Collar or harness? What happens to your dog's neck when it pulls

A collar is the simplest piece of equipment a dog can wear. It is also the one that puts the leash force on a vulnerable part of the body. This article looks at what sits inside a dog's neck, what happens when the dog pulls, and what tracheal collapse is – a condition in which pressure on the neck can aggravate the symptoms.

What's inside the neck

The neck is a narrow passage for a lot of critical structures, with little protection in front:

• The trachea (windpipe) – the tube that carries air to the lungs, held open by C-shaped rings of cartilage.
• The larynx – at the top of the trachea, where the voice is produced and the airway is protected when the dog swallows.
• The esophagus – running alongside the trachea down to the stomach.
• The thyroid gland, the jugular veins and carotid arteries, and nerves that control, among other things, breathing and heart rate.

Under a collar, all of this lies only a few centimeters beneath the skin.

What happens when the dog pulls

When a dog leans into a collar, the leash force is concentrated on a narrow band across the front of the neck. Two studies are often cited:

• Pauli et al. (2006) measured pressure in the eye in 26 dogs. The pressure rose significantly when force was applied through a collar, but not through a harness. The likely explanation is that the collar compresses the veins in the neck. The authors recommend a harness for dogs with eye conditions, especially during activity.
• Carter et al. (2020) tested seven collars and a slip lead on a model neck, at forces representing a firm pull (40 N), a strong pull (70 N) and a jerk (about 141 N). The pressures ranged from 83 to 832 kPa, and none of the collars tested gave a pressure the researchers considered low enough to mitigate the risk of injury when the leash is pulled. It is a model, not a real dog – but the researchers' advice was clear: train the dog to walk on a loose leash, or use a harness that puts no pressure on the neck.

Neither study means that a collar is dangerous for every dog on every walk. But they show that the neck takes the force – and the dogs that pull the most take the most of it.

Tracheal collapse

Tracheal collapse means that the cartilage rings in the windpipe lose their stiffness, so the airway flattens as the dog breathes. It is a progressive condition: it usually gets worse over time.

Who gets it: It is most common in toy and small breeds – Yorkshire terrier, Pomeranian, Chihuahua, toy poodle – and is most often diagnosed in middle-aged and older dogs. It can occur in dogs of any size. Overweight dogs and dogs with heart or lung disease are more exposed.

The cause: Not fully known. Weakened cartilage is at the core, and a genetic component is likely since it is so common in small breeds. There is no solid evidence that collars cause the condition. What is well established clinically is that pressure on the trachea can trigger or worsen coughing.

Symptoms: The typical sign is a dry, harsh cough, often described as a goose honk. It tends to get worse with excitement, exercise, heat and humidity, after eating or drinking – and when something presses on the windpipe, such as a collar.

When to see a vet: A dog with a recurring honking cough should be examined. A cough can also come from heart disease, which has to be ruled out. If the dog is struggling to breathe or the gums turn bluish, it is an emergency.

For dogs with tracheal collapse, a harness instead of a collar is a standard part of the vet's advice, together with weight control and avoiding smoke and other airway irritants. One honest caveat: the research has not shown that a harness slows the disease itself. But keeping pressure off an airway that is already weak is basic common sense.

A harness can press on the throat too

Switching to a harness does not solve everything. Two things to check:

• A horizontal strap across the chest. If it sits too high, it can shift the load toward the throat when the dog pulls.
• A harness that rides up. Many harnesses sit fine when the dog stands still, but slide up toward the throat as soon as the dog leans forward. Check the fit with the dog in a pulling position, head low – not only standing.

The front of the harness should rest on the breastbone, and the neck opening should leave the throat free, also under load. Read more about the four requirements for an ergonomic harness.

Why MEGIN is built around the breathing bridge

This is the problem MEGIN was designed to solve. The breathing bridge, patented in Norway, is a structural element at the front of the harness, designed to keep pressure away from the airway – also when the dog works in the harness. The rest of the harness is formed panels and rope that adjust to the dog's body, with no straps across the front of the neck.

We call it a free-breathing harness, because that is what it is for.

See the MEGIN harnesses →

FAQ

Collar or harness for a puppy?

A well-fitted harness is often a good choice for a puppy that is still learning to walk on the leash, because it keeps the pulling force off the neck. A light collar can still be used for the ID tag.

Why does my dog cough when it pulls?

Pressure on the windpipe triggers coughing, also in healthy dogs. If the cough continues after the pressure is gone, or sounds like a honk, get it checked by a vet.

Can a collar cause tracheal collapse?

There is no good evidence that ordinary use of a collar causes tracheal collapse. In a dog that already has the condition, however, pressure on the windpipe can trigger or worsen coughing.

Can a harness cause tracheal collapse?

There is no evidence of that. But a harness that sits too high or rides up can press on the throat in the same way as a collar – so a correct fit is important.

Is a wide collar better than a thin one?

A wider collar spreads the force over a larger area, but the force still ends up on the neck. Carter et al. found problematic pressures from all the collar types tested.

Sources

• Pauli AM et al. (2006). Effects of the application of neck pressure by a collar or harness on intraocular pressure in dogs. J Am Anim Hosp Assoc 42:207–211.
• Carter AJ, Roshier AL, McNally DS (2020). Canine collars: an investigation of collar type and the forces applied to a simulated neck model. Veterinary Record 187(7):e52.
• Ridgway M (2026). Health implications of dog-worn equipment: a review of known and alleged physical risks. Frontiers in Veterinary Science 13:1711781.
• Rozanski EA (2022). Tracheal collapse. Today's Veterinary Practice, March/April 2022:50–56.
• Merck Veterinary Manual: Tracheal Collapse in Dogs.
• VCA Animal Hospitals: Tracheal Collapse in Dogs.
• Cornell University College of Veterinary Medicine: Tracheal collapse.

This article is general information and does not replace an examination by a veterinarian.