Leo K. Bustad Companion Animal Veterinarian of the Year Award
Recipient, American Animal Hospital Association Animal Welfare and Humane Ethics Award
Recipient, Dog Writers Association of America Award for Best Blog
Recipient, Eukanuba Canine Health Award
Recipient, AKC Club Publication Excellence Award
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Please visit http://www.speakingforspot.com to read excerpts from Speaking for Spot and Your Dog’s Best Health. There you will also find “Advocacy Aids”- helpful health forms you can download and use for your own dog, and a collection of published articles on advocating for your pet’s health. Speaking for Spot and Your Dog’s Best Health are available at www.speakingforspot.com, Amazon.com, local bookstores, and your favorite online book seller.