In the fall of 1993, I escaped the pressures of finding my first office job by fleeing to Australia for a year and working as a groom at a show-jumping stable in Western Australia. My charges included a transient group of green sale horses, a few seasoned show horses and Convoy, a 20-year-old grand prix horse. The old campaigner was the quintessential grumpy grandfather. A talented jumper in the ring, he was a grizzled old guy who could be downright cantankerous when handled behind the scenes.
At home, he sidled up to Marvel, his favorite pasturemate, and to David Dobson, his longtime owner and rider. But with me, the new groom, Convoy made it clear that he didn't like his back brushed, he didn't want to take his medicine, and he didn't want to be bothered by the younger horses around the barn. Like an old man with bushy eyebrows and wrinkled skin, Convoy's age showed in his droopy lower lip, the flecks of gray in his copper coat and his deepening swayback.
Nevertheless, I appreciated Convoy's competitive prowess, and he taught me a lot. Mostly, I learned that aged horses require more attentive routine care than younger horses. Despite daily grooming, Convoy was prone to rainrot, scratches and other skin conditions that didn't affect his stablemates. While he was in my care, he required twice-daily squirts of ophthalmic ointment to treat a stubborn eye infection. In addition, he had a history of skin tumors; when one opened up near his stifle, we swam him in the surf each morning to soothe the exposed flesh.
What I hadn't realized at the time was that Convoy could have been the poster horse for equine geriatrics. On the surface his life hadn't changed--he lived in the same field and stall and competed as he always had--but, because of his age, his needs were changing. Maintaining his good condition required more attention and effort with each passing year. Convoy's continuing show ring success
into his teens and beyond was a tribute to his owner's excellent care.
There's no obscure formula for successful elder care for horses; vigilant attention and timely responses to whatever abnormalities arise head off most age-related complications before they become full-blown problems. The point at which a horse becomes "geriatric" and in need of additional care is as individual as the entryway to "elderly" for people. Your 22-year-old horse may pass as a senior citizen on paper, but until he shows physical signs of slowing down, he'll get along fine with management as usual.
"Just because he's gray around the eyes doesn't mean he needs a lot of changes," says nutritionist Sarah Ralston, VMD, PhD, who has conducted studies involving aged horses at New Jersey's Rutgers University. "Like people, horses don't have a set age where they need dietary or other changes."
However, studies do indicate that older horses need more attention to stay healthy. In research completed in 1988 and 1989, Ralston found that about 70 percent of horses over age 20 had conditions requiring special care. This "special care" runs the gamut from timely dentistry to changed social arrangements, from arthritis medication to altered exercise programs. When you take on the care of a horse who has passed that ill-defined line into an aged state, the challenges to keeping him going in good shape are rather predictable. Fortunately, you are often able to meet those challenges with only modest changes to your care-taking routine, assuring your older horse the quality of life he deserves.
CHALLENGE 1: MAINTAINING A HEALTHY WEIGHT
Weight loss is often the most visible sign that a horse has entered into old age. Whether it's due to dental problems, reduced digestive efficiency or inappropriate nutrition, horses over age 20 become less able to process and absorb the energy needed to keep them in full flesh. The round, robust horse who has always been an easy keeper may grow thin and ribby after he leaves his teens. Some of the appearance of weight loss is an illusion caused by the changing shape and reduced muscularity of the older body. Weight gain, on the other hand, may occur when retirees from rigorous training or competition continue to eat as usual. Obesity is no healthier than underweight; excess weight stresses arthritic joints, strains soft tissues and exacerbates age-related problems.
When sizing up your horse's weight and body condition, take into account age-related muscle loss and slackening of connective tissue that may have occurred. The characteristic swayback and abdominal sag of old horses can give a false appearance of underweight and unhealthy hay belly. Robert Holland, DVM, PhD, a Lexington, Kentucky, practitioner whose patients have included aged horses at the Kentucky Horse Park, reminds people to use their hands, not just their eyes, when evaluating a horse's weight.
"When considering the normal horse's ideal body condition, you may not see the outline of the ribs but you can feel them when you run your hand along the horse's side," says Holland.
If your older horse's weight has dropped noticeably, it's a good idea to have him examined for underlying medical conditions, particularly kidney or liver dysfunction, that could be responsible for the change. But the following, less dire causes of geriatric weight loss are more likely to be at work, and you can take management action to halt the changes.
