Being fine-tuned to his surroundings is part of your horse’s nature, and a keen sense of hearing is a big part of that. In this article, two experts shed light on how hearing helps horses make sense of his environment and how to handle hearing-related problems. Allison J. Stewart, BVSC, DACVIM, DACVECC, is a professor of equine internal medicine at Auburn University. Bonnie Beaver, DVM, focuses on animal behavior as a professor at Texas A&M University.

A horse’s hearing isn’t very different from yours, the experts say. You can detect sounds with wave frequencies from 20 hertz (lowest pitch) to 20,000 hertz (highest pitch); for horses, the range is 55 hertz to 33,500 hertz. “They can’t hear quite as low as we can and can hear just slightly higher,” Beaver says. Many animals, including dogs, hear higher-pitched sounds; many can hear lower.

But horses excel at capturing faint sounds that you may easily miss and honing in on the directions sounds come from. Their ears contain the same structures yours do, but differences in design enhance these abilities.

What Big Ears You Have

Those big ears make a big difference. With its large size and cupped shape, each outer ear (pinna) is like a radar dish, collecting and concentrating sound waves. You have to turn your head to focus on the source of a sound, but your horse has ten muscles that can rotate each pinna in a full 180-degree arc—and he can move them independently, so that one turns forward while the other aims back.

The pinna funnels sound waves into the ear canal, which amplifies them in the same way that talking into a tube amplifies sound. At the middle ear the sound waves strike the eardrum (tympanic membrane), making it vibrate. The vibrations travel through the membrane to the ossicles, three tiny bones on the far side. These bones—called the hammer, anvil and stirrup for their shapes—form a chain that transmits the vibrations to a second membrane, which marks the start of the inner ear.

The inner ear holds sensory organs for both hearing and balance. The cochlea is the hearing part. It’s shaped like a snail shell and filled with fluids that move as vibrations from the membrane travel through them. The movement stimulates tiny hair cells (cilia) that send nerve signals to the brain. Different hair cells are sensitive to different sound frequencies.

Inner-ear fluid also circulates through the semicircular canals, which help the horse stay steady on his feet and in balance. The canals are lined with sensory hair cells and set at different angles, so they detect different movements—side-to-side, up-and-down, angled.

Run First, Ask Later

A twig snaps and your horse is off like a shot. His hair-trigger reactions are nerve-wracking when you’re riding or handling him, but they developed as a defense against predators. Back when his ancestors were wild, horses that didn’t run when a twig snapped were likely to be dinner for lions. Those that took off survived, and over generations that quick flight response became hardwired.

All horses share the basic response, but reactions to sudden sounds vary from one horse to the next. When a pebble hits the arena wall, one horse may spook 10 feet sideways while another barely alters his stride. Genetics and experience account for the differences, Beaver says. “Some individuals are ‘spookier,’ and that can have a genetic basis. Other individuals have not had experiences that would expose them to different environments that contain noise, so they may overreact,” she says. “We haven’t done enough hearing tests to know if there are differences in sensitivity to sound. If there are, they are probably minor.”

“The best way to deal with these episodes is to stay calm and guide the horse away from the perceived danger,” she adds. “A calm, consistent rider is best for horses that tend to react, so that they learn to trust the rider.” Punishing a horse for spooking will only reinforce his fear.

Exposing the horse to sounds in non-frightening situations is the best way to teach him to accept them, Beaver adds. The techniques of desensitization and counter-conditioning can help. In desensitization, the horse is exposed to the sound when he’s in a safe and familiar environment. (Think of Anna Sewell’s Black Beauty, who was pastured next to railroad tracks so he would learn to accept the terrifying sight and sound of trains.) In counter-conditioning you reward the horse while he’s exposed to the scary sound, typically with treats like carrot bits or feed pellets, so he comes to associate the sound with something pleasant. In both techniques it’s important to start with short sessions and low noise levels, increasing only as he tolerates the sound.

“Horses tend to respond to sounds separately,” Beaver says, so don’t assume that your horse will apply what he learns to new situations. He may realize that the sound of a tractor grooming the arena is not a threat, but that doesn’t mean he’ll accept the sound of a tractor-trailer coming up behind him on the road.

Cotton or equine earplugs can muffle sounds when sudden noises may be a problem—when construction is going on nearby, say, or in a snow-covered indoor arena where ice may abruptly slide off the roof. (Check the governing rules for your discipline before using earplugs in competition, though. They’re not allowed in dressage.)

Even with earplugs, some horses are so freaked out by loud sounds such as thunder and fireworks that they can injure themselves (or you) in their panic. When storms move in (or July 4 rolls around) these horses are safest in their stalls.

Hearing Loss

It’s likely that many horses lose some hearing ability with age, Stewart says, although this is something that hasn’t been widely tested. Researchers in Australia recently compared hearing ability in two groups of horses, ages 5 to 8 and ages 17 to 22, and found mild to moderate losses in the older group. (The researchers used brainstem auditory evoked response, or BAER, testing, in which electrodes attached to the skin of the horse’s head monitor the brain’s response to clicking sounds.) People also hear less well as they age—a lifetime of exposure to noise takes a toll on the sensory receptors in the inner ear. Beaver says that horses may suffer less loss than people do. “Horses don’t live as long or in the same environments [think rock concerts and iPods] as humans,” she notes. Day to day, you probably won’t notice mild hearing loss in your horse.

Deafness is rare in horses. It can be ruled out by electronic testing or simply by checking the horse’s reaction to a sudden noise, like clapping your hands or dropping a bucket. The sound should prompt a startle reaction—at minimum, a twitch of an ear. If the horse shows no response at all, he probably can’t hear it.

A congenital form of deafness occurs in some horses with “splashed white” coat patterns, Stewart says. A splashed white horse has an extremely wide blaze or “bald” face, often with blue eyes, and variable white markings on the legs and body. Some of these horses are born deaf. Researchers have identified three separate genetic mutations that can produce the pattern. Two turned up only in Paints and Quarter Horses, and the third appeared in those breeds as well as in Morgans, Trakehners and a few other breeds.

Splashed white horses have white faces and blue eyes because, during development, their genes suppress pigment-producing cells called melanocytes. If the lack of pigment extends into the inner ear, it affects the sound-sensitive hair cells and leads to deafness, Stewart says. Not all white markings come with the same risk of deafness, and horses can be tested for the splashed white mutations. (The University of California, Davis, offers a test.)

Hearing should be tested as part of a pre-purchase exam, Stewart says. But, she notes, deafness isn’t a huge handicap for a horse. Because a deaf horse doesn’t hear what’s going on around him, he obviously won’t spook at sounds—but he may spook if something suddenly touches him or pops into view without warning. “It’s usually not a problem if you don’t sneak up behind the horse,” she says.

Beaver agrees. “Hearing is often a first or second alert system for potential predators, and that isn’t much of a factor for most horses today,” she says. You may need to modify your aids, she adds—“obviously things like ‘whoa’ won’t work”—but most deaf horses adapt well. Many have had successful show careers.

Pinna Problems

The most common ear conditions in horses are ones you can see—skin problems that affect the pinna.

Fly bites. Black flies and other biting flies love horses’ ears, and the bite sites can become inflamed, crusty, itchy and sometimes infected. Use a topical antibiotic ointment to help control infection while the bites heal. Keep the flies away by using repellents, a fly mask with ear covers for turnout and an ear bonnet when you ride. Avoid clipping the ears unless you must do so to treat an infection—the hair helps protect the skin from bites.

Aural plaques. Aural plaques are flat, scaly, whitish growths on the inside (concave) surface of the pinna. They’re caused by papilloma viruses that are often spread by biting black flies. “Ignore them,” Stewart says. Although the plaques don’t look pretty, they do no harm to the horse. Attempts to remove them typically cause so much discomfort that the horse becomes sensitive about having his ears handled. Use the steps above to prevent black flies from getting to the ears. These flies are most active around dawn and dusk, so keep the horse in at those times.

Sarcoids. The ears are a prime spot for these common skin tumors, Stewart says. Sarcoids are not malignant but can grow aggressively. They can appear as hairless, scaly areas; hard bumps under the skin; or warty or fleshy growths. Some become raw and irritated, and some grow massive and cauliflower-like. It’s thought that infection with bovine papilloma virus, the cause of warts in cattle, may trigger the growths.

“Sarcoids are unsightly, but we generally leave them alone unless they are so large that they cause a problem for the horse,” Stewart says. There are many different treatments—surgery, cryotherapy (freezing), chemotherapy, radiation and more—but none is a sure bet, and the tumors tend to grow back. “Treatment overall has a 70 percent success rate. You may need to retreat several times,” she says. “The horse may come to vigorously resent having his ears handled, and the ear can be disfigured.”

So far no one has found a way to prevent sarcoids. Good fly control may help, however, as flies can spread the virus. Treatment with the chemotherapeutic drug cisplatin seems to slow the regrowth of these tumors. The drug is injected or released by implanted beads.

Deep Trouble

If a horse has a problem deeper in the ear, he may shake his head or hold the affected ear at an odd angle, tipped down to the side, because it’s irritated. He may also object to having the ear handled, but this isn’t a reliable sign. “Ears are sensitive and are naturally something to be protected. If the horse has also had a painful experience or been mishandled, especially while being clipped, it can aggravate the avoidance behavior,” Beaver says.

Ask your veterinarian to examine the ear. Stewart says it’s difficult to see into the ear canal even with an otoscope, the device used in many other animals as well as people, because the horse’s canal has a 90-degree bend. The vet can get a better look using a small flexible endoscope. The exam might discover:

Ticks. Ticks can attack the ear canal as well as the pinna. A type of tick found in the Southwest, the spinous ear tick, is especially known for this; infestation with these ticks can cause pain, inflammation and sometimes even muscle spasms. The horse will need to be heavily sedated for the ticks to be located and removed.

Mites: These tiny tick relatives can also get into the ear canal, although they are less common in horses than in some other animals. Deworming with ivermectin can help control them.

Infection: Ear-canal infections of the sort that plague dogs and cats are very rare in horses. “I haven’t seen one in 20 years. In a small animal practice, you’d expect to see one every day,” Stewart says. Bacterial infections can result from tick infestation, though. They are treated with topical and systemic medications.

Middle-ear infections are also extremely rare in horses, but they occur. Infection can spread from the respiratory system by way of the Eustachian tubes, which link the middle ear to the pharynx, or the guttural pouches, which open off the Eustachian tubes. It can also reach the middle ear from the outer ear canal or through the blood. These infections are treated with systemic antibiotics.

Ear Talk

Horses use body language to communicate with each other. Head and body positions, facial expressions and tail action all speak volumes. But for a quick read on what a horse is thinking, just look at his ears.

Ears held loosely to the side: “Just chillin’.” He’s relaxed.

Ears pricked forward: “What’s up?” If what he hears is really interesting (or alarming), he turns to face the sound and freezes in place.

