signs of aging | vision | arthritis | tumors | kidney or liver failure/disease | glandular malfunction | dental problems and dentition | feeding and nutrition | general care guidelines
Introduction: When a horse reaches 16-18 years of age, it is considered a geriatric or senior animal. It is around this time in the animal’s life when many horses begin to manifest signs of aging. These signs of aging can be very obvious in some horses, while other horses can continue to be in great condition throughout their early twenties. The difference in how a horse ages can often be the result of how much care it receives during its life and throughout the geriatric years. The following information will address the various health problems associated with an older horse and will outline some of the more common ways to prevent these problems.
Common Problems
Older horses experience a number of physiological changes that can lead to problems as they age. Many of these common problems can be lessened or eliminated by monitoring the horse’s health on a regular basis and administering care as required. Some of the more common signs associated with aging are listed below:
Vision
Most older horses experience minor vision impairment, though not significant
enough to cause noticeable changes in the horse’s behavior. Due to the fact that
horses will often cling to familiarity in both surroundings and routine in order
to compensate for poor vision, changing pastures or stalls, or even changing
their exercise routine could cause noticeable difficulties for the horse at
first. Being aware of and sensitive to potential difficulties with vision can
help prevent injury or stress.
Arthritis
Often the aging horse will experience arthritis or stiffness in their joints.
Arthritis simply means that the horse has inflammation or deterioration of the
joint. This could be caused by a misstep, a blow, or long-term wear that has
begun to destroy the joint. Signs of arthritis include joint inflammation
manifested by heat, pain, swelling, and redness in the area. Arthritis can be
treated by administering a variety of anti-inflammatory drugs, a common one
being phenylbutazone). Over use of phenylbutazone can have drawbacks, however,
and oral glucosamine compounds are becoming an increasingly popular alternative
(See Section G for information on anti-inflammatory agents). Topical treatments,
such as DMSO, help boost the health of the affected joint without being injected
or consumed. Other forms of arthritic relief can be found in injections, such as
hyaluronic acid or polysulfated glycosaminoglycans (PSGAG5), which are believed
to prevent further cartilage damage. Increases in supplementation of vitamin E,
C, and B-complex can also provide relief to horses with arthritis. Allowing the
horse to get plenty of rest and providing regular farrier work can also help. A
veterinarian should assess the horse’s condition before invasive treatments,
such as hyaluronic acid injections, are begun.
Parasitism and Infectious Disease
As a horse ages, its immune system weakens, making it more susceptible to
disease and especially to parasites. Basic management and careful monitoring of
the horse can help prevent and identify possible parasite infections. For
example, removing manure from paddocks or fields can help reduce the risk of
parasitism. Regular vaccinations should also be given to the horse to help
prevent infection. (See pages A620 and A905 for types and treatments of
parasites and certain infectious diseases.)
Heaves (See page E305)
Older, stabled horses become more sensitive to dust, mold or other allergens.
The initial step in preventing heaves is to change the horse’s environment so
air quality is improved and airborne dust, pollen, and mold spores are
eliminated as much as possible. Using natural bedding such as shavings or paper
and sprinkling bedding with water to eliminate dust will help reduce the
frequency of coughing. Corticosteroids and bronchodilators can be administered
to the horse to help relieve sensitivity and reduce inflammation.
Tumors (See page E770)
Melanoma tumors are common in older horses, especially in gray horses. Over
80% of gray horses aged 15 or older reportedly have melanoma tumors. Other types
of tumors include sarcoids and squamous cell carcinomas. Sarcoids are skin
tumors that account for over one-third of reported horse tumors. Squamous cell
carcinomas are the second most common tumor in horses. They usually appear as
skin tumors and are located around the eyes, muzzle, or genitalia. They can also
be found in the nasal cavity, mouth, throat, or stomach.
Several methods of treating these different types of tumors exist, including surgical removal, freezing, immune system stimulation, radiation, or anti-cancer drugs. Accurate detection and early treatment are the most effective methods of eliminating or lessening the impact of tumors.
Kidney or Liver Failure/Disease (See page
E475)
Major organs such as the kidneys, liver, and large intestine naturally
degrade as a horse ages. This deterioration cannot be stopped, but can be slowed
by altering the diet of the older horse. Horses with kidney disease should have
a decreased intake of calcium. This is important because the kidneys normally
filter the calcium and high levels of calcium in their diet will potentially
cause calcium build-ups. Protein and phosphorus intake should also be limited.
Horses with liver disease should also have an altered diet. They should be given
an increased amount of carbohydrates and should be supplemented with vitamin C
and B-complex.
