DRAFT — Revise into your voice before publishing.
Reactivity is one of the most common issues reported by Australian Cattle Dog owners, and one of the most frequently mismanaged. The dog sees another dog across the street and erupts — barking, lunging, fixating — and nothing the owner does in the moment seems to help.
Here’s what’s happening, and here’s what actually works.
What reactivity is (and isn’t)
Reactivity is an overreaction to a stimulus. The dog’s emotional response to a trigger — another dog, a stranger, a bicycle, a car — exceeds what’s proportionate to the actual threat, and the response spills out as barking, lunging, hard staring, growling, or a combination.
Reactivity is not the same as aggression, though it can look similar and can escalate into aggression if badly managed. Most reactive dogs are not trying to fight — they’re overwhelmed and communicating that overwhelm loudly.
Heelers are particularly prone to reactivity for a few reasons:
Genetic vigilance — ACDs were bred to be hyperaware of their environment. A dog that misses the approach of a steer from the left is a dog that gets kicked. This hypervigilance is a feature in the field and a liability on a leashed walk.
High arousal threshold — Heelers run hot. Their arousal ramp-up is fast and their cool-down is slow. This makes it easy to blow past the point of being able to think clearly.
Under-socialization in the critical window — Many heelers are working dogs or working-dog adjacent, raised with less early socialization than companion breeds. Novelty becomes threatening.
Frustration — Leash frustration is real. A dog that would happily greet another dog or person off-leash may react intensely on-leash because the leash prevents the normal approach-and-assess behavior.
The threshold concept
Understanding threshold is the foundation of working with a reactive dog.
Under threshold: the dog is aware of the trigger, but can still think. They may glance at the trigger, orient toward it, but can take treats and respond to cues.
At threshold: aroused, focused on the trigger, starting to ignore treats and handler.
Over threshold: fully reactive. The dog cannot take treats, cannot respond to cues, cannot learn. This is not a training moment. This is survival mode.
Nearly all reactive dog training works by keeping the dog under threshold and doing desensitization and counter-conditioning work there. Working a dog that’s already over threshold accomplishes nothing except reinforcing that the trigger causes this state.
What not to do
Don’t punish the reaction. Corrections (leash pops, shock collars, yelling) when a dog is reacting suppress the warning signs — the growl, the stiff posture — without addressing the underlying emotional response. You end up with a dog that bites without warning, which is worse.
Don’t flood. Flooding means forcing a dog to remain in proximity to the trigger until they “get used to it.” This sometimes works temporarily and reliably creates long-term behavioral fallout.
Don’t drag them past it. Yanking a reactive dog past a trigger while it’s reacting tells the dog nothing useful and often intensifies the reaction.
What to do: desensitization and counter-conditioning (DS/CC)
This is the evidence-based approach to reactivity. It works. It takes weeks to months. There’s no shortcut.
The principle: Pair the trigger, at a distance where the dog is under threshold, with something the dog loves (usually very high-value food — chicken, cheese, hot dogs). Over many repetitions, the dog’s emotional response to the trigger shifts from “threat” to “chicken is coming.”
Step by step:
Find the threshold distance. This is the distance at which your dog can see the trigger but isn’t reacting — usually much farther than you think. Start 50, 80, even 100 feet from other dogs if needed.
Mark and feed. The moment your dog sees the trigger, feed treats. High rate. Trigger appears = chicken rains from the sky. Trigger disappears = chicken stops. (This is called BAT when structured formally, and LAT — “look at that” — is a popular foundation exercise.)
Never push the distance. Move closer only when your dog is consistently calm and orienting back to you rather than staring at the trigger.
End before reaction. If you’re getting close to the edge, leave. A clean exit is better than a blown session.
Practice requirements: Multiple short sessions (5–10 minutes) several times per week, in controlled settings before moving to real walks. This takes months.
Management on walks
While you’re doing the training work, manage the environment to prevent rehearsal of the reactive behavior. Every reactive episode makes the next one more likely.
- Avoid triggers. Cross the street early, turn around, duck into a driveway. Not forever — while you’re building new associations.
- Increase distance. You need more space than you think. Heelers do not start calming down at 10 feet.
- Use visual blocks. Parked cars, bushes, corners — put something between your dog and the trigger while you pass.
- Watch your own body language. Tensing the leash when you see a trigger is involuntary and your dog feels it. Practice loose-leash handling and deep breathing.
- Don’t wait for the reaction. Turn away, drop treats, create movement before the dog hits threshold. Intervene early.
Enrichment and reactivity
Reactivity is worse in under-enriched dogs. A dog running at 90% arousal from boredom and unmet cognitive needs hits threshold faster and recovers more slowly.
Enrichment — nose work, puzzle feeders, training sessions — lowers baseline arousal. A dog that has had a snuffle mat breakfast and a 20-minute nose work session is starting the walk from a calmer baseline than a dog who hasn’t. This matters more than most people realize.
Mental stimulation routines — practical enrichment that reduces baseline reactivity.
When to get professional help
Get a professional if:
- The reactivity is directed at people (not just dogs/animals)
- There has been a bite history
- The dog is showing aggression inside the home
- The reactive behavior is escalating
- You’ve been working on it for months with no improvement
Find a Certified Professional Dog Trainer (CPDT-KA) who uses force-free methods. Be explicit: you want desensitization and counter-conditioning, not suppression. Get references.
Related: Mental Stimulation Routines — reducing baseline arousal is the first step in managing reactivity.