Ears back: “I don’t like this.” He may be worried, fearful or feeling discomfort.

Ears pinned flat back: “Get out of my space!” He means business.

Ears shifting forward and back: “Lots going on here.” Constant motion is the default mode for a horse’s ears, helping him keep tabs on his surroundings. Rapid flicking can suggest nervousness; you’ll often see this when a horse is in a new environment with unfamiliar noises.

One ear back: “I’m listening.” He may be focusing on his rider or a horse approaching from behind with one ear, but he’s still scanning his surroundings with the other.

Ears drooping: “Tuned out.” Ears may droop when a horse is dozing, doped or sick. This can also be a sign of submission.

For More:

• Read more about how to protect your horse from ticks here.
• Learn how to beef up your fly-control program to prevent flies from driving your horse (including his ears) crazy this summer here.

This article originally appeared in the November 2014 issue of Practical Horseman.

Brought to you by Boehringer Ingelheim 

An estimated one-third of the world’s 60 million horses are over the age of 15. Considered seniors, this population is at higher risk of endocrine issues (Ireland et al. 2016).  

In January 2025, researchers from around the world convened at the 6th Global Equine Endocrinology Symposium (GEES), held in Ocala, Florida, to deliver 37 presentations on this important topic. We were on-site to bring you notes from this exclusive gathering.  

Forage NSC Increases Affect Horses With and Without Insulin Dysregulation 

Key takeaway: Be cautious when determining if and when horses can graze on fresh forage that could be high in nonstructural carbohydrates (NSCs, or starches, sugars, and fructans). 

Research showed that high NSC levels in pasture can affect horses both with and without insulin-­dysregulation (ID, an inability to regulate blood insulin levels). Morgan Askins, a graduate student in the University of Kentucky’s Department of Veterinary Science, Gluck Equine Research Center, presented these findings. Study co-authors included Pat Harris, MA, VetMB, PhD, DECVCN, MRCVS, of Waltham Petcare Science Institute; Erica Jacquay, MS, PhD, of Midway University; and Gluck Equine Research Center colleagues Brittany Kerley, MS, PhD, Maggie McClendon, MS, and Amanda Adams, MS, PhD. 

Objectives 

The researchers hypothesized that if and when the NSC content of fresh forage increases throughout the day, it will lead to heightened insulin responses in ID compared to non-ID horses. 

The objectives of this study were to: 

• Determine changes in forage’s nutritive content over 24 hours at two time points (late summer 2023 and spring 2024). 
• Examine how changes in fresh forage influence insulin concentrations in ID and non-ID horses. 

The researchers also wanted to place the ID horses on a drylot with free-choice access to low-NSC hay (< 10% dry matter basis) to determine insulinemic response. 

Methods 

The study involved 12 mixed-breed adult horses with an average age of 19 classified as being either ID or non-ID.They were housed on pasture in Central Kentucky in late summer 2023 (Phase 1) and spring 2024 (Phase 2). Immediately following Phase 2, the ID horses were housed on a drylot with low-NSC hay (Phase 3). 

The researchers collected blood and pasture samples every two hours for 24 hours starting at 7 a.m.  

The same pasture was utilized in late summer and spring. Horses were moved onto the pasture 24 hours before sample collection started. Blood samples were analyzed for insulin.  

Phase 1 and 2 Results 

In Phase 1 on the late summer pasture, NSC peaked at 15.4% at 7 p.m. It slowly decreased to 7.5% by 5 a.m. the next day.  

The ID horses’ blood serum insulin concentrations increased significantly from baseline at 7 a.m., and insulin was elevated significantly from 3 to 11 p.m. Serum insulin concentrations began to decrease overnight, starting with the 11 p.m. reading. The researchers deemed the safer turnout to be from 5 to 11 a.m. 

During Phase 2 in spring 2024, the pasture NSC levels stayed consistently high and ranged from 19.0-24.7%, with a peak at 7 p.m. This resulted in ID horses’ insulin remaining consistently high throughout the day.  

Importantly, the researchers found four of the six non-ID horses also showed significant insulin responses during the day. Askins said three of the non-ID horses remained above the diagnostic cutoff.  

In the forage analysis for Phase 2, the NSC levels were never below the currently recommended 10% NSC dry matter basis. Therefore, the research team deemed turnout unsafe for ID horses—and many non-ID horses—­during this time on that type of pasture. Askins noted the individual variability in response to NSC in pasture. 

None of the study horses displayed clinical signs of the hoof disease laminitis—a risk associated with high blood insulin levels.  

Phase 3 Results 

The ID horses from the first two studies were taken off pasture immediately after Phase 2 and placed on a drylot with low-NSC hay (8.9% dry matter basis). Within 24 hours of being on the drylot, their insulin levels lowered. The researchers said the extent and speed of the decrease varied depending on the individual.  

Askins said it is “currently unknown at what NSC level do ID horses’ insulin responses change from mirroring the NSC to remaining consistently high.” 

Effect of Day and Time on Pasture NSC and Insulin in ID Horses 

Key takeaway: Trying to time turnout for ID horses can be difficult because of changing NSC levels in pastures, even at the same time of day. 

Managing horses that are at risk for laminitis so they can have pasture turnout has been an important topic in the equine industry. Owners often ask their veterinarians for turnout recommendations for these horses. 

To help address this question, Askins, Harris, McClendon, Adams, and Gianna Palmieri, DVM, and Alexandra Gregory, of Lincoln Memorial University, recently studied ID horses grazing on Kentucky cool-season pasture in early summer.  

(The authors noted this material is original and had not been presented elsewhere.)  

Objectives 

Previous general recommendations for grazing horses at risk of laminitis on cool-season grasses after the spring flush has been to limit them to morning hours. This is when NSC levels should be lowest. However, there had not been research to correlate early summer pasture NSC and insulin response in ID horses. 

The researchers hypothesized that NSC content in pasture changes from day to day as well as by time (a.m. and p.m.) daily. This results in changes in circulating insulin concentrations in ID horses. 

Methods 

The June 2024 study involved seven mixed-breed, mixed-sex horses group-housed on the same paddock growing Kentucky cool-season grass. All horses were classified as being ID. 

The two phases of the study utilized the same horses and paddock with green, active-growth vegetation. 

In Phase 1, the researchers collected blood and pasture samples and recorded daily environmental temperatures during the same morning hours (between 8 and 9 a.m.) for five days. The following week in Phase 2, they collected blood and ­pasture samples and recorded the environmental temperature at two time points (8 a.m. and 3 p.m.) on one day.  

Blood samples were analyzed for insulin, and forage samples were immediately stored at -4 degrees F (-20 degrees C) prior to being shipped on ice to be analyzed by Equi-Analytical. 

The researchers said all study horses remained clinically healthy and had no signs of laminitis throughout the trial.  

Phase 1 Results  

In Phase 1, Askins et al. found no correlation between daily environmental temperature and pasture NSC.  

For example, the highest temperature was on Day 3 at 71 F (22 C), when NSC was 11.5% on a dry matter basis. The lowest temperature was on Days 1 and 2 at 66.2 F (19 C), when NSC was 15.4% (the highest recorded in this phase) and 12.5%, respectively. Day 4 had a temperature of 68 F (20 C) and 11.4% NSC. Day 5 had a temperature of 69.8 F (21 C) and 10.1% NSC.   

As expected, the decreases in NSC dry matter were associated with changes in serum insulin concentrations—as NSC went down, so did horses’ blood insulin levels. 

Phase 2 Results 

As expected, in Phase 2 both environmental temperatures and NSC increased from the morning to the afternoon. Serum concentrations also increased significantly from the morning to the afternoon samples. 

The morning temperature was 75.2 F (24 C), when NSC was 9.5% on a dry matter basis and insulin concentrations were 78.17 +/- 44.94 mIU/mL. The afternoon temperature was 89.6 F (32 C), when NSC was 13.4% and insulin concentrations were 101 +/- 50.97 mIU/mL. 

Conclusions 

The study confirmed that NSC changes can occur rapidly in pasture grasses. Importantly, the study showed that “NSC increases can occur between the morning to mid-afternoon in cool-season pastures even under warm/hot conditions.”  

These NSC increases were reflected in increased insulin concentrations, the research team noted. They also highlighted the tremendous individual variability in the ID horses’ responses to the pasture and the changes in its NSC content. 

Just because it is morning doesn’t mean NSC will be low, the study authors pointed out. “Morning pasture NSC can change significantly from day to day,” they noted. “Even in early summer, the morning NSC percentage in the grass may result in undesirable insulin concentrations in some grazing ID animals.” 

That means owners and managers must be careful assuming all morning grazing after the spring flush will be sufficiently low in NSC to be suitable for equids prone to laminitis. 

The researchers also reminded horse owners and managers that because NSC can change rapidly and horses’ insulin responses to NSC vary, it is important to monitor individual insulin responses frequently. This is especially true in high-risk ID animals.  

Horse Owner Survey on ­Knowledge of PPID 

Key takeaway: About 43% of survey respondents had a self-proclaimed incomplete understanding of pituitary pars intermedia dysfunction (PPID, aka Cushing’s disease). This means veterinarians have room for educating owners on better care of affected horses. 

Harris presented the results of a horse owner survey she and her colleagues (Nicolas Galinelli, PhD; Nicholas Bamford, PhD, DACVIM; and Simon Bailey, BVMS, PhD, DECVPT, from the University of Melbourne) conducted to gauge knowledge of PPID. Why? Because PPID “is an important and common condition in older horses and ponies and is linked to a range of other problems such as laminitis and loss of muscle mass.”  

A total of 1,143 survey responses from Europe (49%), Australia and New Zealand (32%), and North America (18%) met the inclusion criteria. Respondents were grouped based on their self-declared understanding of PPID. Forty-three percent classified themselves as having an “incomplete understanding,” and 57% classified as having a “good understanding.”  

Objectives 

The aims of this study were to assess: 

• Owners’ ability to recognize PPID. 
• Their understanding of PPID. 
• Factors influencing owners’ decisions about management, veterinary involvement, and treatment of PPID. 
• How they feed horses with and without PPID. 
• Areas of further education and the channels through which owners are most likely to seek this information. 

Owner understanding of PPID and “their ability to make appropriate ­management decisions are crucial factors in maintaining the quality of life of ­affected horses,” the authors said. “Assessing owners’ knowledge and understanding of PPID will provide information that will help veterinarians, researchers, and allied professionals to target and design owner education more efficiently.” 

If a survey respondent was managing an animal with PPID, the study also investigated factors influencing their decisions about management, veterinary involvement, and treatment.  

Methods 

Harris et al. distributed an online survey worldwide. It included questions about factors that impact decisions related to the management of horses, the role of veterinarians, and factors influencing the management of horses with PPID.  

Results 

The researchers found that 52% of respondents had horses 15-20 years old, 47% had horses aged 20-25 years, and 40% had horses over 25 years old. The results included a variety of purebred and mixed-breed horses as well as ponies.  

