Are there risks associated with spaying (sterilization by removal of reproductive organs) or neutering (surgical procedure to render an animal infertile)?

Risks Associated with Spaying/Neutering in Dogs and Cats

Spaying and neutering procedures carry significant breed-specific and sex-specific risks including increased rates of certain joint disorders and cancers, particularly when performed at an early age in larger dog breeds.

Breed-Specific Risks of Neutering

Recent high-quality research has revealed important breed differences in vulnerability to health complications following neutering:

Joint Disorders

• Large breed dogs: Higher risk of joint disorders when neutered early 1, 2
  • Hip dysplasia (HD)
  • Elbow dysplasia (ED)
  • Cranial cruciate ligament (CCL) tears
• Breed-specific findings 1:
  • German Short/Wirehaired Pointers: Both males and females show elevated joint disorder risks
  • Mastiffs: Males show increased CCL tears
  • Newfoundlands: Females have heightened risks for joint disorders
  • Dogs weighing more than 20kg: Generally higher risk of joint problems

Cancer Risks

• Cancer types associated with neutering 1, 2:
  • Lymphosarcoma (LSA)
  • Mast cell tumor (MCT)
  • Hemangiosarcoma (HSA)
  • Osteosarcoma (OSA)
• Breed-specific findings:
  • German Short/Wirehaired Pointers: Both sexes show increased cancer risks
  • Mastiff males: Increased lymphosarcoma risk
  • Rhodesian Ridgeback females: Heightened mast cell tumor risk with very early neutering
  • Golden Retrievers (females): 2-4 times higher cancer risk with neutering at any age 2

Other Potential Complications

• Urinary incontinence (particularly in female dogs)
• Altered metabolic rates in cats 3
• Potential for age-related cognitive dysfunction 4
• Elevated levels of luteinizing hormone due to gonad removal 4

Timing Considerations

The timing of neutering significantly impacts risk profiles:

• High-risk period: Neutering before 6-12 months of age is associated with the highest risk of joint disorders in susceptible breeds 2
• Cats: Can typically be safely neutered at any age after 6-8 weeks 5
• Small dog breeds: Generally show minimal increased risks of joint disorders associated with neutering 2

Decision-Making Framework

When considering spaying/neutering, evaluate:

1. Species: Cats generally have fewer timing-related complications than dogs
2. Breed: Consider breed-specific risks (refer to studies covering 40 dog breeds)
3. Size: Larger dogs (>20kg) have higher joint disorder risks
4. Sex: Males and females of the same breed may have different risk profiles
5. Known breed-specific diseases: Some breeds have unique risk factors

Balancing Benefits and Risks

Despite these risks, spaying/neutering offers important benefits:

• Prevention of unwanted pregnancies and pet overpopulation
• Reduction in certain undesirable behaviors
• Prevention of reproductive diseases (pyometra, testicular cancer)

Practical Recommendations

• Large breed dogs: Consider delaying neutering until after growth plate closure (12-24 months)
• Breeds with documented risks (e.g., Golden Retrievers, German Shepherds, Labrador Retrievers): Follow breed-specific guidelines
• Small breed dogs and cats: Can generally be neutered at standard ages with minimal risk
• Working with veterinarians: Discuss breed-specific risks and benefits to make an informed decision

The traditional "one-size-fits-all" approach of neutering at 6 months is being replaced by a more nuanced understanding that considers individual factors for each animal 4. The optimal age for neutering should be determined on a case-by-case basis, taking into account the specific breed, sex, and individual health considerations.