Your Aging Horse is Only as Old as He Feels
Advances in medicine and health care have boosted the average human life span from 45 years in the early 1900s to 72 or more years in the 1990s. Parallel advances in veterinary medicine, and horse owners' willingness to care for their horses beyond their utility, also have increased equine longevity. While most individuals are aware that humans are living longer, many people aren't aware that horses are living longer, and that their owners have the power to extend their active years as well.
I write from experience. In 1985, I retired my Quarter Horse/Thoroughbred gelding at 19 expecting he would drop dead under me any day. Eleven years later, I'm still feeding the old hayburner. Had I known Jake, 30, was going to live this long, I would not have turned him out to pasture so soon. The mistake I made was thinking he was chronologically old instead of paying attention to his physical condition and peppy attitude. It has only been the last couple of years that he has begun to show the ravages of old age--hay belly, sunken back, protruding withers, a sprinkling of gray on the face, and sloppy eating habits.
"As with humans, chronological age does not always match the aging process," said Sarah Ralston, VMD, PhD, ACVN. "Although 60% of the horses I have studied over 20 years old required special care, they were still serviceably sound. Indeed, many of these horses were still rideable, or in the case of stallions and mares, used for breeding."
Although Ralston did not study these horses, several notable horses have enjoyed or are enjoying a long life: Quarter Horse greats Joe Moore (34), and Go Man Go (29), renowned Thoroughbreds Gallant Man (34) and Primonetta (35), and the popular Arabian stallions El Kumait and Nasik were 30 when they sired their last crops of foals. Ken Kopp, DVM, manager of horse feeds for Southern States Cooperative of Richmond, Va., said he knows of several horses in their late 30s and early 40s.
So, rather than gauging a horse's age by years, Ralston recommends horse owners base an animal's retirement and/or health care management on the horse's physical fitness. As horses move into their late teens and early 20s, some might experience problems related to aging, while others, such as Jake, can live well into their 20s before the aging process slows them down. Physical signs of aging include arthritis-related lameness, tooth loss, loss of appetite and vigor, weight loss and/or poor condition, protruding withers, and gray hair appearing around the ears, eyes, and forehead. Less obvious initially, but possibly more serious problems can include anemia, increased blood sugar, pituitary/thyroid dysfunction, and kidney, liver, or respiratory failure. Because of chronic parasite damage, reduced activity, and reduced intestinal motility, some senior horses might experience digestive disorders, including chronic colic.
"If problems related to aging are present, changes in management and medication might be needed to keep an older horse comfortable," Ralston said.
She added that geriatric horses are naturally more prone to illness and injury, and that horse owners must take the responsibility for protecting their old horses from increased risks of infection and disease, digestive disorders, environmental stress, joint degeneration, and from younger, stronger horses that might try to dominate and/or injure an older horse.
Ralston specializes in equine nutrition research and is an associate professor with the Department of Animal Sciences, Cook College, Rutgers University in New Brunswick, N.J. She also has done numerous studies on geriatric nutrition and metabolism, and she currently is studying nutrition and bone growth in young horses.
Although there are many things a horse owner must consider when mapping out a management plan for a senior horse, dental care and nutritional needs should be the first issues addressed. However, according to Ralston, nutritional management of the geriatric horse (more than 20 years old) is frequently a challenge. In a study conducted by Ralston and her associate Leslie H. Breuer, PhD, the researchers found that abnormal, worn down, or missing teeth reduce the older horse's ability to adequately chew and digest feed and that salivation and esophageal muscle function might be reduced. They also found that the ability to digest protein, fiber, and phosphorus was reduced in horses 20 and older. These health problems and deficiencies, and quite often, the horse owner's failure to keep up with an appropriate deworming schedule, can take a heavy toll on an aged horse.
"These (aging) alterations may contribute to the development of weight loss, brittle bones, and increased susceptibility to viral infections," the researchers outlined in a study on Field Evaluation of a Feed Formulated For Geriatric Horses published in 1996.
Even if an aged horse doesn't suffer from aging ailments, is on a regular deworming program, and appears to be in good health and bloom, it might still benefit from a diet designed to meet the requirements of an older horse. Research suggests, however, that horses which are in poor condition or failing health benefit the most from feeds developed specifically for geriatric horses.