Respondents who declared an ­incomplete understanding of PPID rated long and curly hair as the most indicative clinical sign. The researchers noted that this is the most obvious sign of PPID. 

Respondents who declared a good understanding of PPID rated laminitis as the most important clinical sign followed by susceptibility to infections. The researchers noted that while laminitis is not always associated with PPID, it is perhaps the most clinically serious condition that might occur in PPID animals. 

Information sources for health and management differed between owners in the two groups. Both groups selected veterinarians as their main information source. However, the “incomplete understanding” group ranked nutritionists, trainers, and farriers as more important sources than the “good understanding” group, whose second-most selected category was scientific papers.  

In the study’s nutritional evaluation, Harris said factors considered for PPID horse diets included laminitis, the animal being obese or underweight, and dental problems. Despite laminitis being a key consideration for many, a high proportion of owners of PPID horses were feeding high-NSC diets. 

Conclusions 

“There is considerable scope for education of horse owners regarding PPID,” noted the researchers. “Almost half of respondents declared an incomplete understanding of this condition.  

“Being aware of what horse owners know about PPID will help to inform future education strategies,” they said, which should help optimize health outcomes for equids with PPID. 

Use of Dexamethasone as a Model of Insulin Dysregulation 

Key takeaway: While dexamethasone induces insulin resistance consistently over prolonged periods, its effect on insulin secretion seems temporary. 

The corticosteroid dexamethasone is used to create experimental models of insulin resistance. However, its impact on insulin secretion is unclear. In a recent study, Francois-Rene Bertin, DVM, PhD; Andrew van Eps, BVSc, PhD, MACVSc, DACVIM; Demia de Tonnerre, BVSc, DACVIM-LAIM; Jeaneen Kulp; and Darko Stefanovski, MS, PhD, assessed dexamethasone-treated horses’ response to an oral carbohydrate challenge, citing a need for an inducible/­reversible model of ID. 

Methods 

Eight Standardbreds received 0.08 mg/kg of dexamethasone intramuscularly every 48 hours for 15 days. Oral glucose tests were conducted before treatment (Day 1) and on Days 8 and 15. The researchers measured glucose, insulin, total and active glucagonlike peptide-1 (gut hormones tGLP-1 and aGLP-1), and glucose-dependent insulinotropic polypeptide (GIP, another gut hormone) at baseline and intervals up to 240 minutes after the oral glucose tests.  

Results 

After eight days of dexamethasone administration, the research team noted significant increases in areas under the curve (AUC) and maximum concentrations (Cmax) of glucose, insulin, tGLP-1, and GIP. However, these effects were blunted by Day 15. Glucose, insulin, and aGLP-1 AUC and Cmax were significantly lower than on Day 8. tGLP-1 and GIP AUC and Cmax did not differ from Day 1. 

Conclusions 

Dexamethasone markedly increased insulin secretion after an oral carbohydrate challenge. This showed how exogenous glucocorticoids like dexamethasone can cause or exacerbate ID, even in healthy horses. However, the effect was transient and partially reversed by Day 15. While dexamethasone induces insulin resistance consistently over prolonged periods, its effect on insulin secretion seems temporary. Therefore, the dexamethasone model of ID is an unstable model for testing medication. 

(Note: This work was funded by a Grayson Jockey Club Research Foundation grant. No horse developed clinical laminitis.) 

Long-Term Canagliflozin ­Therapy in ID Horses 

Key takeaway: Preliminary results indicate canagliflozin is a promising drug for the long-term treatment of ID horses. 

An ongoing study on the effect of canagliflozin on ID horses concluded its second year. Elin Svonni, DVM, PhD student with the Department of Clinical Sciences at Swedish University of Agricultural Sciences, presented the preliminary report. Her research colleagues are Sanna Lindåse, DVM, PhD, and Johan Bröjer, DVM, MSc, PhD, DACVIM (LAIM), DECEIM, of the same ­institution. 

Methods 

The study involved 16 horses diagnosed with ID. They underwent an oral sugar test and a meal tolerance test at baseline. Those tests were repeated after one year and two years of treatment with once-daily canagliflozin (0.4 mg/kg). 

Objectives 

Velagliflozin and canagliflozin are sodium-glucose co-transport 2 (SGLT2) inhibitors that have been studied in horses. These SGLT2 drugs reduce glucose reabsorption in the kidneys, promote glucosuria (glucose excreted in urine), and consequently decrease blood glucose and insulin concentrations. 

The researchers acknowledged that short-term treatment with SGLT2 ­inhibitors has been shown to decrease the postprandial (after a meal) insulin response in ID horses. The aim of this study was to investigate the effects on postprandial insulin responses, serum triglyceride (TG, a type of fat in the blood), and concentrations of the enzyme glutamate dehydrogenase in ID horses treated with canagliflozin for up to two years.  

Results 

Svonni reported that postprandial insulin responses decreased with canagliflozin treatment and remained low for two years (see graph).  

For the oral sugar test, she said, “the average insulin responses were 29.3% and 37.6% of the baseline response at one and two years, respectively. The corresponding data for the meal tolerance test were 28.2% and 33.7%.  

“There was no difference in glutamate dehydrogenase concentrations at any time point compared to baseline,” she added. “Some individuals developed elevated serum triglyceride concentrations during canagliflozin treatment but showed no clinical signs of hyperlipemia (high levels of fat in the blood).” 

Conclusions 

These results indicate horses treated with canagliflozin “have sustained decreases in postprandial insulin responses over two years without severe side effects related to hypertriglyceridemia. Thus, canagliflozin is a promising drug for long-term treatment of ID horses.” 

(Note: The Swedish-Norwegian Foundation for Equine Research funded this study.) 

Pergolide’s Effects on Horses’ Thyroid Function  

Key takeaway: Pergolide is unlikely to cause low thyroid hormone concentrations in PPID horses. 

Pergolide mesylate is labeled for the treatment of PPID in horses. While PPID is not associated with a primary thyroid disorder, it is part of the nonthyroid illness syndrome, said Bertin, who co-­authored a study on the topic with Martyna Jargielo, DVM, and Janice Kritchevsky, VMD, MS, DACVIM, all of Purdue. 

Objectives  

Bertin said pergolide is “over 90% protein-bound. As such, it could cause a decrease in thyroid hormone concentrations by displacing them off circulating proteins.” The Purdue study’s aim was to determine the effect of pergolide administration on horses’ thyroid function. 

Methods 

The study involved six lightbreed horses. Each received 1 mg of pergolide mesylate orally once a day for five days. Total thyroxine (tT4, a hormone produced by the thyroid gland) was measured daily from Days 0 to 11 (before, during, and after pergolide ­treatment). 

The researchers conducted thyrotropin-releasing hormone (TRH) stimulation tests on Days 0 and 6. “Total triiodothyronine, tT4, and free thyroxine were measured at baseline, 2 hours, and 4 hours after TRH administration,” said Bertin. 

Results 

Bertin said they detected no effect of pergolide administration on tT4 during or after treatment. TRH administration resulted in a significant increase in all thyroid hormones. However, it did not have a significant effect on thyroid function. 

Conclusions 

“Pergolide has no detected effect on thyroid hormone concentrations or thyroid gland function in horses,” Bertin concluded, noting that protein-bound agents do not necessarily affect blood T4 concentrations. Low thyroid hormone concentrations in PPID horses are unlikely to be caused by pergolide, he added. 

California ranch owner Bob Manns’s horse, Magic, was the oldest registered Arabian horse in the U.S. She remained healthy and sound throughout her 51 years and went on an hour-and-a-half trail ride just a month before she died peacefully in 2020. 

Horses have lived and thrived well into old age for centuries, but now there are more aged equines who are healthier and more active than ever before. Conversations with your veterinarian will help identify the particular issues and challenges your older horse is facing, and routine yearly blood work screening, consistent dental care, nutritional management and attention to joint health are key to his longevity.

Horses and Owners Aging Together     

There is increasing evidence that older horses are becoming a more significant part of the equine industry. A 2001 study published in the Journal of the American Veterinary Medical Association showed that the number of geriatric horses (older than 20) went from 2.2% of total equine patients in 1989 to 12.5% in 1999, while a 2015 National Animal Health Monitoring System equine study showed that the number of aged horses continued to double from 1998 to 2015. These increases are likely due to a number of factors.

There has been a rise in specialized veterinary services for older horses, which specifically address the common problems and needs of geriatric equines. Additionally, there has been a change in perception as to what older horses can still do with proper fitness and an increase in owner willingness to seek out and finance services to keep them going longer. 

This perception shift has likely been influenced by the increasing viability and longevity of the human population. And many equestrians, who are staying healthier and more active at older ages, want to help their equine companions keep pace. The United States Dressage Federation offers a Master’s Challenge Award for riders over 60, and in the ultimate acknowledgement of both aging human and horse athletic capabilities, The Dressage Foundation’s Century Club recognizes any horse-and-rider pair who completes a dressage test, at any level, with a combined age of 100 or more. 

In a 2011 research article titled “Welfare of Aged Horses,” Catherine McGowan, a researcher at the Institute of Aging and Chronic Disease and professor of equine internal medicine at the University of Liverpool England writes, “In the past few decades, the role of the horse as a companion animal has become more apparent.” She goes on to discuss a survey of 47,000 horse owners across the U.S. that showed 38.4% considered their horse to be a family member and over half (56.5%) considered them a pet or companion. This explains the drastically intensified care and attention that owners have given their horses, resulting in healthier, more athletic animals throughout their golden years.

Wellness Care to Keep Older Horses Vibrant    

The equine “fountain of youth” starts with better health in general. And paying close attention to seemingly simple details in older horses is crucial because small problems often have a ripple effect in seniors. Veterinarians are increasingly focused on their older patients and can more rapidly identify and treat problems and conditions affecting them than in previous decades. The basics are still very important. Vaccination programs help keep all horses protected from most common diseases, but it’s even more crucial for older (and younger) horses because they generally have weaker immune systems and can be more seriously affected by diseases. Consistent deworming with quality, targeted products has drastically reduced parasite damage in horses’ intestines, and with the reduced absorptive capabilities of some senior equines, more accurate deworming helps older horses maintain weight and reduces stress on their immune systems. 

Routine blood work screening has also enabled veterinarians to identify certain conditions in senior horses and initiate more effective treatments much earlier. Older horses are sometimes anemic, and a complete blood count (CBC) will identify such a problem. Veterinarians can then look for the cause of blood cell loss or reduced red cell production, which can range from low-level liver dysfunction to age-related bone marrow dysfunction, and initiate a treatment plan. In some cases, something as simple as adding a “blood builder” tonic or other specific supplement to an older horse’s diet can improve the red blood cell and hemoglobin levels. 

