The number most people use, and what it really means
Fifteen is the age the horse world generally reaches for: feed companies formulate their senior feeds from it, insurers start asking different questions, and vets begin framing check-ups around age-related change. Past twenty, most horses are fairly described as geriatric, and by the mid-twenties a horse is at an age its grandparents' generation rarely reached at all. But 'senior' in this sense is a care category, not a decline diagnosis — it marks the point where the wear of life starts needing management rather than the point where usefulness ends. Plenty of horses in their late teens are in full work, competing and thriving; what has changed is that their teeth, joints and digestion reward attention earlier than they did at nine.
Why breed and history move the line
The spread around that fifteen-year mark is wide, and it is honest. Native ponies and cobs, lightly worked and easy-keeping, commonly stay robust well into their twenties, and their owners often meet old age first in the feet and the waistline — laminitis risk and stiffness — rather than in frailty. Thoroughbreds and other horses that started work young and hard, especially racing and competition horses, tend to show mileage earlier: hock and fetlock wear, teeth that have been working hard for two decades, and a back that begins to dip. A horse's senior status is therefore better read off the individual — previous workload, injuries, how it holds condition — than off the calendar. Two horses foaled the same spring can honestly be five years apart in the only sense that matters to their care.
The signs that say senior care should start
Rather than waiting for a number, watch for the cluster of changes that announce the transition. Teeth are the classic first: chewing becomes slower, quidding — dropping balls of half-chewed hay — appears, and long forage starts passing through undigested because the grinding surfaces have worn smooth or angled. Weight follows teeth: the horse that always lived on air starts needing help to hold condition through winter. Add greying around the eyes and muzzle, a deepening hollow above the eyes, loss of muscle along the topline even in work, slower recovery after effort, and stiffness that shows on cold mornings and eases with movement. Any one of these is unremarkable; several arriving together are the horse telling you the senior regime — dental checks at least twice a year, forage reviewed, workload adjusted — should begin now.
What changes in practice
Senior care is mostly the same care with the intervals shortened and the observation sharpened. Dental appointments move from annual to twice yearly, because a worn mouth deteriorates fast and every feeding problem downstream starts there. Feeding shifts toward forage the horse can actually chew — chopped fibre and soaked feeds replacing long hay when the teeth say so — and weight gets checked by tape and hand regularly rather than by eye at rug changes. Work is tailored rather than stopped: regular, moderate exercise protects joints, gut and mind far better than retirement to a field, though jumping and hard schooling give way to hacking and schooling on good ground. Worming, vaccinations and blood work stay current, and new lumps, drinking changes or coat changes get mentioned to the vet rather than filed under 'just old age', since several of the common conditions of older horses are manageable when caught early and miserable when assumed to be inevitable.
Keeping the record as the years accumulate
An older horse generates paperwork: dental charts, weight records, blood results, notes on which feed kept condition last winter. That history is genuinely clinical information — a new vet, a yard move or an emergency vet at midnight all work better with it in hand. KinsLe's Pet Passport is built for exactly this: it keeps your horse's records together in one portable packet, ready for vet visits and handoffs, so the senior years are documented as carefully as they are managed, and the story of what works for this particular horse is never left to anyone's memory.