When does a dog become a senior? Which tests should be done regularly? How to adjust diet and activity? A complete guide to caring for an older dog.
The answer depends on size. Larger breeds age faster than small ones:
| Size | Becomes senior at |
|---|---|
| Small breeds (under 10 kg) | 10–12 years |
| Medium breeds (10–25 kg) | 8–10 years |
| Large breeds (25–45 kg) | 7–8 years |
| Giant breeds (45 kg+) | 5–6 years |
A 7-year-old Great Dane is already in his senior years; a 7-year-old Chihuahua is middle-aged.
Healthy adult dogs need an annual check-up. Senior dogs should see the vet every 6 months, even if they seem fine. Many age-related conditions. Kidney disease, thyroid problems, early tumours: are best treated when caught early.
Ask your vet which tests are appropriate for your dog's breed and history.
Slower metabolism: Senior dogs burn fewer calories. Many gain weight on the same food they've eaten for years.
Joint changes: Arthritis is extremely common. Watch for: stiffness after rest, reluctance to jump, difficulty with stairs, visible discomfort.
Reduced senses: Hearing and vision deteriorate gradually. Your dog may not respond to commands as quickly, don't assume disobedience.
Cognitive changes: Some dogs develop Canine Cognitive Dysfunction (dog dementia). Confusion, altered sleep patterns, accidents indoors, apparent forgetfulness.
Skin and coat: Coat may thin, grey around the muzzle, and skin becomes less elastic.
Most senior dogs need 20–30% fewer calories than adults. Switch to a senior formula or reduce portion sizes, and weigh your dog monthly to catch changes early.
Contrary to old advice, healthy senior dogs need adequate protein to maintain muscle mass. Only reduce protein if your vet specifically recommends it for kidney disease.
Foods or supplements containing glucosamine and chondroitin support cartilage health. Omega-3 fatty acids (fish oil) have anti-inflammatory benefits. Ask your vet for dosing guidance.
Older dogs are more prone to dehydration. Encourage water intake. Multiple bowls around the house, a pet fountain, or adding water to dry food.
Don't stop exercising, adjust it.
Watch your dog during and after walks. Lagging behind, panting heavily, or reluctance to continue are signs to slow down.
If your vet diagnoses arthritis:
As your dog ages, the health history becomes more valuable: not less:
Having complete records accessible at any vet visit is especially important for seniors, where history matters most.
Ageing is not a disease, it's a life stage that requires adjusted care. More frequent vet visits, a modified diet, gentler exercise, and early attention to warning signs will give your senior dog the best quality of life for their remaining years.
Consult your vet regularly. The most important thing you can do for a senior dog is notice changes early and act on them.
This article is informational and does not replace a consultation with a veterinarian. Vaccination and deworming schedules and dietary advice are chosen individually. For the age, health and lifestyle of a particular animal. If you notice worrying symptoms, contact a vet.
Krystian Rygiel
Creator of PetsyPlanet. Writes about dog health because he's a dog owner himself and knows how important good medical records are.
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