Sources

The sources behind our Senior Dog Basics compact guide, in the order of its topics. Where our own arithmetic or opinion sits on top of a source, the guide labels it, and the notes below say so.

We list what we read and what kind of source it is. Several pages below are written by companies or paid for by affiliate links; we say so on each line. Prices change, and every figure in the guide carries the date we saw it. A vet will know more about your dog than any of these pages.

Guidelines and professional bodies

• AAHA, 2019 Canine Life Stage Guidelines (JAAHA 55:267-290, 2019). Professional association guideline
• AAHA, 2023 AAHA Senior Care Guidelines for Dogs and Cats. Professional association guideline
• AAHA, Table 1: Diagnostic Tests and Recommended Frequencies for Senior Dogs and Cats (2023). Professional association guideline
• AAHA, Senior dog life stage (owner page, modified December 2024). Professional association, owner-facing
• AAHA, A watchful eye: recognizing senior pet health problems (October 2024). Professional association, owner-facing

When is a dog senior, and how long do dogs live

• Urfer et al., Risk factors associated with lifespan in pet dogs evaluated in primary care veterinary hospitals, JAAHA 55(3):130-137 (2019). Peer-reviewed. Our senior start ages are our own arithmetic on its median lifespans.
• Kraus, Pavard and Promislow, The size-life span trade-off decomposed: why large dogs die young, American Naturalist (2013). Peer-reviewed (abstract page)
• Teng et al., Life tables of annual life expectancy and mortality for companion dogs in the United Kingdom, Scientific Reports (2022). Peer-reviewed. UK data, not US.
• NIH, NIH researchers reframe dog-human aging comparisons (9 July 2020). Government news release on a study of 104 dogs, mostly Labradors

Signs, conditions and home monitoring

• MacQuiddy, Moreno, Kusick and McGrath, Assessment of risk factors in dogs with presumptive advanced canine cognitive dysfunction, Frontiers in Veterinary Science (2022). Peer-reviewed
• Merck Veterinary Manual (dog owner version), behavior problems in dogs. Reference text
• Anderson et al., Prevalence, duration and risk factors for appendicular osteoarthritis in a UK dog population under primary veterinary care, Scientific Reports (2018). Peer-reviewed. UK data.
• Fleming, Creevy and Promislow, Mortality in North American dogs from 1984 to 2004, J Vet Intern Med (2011), as reported by ScienceDaily. We read the press release, not the paper. Teaching-hospital cases.
• Tufts, Monitoring heart disease treatment at home. Veterinary school hospital. Written for dogs with known heart disease.
• Tufts Your Dog, Check your dog's muscle mass. Veterinary school publication, undated

Vet visits, tests and results

• Cornell University Animal Health Diagnostic Center, Reference intervals. Veterinary school laboratory
• Role of repeated screening in older dogs, J Vet Intern Med 2025;39(4):e70166 (122 dogs, two-year cohort). Peer-reviewed. No unscreened comparison group. We read the study through a mirror of the publisher's page, so check the details against the original.

Food

• Churchill and Eirmann, Senior pet nutrition and management, Vet Clin North Am Small Anim Pract 51:635-651 (2021). Peer-reviewed review
• FDA, 'Complete and balanced' pet food (28 February 2020). Regulator
• Tufts University, Wide variety in nutritional content found in 'senior' dog foods (16 March 2011). University news release. Old: it shows variation, not today's products.

Insurance

• NAIC, Pet Insurance Model Act (Model #633). Model law. Whether your state adopted it, and in what form, varies.
• NAIC, A Regulator's Guide to Pet Insurance (2019). Regulators' association guide. Dated.
• NAPHIA, State of the Industry 2026 (highlights). Industry trade group

Prices

• webvet.com, Dog bloodwork cost (5 July 2026). Affiliate-funded article. Prices are ranges, not quotes.
• webvet.com, Dog X-ray and ultrasound cost (5 July 2026). Affiliate-funded article. Prices are ranges, not quotes.

Corrections

If a link has moved or a figure is out of date, write to hello@seniorpetverdict.com with the source if you can. We correct the page and update the date.

Last updated October 10, 2026.

General information, not veterinary advice. Talk to your vet before changing your pet's treatment, diet or medication.