Providing Care for Your Senior Horse
Not all that long ago, a horse in his teens was considered old. Today in many undeveloped countries, this is still considered to be the case. But in the sophisticated horse world, what is considered "old?" We consider a horse to be "aged" when he crosses over into his 20s. However, it's not just the human life span that has been lengthened by good nutrition and preventive care; horses are living well into their late 20s and 30s. And these aged horses are doing so with a good quality of life. But just as some humans have aged beyond their years at, say, 65, some horses are old by 18 years even in the best of circumstances.
Technology and advances in medicine have given us tools to keep our horses alive longer and, in many cases, to help them remain athletically active into old age. Let's look at some old horse tendencies and problems, then discuss how to successfully manage these concerns to give your older horse the life he deserves.
Nutrition and Dental Concerns
Just because a horse is up in years does not necessarily mean that he needs a geriatric ration. Many senior horses do well on the rations they have been fed since they were in their prime. However, an old horse might have dietary requirements that are similar to that of a young, growing horse: If he can't maintain weight on a normal ration and is otherwise healthy, he might benefit from a ration similar to that which he was fed as a colt; a relatively high-protein (12-14%) and high-fat (7-10%) diet as well as an excellent source of quality fiber. The younger horse needs this because his growing body requires this diet for growth and energy; the older horse because his system absorbs a lower percentage of many nutrients, perhaps due to chronic parasite damage. These increased nutritional demands are met by various commercial "senior" feed products. Such "senior" products are easy to chew even for a horse with compromised dentition (teeth), are easy to digest, and are quite palatable.
An old horse often demonstrates poor body condition or is seen to lose weight despite plenty of food and a good appetite. Before assuming he needs a special diet, always check his teeth and overall health--especially liver and kidney function. Many older horses have trouble absorbing their feed, and their teeth are an important variable. Although called "long in the tooth" in reference to lengthy incisors, an elderly horse actually has shortened grinding teeth in the back of his mouth. After a certain time in a horse's life (approximately late 20s to early 30s for most), there is no more tooth left to erupt from the sinus cavities of the head; what is left of the cheek teeth will eventually be ground down to nubs. Loose cheek teeth fall out in many old horses, and they are left with gaps in the dental arcade. The opposing tooth has nothing to grind against, so it tends to overgrow into the space where the tooth was lost. This results in a "wave mouth," which makes chewing hay or pasture grasses difficult. Horses with dentition problems tend to "quid" their hay, rolling it into balls of wadded up feed that are then spit out onto the ground.
Many horses have sharp edges on their teeth that need to be filed away (floated) to prevent ulcers on the insides of the mouth and gums. If the incisors have grown overly long with age, then opposing cheek teeth are unable to touch; this creates another reason why a horse might have difficulty grinding his feed. If hay and forage are not well-chewed, the horse might not be able to digest them well enough to obtain sufficient nutrition. Further, poorly ground feed material can cause esophageal choke, impaction colic, and/or diarrhea.
So with this in mind, regular dental care is an especially important part of successfully managing the older horse. You should schedule visits at least twice a year with a veterinarian who specializes in dentistry. If you notice your horse having trouble chewing, or dropping a lot of grain or pellets, or if he commonly spits out matted balls of hay or grass, it is past time to have his teeth worked on by your veterinarian. Overly long incisors can be cut down with diamond-edged tools; long hooks on the back molars can be ground down with power tools. The remaining teeth can be shaped to their best advantage.
Some old horses don't have sufficient length or number of teeth to chew food. These horses are candidates for a diet of mash made by soaking complete feed pellets, hay cubes, and/or beet pulp pellets in ample water. A mash or gruel is easily gummed by the horse, swallowed, and digested. Water added to feed (a half-gallon of water per pound of feed) also increases fluid intake to avert impaction colic and esophageal choke.
Horses which are still capable of chewing hay should be offered a high-quality roughage that is free of dust or mold. Respiratory problems like heaves can result from irritation to the airways by molds and dust that are inhaled from poor-quality hay. Also, hay that is too coarse or "stemmy" can lead to choke, particularly in a horse with poor dentition.
