Like people, horses age and cope with ageing at different rates. The type of work they do now, how hard they have been worked in the past, previous injuries and the individual constitution of the horse will all play a role in how well a horse can continue to function in the later years of its life. The key to knowing when the horse should be retired is in the art of understanding your horse.
A geriatric horse was once described as one that was over 16 years of age. Now, as the equine population lives longer due to better husbandry and advancements in veterinary care, over 20 years of age is a more realistic guide to calling a horse geriatric. Some horse breeds have a life expectancy in the mid-20s whilst other breeds, particularly ponies, can live well into their 40s, meaning a 20-year-old pony is still relatively young and will not become a geriatric until much later in life.
A horse that has been relatively consistently exercised throughout its life is a better candidate for riding throughout the twilight years than a horse that has sat dormant in a paddock for several years. Research has shown that those horses that have done a lot of exercising in their early years (from weanling stage through into adulthood) are much better at maintaining an athletic usefulness than horses that are not.
As horses age, changes in the body occur, making them less able to deal with the same conditions and demands on their bodies as their younger counterparts. Simple husbandry requirements such as feeding (nutrition), dentistry and protection from the weather all become increasingly important when caring for the geriatric horse. In this discussion, we will concentrate more on the horse’s ability or inability to continue being worked as its ages, leaving the other aspects of geriatric care for a different article.
If we ignore the logical reasons why a horse cannot be ridden, such as illness, accidents or permanent disabilities, then the limiting factors that restrict the use of an aged horse are musculoskeletal, cardiovascular, respiratory, optical and metabolic. The most common reason for the inability to continue being ridden or performing is usually musculoskeletal and is manifested as lameness. As the body ages, the ability of the cells to regenerate and recuperate diminish. From mid to late teens, the collagen in tendons and muscles weakens and deteriorates, making injury to the tendons and ligaments in the legs more likely and repair of these injuries less successful. This means old horses doing similar exercises to much younger horses are more likely to suffer from a soft tissue injury and are less likely for this injury to repair itself in a timely manner.