Changing Perspectives on Spay Neuter Recommendations for Dogs: Part I

In honor of Spay Neuter Awareness Month, I’d like to bring you up to speed on the past decade of spay neuter research in dogs. This is the first in a series of posts addressing research, vasectomy, and ovary-sparing spay.

Photo by Shirley Zindler, author of The Secret Life of Dog Catchers

Every time I write or speak about neutering dogs, I issue the following disclaimer:

“When considering if and when to neuter a dog, the number one priority must always be the prevention of unintentional litters.”

At the heart of any spay neuter conversation is owner responsibility. Did you know that in some Scandinavian countries, neutering dogs is illegal? Yep, you read that correctly. Yet, these same countries don’t have significant pet overpopulation problems. The only way to explain this boils down to owner responsibility. Can you tell this is a pet peeve of mine? But I digress…

The Research

Neutering dogs during their first year of life has been well-accepted dogma for decades. Recent spay neuter research questions this, particularly for certain breeds. Dr. Lynette Hart, a professor at UC Davis School of Veterinary Medicine and leading researcher on this topic, states:

“Issues regarding spaying and neutering dogs have become increasingly complex as more knowledge arises on interactions with diseases, behavior, welfare, and general health of dogs. The new paradigm involves assessing the lifestyle and entire situation of the particular dog as one decides whether and when to neuter a specific dog.”

Her 2020 study, “Assisting Decision-Making on Age of Neutering for 35 breeds of Dogs: Associated Joint Disorders, Cancers, and Urinary Incontinence,” followed 15,225 dogs for up to 11 years of age. The research correlated the dog’s age at the time of neutering with the incidence of joint disorders (cruciate ligament disease, hip dysplasia, elbow dysplasia), cancers (lymphoma/lymphosarcoma, hemangiosarcoma, mast cell cancer, osteosarcoma), and urinary incontinence. It is the largest study of its kind covering multiple dog breeds, including:

• Australian Cattle Dog (237)

• Australian Shepherd (440)

• Beagle (256)

• Bernese Mountain Dog (235)

• Border Collie (399)

• Boston Terrier (291)

• Boxer (761)

• Bulldog (558)

• Cavalier King Charles Spaniel (286)

• Chihuahua (1,037)

• Cocker Spaniel (369)

• Collie (116)

• Corgi (Pembroke and Cardigan combined) (240)

• Dachshund (658)

• Doberman Pinscher (358)

• English Springer Spaniel (212)

• German Shepherd Dog (1,257)

• Golden Retriever (1,247)

• Great Dane (353)

• Irish Wolfhound (86)

• Jack Russell Terrier (92)

• Labrador Retriever (1,933)

• Maltese (272)

• Miniature Schnauzer (231)

• Pomeranian (322)

• Poodle-Miniature (199)

• Poodle-Standard (275)

• Poodle-Toy (238)

• Pug (383)

• Rottweiler (854)

• Saint Bernard (94)

• Shetland Sheepdog (133)

• Shih Tzu (432)

• West Highland White Terrier (142)

• Yorkshire Terrier (229)

The graphic below details breed-specific neutering recommendations based on results of the study (might need to put your reading glasses on).

To learn the specifics about a particular breed, I encourage you to read the study. If you have questions, please reach out to me.

General conclusions derived from this study include:

1. The relationship of neutering on joint disorders and cancers, appears to be breed-specific.

2. Within some breeds, male/female differences exist.

3. Small dog breeds had no increased risks of joint disorders associated with neutering.

4. Only two small breeds (Boston Terrier and Shih Tzu) demonstrated a significantly increased cancer risk with early neutering.

Heads up — it often takes veterinarians a decade or so to adapt to changes in well-established dogma. This was definitely the case when vaccine recommendations changed. If your veterinarian is unwilling to have a discussion about if and when to neuter your pup, it might be time to find another veterinarian.

Please stay tuned for more on the topic of neutering dogs. I will present more research, address the impact of neutering on behavior, and gonad-sparing sterilization techniques.

Does your dog appears on the breed list above? If so, care to add to the conversation?

Best wishes to you and your four-legged family members for abundant good health,

Dr. Nancy