One alternative is to feed hay cubes, which are more easily chewed than regular hay and can be moistened for easier chewing. Ideally, use hay cubes that are either straight grass hay or a blend of grass hay and alfalfa--a diet of straight alfalfa (plus or minus beet pulp) is too rich in dietary calcium. Excess calcium intake increases the likelihood of the horse developing kidney stones.
Feeding the correct amount of food is as important as the horse's ability to eat it or derive balanced nutrients from it. Keep the body condition score of an aged horse as close to the ideal of 5 as possible. Too much fat (scores of 7, 8, or 9) can lead to a higher risk of laminitis, exacerbate glucose intolerance problems associated with Cushing's syndrome, and add stress to the joints and limbs. A horse which is too thin (scores of 2, 3, or 4) can be more susceptible to infections or to becoming anemic due to under-nutrition. A thin horse also has a hard time staying warm in bad weather. To add calories without relying on grain, supplement with one to two cups of vegetable oil or rice bran per day--both are high-fat supplements that must be introduced slowly and used only if liver function is normal. Protein supplements such as a cup of soybean meal can also prove beneficial. Many older horses which get too thin can be improved in body condition with careful attention to the finer details of feeding.
If you watch older horses in the pen or pasture, you'll see them dozing more often than the younger horses. An aged horse usually doesn't run for his food; he walks serenely, neither wasting energy nor pounding on his old legs. After eating for a while, the aged horse often tends to leave the food before it's all finished. In addition to ensuring a balanced ration, it is also important that you consider availability of food, especially if you have geriatric horses mixed in with younger ones. You'll need to make sure the old-timer has plenty of food available when he decides he's hungry later in the day. If you are soaking his feed, however, it might ferment by mid-day. Feeding smaller amounts more frequently (three or four meals per day) will help him get the nutrition he needs.
Whenever you institute dietary changes in your horse's feeding program, start slowly with the new components, especially when adding richer feeds. Spend about two weeks gradually increasing the volume of the new feedstuffs to the desired amount. This allows the intestinal flora to adjust slowly, and limits attacks of diarrhea or colic.
Specific Organ Problems
An older horse is a high-risk candidate for developing liver disease and kidney disease. Unlike the propensity seen in small animals to develop liver or kidney disease, these problems in horses are not that common, but they do occur. The function of the internal organs can be checked with blood tests for chemistry profiles. Chronic infections might also show up as white blood cell abnormalities on a complete blood count (CBC).
Poor kidney function is associated with kidney and bladder stones, weight loss, and decreased appetite. Diet is important in managing failing kidneys--steer away from legume (alfalfa or clover) diets as the high calcium content in these forages cannot be excreted by kidneys already in trouble, resulting in dangerously high levels of calcium in the bloodstream. Protein levels should be limited to 8-10% in those horses. The calcium to phosphorus ratio should be kept as close to 1.2:1 as possible. Beware of feeds like wheat bran, which is high in phosphorus and protein, or beet pulp, which is relatively high in calcium. However, beet pulp is preferable to the legumes as a forage source in horses with restricted ability to consume hay or pasture.
Liver failure is associated with weight loss, jaundice, malaise, and decreased appetite. In advanced cases, neurologic signs can appear. Protein and fat intake in horses with liver disease should be restricted. Sufficient calories can be provided by 10-12% protein corn-based grain/concentrates without added fat, grass hays or grass hay products, and beet pulp. B complex vitamins and vitamin C should be supplemented in a liver-compromised horse since the liver normally synthesizes some of the B vitamins (i.e. niacin) and vitamin C.
Because dietary strategies are vastly different depending on the organ problem, it is important to carefully screen horses with weight loss and depressed appetites for the specific cause of the problem. The syndromes that elicit these problems are varied, and each needs to be addressed specifically. Annual or biannual blood profiles will help identify problems with kidney or liver function that could be controlled with dietary management strategies.
It is especially important to maintain regular deworming and vaccination schedules for the aged horse. The immune systems of a very young and an old horse don't respond as well to the barrage of parasitic, viral, and bacterial organisms around them as that of a healthy young adult. Whereas the young horse is immunologically naïve, the old horse tends to lose efficiency in his immune system with age. Some disease conditions, like Cushing's syndrome (more on this later), further reduce the effectiveness of an older horse's immune system.