This improved oxygen-carrying capacity in the blood can provide senior horses with more energy, which leads to more activity and helps build and maintain muscle mass—something that is so important in older horses. More activity often leads to increased grazing, which helps address dietary concerns and weight management, and older horses with more energy tend to interact more with herdmates. Social interaction for senior horses is often overlooked but has proven important for reducing stress, boosting immunity and contributing to the quality of life for older equines. 

Blood work screening can also identify problems with liver, kidney, cardiac, and many other organ systems to help veterinarians and owners determine if any dietary, exercise or treatment changes are necessary. This can often add functional years to a horse’s life.

Addressing Dental and Metabolic Issues

Equine dental care has improved greatly in recent years. Dental problems are a major concern in older horses who often suffer from tooth loss, uneven wear patterns, sharp points, worn-down teeth and other dental diseases. Equine odontoclastic tooth resorption and hypercementosis (EOTRH) is a disease seen in horses generally older than 15. While it has likely been around for many years, the increased care and attention given to older horses, especially dental care, has caused the condition to be more widely recognized in recent years. EOTRH causes tooth damage and resorption which can lead to infection, abscesses and dental fractures. Older horses with EOTRH or other dental problems can show signs of weight loss, difficulty eating and associated performance and behavioral issues stemming from constant pain and decreases in food intake. 

Older horses are also much more likely to experience metabolic problems, but increased use of early blood screening tests is helping to identify these conditions and provide earlier care. Pituitary pars intermedia dysfunction (PPID, formerly known as Cushing’s disease) affects a large percentage of older horses (20% or more in some studies). Common symptoms include a long, curly coat and muscle loss, but early signs of PPID and other metabolic problems (insulin resistance or equine metabolic syndrome) can be harder to spot. Long-term weight and muscle loss; lack of energy; depression; susceptibility to skin infections, hoof abscesses, laminitis and other problems brought on by poor glucose regulation and a stressed immune system were often thought to be inherent consequences of old age. But through early detection, veterinarians can provide these horses with pharmaceutical treatments, exercise programs and dietary changes to help slow the progression of metabolic problems and remain healthier and more active.

Feeding the Older Horse

As veterinarians identify more dietary-related problems in senior horses, such as obesity, laminitis, PPID and other metabolic concerns, gastrointestinal irregularities and arthritis, the equine nutrition industry has developed new feeds with targeted ingredients and feeding strategies to help manage these conditions.

A variety of new feed types, including pellets, cubes and chopped hay products, are also now available for older horses with poor dental conditions who might have a reduced ability to digest forage, which can lead to a host of other medical issues from choke to weight and muscle loss. 

Concern for aged equines has created an entirely new market for supplements designed to rebalance the bacterial environment of the older horse’s gut. These prebiotic and probiotic products promote healthy gut bacteria, which can help reduce loose stool and excessive gas, allow for better digestion and absorption and ultimately promote more stable weight and muscle mass in older horses. 

New research on protein, carbohydrate and other nutrient requirements of seniors—and the feeds developed based on this research—are providing older horses with more energy, which in turn enables them to be more active and functional athletes as they age.

A report from the University of Tennessee Institute of Agriculture concludes that “nutrition for geriatrics, or old[er] horses with age-related diseases, has become more prevalent because horses are living longer and more data is available on nutrition risk factors for diseases and digestive disorders. We now have a much better under standing of how to manage the special needs horse.”

Healthy Joints for an Active Horse     

Optimizing joint function and reducing symptoms associated with osteoarthritis is another major area of veterinary research and product development that has extended the athletic capabilities and lifespans of older horses. As all animals age, they develop wear and tear injuries to their joints. This long-term joint stress eventually leads to osteoarthritis that can be career-ending, crippling and sometimes even life-threatening. Anything that reduces a horse’s mobility will affect his ability to graze, which can result in weight and muscle mass loss. Additionally, pasture grass provides horses with needed essential nutrients such as Vitamins A and E, omega-3 fatty acids, and minerals like calcium, phosphorus, copper, iron, magnesium, potassium and selenium. Horses who don’t graze enough and consume decreased amounts of these nutrients are less healthy and more susceptible to disease. 

Also, when horses cannot move around freely, they lose that important ability to interact with their herdmates, which can lead to isolation, depression and physiologic stress. 

The majority of drugs previously available for arthritis pain control, such as phenylbutazone (Bute) and Banamine^®, can cause stomach ulcers and intestinal issues as well as kidney damage with long-term use. However, new, pain-relieving medications, such as firocoxib, have been a major factor in increasing equine longevity, as they’re not as harmful to a horse’s intestines and organ systems and can be used for long periods of time. Long-term pain management enables some older horses to continue competing at lower levels while keeping others pasture-sound for much longer than previously possible. 

Glycosaminoglycans, hyaluronates, chondroitin-based products and any number of osteo-protective substances have been proven to slow the progression of arthritis. This class of medications works by promoting healthy joints and cartilage while also slowing joint deterioration and extending the functional life of older joints. The common use of these products at earlier ages is creating a population of older horses with joints that are in much better condition than similarly aged horses in past decades. 

The more recent development and use of regenerative medicine products such as stem cells, platelet-rich plasma (PRP), interleukin-1 receptor antagonist protein (IRAP), Pro-Stride^® and numerous other intra-articular joint injections has also greatly enhanced veterinarians’ abilities to treat early joint issues and maintain better joint function as horses age. With improved joint health, continued exercise is not only possible for older horses but is essential to keeping them engaged and functional.

Overall, horses are definitely living longer and better lives. The key to helping older horses get the most out of their golden years is to consider each as an individual. Not all older horses are the same, and age, after all, is just a number. Specific decisions and treatments tailored for each older horse can be determined with the help of your veterinarian. But not seeing your horse as simply “old” is the first step. Continuing to train, exercise, compete and enjoy your senior equine partner, as much as is possible, is the ultimate way to grow older and better together.

Age: What’s in a Number?

Traditionally, the veterinary community has considered horses 20 and over as “aged” or “senior” when considering their nutrition, joint care, reproductive considerations and management. But this classification system is largely arbitrary, with the 20-year mark decided upon with little research. Recent work by the National Research Council and others suggests that there may be better ways to define “old age,” which can help veterinarians provide more specifically targeted ways to care for aging horses. Researchers have suggested that equine age be defined by a combination of three factors: physiologic age, chronologic age and demographic age. 

Physiologic age refers to the internal factors of the animal—natural decreases in reproductive performance; decreases in tendon, ligament and joint function; decreased muscle mass and reduced capabilities in digestive, liver, kidney, cardiac and other organ systems. The generally accepted age for an “older” horse, from a physiological age perspective, is from 15 to 20. A reining horse who has been extensively competed as a young horse and experienced a reduction in his musculoskeletal system health may be considered “old” at 10, while a lightly used trail horse may be functionally sound and healthy and not “physiologically old” at 25.

Chronologic age refers to the number of years from birth compared to expected longevity. There are horses that live to be 40—and some well beyond that—and the number of these “seniors” is growing. Using this criterion, horses are classified as “old” when they’re between 20 and 30 and “very old” if over 30. As more horses continue to live longer, you can expect these chronologic age classes to be periodically revised.  

Demographic age is determined by survival relative to a specific subset of a population defined by a region, discipline or other factors, including economics, use or social issues. The age at which an individual becomes “demographically old” is the age at which they are older than 75% of the other members of that specific group. Horses living in harsh climates generally may not live as long as horses in milder weather locations. Some areas view horses differently from a societal perspective, which often determines the level of care that they are given, and some horse-owning populations have differing economic concerns, which can affect horse care, health and, ultimately, longevity.

A 15-year-old horse living in generally harsh conditions in northern Sweden may be seen as a “senior” relative to the majority of other horses living there. Racehorses are generally put under more stress at an early age and have higher incidences of injuries associated with their use, so as a demographic group, they may not live as long as horses in other disciplines, such as dressage or endurance. Therefore, classifying an off-the-track Thoroughbred as “old” at 18 may be more correct than applying that same label to an 18-year-old dressage horse. Demographic age considers all these different factors and can help make discussions about equine aging much more productive. 

The bottom line is that age, for all of us, is so much more than just a number. Using a combination of all these age criteria for each individual may be a better way at arriving at a horse’s more accurate and functional “age,” which can then determine management and maintenance programs for these equine seniors.

About Kenneth L. Marcella, DVM

Kenneth L. Marcella, DVM, is a graduate of the New York State College of Veterinary Medicine at Cornell University. For more than 30 years, he has treated sporthorses of all disciplines and levels, including international competitors. Dr. Marcella has served as a veterinary official at many events around the world, including national championships, world championships and Olympic competitions. He is board-certified in thermal imaging and is currently a member of the board of directors of the American Academy of Thermology. With an undergraduate degree in English from Dartmouth College, Dr. Marcella has also written articles for numerous publications. 

EVENTS

• Ocala Winter Classic: Feb. 4 – 9; Ocala, Florida
• Desert Circuit 5: Feb. 5 – 9; Thermal, California
• Global Dressage Festival 5: Feb. 5 – 9, Wellington, Florida
• I Love Dressage: Feb. 8 – 9; Aiken, South Carolina
• Winter Spectacular VII CSI5*: Feb. 11 – 16; Ocala, Florida
• Gulf Coast National: Feb.13 – 16; Gulfport, Mississippi
• Ledges Winter February: Feb. 13 – 16; Roscoe, Illinois
• Old Salem Farm February I: Feb. 13 – 15; North Salem, New York
• Scottsdale Arabian Horse Show: Feb. 13 – 23; Scottsdale, Arizona
• All For the Horses Expo: Feb. 15 – 16; Ocala, Florida
• Adequan® Global Dressage Festival CDIO3* and National: Feb. 19 – 23, Wellington, Florida
• WEF Week 8 – CSIO4*, U25, USEF Premier “AA”: Feb 25 – March 2; Wellington, Florida
• WEF Sport Horse Auction: Feb. 27; Wellington, Florida
• Horse World Expo: Feb. 27 – March 2; Harrisburg, Pennsylvania

TO-DO LIST

Deep Clean Your Tack and Boots: Extend your tack’s life expectancy (and save money down the road) and get a jumpstart on the upcoming show season by giving all your tack some extra TLC. This is also a good opportunity to do a safety check for loose threads, cracked leather, rusted hardware or anything else that might compromise your tack’s integrity. While you have your soap and leather conditioner out, you might as well give your boots a thorough cleaning.

Barn Fire-Safety Check: Most barn fires occur in winter. During slower training days this month, help protect your horses and barn with the following:

• Schedule a barn inspection with an electrician and a rep from your local fire department.
• Install smoke alarms, sprinklers and fire extinguishers (or inspect your current ones to ensure they’re working properly).
• Sweep barn aisles, remove cobwebs and other debris, vacuum dust around electrical outlets.
• Unplug any electrical appliances when not in use.
• Clean up dead leaves and twigs around the barn.
• Store machinery and flammable materials like hay, bedding, fuels and fertilizer in separate structures or areas separated from the horses by firewalls.