Dietary Requirements of the Aged Horse
According to Ralston, an aged horse's diet should include at least 12-14% protein, limited calcium (less than 1.0%), and slightly increased phosphorus (0.3-0.4%) relative to maintenance requirements. Digestibility of the concentrates should be maximized by processing, either by extrusion (precooked) or pelleting. A typical ration might consist of top-quality hay, preferably a grass/alfalfa mix, highly digestible pellets or extruded feeds designed for geriatric horses, plus free access to water and salt. Soybean meal is also an excellent protein supplement.
Daunted by the task of reading feed bag labels and mixing and measuring feeds, vitamins, and minerals? No need to be. Several feed companies, including Purina Mills, Southern States Consolidated, Buckeye Feed Mills, and Nutrena Feeds, have developed feeds designed to meet the nutritional needs of older horses. Purina's Equine Senior is a "specifically formulated horse feed which addresses the special nutritional needs of the older horse whose metabolic system may be less than efficient." Equine Senior is an "all-in-one" mixture of pellets and supplements that are pre-cooked and can be fed as a complete feed or in combination with pasture or hay. Purina claims that Equine Senior is easy to chew and highly digestible and palatable. It contains vitamin C and B12, trace minerals, biotin, adjusted levels of calcium, phosphorus, and protein, and essential polyunsaturated fats, which are associated with improved skin and hair coat.
Triple Crown Senior, developed by Southern States Cooperative in partnership with Triple Crown of Minnesota, is also a complete feed. It offers a high fat content, which is energy dense and enhances physical condition, according to Kopp. It also has a high content of sugar beet pulp for fiber, and a series of digestive aids, including digestive bacteria, enzymes, and yeast for aiding protein digestion.
"We know the older horse has trouble digesting fiber as he ages, but a lot of hay being fed to horses today is old, over-mature, and the fiber is hard for the older horse to digest," Kopp said. "Sugar beet pulp, on the other hand, is high in pectin and very digestible, but low in lignin, which is a protective fiber found in mature hays. The more lignified the hay, the harder it is to digest."
Although not developed specifically for aged horses, Buckeye's Endurance 101 is a "highly digestible, energy-dense feed formulated for both performance and older horses. For older horses, it offers elevated mineral and vitamin levels, added oil for additional calories and improved hair coat, and is extruded for easy digestion."
Nutrena's Senior is a pelleted feed which "provides nutritional formulas precisely shaped to bring out the best in your horse during (its) senior stage," according to company literature. Although most of these senior feeds are more costly than grains and hays combined, they have been well received by horsemen.
"These rations do in fact cost more," Kopp said. "But if you have an older horse, and you can extend their usefulness using these feeds, then you're really amortizing your investment over a longer period."
Kopp also pointed out that although the feeds might cost more, their digestibility makes them less costly because they should reduce incidences of colic and associated veterinary cost. Kopp deduces that older horses are more likely to have intestinal damage from parasite infestation. Horses subjected to years of parasite infection are likely to suffer damage to the arteries, and that reduces blood supply to the gut/intestines. This damage can encourage aneurysms and eventually blood clots. In turn, blood clots can inhibit the free flow of blood. Depriving part of the intestine of blood can cause pain that can lead to colic or even death from stroke if the clot blocks a major artery.
Parasitic damage to the intestine also can reduce a horse's ability to digest food properly and to absorb nutrients, resulting in poor condition, increased sensitivity to colic, and loose stools.
"The key to prolonging a horse's health is to start feeding it a better diet before it starts declining in health," Kopp said. "Too often people wait until problems are obvious, and by then they are usually more difficult to manage."
Before making any changes in a senior horse's diet, Ralston recommended having a veterinarian check the horse for kidney or liver problems. High protein and calcium feeds such as alfalfa can be detrimental to horses suffering kidney and liver disease. Also, any changes in an older horse's feed or feeding schedule should be gradual and subtle. Unexpected changes can disrupt an older horse's digestive system much more quickly than a younger horse's system. In addition, if the horse resides in a colder climate, it might be necessary to seasonally adjust the feed to compensate for its increased energy needs.
Cold can zap an older horse's energy while compromising its immune system. Cold weather also can reduce a horse's desire to drink. Encourage drinking by giving horses warm or tepid water. If a horse does not get enough water, it might suffer constipation and pain and be at risk for colic. Constipation/impaction problems can be reduced year-round by assuring free access to clean, fresh, unfrozen water. If the horse does not drink well, feeding water-soaked feeds or mashes (at least two gallons of water per feeding) will help increase fluid intake. Adding one or two ounces of salt to the feed also will encourage increased water intake, but should be done only if the horse has unlimited access to water.