Check for dental abnormalities and tooth loss. Possibly the most common and easily overlooked cause of malnutrition or weight loss in old horses is tooth loss or dental damage. Years and years of grazing gritty grass and grinding up hay and grain 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~/2 inches of his 2 1/2~ inch-long teeth. Some horses live long enough to wear their teeth right down to the roots, leaving them incapable of chewing the normal equine diet.
Short, evenly worn teeth remain serviceable for
geriatric horses, but abnormal wear patterns or gaps in the lineup cause serious chewing problems. Shear mouth, a condition in which the teeth wear off at an extreme 60- to 75-degree angle rather than the usual 15-degree angle, inhibits the circular grinding motion necessary for effective food processing. In wave mouth, uneven wear of adjacent and opposing teeth produces highs and lows along the line of molars, which also makes circular food grinding impossible.
Still other problems develop with tooth loss. "Normally, horses' teeth are closely packed together with no spaces in between," says Jack Easley, DVM, of Shelbyville, Kentucky, who has written and lectured about equine dentistry. "If a horse loses a tooth, the others shift to close the gap. As they shift, other gaps form where food can get packed, leading to dental disease, abscess or infection."
Damaged, infected or unevenly worn teeth can cause a horse to swallow his feed without grinding it, allowing roughage and grain to pass through the gut practically undigested. Poorly masticated food puts the horse at greater risk for choke and colic and severely reduces nutrient absorption. Horses with damaged or painful teeth often dribble grain as they try to process it, or they partially chew a wad of food, then spit it out in a process referred to as "quidding."
The good news for old-horse owners is that most of these dental problems can be avoided or managed through regular preventive checkups. If your horse is maintaining his normal weight, Holland recommends an annual dental examination. He suggests semiannual checkups once a horse begins to lose weight or reaches the age of 15.
"The teeth don't have to be floated twice a year," he says. "There isn't much enamel crown left at that age, and you don't want to wear it down, but checking them for sharp points and abnormal wear is vital."
According to Easley, owners too often wait until horses exhibit discomfort or have problems eating or maintaining weight before thinking to have dental checkups. "Once you reach the point when the teeth are already loose and the horses have dental disease, those problems can't be corrected, and you end up pulling the tooth," he says. "But if you can detect the problems early, they are correctable." Easley adds that most horses whose mouths are examined throughout their lives can have normal, healthy teeth even into their 30s.
Review nutritional requirements periodically. Not only do geriatric diets require alterations in nutrient levels and the feedstuffs through which they're delivered, but you also have to factor in the horse's ability to process them. Energy, fiber, protein and fat are dietary requirements for all horses, but geriatric horses' needs are often different from those of their younger counterparts. The average moderately worked 1,000-pound mature horse requires about 20,000 Calories (20 Mcals) a day to maintain his weight and perform light work. This energy is best delivered by fibrous feeds containing about 1,000 to 1,200 Calories per pound. Grass, the natural equine diet, gets high marks because it is easy to chew and digest, which is ideal for the geriatric horse, so long as he is not at high risk for laminitis. The next-best fibrous energy source for older horses is grass hay, such as timothy, brome grass and orchard grass, cut and baled at bud stage (before the mature seed head forms). These hays are more digestible than stemmy hays, such as alfalfa or over-mature grass.
Alfalfa and other legumes have an additional drawback as elder feed because of their high calcium levels. "If older horses take in and absorb more calcium than they need," says Ralston, "it will have to be excreted through the kidneys. It's just a little extra stress on their aging kidneys." Aged horses get adequate amounts of this mineral if their total ration contains between .6 and 1 percent calcium with lower levels of phosphorus, says Ralston.
Protein needs may rise in geriatric horses because they are sometimes less efficient at absorbing and utilizing this tissue-building nutrient. Younger mature horses typically require about 9 to 10 percent protein in their diet but some aged horses need about 12 to 14 percent. "The metabolism and hormones are not being primed to ensure efficient use of protein in an older horse," says Eleanor Kellon, VMD, of Akron, Pennsylvania. Kellon, author of books about geriatric-horse care, adds that the aged horse's overall ability to process food decreases. "For example, a younger horse may utilize 75 percent of his diet, while an older horse may utilize only 60 percent of that same diet, largely because of inadequate chewing."