For more tips on barn-fire safety, click here.

Get—and Stay Fit: Even if your New Year’s fitness resolution has waned since January 1, use time stuck indoors this winter to get your riding muscles in pique condition. You and your horse will be thankful! In a recent Practical Horseman Podcast, five-star eventer Cornelia Fletcher became an avid Pilates fan during her recent pregnancy and highly recommended it for improving riders’ core strength. If you’re bored with your same-old gym routine, check out these exercise ideas to get out of your fitness rut and improve your game in the saddle. You can also find rider Pilates videos on EQUESTRIAN+ for inspiration.

Get Your Groundwork On: Stuck in small indoor training spaces during the colder months? Incorporate natural horsemanship groundwork into your training routine. It will improve the communication skills you share with your horse, help establish your role as his mentor and teacher and enhance your bond. Try these tips from top eventer and natural horsemanship advocate Tik Maynard.

Pamper Your Equine Valentine: Treat your heart horse to a spa day—a soapy bath with his favorite shampoo, a thorough grooming session that includes plenty of massage, a mane-and-tail blowout for luscious locks and plenty of leisurely grazing topped off with special treats. More ideas to come!

Show Clothes Eval: Take inventory of your show wardrobe—breeches, show shirts, jacket, boots, helmet, gloves etc.—to determine if any items need to be repaired, replaced or dry cleaned. If you’re in the market for new tall boots this upcoming show season, you might consider purchasing them now to allow for plenty of break-in time. This is also a smart time to get any items embroidered or personalized before orders start piling up as we get closer to show season. If your horse has his own show wardrobe (coolers, quarter sheets, show halter), make sure his digs are in good repair, too.

Tune Up Your Course-Riding Skills: When you’re cooped up due to the weather, check out German show jumper Ronny Riemer’s new video series on EQUESTRIAN+ and learn how to plan your course walks for success, tackle tricky distances and stay open to creative course-riding options.

Mid-Winter Checks: Half way through the cold season, take a few quick moments to do some mid-winter health and safety inspections.

• Inspect your horse’s turnout sheets and blankets for any rips, tears, hardware malfunctions, loose belly bands or leg straps that could compromise their integrity or risk his safety.
• Monitor senior horses for weight loss, especially those with long winter coats. Older horses often have trouble maintaining their weight in cold weather and might not get their share of grain if fed in groups with younger, more dominant horses.
• Plan to feed more hay (not grain) on the coldest days. Digestion produces heat to help horses maintain their body temperature, and additional forage is a better option than extra grain, which could increase risk of colic.
• Check outdoor water troughs and break up any ice to ensure horses have access to fresh water, and inspect any heated indoor water troughs to ensure they’re in good working condition and don’t pose any fire risk.

Organize & Purge Your Tack Room: When you’re snowed in this winter, motivate yourself to knock out some much-needed organization chores around the barn. Trash or recycle old, broken tack; hopeless pads, blankets or coolers; empty containers, expired products or anything you haven’t touched in half a decade. While we all love our mile-high tacks of favorite saddle pads, consider paring down your collection and starting a donation pile. (In addition to equine welfare organizations, you can also donate pads to animal shelters to provide homeless cats and dogs with extra bedding.)

Clean, store and organize all supplies and tack you intend to keep. Inexpensive Rubbermaid totes and drawers are super handy for tack-room organization. If you’re out of wall space, consider purchasing two or more vertical-scale storage units (you can find at most home improvement stores) and position them back to back in the center of the room to create a storage tower in otherwise dead space.

Happy February, from your friends at Practical Horseman!

— Kathy P., Pennsylvania

A: Vitamin E is a fat-soluble antioxidant that plays a crucial role in supporting horses’ immune systems and other physiological processes. In its most active form, alpha-tocopherol, vitamin E is most potent as an antioxidant and serves to protect immune cells from oxidative stress, boost antibody production and reduce inflammation.

Oxidative stress arises when free radicals (unstable molecules generated through metabolism or environmental factors) accumulate and cause cellular damage. Vitamin E helps neutralize these free radicals, preventing the destruction of cell membranes and other essential cell structures.

Horses cannot synthesize vitamin E on their own, and therefore must obtain it from their diet, primarily through fresh forage. Ensuring adequate vitamin E intake through diet or supplementation is a priority for horse owners, especially considering its profound impact on the neuromuscular system.

Vitamin E deficiency often occurs when horses have limited access to fresh pasture, as dried forages like hay and processed feeds contain significantly lower levels of vitamin E. Primary clinical signs and conditions associated with vitamin E deficiency in horses include muscle loss, weakness, poor performance and, in some cases, neurologic disease.

Evaluating Your Horse’s Vitamin E Intake

Many variables need to be considered when evaluating your horse’s vitamin E intake. The amount of vitamin E provided by pasture grazing depends on factors such as location, season, plant species, soil type and the amount of time your horse spends on pasture.

It’s challenging to make even broad generalizations about what type of pasture and how much would provide adequate vitamin E for any given horse because there simply hasn’t been enough research into the amounts of vitamin E in different pasture types—and due to the variation in absorption rates between individual horses. So, for example, we can’t say that if your horse is on timothy pasture for X hours a day in the spring, then his vitamin E levels are probably OK. It’s best to have his vitamin E levels checked directly.

It’s also important to consider the amount of vitamin E your horse gets from his daily rations, including targeted supplements (You can find this information in the ingredients’ label.) Most equine feeds and ration balancers, however, contain synthetic vitamin E, which is not well absorbed in horses and therefore usually doesn’t provide adequate amounts of the vitamin.

The National Research Council recommends that horses consume 1-2 international units (IU) per kilogram body weight of vitamin E daily. This equates to 500-1,000 IU for a 1,100-pound horse. Higher levels may be recommended for horses in hard work or those with certain health issues.

When determining whether your horse needs vitamin E supplementation in the late fall and winter, it’s also important to keep in mind that horses store vitamin E in the liver and fat tissues. Depending on pasture access in the spring and summer months, they can rely on these stores for up to 18 months before problems related to dietary vitamin E deficiency may be observed. This is how wild horses maintain their vitamin E levels throughout the winter.

However, individual horses metabolize vitamin E at different rates, so the time they can go without consuming vitamin E can vary. Additionally, some horses are genetically predisposed to diseases caused by vitamin E deficiency such as equine neuroaxonal dystrophy/equine degenerative myeloencephalopathy, a neurologic disorder that can cause ataxia (incoordination), dragging the feet and weakness.

Establish a Vitamin E Baseline

Due to the many variables that affect individual vitamin E levels in horses, establishing a baseline blood vitamin E level is important to determine whether your horse is deficient in vitamin E. If he is, work with your veterinarian to determine the appropriate supplement for him and to recheck his vitamin E levels after supplementation to ensure they’re not too low or too high. From there, your veterinarian can advise you on making any necessary adjustments to his supplement dosage.

The timing on when to recheck his levels depends on the type of vitamin E supplement he’s getting. Water-dispersible vitamin E products are highly bioavailable; therefore, it’s generally recommended to recheck within two weeks of starting. For powders and pellets with natural vitamin E, the bioavailability is lower, so it takes two to three months to increase levels.

Once a reasonable level is achieved, it’s always wise to recheck your horse’s levels once or twice a year. This is especially true if his diet changes significantly or if you notice any changes in his health that could be related to vitamin E levels, such as muscle loss, decreased performance, incoordination or weakness. On the other end of the spectrum, excessive vitamin E can cause health issues such as increased bleeding risk. Vitamin E interferes with vitamin K metabolism, which can increase the risk of bleeding.

Regardless of your horse’s situation, always consult with your veterinarian before making significant changes to vitamin E in your horse’s diet.

For More:

To learn how vitamin E can help support your performance horse’s immune health, click here.

About Carrie Finno, DVM, DACVIM, PhD

Carrie Finno, DVM, ACVIM, PhD, is an equine internist who serves as associate professor in veterinary genetics and the Gregory L. Ferraro Endowed Director of the Center for Equine Health at the University of California, Davis. She received her veterinary degree from the University of Minnesota in 2004 and then completed a three-year residency in large animal internal medicine at UC-Davis. She elected to pursue a career in translational genetic research, with a strong focus on inherited neuromuscular diseases. Her research studies the interaction of vitamin E and neural development in a naturally occurring disease in the horse.

My Senior Horse’s mission is to promote the health and welfare of senior equids through comprehensive educational resources. The website will deliver valuable content across various digital platforms, including social media, videos, and more. My Senior Horse’s vision is to provide the most reliable and easy-to-understand information to help care for senior horses, donkeys, and mules globally.

The website will feature contributions from industry experts who are passionate about senior equids. Topics will range from the basics of “What is a Senior Equid?” to the latest research affecting older horses, donkeys, and mules. Whether it’s Olympic horses or beloved backyard pets, MySeniorHorse.com will cover it all.

“MySeniorHorse.com has been a passion project for our editorial team for the past few years,” said Tom Winsor, CEO of Equine Network, LLC. “We know our audiences are hungry for a fact-based, easy-to-understand resource to help them care for their senior horses, donkeys, and mules, and we are excited to have found the perfect partner to bring it to life in Linda Mars and the team at Mars portfolio of equine-focused products and services.”

Linda Mars added, “Caring for a large herd of senior equids myself, this is a passion project for me. MySeniorHorse.com will offer invaluable resources to ensure these magnificent animals receive the best care possible as they age.”

The Mars portfolio of equine-focused products and services includes BUCKEYE Nutrition, SPILLERS, WALTHAM Equine Studies Group, ANTECH, SOUND® and MARS EQUESTRIAN. For more information about My Senior Horse and to access the resources, visit www.MySeniorHorse.com.

Contacts

• Media Inquiries: Marla Bickel, Vice President of Data and Content – mbickel@equinenetwork.com
• Partnerships and Collaborations: Katie Clinebell, Director of Client Services – kclinebell@equinenetwork.com

—

About Equine Network, LLC

Equine Network, LLC, is a leading provider of media, events, and digital content in the equestrian industry. With a mission to educate, entertain, and connect equine enthusiasts, Equine Network produces a wide array of publications and digital platforms dedicated to the horse community.

About the BUCKEYE Nutrition Brand

The BUCKEYE Nutrition brand combines science, innovation and a genuine passion for horses to produce the highest-quality, safest feed possible. Every product is formulated by equine nutritionists and produced in a state-of-the-art, medication-free facility. The BUCKEYE Nutrition brand takes feed safety seriously, using only 100 percent pure ingredients delivered daily and traced from field to feed bucket. These stringent quality standards are backed by Mars, Incorporated. All BUCKEYE Nutrition products are underpinned by science from the Waltham Petcare Science Institute, a world-leading authority on animal care. In business since 1910, Mars Horsecare US is passionate about unlocking the full potential of horses, allowing them to live longer, healthier and happier lives. Visit BuckeyeNutrition.com.