Just as important as a good diet is a good dental plan for senior horses. As a horse ages, its teeth continue to grow. While some teeth wear down to flat edges, others might grow unevenly and produce sharp edges on the outside of the upper molars and the inside of the lower molars. These sharp points can interfere with chewing, which can reduce intake and digestion. The sharp points also can lacerate the tongue and/or cheeks, enhancing the potential for infection and even discouraging the horse from eating, resulting in weight loss and poor condition. A horse having difficulty chewing will slobber and drop feed out of its mouth and sometimes thrust its head forward in an attempt to keep feed from falling out of its mouth.
"Older horses, especially those known to have missing molars, should have their teeth checked twice a year or more frequently," Ralston said. "If chewing is difficult, soups of hay cubes, pellets, or extruded feeds may be fed, but make sure enough water is added to make it soupy enough to prevent choking. Hay can still be fed if choking is not a problem, even if most of it is wasted."
Ralston stresses the feeding of "complete feeds," saying that many pelleted feeds are only grain substitutes designed to be fed with hay and might not contain a balanced calcium to phosphorus ratio.
Kidney And Liver Failure
Some old horses might experience degeneration of the liver and kidneys. This degeneration reduces the organ's ability to function and is progressive and irreversible. However, with proper management, the degeneration process can be slowed and the clinical signs managed somewhat by diet. According to "Management of Old Horses," a pamphlet produced by Ralston through Rutgers Cooperative Extension, reduced kidney function can result in renal and bladder stones, weight loss, loss of appetite, and potentially death.
"Horses are unique in that they excrete excess dietary calcium through their urine instead of their feces as do other animals," the pamphlet states. "If kidney function is reduced, renal and bladder stones of calcium oxalate are more likely to occur, as well as an increase (potentially lethal) in blood calcium. Horses with kidney failure should be put on a low calcium diet (less than 0.5-0.65%). Protein and phosphorus should also be restricted to less than 8-10% and 0.03%, respectively."
Good quality grass hay and corn might meet most, or all, of the above requirements. Horses suffering kidney failure, however, should not be fed legumes like alfalfa, clover, or beet pulp because of their high calcium content. They also should not be fed wheat bran or excessive phosphorus (greater than 1.0%) or protein (16%). Liver failure generally results in loss of appetite and weight in older horses, but it also can cause lethargy, jaundice, and an intolerance of fat and protein in the diet. If severe, the horse might show behavioral changes, including irritability, aimless wandering or circling, or pressing its head against objects. Affected horses require increased sugar sources to maintain their blood glucose levels, and their diet should emphasize starch intake (grains or concentrates) and fiber (hay or beet pulp) to avoid gastrointestinal dysfunction.
Ralston recommends grass hay, low protein sweet feeds, corn, and milo as part of the horse's diet. Although detrimental to horses with kidney failure, beet pulp is an acceptable supplement for horses with liver disease. Also, since the liver is the site of synthesis for vitamins B and C in the horse, daily oral supplements of B-complex and ascorbic acid might be beneficial.
In a 1989 study of geriatric horses, Ralston found that 70% of the study horses over the age of 20 had at least sub-clinical signs of pituitary or thyroid dysfunction such as glucose intolerance and excessive cortisol secretion. Clinical signs include failure to shed, increased drinking and urination, and chronic founder. Mares appeared to be predisposed to pituitary dysfunction, whereas thyroid dysfunction was more common in geldings. (See Cushing's article on page 35.)
"Although thyroid dysfunctions usually are considered to be benign, they can increase the incidence of obesity and founder," Ralston said. "Old mares with pituitary dysfunction are more susceptible to viral infections. Both types of dysfunctions can cause relative glucose intolerance, and after a high sugar or starch meal, such as sweet feed or processed grains, glucose and insulin levels in the blood become abnormally high, resulting in increased thirst and urination."
Ralston's studies have revealed that pelleted or extruded feeds, especially those formulated as a "complete" feed, do not push a horse's glucose and insulin levels as high.
"Treatment is available for thyroid dysfunction," Ralston added. "If the horse is hypo (low thyroid), it can be placed on thyroid hormone replacement therapy. If the horse is hyper (high thyroid), it can be placed on human drugs that are available, but not officially for use in horses. However, if properly managed, horses with pituitary dysfunction can live for years after the appearance of clinical signs."