Shelter is important, since the older horse is not as efficient at regulating body temperature; hence he is more sensitive to cold or bad weather. Instead of stall confinement, use blankets to keep a horse warm and dry in nasty weather. A paddock with a run-in shed is ideal so the older horse can continue to move at will to minimize discomfort from arthritis. Ample bedding in the areas where a horse likes to lie down also improves his comfort.
Many older horses have arthritic conditions not only by virtue of the work they performed as a young and active horse, but also simply due to natural, cumulative wear and tear on the joints with time. Arthritis is evidenced by chronic lameness, stiff gait, and/or bony enlargements around the joints.
Medical and alternative therapies might keep an older horse feeling younger for longer while improving his quality of life. He might be supported well enough to render him useful for light riding; continued activity further improves his quality of life. Allowing an aged horse to live in a large paddock or pasture is far better for the health of his joints than being confined to a stall. Constant movement keeps the joints lubricated and the muscles toned. He will be more comfortable if he is left out to mosey around at will than if his movement is restricted by confinement.
Technology has now given us effective medications to manage and treat arthritic horses. Previously the only therapy available was to give the horse phenylbutazone (Bute) whenever necessary to keep him comfortable; now we have the option of using glucosamine/chondroitin sulfate therapies.
It is not uncommon for an old horse to have trouble rising after lying down. This is often due to pain in the hocks that makes it difficult for the horse to push himself to his feet. Some of these old, creaky horses are reluctant to lie down at all because of this, and subsequently spend all of their time on their feet. They will sleep standing up, with the occasional episode of suddenly starting to fall. They might show abrasions on the front of their fetlocks or knees where they have dropped, yet caught themselves before fully falling. There are usually tell-tale signs that a horse has been lying down, such as shavings or dirt on the belly, body, or tail. If these are not seen on your old horse for prolonged periods of time, it is an indication that he is either unable or afraid to lie down for fear of not being able to get up again. Whether the horse has trouble getting up or refuses to lie down in the first place, there are solutions to help his plight.
Directly injecting the hock joints with anti-inflammatory medications has proven to give excellent relief from arthritis pain. It is also important to make sure the hooves are trimmed regularly to enable the horse to have a solid base of support for good traction.
In general, maintain a regular trimming/ shoeing schedule to help the aged horse stay comfortable on his feet during exercise or ambling about in retirement. Good hoof care minimizes stress on the joints and hoof structures, and should be a regular part of routine preventive care.
Acupuncture is also helpful in providing relief from musculoskeletal pain. Oral "nutraceutical" products such as glucosamine/ chondroitin sulfate have been reported to give pain relief to ailing joints, yet more research is needed to support this.
The Active Aged Horse
Not all old horses are retired; many are still in active work even into their 30s. In fact, regular exercise is the best thing for those which are sound enough to do so. Good muscle tone keeps an older horse feeling better for more years. Sagging ligaments and muscles result from diminished intensity of exercise and age-related decline in muscle strength. It is important to check for comfortable saddle fit on an older horse because the saddle that might have fit him well as a teenager will no doubt need some adjustment for his aging body.
Don't forget to carefully warm up and cool down the elderly horse. His musculoskeletal structures might take a little longer to get going than when he was younger. Spend a little time helping him get the creaks and stiffness out before asking him for more strenuous effort. Be practical in how much you ask of him: Too much speed, distance, or rigorous maneuvers will tire him unless he has remained fit for the task.
Many older horses make wonderful riding companions for children who don't weigh very much and who demand little of their mounts. There is nothing more heartwarming than watching the gleeful smile of a young child as he or she sits proudly astride a horse. The horse also enjoys the attention, grooming, and the love that is showered upon him. These old-timers should be treated tenderly as they are, after all, in their golden years.
A common question that arises is whether it is okay to breed a mare in her early to mid-20s. There is probably no harm in doing so as long as you are aware that fertility in the horse steadily declines after the age of 14. There is a greater possibility that a mare in her 20s will remain barren despite reasonable uterine health as determined by a pre-breeding exam. Her ovaries are not as active with functional follicles, and her hormones are not as stable to support conception. In all cases, fertility is affected by nutrition. Fertility is diminished by a low-energy diet, poor-quality feed, poor body condition, and weight loss. Thus it is in your best interest to bring an older mare to the breeding season in good flesh using a balanced ration. If she becomes pregnant and foals uneventfully, there is no reason why the older mare can't be an excellent mother. But it is important for you to keep your breeding expectations realistic. Having a breeding soundness exam done can tell you if she is a good breeding candidate.