About the SPILLERS Brand

The SPILLERS Brand is a proud partner in care and strives to lead, support and communicate research to continually expand knowledge and improve horse health worldwide. Having produced the first ever compound feed for horses back in 1958, the SPILLERS Brand now has feeds to suit all types of horses and ponies, including fibers, balancers, Laminitis Trust approved products and a superior range of thoroughbred breeding and racing feeds.

All SPILLERS products are underpinned by science from the Waltham Petcare Science Institute, a world-leading authority on pet nutrition and home to the WALTHAM Equine Studies Group, led by Professor Pat Harris, MA, PhD, VetMB, DipECVCN, MRCVS.

The SPILLERS Brand is part of Mars, Incorporated, who put quality at the heart of everything.

About the Waltham Petcare Science Institute and the WALTHAM Equine Studies Group

The Waltham Petcare Science Institute is Mars Petcare’s pet research center. Our work focuses on the nutritional and behavioral needs of pets, as well as preventive health. We use this knowledge to support development of innovative products and services, advancing science to deliver our Purpose: A BETTER WORLD FOR PETS. The WALTHAM Equine Studies Group, which is headed by Professor Pat Harris, MA, PhD, VetMB, DipECVCN, MRCVS, is dedicated to advancing the science of horse nutrition and provides the scientific support for Mars Horsecare globally including the BUCKEYE Nutrition, SPILLERS, and WINERGY brands. By collaborating with key research institutes and universities around the world its work remains at the forefront of equine nutritional science.

About ANTECH and SOUND^® EQUINE

ANTECH has been a trusted partner to veterinarians for nearly 40 years. Our complete diagnostic solution for both large and small animal practitioners includes veterinary reference laboratories across North America, Europe, and Asia; a complete lineup of in-house diagnostic analyzers from Heska and Scil; best-in-class imaging equipment and services from Sound^® and Scil; and the industry’s most trusted telemedicine offerings and AI-powered diagnostic tools from ANTECH Imaging Services. Above all, we value partnership, both in our long-standing relationships with industry-leading vendors and our continued dedication to the largest veterinary customer base in the market. 

The right diagnostics at the right time — all from ANTECH. Visit us at antechdiagnostics.com.

About MARS EQUESTRIAN

MARS EQUESTRIAN, funded by Mars, Incorporated is the link between our iconic brands and the equestrian community. For generations, Mars has celebrated a rich equestrian heritage, and through purposeful partnerships, MARS EQUESTRIAN is committed to the sport and building an enduring legacy. From world-class competitions across all equestrian disciplines, to stewarding the power of horses on society and sustainability, the MARS EQUESTRIAN Brand is dedicated to our purpose to improve the lives of horses, pets, and the people who love them. For more information please visit www.marsequestrian.com and join us @marsequestrian.

Supplements and joint health have always been major points of conversation in every equine circle—especially when the topic of Bute (phenylbutazone) comes up, and how some horses “are always on it.” What’s healthy and good for the equine body, and what’s not? We brought this up with our featured veterinarian, Dr. Tracy Turner, who specializes in equine lameness, to hear his professional opinion.

“You have to put oil and gas in your car to keep it running, right? Well, you have to do the same for a horse, but it’s a bit more complicated,” states Turner. “These days, the nutrients are typically depleted in grass and soil, plus water can be somewhat polluted. Therefore, providing supplements that aid in the biochemistry and amino acids that support the building blocks for the body to function well will only help the horse, aka make the machine work more efficiently. Nutritional supplements with natural ingredients are great to provide to horses; however, they really do need to be on them consistently for six months to see a real difference. I suggest taking ‘before and after’ photos to compare their body condition.

“When I hear horse owners say their horses are on Bute every day, I tend to ask ‘Would you take Advil or ibuprofen every day?’ I would hope they would say no, because it is not healthy for your body if taken long-term. Eventually you’ll think it’s not working and take more; then it’s still not good. When you need it, yes, it’s good for you in short time spans. That is how I tend to view inflammation with horses,” he says.

“For body functionality for the horse that has some issues and needs a low level of anti-inflammatory for everyday use to be comfortable, nonsteroidals every day can create problems medically if taken long-term,” Turner explains. “When you really need it, for a short time, use the nonsteroidal in short time spurts. That’s completely OK and why we have them.

“But for the horses that need long-term support with inflammation, if I can provide that to them with a more natural, plant-based product with less metabolic interference, I’m going to choose that. I would recommend products that have clean ingredients such as yucca, boswellia, B12, devil’s claw, curcumin and MSM. All of these have great qualities that stimulate circulation, improve digestion and help relieve inflammation related to joint pain.

“If you’re looking for more specific joint support, looks for key ingredients such as glucosamine, chondroitin and hyaluronic acid (HA). Absorbine actually make a product that I have started using on some of my horses that need inflammation relief on a daily basis. It seems to work well for them; it’s called Bute-Less. They have a show-safe version of it, as well, for those that are competing,” states Turner.

Finally, he concludes, “I also really like when a company puts their money where their mouth is and provides clinical research about their products and the ingredients within them. You see magazines with claims every day, but look and read the research available. That says a lot about their dedication to efficacy and standing behind their products.”

If you would like to go down the rabbit hole to learn how each of these key ingredients work, check out the recent article “Supporting Equine Mobility: What’s in your Nutraceutical?”

Safe and Healthy Options for Your Horse

When looking inflammation relief and is still safe for everyday use, consider Absorbine’s Bute-Less® supplement. It is this blend of natural ingredients that makes Bute-Less so effective in providing long-term comfort. It is also gentle on the stomach so you can give it daily without worry. For those that compete on a regular basis or need additional support, check out Bute-Less® Performance. It is a curcumin-based formula, contains no substances currently prohibited by the USEF or FEI, and is still a healthy option for your horse that is gentle on the stomach. Bute-Less Performance is made with a patented curcumin that is 65x more bioavailable than unformulated curcumin, this means it starts working faster to provide relief. Check out this Bute-Less Performance pharmacokinetics study showing the curcumin reaches the blood stream in hours.

If your horse needs a little more specific joint health support, consider Absorbine’s Flex+Max® Joint Health Supplement. Its highly effective formula, with guaranteed levels of chondroitin and glucosamine, can give you peace of mind that your horse is actually getting what he needs for his joints. It also contains HA, MSM and boswellia serrata to provide additional joint support. Visit www.FlexMaxPlus.com for more information. 

To read more about the topics that Dr. Turner covers, click here. 

Winter is in the air, and soon the “snowbirds” of the hunter/jumper and dressage worlds will be flocking south to Florida for the prestigious Winter Equestrian Festival (Jan. 6–April 4, 2021) and the Adequan Global Dressage Festival (Jan. 13-April 4).

That means three months of nonstop, high-caliber competition: a lot of fun, but also a lot of potential stress for your horse. Even for those hardy souls who rise to the occasion time after time, this can translate to gut issues—which can spell big trouble. It has been estimated that upwards of 70 percent of performance horses experience ulcers, and colic is among the leading causes of equine deaths.

How to prevent a troubled tummy? It’s all about careful management. Here are some ideas to get you started.

Suppress the Stress
Before you start packing, devise a health-minded strategy for your horse’s away-from-home care. Consult your veterinarian about your impending trip and arrange any deworming, dental work, vaccinations and/or Coggins tests sufficiently in advance of your ship date to allow your horse recovery time. Also be sure to inquire about any special COVID-related tips or requirements.

Shipping itself is very stressful, so begin by bringing plenty of water from home and enough familiar hay and favorite treats to last the trip. Plan adequate rest stops or layovers at horse-friendly digs on your drive to the Sunshine State, keeping in mind that COVID restrictions may impact your usual route and stops. Unload your horse and allow him to stretch his legs as much as is safely possible. Remember the stall toys! And consider packing a supply of probiotic paste to help replenish and maintain healthy gut flora during your horse’s journey. A good omeprazole paste (a common ulcer preventative) is also handy to have on the road.

Once on the show grounds, you’ll want to set up a routine that’s as close as possible to your horse’s routine at home. Consider using your smartphone’s alarm/notification features to remind you of feeding, medication, exercise and blanket-check times.

In situations like those at Wellington, where turnout space is often minimal and turnout time even more so, you will need to get creative to ensure your horse’s physical and mental relaxation. Think porta-pens, morning hacks away from the ring, plenty of hand-grazing and again, those all-important stall toys! Locating your horse near an equine buddy can help, just as locating him near a bully can hurt. Also try things like tuning your barn radio to a classical music station (but keeping the volume down).

Stay aware, too, of temperature changes. Even in sunny Florida, a sudden chill without a sheet or blanket can upset your horse’s system. (You did remember to pack all his clothes, right?)

Feed for Success

Diet is the single most important factor when it comes to managing gut health. It bears repeating that good quality forage should always come first and often, whether it’s in the form of pellets, cubes, hay or fresh grass. This is the best way to simulate a horse’s natural 24/7 eating pattern, for which his system is uniquely designed after eons of grazing at will.

Whenever your horse is stall bound, this pattern is obviously disrupted. During the circuit, of course, he’s giving you his all in the ring. But resist the temptation to pile on the grain. It’s true that a horse needs to eat continuously in order to produce saliva, which helps neutralize potentially damaging stomach acids. However, less saliva is actually produced when chewing grain than when chewing forage. Worse yet, the starch in grain can ferment, leading to the creation of volatile fatty acids that can trigger exactly what you’re hoping to avoid: gastrointestinal distress.

For these reasons, experts recommend a diet that emphasizes fiber and fats over carbohydrates and starches. For a GI-friendly regimen, you’ll want to divide your horse’s concentrates (those commercial feeds and cereal grains) into three or more smaller meals. Adding alfalfa, with its higher levels of acid-buffering calcium, might be an option. Also consider using a slow-feeder device for your horse’s hay.

By the way, did you know that you should never train (or worse yet, compete) a horse on a completely empty stomach? However, that doesn’t mean feeding a full meal prior to your next class. Simply ensure that he has at least a little hay in his belly to keep those stomach acids busy in a productive (rather than a destructive) way. Without something to digest, churning acids can wreak havoc on the stomach lining.

Then there is the matter of dietary supplements. Whenever you’re away for an extended period, your horse may be getting types of feed and hay to which he is not normally accustomed—another potential GI issue. This is the perfect time to consider adding a supplement designed specifically to promote gut health. Look for one that is high in fiber and low in sugars and starches. Ideally it should include certain vitamins (like E) and minerals (like naturally derived calcium and magnesium) that help buffer acids and support optimal gastric health at a stomach-friendly pH level.

Last but not least, consider backing off any equine medications with known gastric effects. The most common culprits include nonsteroidal anti-inflammatory drugs (NSAIDs) such as phenylbutazone, especially if administered in large doses or over a long period of time. Antibiotics, too, can throw a horse’s GI system out of whack if not countered with prebiotics and probiotics.