The "senior" feeds developed in the last decade simplify the dietary management of older horses. These scientifically formulated rations are available in grain-only formulations to be fed with grass/hay or in "complete" formulations containing both concentrates and roughage. Most of these rations contain approximately 12 to 14 percent protein, 14 to 20 percent fiber and 3 to 7 percent fat. Senior feeds also have the added digestive benefit of being extruded -- cooked and processed into a paste, then puffed up into pelleted form -- which breaks down the coarser elements. "Senior feeds help the older horse absorb his protein and carbohydrates better," says Kellon.
She adds that beet pulp is a good substitute for grain because "it is largely digested in the large intestine, the way nature intended digestion to proceed."
To further improve the digestibility of feed, particularly for horses with missing or nubby teeth, wet the feed before serving it. "If you put warm water on any of these pelleted or extruded senior diets, in 10 minutes you've got a nice soup," says Ralston. "Soaking the feed reduces the chance that the horses will choke, and it gets extra water into them."
It's prudent to introduce dietary changes gradually for any horse, but it's even more important for aged horses. Convert an older horse's gut to new feed by mixing increasing amounts of the replacement ration with decreasing amounts of the old feed, taking three weeks to complete the changeover.
Remain vigilant against parasites. Many veterinarians credit the modern horse's expanded life span to the improvements in parasite control introduced in the last half of this century. Opinions differ on how age affects horses' susceptibility to parasites:
Some practitioners suggest that age imparts increased immunity to strongyles; others suspect that the geriatric horse's weakening immune system increases his vulnerability to parasites.
"As the gut and the kidneys' functions diminish with age, older horses often experience difficulty in maintaining normal protein metabolism," says Craig Reinemeyer, DVM, PhD, a parasitologist at East Tennessee Clinical Research, Inc., in Knoxville. "Since the major, sub-clinical impact of parasitism is probably protein loss, the impact of worms could be greatly exaggerated in geriatric horses who are already on shaky ground. But no one knows for sure."
Whatever the age-related responses to parasites may be, keeping worm burdens at minimum levels remains a paramount health concern throughout horses' lives. To do so, remove manure from paddocks and fields, and diligently administer deworming agents according to your veterinarian's recommendation.
Arrange for him to eat in peace. Even the bossiest old horse can be muscled away from the communal feeder as new challengers emerge in the herd. When group dynamics change, older horses may burn more calories in their efforts to evade their tormentors or find their eating time being cut short by bullies. Even when the geriatric horse gets an opportunity to eat, he's still likely to bolt his meal if he feels threatened by pasture-mates.
Holland attributes the increased incidence of choke among older horses to changing field dynamics. "If given the opportunity, older horses take the time to eat their food properly," he observes, "but they tend to choke because they're gobbling their food in anticipation of a youngster coming to bother them." Holland suggests feeding horses age 15 and older in private spaces where they can eat at their normal pace.
CHALLENGE 2: ENSURING PHYSICAL AND MENTAL COMFORT
You can't hold back the aging process, but you can ensure your horse's comfort during this life stage. With just a little more attention to his physical condition and attitude, you can adjust care-taking, turnout and exercise routines to keep him feeling fine in body and spirit.
Watch for skin conditions and other surface ailments. The precise effect of age on equine immunity remains unknown, but veterinarians see evidence that the natural defenses weaken as horses age. Geriatric horses tend to be more susceptible to infections, abscesses and other ailments than younger horses living under the same conditions. This seems to be particularly true of skin conditions, such as rain-rot, mange and scratches. Holland recalls a situation in which age seemed to be the only distinguishing factor between those who succumbed and those who didn't: "There was a field of horses where everyone got the same type of feed and was exposed to the same conditions," he says. "The two old horses got rain-rot, while the other 13 horses, who were younger, didn't."
Regular grooming and up-close inspections of your horse's surface condition aid in early recognition and treatment of superficial wounds that can open the door to more troublesome infections. Additionally, supplemental vitamin C has some scientific support as an immune booster for this class of horse. "Some research suggests that geriatric horses can benefit from 10 grams of vitamin C twice a day," says Ralston, "especially those who get rain-rot, hoof abscesses or chronic infections. It seems to help their immune systems." Holland adds that turning horses out in the sun and avoiding frequent bathing may reduce the incidence of rain-rot and similar moisture-loving bacterial conditions.