An older stallion might still have the enthusiastic desire to breed a mare, but it is possible that the quality of his semen has undergone an age-related decline due to age-related testicular degeneration. Before booking him for an active breeding season, have your veterinarian evaluate the quality of his semen ahead of time so there are no disappointments by mare owners in the months ahead. In addition, chronic hind end problems can result in a stallion that is unwilling to mount a mare.
There are a few older horse diseases to watch for. One common disease of the aging horse is called Cushing's syndrome, or pituitary pars intermedia dysfunction. This syndrome results from abnormal function of the pituitary gland that resides in the brain. The end result is an imbalance in the horse's hormonal function, along with altered glucose and cortisol metabolism.
One study revealed that 70% of horses over the age of 20 showed some obvious or subclinical signs of dysfunction of the pituitary gland. Affected horses often have long, shaggy coats that don't fully shed out in the spring. Many other signs of Cushing's syndrome might seem to be "normal" indications of old age, but a collection of signs when taken together can hint at an impending problem.
If you stand back at a distance and look at the suspect horse, you might notice a pot-bellied appearance that results from a loss of muscle mass and tone. On first impression, this could be attributed to sagging muscles. Look carefully at the orbits around the eyes. Do they seem puffy and protrusive? This often occurs in a Cushing's horse due to fat deposits.
Some affected horses have a low energy level, while others have an increased appetite with no apparent weight gain. Many owners complain that the horse with Cushing's seems to drink a lot more than usual, as much as three or four times more. With this excess thirst comes excess urination. The stall might seem wetter than usual, your horse might be seen to urinate more frequently, and water buckets might be drained frequently. It is important to rule out boredom or an overzealous attack on the salt block as a cause of excess thirst and urination before jumping to conclusions that your horse is affected by Cushing's.
Because of the high circulating levels of corticosteroids created by abnormal feedback from the diseased pituitary gland, these horses have poorly functioning immune systems.
Frequent viral and/or bacterial infections occur; one common development is a chronic sinus infection that responds poorly to antibiotics. Despite regular deworming schedules at frequent intervals, the horse's immune system does not function as well when he is older, and he might appear unthrifty due to continued gastrointestinal parasitism. Some Cushing's horses are slow to heal. This is because of the the immuno-suppressive effects of continuously high levels of circulating corticosteroids elicited by overactivity of the adrenal glands as a result of feedback by the abnormal pituitary gland. Oral ulcerations and gum disease are also frequent findings in horses affected with Cushing's.
One of the biggest problems seen with Cushing's syndrome is the eventual development of chronic laminitis as a result of the influence of ever-persistent, high levels of cortisol, and also due to changes in carbohydrate and fat metabolism. It is often the crippling effects of laminitis that necessitate euthanasia of the Cushing's horse, so our strategy in prolonging the life of a Cushing's horse is to curtail the development of laminitis. Feeding a high-fat, high-fiber diet might improve glucose and insulin metabolism in Cushing's horses and reduce the risk of founder. Avoid feeding these horses high-carbohydrate grains or feeds with high molasses content, because these feeds upset an already altered carbohydrate metabolism. Make all feed changes even more slowly than usual, especially when introducing to a lush pasture in the spring.
Medications such as cyproheptadine or pergolide are available to control the effects of Cushing's in aged horses; these medications are most effective before laminitis develops, so it is important to recognize the early warning signs of this problem.
A variation on Cushing's termed Peripheral Cushing's Syndrome is being investigated. Despite dietary restriction, it is difficult to reduce the weight on affected horses, especially the fat distributed in the crest of the neck, in the rump areas, and within the prepuce of male horses. Affected horses are often difficult to breed due to infertility issues. This malady resembles classic Cushing's in many outward signs, but instead of being a primary problem within the pituitary gland, the source of the high level of circulating cortisol originates from enzyme activity in intestinal sources. These sources include the liver or the fat cells of the omentum that covers the bowel. The fat cells are responsive to endocrine (hormone) signals; the more fat cells (as occurs with obesity), the greater the risk of hormonal irregularities.