Glandular Malfunction
Also common in older horses is the abnormal function of the adrenal, thyroid,
and pituitary glands. For example, tumors on the pituitary that trigger
glandular hyperactivity cause a disease called Cushing’s. It causes
abnormalities in the utilization of blood sugar and fat. Calcium-phosphorus
imbalances also may occur as a result. Horses with Cushing’s disease are also
more susceptible to laminitis and founder, infection, and parasite infestation.
(See page E136 for a more complete discussion of Cushing’s disease).
Tumors on the thyroid also occur and can cause poor hair coats, excess shedding, muscle weakness, loss of energy, and difficulty maintaining a healthy weight. (See page E818 for more details on thyroid disease).
Dental Problems and Dentition (See page
A148)
"Years and years of grazing and grinding hay and grain can wear, weaken, or
even loosen the teeth. Horses’ teeth grow for about six years. Then, each year
thereafter, they undergo a process of wear and eruption that uses up
approximately one-eight inch of tooth per year. By the age of 20, the average
horse has worn away approximately 1 ½ inches of his 2 ½-inch-long teeth"
("Managing the Changing Needs of Older Horses," Joanne Meszoly, EQUUS,
Nov. 2000, Pg. 3). As a result of this continuous wear, it becomes increasingly
difficult for the horse to chew and the horse no longer gets the most out of its
feed. Generally, it is fairly easy to identify dental problems in older horses.
Some symptoms may include the following:
There are primarily two types of dental problems that adversely affect older horses: shear mouth and wave mouth. Shear mouth is a dental condition in which the teeth begin to wear off at 60-75 degree angles as opposed to the usual 15-degree angle. This condition hinders the horse’s circular grinding motion necessary for effectively utilizing feed. Wave mouth is classified by the highs and lows along the molars created by uneven wear of adjacent and opposing teeth. Dental disease, abscess, or infection can also be caused by teeth shifting to fill gaps left by teeth that have fallen out.
Prevention of these dental problems is critical to making sure the horse is able to absorb as many nutrients as possible from the feed. Though the teeth may not need to be floated every six months, it is important to have annual or even semi-annual dental checkups.
Aside from frequent body condition monitoring, the older horse may require changes in diet to maintain a good weight. See Figure 1 for dietary considerations for specific diseases or conditions. The majority of older horses should have a protein intake of about 10-14%. They should also receive a higher level of energy that can often be found in soluble carbohydrates, fats, and oils. Fiber intake should be limited to less than 30% of their total diet. Mineral supplements should be given, but calcium intake should be limited to avoid build-ups in the body as mentioned earlier. Vitamins should also be supplemented, including vitamin C, although too much of this vitamin can also be harmful to the horse’s health. To avoid causing colic or other digestive problems, these changes in diet should be introduced gradually, possibly even over a 2-3 week period.
The horse’s feed should be easy to chew and digest. Overall, the total amount of feed should be increased by 10-15% without exceeding the 30% fiber guideline (see A575 for normal feed ratios). Because senior diets contain the necessary nutrients and are often created from feed that has been cooked and turned into a paste that is then puffed into pellet form, these feeds can be beneficial to the older horse. These senior feeds make it easier for the horse to absorb protein and carbohydrates because they are largely digested in the large intestine where digestion should naturally occur. Geriatric horses often do better when fed several small meals throughout the course of the day as opposed to one or two large meals per day. Supplements such as beet pulp can also be given as source for energy, but they should not exceed 30% of the horse’s total diet. It is also important to maintain a fresh, clean water supply for the horse at all times.
Figure 1: Dietary Considerations for Specific Diseases or Conditions
| Condition | Recommended Diet | Feeds/Supplements |
| Weight loss (non-disease related) | 12-14% protein 7-10% fat High digestibility Easily chewed |
Complete pelleted feeds Beet pulp Soybean meal |
| Poor teeth | Easily chewed feed | "Soup" of soaked pellets or hay cubes Complete feed |
| Pituitary/Thyroid dysfunction | Reduced starch Highly digestible fiber Vitamin C/B-complex |
20g vitamin C/day Avoid sweet feeds |
| Kidney failure | Restrict calcium, protein, phosphorus | Grass hay and corn Avoid legumes, wheat, bran, and beet pulp |
| Liver failure | Restrict protein (8-10%) High starch Extra vitamin B and C |
Corn, beet pulp, grass hay Avoid legumes and wheat bran |
| Arthritis | Avoid overfeeding | Extra vitamin B, C, and E |
Other General Care Guidelines
The older horse should:
Summary: There is no guarantee that a given horse will live into its twenties without suffering from some age related problem. However, with some effort on the owner’s part, many age related problems can be avoided or kept to a minimum. The suggestions contained in this article are intended to be a starting place for owners that want to take better care of that beloved geriatric horse.
The picture below shows a 22 year-old stallion in excellent condition and good body weight due to proper nutrition and care.