Take precautions during extreme weather. Spend a little time around elderly people, and you'll notice that they are easily chilled and remain bundled in sweaters during what's short-sleeve weather for the rest of the world. Doctors attribute this thermoregulatory difference to a combination of factors, including a slower metabolism and changes in aging skin, that increase sensitivity to cold and heat.
Equine thermoregulation, especially in geriatric horses, has not been thoroughly studied, though some research suggests that age affects a horse's cooling capabilities during exercise. In 1997, Kenneth H. McKeever, PhD, of the Rutgers University department of animal sciences, used a treadmill to exercise unfit horses aged 4 to 9 and unfit horses aged 20 to 26 and found that the older horses reached the target temperature of 40 degrees Celsius (104 degrees Fahrenheit) twice as fast as the younger group. Once exercise was suspended, however, both groups recovered at the same rate during a 10-minute rest period.
"Thermoregulation involves the ability to transport heat from the body's core to the surface of the skin and blood vessels," says McKeever. "The older horses had substantially higher heart rates during exercise, showing that their hearts had to work harder to pump blood to dissipate the heat. The study suggests that older horses can't handle the combined demand of exercise and heat as well as younger horses."
At both hot and cold extremes, take special heed of the old-timers, who may be the only ones in the whole herd who truly need blanketing and stabling in winter and who absolutely need shade and cooling aids when the heat index is high. Diet is also important in older horses' cold-weather comfort. "Malnutrition is a prime cause of actual lower body temperature in the aged horse," says Kellon. "It occurs when the body is not taking in enough energy."
Provide amicable companionship. Harmonious social dynamics in the field are a great boon to an aging horse's health and attitude. Pushy younger horses can deprive him of the basic creature comforts, including food, shade and shelter. In addition, a constantly picked-on old-timer can become cranky and defensive. Pairing your older horse with a friendly pasture-mate reduces the risks of his getting kicked or otherwise injured and raises his social spirits.
"One of the biggest mistakes is to turn the geriatric horse loose with a bunch of horses and figure that he'll be okay," says Kellon. "They need protection, more so than younger horses. If the geriatric horse is ostracized or dominated, he may not have access to water or shade. Isolation is not good for any horse." Kellon recommends pairing older horses together or turning them out with non-threatening companions, such as ponies, goats or donkeys.
Keep him active with regular exercise. Total retirement may sound like a just reward for a long-worked horse, but rarely is full-time turnout or complete stall rest in the best interest of any horse. Unless the retiree is unsound, he'll benefit from regular, albeit less demanding, work. He's more likely to remain in good spirits and maintain better body condition, and you can use the work period as another way to monitor his health and well-being.
"It is well documented that, to a large extent, exercise can prevent or reverse age-related changes in muscle mass and strength," says Kellon. "Exercise affects hormone levels, especially growth hormone and thyroid hormone, and the metabolic state of the muscle remains more like that of a young animal."
Older horses who are retired from competition are often capable of similar work at a less strenuous level. "When we talk about horses who are serviceably sound, we're speaking of horses who are not lame but who have a low-grade hitch, an irregular gait," says Holland. "They're great for lower-level competition and for Pony Club. Older horses and young kids are a great combination." Holland, who competed successfully in endurance and trail riding with a 27-year-old horse, recommends any activity that gradually incorporates the walk, trot and, at intervals, the low-speed canter into the exercise regimen. A program performed two or three times a week is just stimulating enough for most older horses.
As your horse ages, his graceful figure may give way to a swayback and potbelly, and his joints may get stiff and creaky, but, unlike elderly people and old dogs, he's not all that likely to lose his eyesight. Horses do undergo age-associated vision changes but rarely to the point of blindness.
"We don't see a lot of older horses presented with vision problems," says Claire Latimer, DVM, an equine ophthalmologist in Lexington, Kentucky. "Typically, deterioration does not progress to the point where it causes a change of behavior that the owner notices." Horses with compromised vision, Latimer notes, often mask their condition by adhering so well to the familiar in their environment and their routine that they don't appear disabled.