Watch for the Signs

As the weeks go by and the ribbons and trophies start to pile up, enjoy the rewards of your hard work! But resolve not to get complacent about your horse’s gut health. If he suddenly starts pinning his ears, for example, or getting uncharacteristically girthy, a little detective work and a chat with your vet might be in order.

Other signs to watch for are teeth-grinding, weaving, cribbing, stall walking and excessive sweating, not to mention an interruption in normal manure production. Has your horse’s performance seemed lackluster lately, or has he gotten fussy about his feed? Both signs of potential problems. And then there are those quiet souls who might not exhibit any signs of stress, but who internalize everything until their coats lose their bloom or they start to lose weight. What you’re looking for are symptoms of developing ulcers or impending colic; anything out of the ordinary bears investigation.

Well-orchestrated teamwork is critical during this time. Make sure you have a local vet’s number on speed dial, and post it prominently in your barn. Also urge your stable manager, groom, farrier, equine massage therapist and braider to look out for any signs of discomfort when working on your horse.

Finally, once these plans are in place, take a deep breath and rest assured that you’ve done the best you can to promote your horse’s wellbeing during this exciting yet challenging season. And good luck!

Sponsored by: 

Q: How can I keep my senior sporthorse healthy? How should I organize a fitness program with the goal of keeping him fit and interested?

A: The first step in maintaining the health of a senior horse is recognizing when your horse has reached senior status. This can be tricky since the definition is not simply based on age. Rather, horse owners and veterinarians must watch for the physical signs of aging and declines in body system function.

Manage His Diet

One of the first facets of a horse’s care that needs to be adapted for his age is diet. Through a combination of loss of dental integrity and the natural aging of the intestines, older horses lose their digestive efficiency. They can’t absorb the nutrition released from the food they eat when it is processed in the colon, and if there is dental disease, they may not be able to properly chew the forage and begin the digestion process in the first place. As a result, aged horses have a higher daily protein requirement of 12 to 14 percent. This is especially important for aging athletes and supplementation with the specific amino acids lysine and threonine can help optimize muscle recovery. High-quality forage is important and a hay analysis can help determine whether you are choosing an appropriate product. As always, free choice water and salt is important.

If a horse is not able to chew his hay properly, then replacing the fiber through forage alternatives is a good option. These can include complete feeds, chopped forage, hay cubes and beet pulp. The commercially available senior concentrate formulations take these concerns into account and offer horse owners a streamlined alternative that includes readily digestible fiber, added fat and reduced sugar. Senior foods are typically available in pelleted or extruded formulations to make them more easily digested compared to textured formulations, which contain whole grains that require the gut to work harder to break down and absorb nutrients.

There are additional supplement recommendations to consider for senior athletes. A probiotic formula that includes prebiotic ingredients will optimize the health of the bacteria that live in the horse’s hindgut. Antioxidants like vitamin E and vitamin C support the immune system, which naturally declines with age. Omega-3 fatty acids can reduce inflammation and support a healthy weight in seniors who are prone to leanness when working hard. Lastly, include a joint supplement that contains ingredients such as glucosamine sulfate and avocado unsaponifiables, which can support joint health in any aged athlete.

Be Proactive

Another way to keep your senior competition horse healthy is to proactively screen for diseases that can undermine his well-being. A baseline cardiovascular workup can be lifesaving for a mature athlete, especially an event horse, for whom the risk of sudden death on cross country significantly increases after 15 years of age. Routine blood tests can identify a decline in kidney or liver function, the organ systems more commonly affected in old age. Long-term use of non-steroidal medications can also affect these body systems, and since many older athletes receive anti-inflammatory medications to support soundness and comfort, monitoring for changes once or twice a year becomes especially important. Endocrine diseases such as pituitary pars intermedia dysfunction (PPID or Equine Cushing’s disease) are more prevalent in senior horses. Recognizing and initiating appropriate treatment early on can help avoid costly injury since the resulting hormone dysregulation from PPID exposes older athletes to weakness in their tendons and ligaments and reduces injury recovery. Daily medication can help normalize the hormone imbalances and prevent career-ending complications like laminitis. But, it should be noted that the most commonly prescribed medication for PPID, pergolide, is not permissible in FEI competition and requires a veterinarian-endorsed therapeutic use exemption to show in USEF competitions.

Regular soundness exams become even more important for the senior athlete. Recovery from intense athletic activity can take longer, and the joints and soft tissues are naturally more at risk for injury and inflammation due to accumulated wear and tear. Managing joint pain due to osteoarthritis with targeted treatment directly into the joint is more successful now with the development of therapies that can be made from a horse’s own blood (regenerative medicine). These biologic-based products can safely extend the careers of senior horses when corticosteroid injections into arthritic joints has become less effective or is riskier due to coexisting endocrine disease. Older athletes are more prone to soft-tissue injuries, and routine ultrasound imaging is a useful tool to monitor the integrity of tendons and ligaments.

Consider Your Training

A low-intensity warm up with lots of walking can ease stiffness and supple the joints. When possible, perform this type of work outside the ring to reduce boredom. Before competition, a shorter warm up can avoid sending a fatigued horse into the ring. Older horses benefit the same as younger horses from alternating intense days with lighter days to allow recovery.

With the help of proper nutrition and attentive veterinary care, we are now able to keep our senior horses performing better than ever into their later teenage years. Although it might be necessary for an owner to gradually transition her equine partner away from the more rigorous aspects of training, there can still be many more happy and productive years ahead of a senior horse. The key is to keep a watchful eye for hints that your athletic partner is aging, and provide age-appropriate support to go that extra distance.

Christina “Cricket” Russillo, DVM, graduated from the Tufts University School of Veterinary Medicine in 2001. After completing a large animal medicine and surgery internship at Texas A&M, she realized her desire was to work on elite sporthorses. Following 13 years of practice at Fairfield Equine Associates in Newtown, Connecticut, focused on high-level show-jumping and dressage horses, she joined Virginia Equine Imaging in 2015. Russillo relocates to Florida every winter to support her clients and patients. She has competed through Third Level in dressage and in February 2017 she was appointed the U.S. Dressage Team veterinarian. She is also a certified member of the International Society of Equine Locomotor Pathology. 

This column has not been approved or endorsed by U.S. Equestrian.

This column originally appeared in the Spring 2020 issue of Practical Horseman.

Thanks to improvements in veterinary care, nutrition and management, horses today live longer than ever. Your favorite equine might easily celebrate birthdays into his 20s or even 30s. Still, most horses start showing some signs of aging in their mid to late teens. And, unfortunately, some studies report that 70 percent of horses 20 years old or older have some type of health problem requiring veterinary care or changes in management.

Maybe that’s not surprising, since a 15-year-old horse is roughly equivalent to a 50-year-old human. At age 20, your horse is like a 60-year-old and at 25, like a 70-year-old.

But senior horse health problems don’t have to mean the end of your horse’s happy days. The key is early detection, says Lisa Kivett, DVM, MS, DACVIM, of Foundation Equine Clinic in Southern Pines, North Carolina. “When we can identify a problem very early, when it’s just getting started, it’s usually fairly easy and inexpensive to treat,” she says. “This also keeps the horse from experiencing pain or discomfort since we’re able to tackle his issue before he really knows he has one.”

With that in mind, Dr. Kivett and Jaime Lehfeldt, DVM, cVMA, CVMMP, DACVIM, of Montana Equine in Billings, Montana, provide a head-to-hoof look at some key issues your older horse might face—plus some tips to help you keep your horse feeling comfortable during those senior years.

Teeth/Dental

“Dental problems are one of the most widely recognized complications of aging in a horse,” says Dr. Kivett. “Though modern horse management and advances in veterinary medicine have dramatically increased a horse’s projected life span, the teeth often wear out before a domestic horse reaches the end of his natural life.”

As a horse ages, teeth not only become worn, but can also fall out or develop sharp points on the outside of the upper cheek teeth and inside of the lower teeth, simply from normal chewing, adds Dr. Lehfeldt. The horse may develop sensitivity due to wear and exposure of the roots of the teeth. Other dental issues that may develop later in life, she says, include “improper alignment of the jaw and teeth, arthritis in the temporomandibular joint [TMJ], which is the joint that makes the jaw move, and ulcerations and abscessed teeth.”

Dr. Kivett adds that horses, like humans, can even get cavities, tartar and gingivitis. “The older a horse, the more likely it is that he will be suffering from one of these dental diseases and they’re often quite painful,” she says. Unfortunately, many owners discount the possibility of dental problems if their horses haven’t lost weight and appear to be eating normally. “This is problematic since horses frequently don’t show any outward signs of a dental problem until there is severe pain and major problems,” she says.

What you can do: Keep up on regular dental exams—every six months is the typical recommendation for older horses. This can help your vet spot trouble early. Also be prepared to call the vet between exams if your horse loses weight, has difficulty chewing, chokes, routinely drops food while eating or has long fibers or grain in his manure—all signs of potential dental issues.

Eyes

While age-related eye problems aren’t as common in horses as in other species, older equines are still more prone to difficulties than younger ones.

“They can develop cataracts and problems with the retina and other structures in the back of the eye,” says Dr. Kivett. On the bright side, Dr. Lehfeldt notes that cataracts “rarely result in complete cloudiness of the lens” and horses can typically compensate well for changes in vision.

Older horses are commonly affected with equine recurrent uveitis, also known as moon blindness. In this disease, the body’s immune system attacks its own tissues—in this case, the tissues of the eye. Over time, this can lead to scarring, cataracts, pain and even blindness.

What you can do: Watch for any changes in the appearance of your horse’s eyes, such as tearing, squinting or alterations in the color of the cornea. “If the eye appears cloudy, has a bluish tint anywhere, has a spot on it or is otherwise different from its normal appearance, have it seen by a vet,” says Dr. Kivett. “Recognizing symptoms of eye problems quickly can lead to faster diagnosis and treatment, which reduces the risk for permanent damage.”

Once a horse has uveitis, treatment is aimed at decreasing inflammation, controlling pain and minimizing further damage to hopefully delay blindness.

Endocrine System

The endocrine system involves the glands that make and secrete hormones. Endocrine diseases rank alongside dental problems as a leading cause of senior horse health trouble—and the most often overlooked in the early stages, says Dr. Kivett. Probably the most common of these diseases is pituitary pars intermedia dysfunction (PPID), also known as Cushing’s Disease.

PPID results from a benign tumor in the pituitary gland at the base of the brain, leading to a reduction in dopamine production. PPID can affect many hormones and thus create “a plethora of clinical signs, such as weight loss, chronic recurring infections, lethargy, diarrhea, foot abscesses, laminitis and overall malaise,” says Dr. Lehfeldt.

Many horse owners are skeptical that their horse could have PPID if he doesn’t exhibit the disease’s characteristic long, curly hair coat, says Dr. Kivett. “Unfortunately, by the time a senior horse has this coat, his condition is often so out of control that it’s very difficult to regulate with medication,” she adds.

