Joints are less able than muscle or bone to repair themselves. The smooth cartilage that lines the joints and is necessary for pain-free athletic motion is easily damaged. Once the process of osteoarthritis, or inflammation of the joints, has begun, a perfect repair is not possible. Unlike muscle and bone, joints do not respond well to concussion and repetitious motion. Damage begins with overwork and trauma at a young age, so prevention of damage to joints is your best approach to prevent aging of the joints.
As your horse ages, his muscles will lose strength, his bones will not be as strong, and he will likely have at least minor osteoarthritis. If your horse has had a good athletic education, however, his efficiency of motion and training will let him continue to exercise happily, often into his thirties.
What About My Horse’s Eyes?
As with all the other body systems, the horse’s eyesight does deteriorate with age. The most common problem in older horses has to do with a disease called recurrent uveitis, or moon blindness. This is an inflammatory eye disease that is still very poorly understood. The complications of recurrent uveitis include cataracts and scarring that can lead to blindness. Because this is a chronic disease, we tend to see these complications more commonly in the older horse. Even in the older horse with healthy eyes, the lens of the eye becomes less compliant with age, and the horse becomes less able to focus on objects. This seems to be less of a problem for horses than for species such as cats that rely heavily on good eyesight. Older horses with vision loss need special veterinary attention, but are often amazingly adept at relying on cues from their owners, other horses, and surroundings to help them navigate.
What About My Horse’s Internal Organs?
Studies in older people suggest that the most important changes occur in the kidneys. The kidneys become less efficient at ridding the body of waste products, and they become less able to concentrate urine, leading to increased loss of body water. What does this mean? It means that we must be more careful using even “safe” drugs in older horses, and we must make sure that they always have adequate supplies of fresh water, so that they don’t become dehydrated.
So, What is My Horse’s Life Span?
All of us know of the 40-year-old horse or pony, and with genetic luck and very good care, your horse may also live into his forties. Whether or not your horse will live this long depends on genetics, good home and veterinary care, and a dollop of luck. We generally find that horses begin to show signs of aging in their mid-teens. If they were living in the wild, poor dentition alone would probably lead to a natural lifespan of 12 to 18 years – not withstanding predators and other mishaps. What can you expect for your horse? If we assume that your horse does not suffer a catastrophic event, such as colic or fractured bones, it is reasonable to expect that your horse will live into his twenties, and many will reach their thirties. Good dental and other veterinary care, good nutrition, and regular exercise, will help your horse to live as long and healthy a life as possible.