Cataracts, a common thief of vision in other species, do affect horses but usually not to an obstructive degree. "When you say ?cataracts,' people think that means a completely cloudy lens," says Latimer. "By definition, it's any focal opacity in the lens. Under magnification, I may see little cataract changes, but they are relatively insignificant."
Age-related immune changes may increase horses' susceptibility to eye maladies. In her studies of older horses at New Jersey's Rutgers University, Karyn Malinowski, PhD, has noted a propensity for corneal ulcers among the school's over-20 herd.
"The ulcers form near the lower lid," she says, "and they are treated with an antibiotic ointment. They clear up, then they come back."
Robert Holland, DVM, PhD, a Lexington, Kentucky, practitioner, says that he has seen more than a few cases of moon blindness -- a recurring immune-mediated inflammation of the eye -- in geriatric horses. "They act like they can see, but not exactly," he says. "If you change their field or stall, they may have problems seeing the wall, or they may bang a hip on the stall door."
Because significant vision loss is rare in the species, most veterinarians do not consider eye examinations to be a must for all older horses, except as part of a general physical exam. Behavioral changes suggesting disorientation are cause for a closer look at the eyes, however.
"If the horse is suddenly spooking, knocking into things, tripping or having trouble keeping his footing with slight changes in elevation," says Latimer, "then vision should be checked."
CHALLENGE 3: PRESERVING SOUNDNESS
Maintaining a horse's soundness can be difficult at any age, but geriatric animals have the added burden of years of wear and slow, insidious orthopedic damage that often catches up with them later in life.
Curing these wear-and-tear conditions is unlikely, but you can keep older horses serviceably sound and comfortable with combination of simple therapies.
Tend to arthritis and other aches. Chances are, your horse will develop some form of joint pain/stiffness during his lifetime. Arthritis is a blanket term for inflammation and deterioration of the joint that may result from a misstep, a blow or long-term wear that has released destructive enzymes into the joint fluid. As the joint fluid loses its viscosity, friction causes cartilage degradation, leading to bony changes.
Fortunately, there is a variety of joint supplements that range from oral "nutraceuticals" to intra-articular injections. Topical treatments, such as DMSO (dimethyl sulfoxide), are the least invasive forms of treatment and help boost the inflamed joint's health. At the other end of the spectrum are injected hyaluronic acid and polysulfated glycosaminoglycans (PSGAG5), which are believed to prevent further cartilage damage. Your veterinarian can assess the horse's condition and prescribe appropriate treatments.
Adjust the work routine. Stiff or puffy joints don't have to mean an end to your horse's regular workouts. In fact, moderate exercise helps stimulate the joints and reduces stockiness or excess fluid that builds up during confinement. Easy movement, whether it's a few laps of walk, trot and canter around the ring, a leisurely trail ride or just hand walking around the barn, bolsters joint health. "Regular exercise not only improves the health of joint cartilage, it improves the outcome of specific joint-supportive drugs and nutritional supplement programs," writes Kellon in her book, Keeping the Older Horse Young. "Every effective arthritis program includes regular exercise."
Make your farrier a partner in care. The type of farriery work your older horse requires may not change appreciably as he ages, but deteriorating hoof quality and joint stiffness can complicate his hoof care. As horses age, their hooves often become more brittle. Doug Butler, PhD, a farrier in Laporte, Colorado, has observed that brittle feet and a rough hair
coat sometimes go hand in hand, which can be indicative of a glandular malfunction, such as Cushing's disease (see Challenge 4). For brittle feet, Butler recommends using a nutritional supplement containing biotin, zinc and other nutrients that help enhance hoof structure.
Slowing hoof growth is another age-related change affecting horses. Butler completed a study at Cornell University in 1976 suggesting that as horses age, hoof-wall growth slows along with slowing of the heartbeat.
"Since then, I've noticed the same results as I've shod older horses," he says. "The older horses have a slower pulse rate, and it affects how much blood goes to the foot and therefore slows the rate of growth."
This slowed growth may reduce the frequency of shoeing or trimming, but it probably won't affect the horse's use or comfort.