Dr. Lehfeldt agrees, noting, “I will have horse owners state that their old horse isn’t acting the same anymore, and they chalk it up to just ‘being older,’ when in fact it could be PPID, which is manageable, especially when identified early in the course of the disease process.”

What you can do: Your best offense is spotting the early signs of PPID. These include “changes in body weight or loss of topline, a slight bulging appearance to the eyes—which is a result of fat being deposited behind the eyes—recurrent skin infections or hoof abscesses, or changes in exercise tolerance or sweating patterns,” says Dr. Kivett. In addition, your horse may exhibit lethargy, decreased athleticism and fatty deposits on the crest of the neck and tail head. Your vet can run blood tests to look for changes in the horse’s hormone levels.

Unfortunately, there’s no cure for PPID, but it can be managed with pergolide, a medication originally used for human patients with Parkinson’s disease. “The medication can help reduce the size of the pituitary gland and therefore affect the hormones produced by the gland,” explains Dr. Lehfeldt. It can improve the horse’s symptoms and quality of life, although it must be given for the rest of the horse’s life.

Dr. Lehfeldt notes that other management strategies may come into play depending on the horse’s clinical signs. “For example, a horse that has foundered should have lower sugars in his diet and may have restricted intake if he is obese,” she says. “A thin horse will need a more calorically dense feed with smaller fiber size to digest it more efficiently to aid in weight gain.”

Back/Spine

A swayback is a classic old-horse stereotype. While the abnormal hollowing may have a genetic component or may develop due to conformation, pregnancy and strain, age can certainly be a contributing factor. In addition, a general loss of topline muscling—even if it doesn’t lead to a swayback—is often seen in older horses, says Dr. Kivett.

“[It] can be related to metabolic disease like PPID that weakens the tendons and ligaments. It can also be due to decreasing fitness and exercise intensity if an older horse isn’t being worked as consistently as he was when he was younger,” she explains.

Arthritis—a common older-horse concern—can also affect the vertebrae of the horse’s spine.

What you can do: “Regular exercise, including working over poles, can help maintain a horse with a swayback or one with spinal injuries,” says Dr. Lehfeldt. “Modalities such as acupuncture and spinal manipulation [chiropractic] can be very helpful to maintain motion in the musculoskeletal system, reducing the formation of arthritis and making [the horse] more comfortable.”

Digestive System, Nutrition, Weight

Gut health, nutrition and weight are, not surprisingly, intertwined. All can cause health concerns for senior horses and may be related to other older-horse health issues. For instance, seniors may be at higher risk for impaction colic, says Dr. Lehfeldt. This can be due to dental trouble that makes chewing difficult, leading to longer food fibers reaching the large colon, where they can become impacted. Another cause, she adds, could be decreased gut motility if a horse isn’t moving as much due to arthritis, injury or other discomfort.

Poor gut health can also contribute to weight loss, a common occurrence in older horses. “Some will become less efficient at absorbing nutrients from the gastrointestinal tract and may not be able to utilize the nutrients the same due to underlying illnesses,” says Dr. Lehfeldt. In fact, some research shows that horses age 20 and older are less able to digest protein, fiber and some minerals than younger horses.

Other underlying causes of weight loss can include dental problems, parasites, chronic pain leading to decreased appetite and inflammatory bowel disease.

On the other hand, says Dr. Kivett, some older horses will suddenly become “’air ferns’ and gain weight despite being on a diet.” This could be caused by a metabolic disease or simply be a result of less activity. It’s a concern because an overweight horse adds more stress to feet, muscles and joints that may already be worn from years of use.

What you can do: Switching feeds may make it easier for your horse to chew, digest and absorb his food, helping to minimize colic risk and weight loss. For instance, you can switch from regular hay to forage that’s chopped, cubed or in pellet form, and grain that’s rolled, crimped, extruded, pelleted or flaked.

Complete senior equine feeds are typically designed with these formulations in mind. In addition, while they should contain enough fiber to keep the digestive tract working, they may provide energy more from carbohydrates and fat than from fiber.

You may also find that it helps to increase your horse’s total feed intake, but to provide it through more frequent and smaller meals throughout the day. If your horse’s teeth are extremely worn, you might consider wet food, such as mashes. This also helps ensure that your horse takes in enough water, as thirst perception can sometimes wane in senior equines, leading to dehydration concerns.

Joints

Lameness is the most common problem of older horses and often among the first signs of aging. Arthritis is frequently the underlying cause of the unsoundness. “It is often simply the result of wear and tear over time. Any horse that lives and works long enough will inevitably develop some arthritis,” says Dr. Kivett. Arthritis, of course, can lead to pain, stiffness, reduced range of motion and lowered performance ability.

What you can do: “Looking for the signs of stiffness and soreness after work or when [the horse is] not worked regularly is important,” says Dr. Lehfeldt. Acupuncture and chiropractic work may help prevent arthritis or reduce discomfort for an already arthritic horse, she adds.

Joint supplements also abound, offering the possibility of pain management. “Every individual is different with how he responds to these products because of the variation in absorption from the gastrointestinal tract,” says Dr. Lehfeldt. “More direct products, such as Adequan[polysulfated glycosaminoglycan], Legend [hyaluronate sodium] and intra-articular injections are also available for treating arthritis.”

Feet/Hooves

Metabolic conditions such as PPID can predispose your horse to laminitis and increase the risk of recurrent hoof abscesses, say Drs. Lehfeldt and Kivett.

What you can do: Keep an eye out for early signs of PPID so you have a better opportunity to manage the disease and its repercussions. In addition, keep up with regular farrier visits. “When horses get older, they still require foot care,” reminds Dr. Lehfeldt. “Due to arthritis that may have developed over time and with an athletic career, taking care of their feet is critical for comfort. The saying, ‘No hoof, no horse’ applies at any age.”

Also, if your horse shows signs of weakening hoof walls (such as cracking, chipping or flares), talk with your veterinarian or farrier about causes and solutions, including the potential benefits of a biotin feed supplement.

Read the Signs

Age is just a number and simply because your horse turns 15, 20 or even 25, doesn’t automatically mean he’s old. Instead of relying on the calendar, watch for these telltale signs that indicate it’s time to start thinking of and treating your horse as a senior citizen.

• Graying hair, particularly around the eyes and muzzle

• Deepening hollows above the eyes

• Slackening or drooping of the lower lip

• Elongation of incisors

• Difficulty eating

• Weight loss (or, less commonly, weight gain)

• Poor coat condition and/or delayed shedding

• Loss of muscle tone, particularly over the topline

• Loss of ligament and tendon strength, which could lead to lower, more sloping pasterns

• General stiffness and reduced overall flexibility

• Reduced energy level

Exercise Tolerance

As the experts noted, typically with age comes arthritis—and that can mean your horse isn’t able to perform as he did in his younger years. Additional problems, such as other lameness issues, weight loss or breathing trouble can force a horse into decreased use or retirement, says Dr. Kivett.

When and whether you’re forced to scale back on exercise depends on your horse because every equine ages differently. “Some won’t be able to do everything they did as a younger horse, whereas others will be able to go strong until the day they die,” says Dr. Lehfeldt.

What you can do: “Let your horse tell you what he can handle as far as workload goes,” says Dr. Lehfeldt. If the regular workload gets harder, then cut back on intensity or duration. As a general rule, try to keep at least some exercise in your horse’s routine.

“I am a huge proponent of exercise for older horses,” adds Dr. Kivett. “If a horse is sound enough and healthy enough to continue some form of exercise—and most are, even it’s just at a walk—frequent, low-intensity exercise is the best thing an owner or rider can do for an older horse.” It can help maintain tendon, ligament and muscle strength, keep blood flowing to the feet and help increase insulin sensitivity. “Older horses who stay active are proven to be more sound and often just seem happier by keeping a routine,” she notes.

Routine Matters

“I often hear horse owners say, ‘My [senior] horse doesn’t need any more vaccines. He’s had enough in his life,’” says Dr. Kivett. “This is completely wrong!” In fact, she adds, keeping up with a regular vaccination routine is even more important for older horses, who have decreased immune function and decreased immune response to vaccinations. That leaves them more susceptible than younger horses “to the diseases that we vaccinate against, like influenza, West Nile virus and eastern equine encephalitis,” she says.

Some owners also have told her they’re less worried about vaccinating because if their horse gets one of the diseases, they’ll have the horse euthanized. “But dying of eastern equine encephalitis is a horrible way to go for a horse,” cautions Dr. Kivett. “And an emergency call and humane euthanasia will cost more than several years’ worth of vaccines.”

Likewise, plan to maintain your older equine on a good deworming program. “The declining immune system of an older horse may leave him more susceptible to parasitism,” explains Dr. Kivett. “It isn’t uncommon for us to see a horse that has routinely had negative fecal egg counts suddenly begin to shed high numbers of parasite eggs.” 

Age and Reproductive Ability

Both mares and stallions can remain reproductively sound well into their senior years—with some caveats. For instance, mare fertility typically starts to decline around age 15 and decreases with every passing year. Older maiden mares, in particular, will be harder to get in foal. In general, you may need to breed your mare during more heat cycles to get a confirmed pregnancy. Pregnancy loss also increases with age.

For stallions, arthritis that prevents them from mounting a mare (or a breeding dummy) is a top factor limiting longevity in the breeding shed. However, semen production can also fall off with age. Owners of senior stallions will probably need to begin limiting their books, particularly for live covers.

If you’re thinking of breeding an older horse, be sure to have your veterinarian or an equine reproductive specialist evaluate him or her for any obvious issues. And talk with her about potential management strategies that could increase your chances of putting healthy foals on the ground.

What About Cancer?

While cancer can strike at any age, and horses are less affected than many other species, the risk does increase with age. “Gray horses are particularly prone to developing melanoma as they age and horses with pink skin (especially of the eyelids, lips and genitals) are prone to squamous cell carcinoma,” says Dr. Kivett.

If you see any “areas of irregular skin or masses, call your veterinarian,” says Dr. Lehfeldt. “One of the benefits to having yearly health exams done by a veterinarian is to ensure these are identified early in the course so they can be treated sooner versus later.”

Benign but Serious: Strangulating Lipoma

While not cancerous, Drs. Kivett and Lehfeldt note that older horses can be at higher risk for another type of tumor—a condition called a strangulating lipoma. While the lipoma itself is a benign fatty tumor, it can develop a stalk or stem that wraps around part of the horse’s intestine, cutting off blood flow and leading to severe colic, explains Dr. Lehfeldt. Unfortunately, there is no way to detect this tumor early and it usually isn’t discovered until the horse is in colic surgery.

Preparation Is Key

Ultimately, every horse, like every human, will age and most will experience health challenges in the process. By understanding common issues and knowing what you can do to prevent, treat or manage them, you can put the odds in your horse’s favor for a longer, healthier, happier life. 

This article was originally published in the February 2018 issue of Practical Horseman.