Over the years I've cared for dozens of so-called "old" horses, and one of the most interesting things to me has always been how differently individual horses age, and how some horses truly appear "old" at a much younger age than others. What does "old" really refer to, after all?

A horse's chronological age certainly plays a role in whether he or she is considered old or not, but I think it's important to consider his physical condition, mental condition, history, and any health problems that might be present.

Photo: Erica Larson

I can recall some perfect examples from the farm I used to work at. The only way you could tell that one 37-year-old Thoroughbred was a day over 10 was by taking a peek at his teeth (or lack thereof); he was still being used in lessons (and teaching kids how to hold on when he played up) when I departed from the farm several years ago. Meanwhile, one of Morgan geldings had barely reached his mid-20s when his health started going downhill rapidly, to the point that the only humane option for him was euthanasia. Still another Thoroughbred gelding was only in his mid-teens and a solid and well-built horse, however some serious wear and tear from his previous career, coupled with an old injury, limited his participation in our lesson program to mainly walking lessons—he rarely trotted, and then it was only if we needed a solid mount for a larger rider and, even then, he received some veterinarian-prescribed phenylbutazone to help his joints cope with the extra stress.

So which of those horses would you consider old? It wasn't too long ago that a 15-year-old horse was widely considered to have entered the "senior" realm. But today, horses are living well into their 30s—and beyond!—on a regular basis. And if you were to ask 10 owners or equestrians what they consider "old" for a horse and why, I bet you'd get 10 different answers.

In my humble opinion, I don't think you can judge a horse's "age" solely on how long they've been on the planet. Don't get me wrong—his chronological age certainly plays a role in whether a horse is considered old or not, but I think it's important to consider his physical condition, mental condition, history, and any health problems that might be present.

Taz, our recently departed Appaloosa gelding whom you've read lots about over the past year or so, got "old" relatively early in his life—in my estimation, he'd hit senior status by his 15th birthday. And by the time he was in his late teens, he was struggling with arthritis, balance issues, and other assorted infirmities. That said, he was still 100% in the game mentally. So before he turned 18, he was retired from competitions and spent the rest of his life enjoying leisurely rides around the farm that were stimulating for his mind, but not too strenuous on his body.

Similarly, Dorado still has the mentality of a 5-year-old, which can get his now 17-year-old body into trouble from time to time. Unlike Taz, Dorado came to me with pretty significant wear and tear on his body from making 55 starts in the span of five years on the racetrack, including at least one fracture and some pretty bad hooves. It takes a well-oiled machine consisting of his veterinarian, his farrier, his day-to-day caretakers, and me to keep this old guy going, but he's really not happy when he's not working: he doesn't eat well and gets depressed after a few weeks of not working. So yes, I consider Dorado to be an older horse, but I say that with pride: I'm so proud that we're able to keep this old guy going, because he would be absolutely miserable sitting around doing nothing.

Sixteen-year-old Sadie, on the other hand, is anything but old. (It does, however, make me feel old when I recall that we purchased her as a spit-fire of a 5-year-old, but that's beside the point!) Since we got her, Sadie has been living the good life. Her joints probably have less damage to them than mine do after 20 years in the saddle, she certainly is still fresh as a daisy. The one good thing about Sadie getting older is that she's finally maturing mentally and calming down a bit. Will a few more years result in a more settled mare? I sure hope so!

Each horse is an individual and, just like we have to customize feeding programs and exercise regimens, I think we have to judge whether a horse is "old" or not on an individual basis. But as I mentioned before, I'm sure everyone has different ideas and now I'd love to hear your thoughts. How do you determine if a horse has reached senior status, and why do you use this method?