With any hoof handling, be considerate of the fact that many aged horses have trouble balancing on three legs or experience pain with prolonged joint flexion. One 35-year-old horse Butler works with has found a way to solve his balance
problem. "He has quite a bit of arthritis and has great difficulty standing on his other three legs," says Butler. "So now he leans against a wall and he never gives us any trouble. It's amazing how horses learn to adapt." Butler adds that stiff or arthritic geriatric horses may need frequent breaks with all four feet on the ground during hoof work.
CHALLENGE 4: TREATING AGE-RELATED DISEASES
A few diseases, though not restricted to older horses, tend to prey on those in their late teens and beyond. Fortunately, the conditions themselves are not fatal and can be managed through nutrition, stabling, grooming and medication.
Be alert for glandular dysfunction. A little loss of condition, sleekness and energy is normal in aging horses. But a woolly, coarse coat retained in warm weather, coupled with weight loss and excessive sweating, thirst and urination may signify hyperactivity of the pituitary
gland, the "master gland" located at the base of the brain. Cushing's disease, as the resulting complex of changes is called, usually afflicts horses in their late teens or 20s. Frequently, tumors on the pituitary trigger the glandular hyperactivity. Blood-sugar and fat-utilization abnormalities occur along with calcium-phosphorus imbalances. The associated over-stimulation of the adrenal" glands, which also become enlarged, results in overproduction of the hormone cortisol, leading to the characteristic Cushing's appearance and behavior changes. Practitioners also note that Cushing's horses are more susceptible to laminitis and founder, infection and parasite infestation.
Cushing's is relatively common in aged horses; in one study, Ralston found that 10 of 13 horses over the age of 20 had at least the sub-clinical signs of altered glucose and cortisol metabolism, possibly indicative of pituitary or thyroid tumors. Some Cushing's horses respond to the drug pergolide, an expensive and off-label treatment that may encourage shedding of the abnormal hair coat and increase energy levels. Cyproheptadine is another drug that is thought to control excess pituitary secretion. General management includes clipping the hair coat in the summer, limiting or halting exposure to lush grass to avoid laminitis and prompt attention to any medical problems, particularly infections. Attentive hoof care is also beneficial in preventing common sole abscesses.
Similar problems are caused by thyroid tumors, which are considerably less common in horses than Cushing's. The usually benign thyroid tumors affect the secretion of hormones that influence the rate of virtually every chemical reaction in the body. The results are poor hair coats that shed in excess, muscle weakness, weight change and lethargy. Thyroid dysfunction or reduced thyroid output can be managed with supplements that increase thyroid levels in the body. A tumorous thyroid may be surgically removed. Grooming and management are similar to that of Cushing's horses.
Combat heaves with an allergen-free environment. Chronic obstructive pulmonary disease (COPD), commonly known as heaves, isn't specifically age-related, but as a progressive condition it may worsen as a horse ages. Heaves is a form of allergic reaction brought on by dusts, molds and even pollutants, causing airway and lung inflammation, wheezing, shortness of breath and elevated breathing rate. Though coughing and wheezing are the most obvious signs of COPD, allergic horses may also exhibit head tossing, sneezing or snorting, labored breathing and runny eyes. Heaves can permanently damage the lungs.
Some horses with heaves are "cured" by physical separation from their allergens, often hay and stable dust, while others require medication to reduce lung inflammation and increase lung capacity. Consult with your veterinarian about treatment and management changes to improve your horse's lung function.
Convoy, the Australian show jumper, remained one of David Dobson's top horses well into his teens and 20s. The gelding competed all over the country, placing in 20 World Cup qualifiers and a host of other shows. At age 20, the old campaigner finished second in his final World Cup qualifier, besting many younger horses. Two years later, Convoy was still competing when he contracted pneumonia and had to be euthanatized.
"I think the trick to keeping him going and keeping him sound when he got older was in the long, steady work we gave him," says Dobson. "It wasn't really hard work, and we didn't jump him very much at all. We took him to the beach a lot and gave him fitness and conditioning work."
A long, well-managed working career may, in fact, be the ideal prelude to a satisfactory old age. And it may be the best preparation for the caretakers as well, because old horses rarely need anything different from what they've always had -- just a little bit more attentiveness in the daily routine.
EQUUS thanks Karyn Malinowski, PhD, at Rutgers University, as well as the researchers and practitioners quoted, for their assistance in preparing this story.
This article first appeared in the November, 2000
issue of EQUUS magazine.