#41 – Aggression between family dogs

April, 2025
NMVMA listserve Veterinary Behavior Tip #41
Jeff Nichol, DVM, IAABC

Aggression between family dogs

Canine warriors tend to be repeat offenders.

  • Beyond the nasty injuries, one well-loved dog can kill another.
    • The aggression itself is a symptom.
    • The underlying motivators need our management.
  • It’s rarely simple.
    • Punishment and reprimands only increase the tension.
    • Many dogs improve but there can be long term risks.
    • Individualized treatment is time-consuming for the veterinarian and the client, although often worth it.

More than group dominance.

  • Many dogs over-react when competing for perceived high-value resources.
  • The innate concept of scarcity:
    • They can fight for food, owner attention, proximity to their person, furniture, a bed of any kind, or any favored resting.
    • Some rush a doorway, agitation escalating as they accelerate, resulting in a brawl at the choke point.

Canine combatants swap subtle body signal threats for months prior fighting.

  • Unraveling the behavioral etiologies is complicated.
  • Fear and anxiety are common.
  • These clients are distraught; they need coaching and empathy.

A fearful victim can inflict more damage than the anxious/reactive bully.

  • Either or both can feel threatened and fight for their lives.
  • These dogs must be immediately and securely segregated.
  • Covering lower portions of windows and glass doors prevents body signal threats when one is outside.

Forget simple solutions.

  • Basket muzzles prevent injury while the animosity worsens.
  • No interactions should be allowed until the triggers are eliminated and each dog is significantly calmer.

Breaking up fights can be dangerous.

  • Prevent human injuries.
  • Rather than reaching into the fracas, clients can have each dog drag a leash from its collar or harness when they are inside.
  • People can safely grab these “drag lines” to safely separate their dogs.

When anxiety and/or fear are involved, pharmaceuticals can help, but not cure, the problem.

  • Fluoxetine is a generally safe anxiolytic that can also reduce impulsivity and aggression.
    • Generic is cheaper but poorly absorbed in many dogs.
    • The Reconcile brand is chewable, intended for the canine intestinal tract, and made in the USA.
    • Dose 0.5 – 1.5 mg/kg sid
    • Available in 8, 16, 32, and 64 mg tablets
  • Alpha 2 agonists, clonidine or guanfacine, reduce noradrenalin release, decrease sympathetic tone, and can attenuate aggressive reactions.
    • Clonidine: 0.01 – 0.05 mg/kg tid – bid. Available in 0.1, 0.2, 0.3 mg tablets
    • Guanfacine: 0.02-0.08 mg/kg bid. Available in 1 and 2 mg tablets.
  • Other drugs work better in some cases.
    • Every anxious/fearful dog is different.
    • They don’t all need drugs; they don’t all respond.

Reuniting former adversaries

  • Every possible factor in the aggression history must be addressed and mitigated first.
  • Trial exposures should be on neutral turf, away from home, with the dogs leashed a significant distance apart.
  • Desensitization should be repetitive and very gradual.
  • Never allow dogs to “fight it out.”

You can call me to discuss cat and dog behavior cases. Referrals are always welcome.

All the best,

Jeff Nichol, DVM, IAABC
Veterinary Behaviorist
Residency trained by the American College of Veterinary Behaviorists
Albuquerque, New Mexico

505.792.5131
jnicholdvm@aol.com
www.drjeffnichol.com