Neutering, also known as castration, involves the removal of a male dog’s testicles. This procedure is a well-known solution to pet overpopulation. Below, we explore how neutering affects behavior, cancer incidence, and orthopedic health.
Behavioral Effects of Neutering
The impact of neutering on behavior is mixed. Some studies show positive changes, while others indicate minimal or negative effects. Behavior is influenced by various factors, including breed, genetics, health, past experiences, the owner’s emotional state, and environmental dynamics. For a deeper dive into this aspect of neutering, check out some of the scientific articles listed below.
Aggression, Fearfulness, Excitability, and Anxiety
Testosterone, produced mainly by the testicles, can increase aggression. Neutering before aggressive behavior develops may reduce the likelihood of aggression. However, studies suggest that neutering mature dogs often fails to reduce existing aggression. In some cases, fewer than a third of dogs show significant improvement.
Neutered dogs may become less confident, more excitable, fearful, and anxious.
Marking, Mounting, and Roaming
Neutering is often used to curb undesirable behaviors like marking, mounting, and roaming. Castrating dogs before these behaviors emerge is usually preventative. Research indicates that neutering mature dogs can reduce these behaviors by 50-60%, regardless of the dog’s age or the duration of the behavior.
Orthopedic Development
Neutering dogs too young can lead to orthopedic issues such as hip dysplasia and cranial cruciate ligament tears.
Cancer Risks
Early neutering increases the risk of cancers like osteosarcoma, lymphoma, and mast cell tumors. However, it eliminates the risk of testicular cancer, which can be detected early through regular exams.
Dermatological and Autoimmune Conditions
Early neutering also raises the incidence of allergies and autoimmune disorders.
Minimizing Long-Term Effects of Neutering
Optimal Timing for Neutering
- Small Dogs (under 45 pounds): Neuter between 6-12 months.
- Large Dogs (over 45 pounds): Neuter between 9-24 months.
Sexual maturity varies by breed, typically occurring between 5-12 months. Signs of sexual maturity include:
- Roaming
- Marking
- Humping
- Whining
- Anxiety
- Overprotectiveness
- Aggression towards other males
If these behaviors appear, consider neutering sooner to prevent them from becoming permanent.
Vasectomy as an Alternative
A vasectomy is another option instead of removing the testicles. Vasectomized males:
- Will still have the desire to breed females in heat.
- Will still exhibit behaviors of an uncastrated male.
- Will not be able to impregnate a female.
(1) The Effects of Neutering on Undesirable Behaviors in Dogs
https://www.veterinary-practice.com/article/effects-of-neutering-on-undesirable-behaviours-in-dogs
(2)The Social Behaviour of Neutered Male Dogs Compared to Intact Dogs (Canis lupus familiaris): Video Analyses, Questionnaires and Case Studies https://openventio.org/wp-content/uploads/The-Social-Behaviour-of-Neutered-Male-Dogs-Compared-to-Intact-Dogs-Canis-Lupus-Familiaris-Video-Analyses-Questionnaires-and-Case-Studies-VMOJ-2-113.pdf
(3) Effects of Castration on Behavior Problems in Male Dogs with Reference to Age and Duration of Behavior
https://pubmed.ncbi.nlm.nih.gov/9227747/
(4) https://www.universityofcalifornia.edu/news/when-should-you-neuter-or-spay-your-dog
(5) https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5146839/ (autoimmune and allergic disorders)