Your teenage dog eats grass on every walk, and the useful questions are which grass and how often

Somewhere around 9 months old your dog started grazing. Ten paces, head down, a mouthful of long grass, and on again. You have started dreading the verge outside the park gate.

What we will and will not claim

You will find confident explanations online. Nausea, a missing nutrient, an empty stomach, boredom. We do not have a source we trust for any of them, so we will not pick one for you.

That is less unhelpful than it sounds. Casual grazing is a different picture from frantic daily grazing, and you can tell those two apart yourself.

Watch for 3 walks and write down 4 things

1. 1

   When it happens. First thing in the morning, before meals, or scattered through every walk.

2. 2

   How it looks. Casual grazing with the tail loose, or head down, fast, and hard to interrupt.

3. 3

   What comes after. Nothing, a burp, or vomiting. Note how many times your dog vomits and what comes up.

4. 4

   What else changed. Appetite, weight, stools, energy, and whether the food or the routine moved in the last month.

Take that note to your veterinary practice rather than a description from memory. Sudden behaviour change warrants a veterinary examination, and pain frequently presents as a change in behaviour rather than as obvious lameness.

The risks are in the grass, not the grazing

Most of what we would manage here is about which grass your dog chooses. Verges and park edges get sprayed, dogs foul them, and long seed heads catch in ears, paws and eyes. Ask your veterinary practice what is worth avoiding where you live, and whether your worming plan covers it.

Managing it on the walk

1. 1

   Learn the 2 or 3 stretches where it always happens, and shorten the leash to 3 feet for 20 paces before each one.

2. 2

   Pay your dog for walking past with something better than grass. Cheese or roast chicken, fed at your knee, 4 pieces as you go by.

3. 3

   Offer a different job in the same place. Scatter 6 pieces of food on the path and let your dog hoover them up, so the nose has something else to do.

4. 4

   Route around the worst verge for 2 weeks. Removing the rehearsal is faster than out-training it.

Do not make it a wrestle

Prising grass out of your dog's mouth or telling them off teaches them to swallow faster and to move away from you. Punishment-based approaches are associated with fear, avoidance and defensive aggression.

Trade instead. Show 3 pieces of food, say your cue once, feed all 3 when the mouth empties, then walk on. Reward-based training has been associated with higher reported responsiveness and fewer reported problem behaviours.

Today's version, in one line: note the time and the manner on tomorrow's walk, and carry cheese for the verge you dread.