Is your dog, or young puppy in pain?

Pain in dogs and puppies is often overlooked. Learn how pain, gut health, and behaviour are deeply connected, and why pain trials are essential.

Is your dog or puppy in pain?

Pain is something none of us want our dogs to experience — yet it’s often far more present, and far more subtle, than we might think. We’re used to looking for obvious signs: a limp after a rough play session, or a yelp when jumping off the sofa. But pain can show up in ways that are quiet, easily missed, or mistaken for "difficult behaviour."

Professor Daniel Mills and his team at the University of Lincoln have done some fascinating work highlighting just this. In one of his studies (Mills et al., 2020), they found that over 80% of dogs referred for behaviour problems had an undiagnosed pain component contributing to those issues. That’s a huge number — and it really changes how we think about "problem behaviours."

Pain and behaviour: deeply connected

Pain and behaviour aren’t separate strands — they are intrinsically and deeply interlinked. Pain affects a dog’s ability to rest, to think clearly, to move freely, and to cope with everyday challenges.

A dog in discomfort may become defensive, reactive, withdrawn, clingy, or appear hyperactive. We may label this as anxiety or "problem behaviour," when in fact, pain is quietly driving these changes in how they interact with the world.

Crucially, fearfulness and noise sensitivities can also be strongly influenced by pain. A dog experiencing pain may feel more vulnerable, which can lower their tolerance for noises or sudden changes in the environment. The world feels less safe when your body hurts — and many noise phobias or generalised fears can be exacerbated (or even caused) by underlying pain.

Dogs don’t always limp or cry out to show us they’re in pain. Sometimes they just hesitate before jumping into the car, avoid the stairs, shy away from touch, or seem more irritable and easily startled.

Puppies and pain: an overlooked reality

We often think of puppies as bundles of endless energy, but they too can experience pain and discomfort — and it can look very different from what we expect.

Puppies experiencing pain (including gut discomfort) may struggle to settle, finding it hard to rest or nap, and may appear constantly "on the go." Instead of quietly curling up after play, they might seem agitated, restless, or unable to relax.

Pain and gut issues can also contribute to hard play biting. While all puppies explore the world with their mouths, a puppy who feels uncomfortable or in pain may bite harder or more persistently, as their ability to regulate arousal and frustration is reduced.

Considering pain and gut health early on helps set puppies up for a calmer, more balanced development, and prevents misunderstandings that might lead to frustration for both puppy and guardian.

Gut health: an invisible influence

Alongside joint or musculoskeletal pain, gut health is another critical piece of the puzzle.

The gut–brain axis — the communication pathway between the gut and the brain — plays a major role in emotional wellbeing, pain sensitivity, and resilience to stress. In dogs, an imbalanced gut microbiome (the community of microbes living in their digestive tract) has been linked to increased anxiety, aggression, and even changes in how they respond to the world around them (Kirchoff et al., 2019; Mondo et al., 2020).

When a dog’s gut health is compromised, they may experience chronic inflammation and reduced serotonin production, which can amplify pain and make them more sensitive to stress.

Importantly, certain gastrointestinal infections — such as Giardia and Campylobacter — can cause significant disruptions to the gut microbiome. Giardia, a common parasitic infection, is known to cause ongoing gut inflammation, malabsorption, and even long-term dysbiosis (Hall & Wass, 2020). Similarly, Campylobacter infections can lead to chronic gastrointestinal upset and shifts in microbial balance that persist even after the initial infection resolves (Cunningham et al., 2017).

These disturbances not only impact digestion but can also affect a dog’s behaviour and emotional resilience, making them more fearful, noise-sensitive, or reactive, and potentially more sensitive to pain.

Supporting gut health through an appropriate diet, targeted probiotics, and a calm, enriched environment can help reduce inflammation and support overall comfort — both in the gut and in the mind. While this isn't a standalone fix, it is a critical foundation for helping our dogs (and puppies) feel better in every sense.

So how do we know if pain is involved?

Here’s the reality: we can’t reliably see pain just by looking — not even experienced vets or behaviour professionals can always tell. Chronic or intermittent pain may not show up in scans, and dogs often mask pain incredibly well.

This is why a pain trial can be so important.

What is a pain trial?

A pain trial is a carefully managed period (usually around 2-4 weeks) where a dog is given veterinary-prescribed pain relief, even if there’s no obvious diagnosis or visible injury.

The aim is to observe changes: does the dog become more relaxed, more willing to move, more sociable, or more settled? Do they play more, sleep better, or show fewer signs of irritability or fearfulness?

If you see these positive changes, it strongly suggests that pain was present — even if we couldn’t pinpoint it before. In many cases, a pain trial is the only reliable way to truly understand whether pain is contributing to behaviour changes. Without it, neither owners or vets can confidently rule pain in or out.

What can we do?

If your dog’s (or puppy’s) behaviour has changed — even if it seems minor — always consider pain as a possible piece of the puzzle.

✅ Speak to your vet about the possibility of pain, and discuss a pain trial if needed.
✅ Work with a behaviour professional who understands how closely pain and behaviour are linked
✅ Look holistically at your dog’s health, including their gut: what they eat, how they digest, and whether their routine supports a calm and resilient system.

And most importantly: listen to your dog. They aren’t being difficult or naughty — they’re often just communicating in the only way that they can.

References

Mills, D. S., Demontigny-Bédard, I., Gruen, M., Klinck, M. P., McPeake, K. J., Barcelos, A. M., ... & Lascelles, B. D. X. (2020). Pain and problem behavior in cats and dogs. Journal of Veterinary Behavior, 38, 1–16.
Kirchoff, N. S., Udell, M. A., & Sharpton, T. J. (2019). The gut microbiome correlates with conspecific aggression in a small population of rescued dogs. PeerJ, 7, e6103.
Mondo, E., Barone, M., Gioia, G. D., et al. (2020). Gut microbiome structure and adrenocortical activity in dogs with aggressive and phobic behavioral disorders. Heliyon, 6(1), e03426.
Hall, E. J., & Wass, M. (2020). Treatment of Giardia infections in dogs. Compendium (Yardley, PA), 42(3), 132–138.
Cunningham, L., Kathrani, A., & Allenspach, K. (2017). Investigation of bacterial infections and the role of Campylobacter spp. in canine gastrointestinal disease. Veterinary Journal, 224, 16–21.