Many of these horses are erroneously diagnosed as hypothyroid (deficient in thyroid hormone). At the current time, there is no approved treatment for hypothyroidism.
Thyroid disease is largely over-diagnosed in horses of any age. It is rare to see a horse with a primary thyroid deficiency. Many aged horses which appear to have thyroid dysfunction in fact are afflicted with Cushing's disease or Peripheral Cushing's Syndrome. Some clinical signs of Cushing's are similar to a truly hypothyroid individual, such as delayed shedding of the hair coat and a decrease in appetite. A hypothyroid horse often has edema (swelling) in the hind legs and is abnormally sensitive to cold.
Fat horses are commonly accused of being hypothyroid when in fact all they might have wrong with them is access to excess calories.
One study reported that more than 80% of gray horses past the age of 15 will have melanomas. Common places to look for melanomas include inside or along the sheath, under the tail, and around the anus and/or vulva in the area known as the perineum. Less frequent, but still common areas for melanomas include the lips and within the glandular tissues of the head (like the area of the parotid salivary gland in the throatlatch). Melanomas also occur as isolated nodules within the skin anywhere on a horse's body. Non-gray horses are not entirely immune; they just develop melanomas infrequently compared to gray horses.
Most of the time, it is best to leave the nodules alone unless they interfere with defecation, breeding, or are located where the saddle, girth, bridle, or bit could irritate them. Surgical excision sometimes makes a melanoma tumor more "angry," and it might regrow or sprout up in another location. The recent application of laser surgery as a treatment method enables complete excision of many of these tumors with the least possibility of metastasis (spreading to other areas). Also, chemotherapy with cimetidine has been reported to be effective in controlling the growth and spread of melanomas.
Another common cancer of older horses is squamous cell carcinoma, which is mostly found at the mucocutaneous (affecting the mucous membrane and the skin) junctions around the eyes, lips, in the perineal area beneath the tail, and on the penis or prepuce of male horses. Internal forms also occur in the stomach and esophagus. External squamous cell carcinoma tumors are amenable to cryosurgery (freezing) and surgical excision, particularly if discovered early. It is a good idea to have your veterinarian sedate your older gelding or stallion once or twice a year to ensure a thorough exam of the penis and sheath to check for tumors.
Lymphosarcoma is a form of cancer that invades the lymphatic tissues; sometimes it assumes a cutaneous form with lumps popping up in various places beneath the skin. Biopsy of these lumps confirms the cancer. More commonly, lymphosarcoma arises in the internal organs. While it's difficult to identify the internal or intestinal form, lymphosarcoma should be considered in an older horse which experiences chronic weight loss, inability to gain weight, mild diarrhea, or is just "doing poorly."
Living the Good, Long Life
Considering all the premium health care we can offer our horses today, there is no reason they shouldn't be living to a ripe old age in the greatest of style. Just being aware of some of the special considerations required by an older horse goes a long way in enabling you to tender the best of care. Your equine friend can retire to the life of leisure he has earned, while his energetic nickers continue to greet you over the fence each morning for some time to come.
Ball, M. "Choke." The Horse, April 2001, 81-85. Article Quick Find #28 at www.TheHorse.com.
Geor, R. "Is Your Horse Fit for the Task?" The Horse, April 2002, 91-96. Article Quick Find #3406 at www.TheHorse.com.
See the Body Condition and Older Horse categories under Basic Health Care at www.TheHorse.com.
See the Cushing's Disease category under Ailments/Syndromes at www.TheHorse.com.
About the Author
Nancy S. Loving, DVM, owns Loving Equine Clinic in Boulder, Colorado, and has a special interest in managing the care of sport horses. Her book, All Horse Systems Go, is a comprehensive veterinary care and conditioning resource in full color that covers all facets of horse care. She has also authored the books Go the Distance as a resource for endurance horse owners, Conformation and Performance, and First Aid for Horse and Rider in addition to many veterinary articles for both horse owner and professional audiences.
POLL: University Equine Hospitals