Whether you consider a horse to be old at 18 or 25, at some point, senior horses are going to start showing clinical signs of aging–moving more slowly or stiffly, becoming unthrifty, developing a dull coat, or displaying subtle or obvious signs of a disease process. Here are some of the common problems you could encounter in your aged friend and what you should know about those topics to help him through those golden years.

Cardiac Dysfunction

"Older horses, in general, do not commonly develop life-threatening or career-limiting cardiac problems," reports Laurie A. Beard, DVM, MS, Dipl. ACVIM, associate clinical professor at Kansas State University’s College of Veterinary Medicine. "Nevertheless, a decrease in aerobic and exercise capacity occurs in older horses. Older horses are not as able to run as fast or as long as younger horses."

Unfit older horses do not thermoregulate as well as unfit younger horses; thus they can become overheated or chilled more easily. The cause of altered themoregulation is unknown, and it’s also unknown if training helps improve the age-related decline in these values, Beard says.

Although usually of little consequence, older horses commonly develop aortic regurgitation. "This is a result of slow degeneration of the aortic valve, leading to leaking of blood across the valve when it shuts," Beard explains. "The majority of older horses with aortic regurgitation are clinically normal and do not have exercise intolerance. There is no treatment, as this does not appear to result in any significant problem. The prognosis for older horses with aor