Aggression toward Familiar People, Strangers, and Conspecifics in Gonadectomized and Intact Dogs

Area of Science:

• Veterinary behavior science
• Animal welfare science

Background:

• Gonadectomy is a common procedure for managing canine behavior problems, including aggression.
• The impact of gonadectomy timing on canine aggression requires further investigation.

Purpose of the Study:

• To investigate the association between gonadectomy, age at gonadectomy, and aggressive behavior in dogs.
• To compare aggression levels in gonadectomized dogs with intact dogs across different age groups.

Main Methods:

• Utilized the Canine Behavioral Assessment Research Questionnaire (C-BARQ) with multivariate analysis on a large dataset (13,795 dogs).
• Defined aggressive behavior using mean scores and by comparing dogs with no aggression to those with moderate or severe aggression.
• Compared intact dogs with dogs gonadectomized at various ages: ≤6 months, 7-12 months, 11-18 months, and >18 months.

Main Results:

• Gonadectomy and age at gonadectomy were not associated with aggression toward familiar people or other dogs.
• A statistically significant, though small, increase in moderate to severe aggression toward strangers was observed in all gonadectomized dogs compared to intact dogs.
• This increased odds of stranger-directed aggression were primarily driven by dogs gonadectomized between 7-12 months of age (26% higher likelihood).

Conclusions:

• Gonadectomy does not appear to alter aggressive behavior towards familiar individuals or conspecifics in dogs.
• A minor increase in aggression towards strangers may be linked to gonadectomy, particularly when performed between 7-12 months of age.
• Considering potential negative health impacts of gonadectomy, alternative sterilization methods like vasectomy and hysterectomy warrant further research.