Although managing these problems might seem overwhelming to the average horse owner, Ralston said the horses can be managed fairly easily. Horses diagnosed with either dysfunction:
- Must be kept on regular deworming and vaccination schedules;
- Should receive 5-10 grams of ascorbic acid (Vitamin C) daily;
- Should have fresh, clean water available at all times.
If chronic founder is a problem, a horse's access to fresh grass and grain must be restricted and sudden dietary changes avoided at all costs. Horses that don't shed should be clipped in the summer and provided with shelter from the sun to prevent overheating.
Again, it cannot be stressed enough that a veterinarian be consulted regarding the day-to-day management of aged horses. An annual checkup, including blood analysis, can detect liver, kidney, pituitary, or thyroid problems.
Just like their human counterparts, senior horses also feel the ravages of Father Time in their muscles, bones, and joints. Their muscles are less flexible, and joints less fluid. These changes can progress into arthritis--a combination of inflammation and degeneration of the tissues associated with a joint that reduces a human's or horse's ability and willingness to flex and bear weight on affected joints. Arthritis can occur anywhere from the shoulder to stifle to foot. Equine athletes, such as jumpers and racehorses, horses ridden and/or driven over hard surfaces, and horses suffering bruises and blows such as falls and kicks, are candidates for equine arthritis. Ringbone, bogspavin, and thoroughpin are all examples of equine arthritis.
Initially, arthritis can be difficult to diagnose. In the early stages, a horse might be sound one day and lame the next. Gradually the lameness will become more persistent. For some horses, it might be nothing more than early morning stiffness or a gimpy gate after a workout and nothing to be alarmed about. For others, it might be so debilitating that the horse will be unworkable.
Arthritis can, however, be managed in most cases. It just takes a little time, common sense, and patience. When riding or driving an aged horse, always warm up the horse gradually. Also, do not confine it to a stall unless it is necessary because of dangerous weather conditions or for medical reasons. Arthritic horses which have the freedom to roam usually have a lower incidence of pain and stiffness compared to arthritic horses confined to stalls. In addition, horses prefer to socialize and roam about, rather than be confined to a stall or small paddock. Horses which are housed in paddocks with shelter, and allowed to go in and out of the shelter as they please, have better mental attitudes and muscle tone and suffer less stiffness compared to horses confined to stalls.
If the horse must be confined, consider a horse's physical ailments, if any, when contemplating bedding alternatives. Although barley or oat straw are the best beddings for heat retention and comfort, too much bedding can make it difficult for the arthritic horse to move about. If the horse suffers from a respiratory ailment, i.e., heaves, then shavings, sawdust, and some grass hays might be too dusty. On the other hand, if the horse has founder or chronic arthritis, bedding a horse on deep straw, shredded newspapers, or rice or peanut hulls might encourage the horse to lie down and rest.
"To make the arthritic horse more comfortable, consult with your farrier and veterinarian regarding the optimal way to shoe or trim the horse," Ralston added. "Use anti-inflammatory drugs recommended by your veterinarian if the horse is in chronic pain. Don't let the horse become obese, since extra weight will increase the stress on its legs.
As noted, geriatric horses are more sensitive to severe weather since their aged bodies do not regulate body temperature as efficiently. Therefore, sheltering an older horse from the elements is a must, especially in the winter when blustery winds, chilly rain, snow, and ice are present. Although a horse might have to be confined to a stall when snow and ice make the going treacherous, as noted above, keeping an older horse penned up might aggravate its aches and pains and slow down circulation and digestion.
In addition, a barn that is too warm and has insufficient ventilation can trap condensation and indoor pollutants like dust and ammonia fumes, which can trigger respiratory problems.
"Confining a horse to a stall is not doing it any favors," Ralston said. "A well-built run-in shed and heavy blanket would be better in most cases."
While most horsemen take precautions when the footing is slick, many don't realize that frozen ground can also be treacherous for an older horse. Frozen, hard ground can aggravate chronic lameness, cause sole bruises, and perhaps even trip the horse as it shuffles over ruts and clumps of frozen dirt. If an older horse does fall, it is more likely to break bones because old bones are brittle, and if broken, take longer to heal. Lastly, if an older horse shares a paddock or pasture with other horses, make sure that younger horses are not bullying the older horse and that it is getting its share of feed and water. Although most horses like the company of other horses, a bully might intimidate, chase, or even injure an older horse. On the other hand, if an older horse is segregated, it might "worry" and/or become lonely. If a horse exhibits stress or loneliness, a companion animal such as a small pony, goat, or sheep can be another way to enhance the senior horse's final years.
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POLL: University Equine Hospitals