Thanks to better nutrition, better veterinary care and perseverance on the part of owners who love their long-time companions, the health and athletic ability of older horses is much better today. If you want to optimize your horse's health as s/he ages, it is first important to know the problems that arise. The earlier you react to these issues, the more successful will be the outcome.
However, some problems are not treatable, and this can be a painful realization if it is sudden. So take a minute to familiarize yourself with the problems that are likely to develop with age, and understand a bit about those symptoms that are serious and possibly untreatable. This will prepare you to provide the best quality of life for your horse until the end.
Appearance of Old Age
Like people, some horses age at different rates than others. The appearance of old age could come as early as 15 to 20 years in some horses or as late as 20 to 35 years in others. Generally, however, most people regard horses as being relatively old after 20 years of age, when old age problems start to become prevalent. Twenty years in a horse corresponds to approximately 50 to 60 human years and 30 years would be around 80 to 90 human years. These estimates are based on the maximum expected longevity of the horse, which is thought to be 44 years.
Accounts of horses over 44 years have been difficult to verify. The average horse is healthier later in life, but the actual life span has probably not changed, and horses reaching their 30s and 40s are still rare. The actual life span may be difficult to improve because of the combination of problems that develop, and for now, the lack of resources to solve all of them, especially when multiple problems exist.
If there are problems that result in a significant loss of function of any body system, cause persistent pain that cannot be easily controlled, and/or there is a lack of response to aggressive treatment, the problem could be life-threatening. These issues involve quality of life, and you should discuss them with your veterinarian, family and friends.
Although it's hard to talk about your horse getting "old", it's going to happen. Every horse is different in the way he reacts and expresses pain and loss of function, so each horse has to be evaluated as an individual. A thorough evaluation should be performed, and if there is any question, you should work with your veterinarian to make your horse as comfortable as possible, yet decide what is reasonable to assure a good quality of life.
Dental problems often cause persistent pain and loss of function such as chewing difficulties and poor digestion. The horse's cheek teeth are continuously growing but at the same time they're being worn down by the action of chewing. This is one reason that horses can no longer cope in nature. As the cheek teeth wear down there is increased risk for other tooth problems such as tooth root abscesses, periodontal (soft tissue) disease and sinusitis, that can be very painful.
Dental care is important for aging horses, and you can reduce the risk of health problems due to dental disease with routine dental care and switching to a diet that does not require a significant amount of grinding action. Still, however, horses without teeth, even when fed purees, mashed carrots and tonics, have problems maintaining their body weight, and once they are drained of body fat and show the ribs, the process can be very difficult to reverse.
Horses that have lost weight to the point where their ribs or back are prominent, will take at least six months under ideal circumstances to return to weight on full feed. This can be extremely difficult to achieve without good teeth. In general, horses with serious lack of teeth that lose weight despite your best efforts to feed them, may have difficulty surviving any change in environment, stresses, or new demands.
Equine Cushing's Disease (ECD)
Cushing's disease causes loss of function of the hormonal system and may not respond to treatment. Many older horses develop ECD, which is caused by a growth on the pituitary gland located at the base of the brain. This very active growth releases a hormone that causes the adrenal gland to be hyperactive and to produce excessive amounts of steroid hormones. The resulting symptoms include: