Dog Neutering: Significance and Medical Classification

What does neutering mean for dogs?

Neutering in dogs involves the surgical or chemical removal of the gonads—the testicles in male dogs and the ovaries in female dogs (often along with the uterus, in which case it is called an ovariohysterectomy). The goal is to halt the production of sex hormones. In Germany, according to Section 6 of the Animal Welfare Act, castration is permitted only for medical or behavioral reasons—castration without medical justification is legally problematic.

This should be distinguished from sterilization, in which only the vas deferens or fallopian tubes are severed; hormone production remains intact. In practice, the term “castration” is commonly used to refer to both procedures.

Background and Academic Context

The body of research on dog neutering has become much more nuanced in recent years. In the past, neutering was generally considered to be beneficial to health. This view is now outdated. Hart et al. (2014, 2020) have shown in a series of breed-specific analyses that the risk of certain types of cancer and orthopedic conditions, such as cruciate ligament rupture or hip dysplasia, may be significantly increased in dogs neutered at an early age, depending on the breed—particularly in Golden Retrievers, Labradors, and Bernese Mountain Dogs.

Salmeri et al. (1991) also demonstrated that castration before puberty affects bone growth because the growth plates close later. McGreevy et al. (2018) painted a nuanced picture: neutered males exhibited more fear-based reactions in some categories—neutering does not reliably reduce fear-based aggression but may actually exacerbate it.

On the other hand, spaying a female dog at an advanced age is an established preventive measure against pyometra, a life-threatening infection of the uterus. The risk-benefit analysis therefore depends heavily on breed, sex, age, and the dog’s overall health.

Vitomalia-Position

We firmly oppose neutering as a standard solution for behavioral problems. If you have a reactive or insecure dog, you need a behavioral assessment, not a scalpel. We recommend a nuanced, case-by-case decision made in consultation with a veterinarian—ideally with a combined perspective from both behavioral medicine and surgery. We oppose early and blanket neutering.

When there is a medical indication—such as a testicular tumor, pyometra, or severe prostate hyperplasia—neutering is an important procedure. However, when the decision is based purely on convenience or unclear behavioral goals, we advise against it.

When is neutering a consideration for dogs?

Neutering is relevant in four situations: when there is a clear medical indication, when there are sexually motivated behavioral issues such as constant mounting or wandering during heat, when a female dog experiences chronic pseudopregnancies, and in the context of planned family planning in a multi-dog household. In all cases, the rule is: diagnosis first, then decision—never because of trends or pressure from others.

Practical application

1. Review the indication: provide a medical or behavioral medical justification and document it in writing.
2. Hormone chip as a test: In the case of a male dog in heat, a temporary hormone chip (Suprelorin) can serve as a reversible test to determine whether behavioral changes occur at all.
3. Timing: For most medium-sized and large breeds, neutering is now recommended after puberty and growth are complete—early neutering should only be performed if there is a clear medical indication.
4. Postoperative care: Immobilization, wound protection, neck brace or body brace. Monitoring of behavior in the weeks following surgery.
5. Managing expectations: Behavioral changes—if they occur at all—happen gradually. Neutering is not a reset button.

Common Mistakes and Myths

• "Neutering makes dogs calmer." This is generally incorrect. McGreevy et al. (2018) show that neutered male dogs may exhibit more anxious behavior across several behavioral categories.
• "Early neutering is healthy." Hart et al. (2014, 2020) show breed-specific increases in the risk of cancer and joint problems associated with early neutering.
• "Neutering reduces aggression." This applies only to sexually motivated aggression—most aggression is caused by fear or pain. See " Aggression in Dogs."
• "A female dog should give birth at least once." There is no scientific evidence that giving birth has any health benefits.
• "Neutering generally prevents tumors." This is true for some types of tumors (testicular tumors, mammary tumors in female dogs neutered at an early age), but for others, it increases the risk.

State of the art in 2026

Consensus: Neutering dogs is not inherently a good or bad practice. It is a decision that must be weighed based on breed, age, and individual circumstances. Early neutering is increasingly viewed with skepticism. The body language and behavior of neutered dogs do not differ as much as was previously assumed. Areas of ongoing research include the long-term hormonal effects on the immune system and the thyroid gland.

Frequently Asked Questions

When is the best time to have a pet neutered?

For most breeds, this is after they have finished growing—that is, around 12 months for small dogs and 18–24 months for large dogs. Surgery may be performed earlier if medically indicated.

Will my dog be calmer after being neutered?

Not reliable. Studies show mixed results. It is more likely to be effective for sexual restlessness, but less so for anxiety-based reactivity.

How much does neutering cost?

Depending on gender, size, and clinic, the cost ranges from 200 to 1,500 euros. Female dogs require more care than males.

Are there any alternatives?

For male dogs, the Suprelorin hormone implant is a reversible option. For female dogs, there is no widely established long-term hormonal solution—spaying is an option that does not involve hormonal changes.

Related terms

• Aggression in Dogs
• Reactivity
• A female dog in heat
• False pregnancy
• Hormones in Dogs
• Puberty in Dogs
• Body language

Sources and further reading

1. Hart, B. L., Hart, L. A., Thigpen, A. P., & Willits, N. H. (2014). Long-term health effects of neutering dogs: comparison of Labrador Retrievers with Golden Retrievers. PLoS ONE, 9(7), e102241.
2. Hart, B. L., Hart, L. A., Thigpen, A. P., & Willits, N. H. (2020). Assisting decision-making on age of neutering for 35 breeds of dogs. Frontiers in Veterinary Science, 7, 388.
3. Salmeri, K. R., Bloomberg, M. S., Scruggs, S. L., & Shille, V. (1991). Gonadectomy in immature dogs: effects on skeletal, physical, and behavioral development. Journal of the American Veterinary Medical Association, 198(7), 1193-1203.
4. McGreevy, P. D., Wilson, B., Starling, M. J., & Serpell, J. A. (2018). Behavioural risks in male dogs with minimal lifetime exposure to gonadal hormones may complicate population-control benefits of desexing. PLoS ONE, 13(5), e0196284.
5. Houlihan, K. E. (2017). A literature review on the welfare implications of gonadectomy of dogs. JAVMA, 250(10), 1155-1166.