As you can imagine, swelling in the jaw or throat region can influence how a horse accepts the bridle. When a swollen area is under compression or load, such as when we ask the horse to come onto the bit, we can experience all kinds of resistance, ranging from slightly stronger or weaker pressure on the bit to severe, adverse behaviors such as rearing, headshaking and pulling on the reins.

In all cases of a sudden change in contact, it is a good idea to carefully inspect the jaw and throat region. Ask your veterinarian for assistance and advice when you notice abnormalities or you run into clear contact or connection problems. The anatomy of the head, neck and jaw is complex, and with many different structures found in this region, it is important to determine, if possible, which specific structures are associated with the swelling. Lumps and bumps may result from direct trauma, indicate inflammation or may develop from the accumulation of tissue in a more chronic process. 

Evaluation of any bump begins with physically examining the area to determine the exact location and to check for wounds, skin irritation, heat or sensitivity. Palpation of the lump to determine its characteristics may help identify which tissues are involved. For example, bone will be hard. Additional diagnostic procedures, including radiographs (X-rays), ultrasound, endoscopy or even biopsy, may be necessary to get a complete clinical picture. 

While we can’t go over every cause for lumps under the jaw here, we can review the most common sources. These include swollen lymph nodes, reactive salivary glands and dental matters. 

Lymph Nodes

Horses have two major sets of lymph nodes located near the jaw: the submandibular lymph nodes, found between the mandibles (lower jawbones), and the retropharyngeal lymph nodes, situated near the throat. Lymph nodes are a part of the immune system and they become enlarged when they react to an ongoing process.

Localized infections, such as an abscessed tooth, are likely to result in enlargement of a single lymph node close to the site of infection. In contrast, respiratory illness may result in swelling of one or more nodes. Many viral infections will cause mild lymph-node enlargement that resolves in one to two weeks with no special treatment.

Streptococcus equi, also known as “strangles,” is a bacterial infection that can result in severe enlargement of the retropharyngeal lymph nodes. This type of swelling may be seen and felt just behind the mandible. 

Horses with strangles will run a fever and may develop thick nasal discharge. In some cases, the affected lymph nodes may become so enlarged that they put pressure on the horse’s airway.

Reactive Salivary Glands

Swelling of the salivary glands is commonly seen in horses turned out to pasture in the spring. The parotid glands are the largest salivary glands and are found on both sides of the head, extending from the jaw to the base of the ear. 

These glands produce saliva, and affected horses may drool excessively. A toxin produced by a fungus on clover is believed to be at the root of this reaction. This condition is usually not painful, but swelling may be significant enough to prevent the horse from flexing well at the poll. 

Simply avoiding pasture turnout for a few weeks usually remedies the problem. Rarely, the salivary glands become infected or develop blockages that can also result in swellings. You should seek advice if swellings in this area come up at other times of year or don’t resolve quickly.

Dental Matters

Teething bumps, or eruption cysts, are hard enlargements seen along the jawline in horses younger than 5 years of age. The bumps are caused by changes in the bone as the permanent premolar and molar teeth emerge and displace the deciduous, or “baby,” teeth. 

Several such swellings can usually be felt at the same time and are equal in size. They should not be painful or hot. Occasionally bumps may also be noted along the bridge of the nose as a similar process can occur with the upper teeth. In general, teething bumps are strictly cosmetic and should spontaneously resolve as the horse matures. 

Occasionally, teething bumps are an indication of problems in shedding of the deciduous teeth, commonly known as “retained caps.” An oral exam by a veterinarian or veterinary dentist can be helpful to determine if more significant dental problems exist.

Other causes of lumps near the jaw include local trauma resulting in soft- tissue injury and even fractures, insect bites and, very rarely, tumors. 

You should consult with your veterinarian about any new swelling that persists for more than a few days or any lumps that are enlarging, painful or located in areas that interfere with your tack or riding.

About Kimberly Johnston, VMD, Dipl. ACVS 

Kimberly Johnston, VMD, Dipl. ACVS, graduated from the University of Pennsylvania and New Bolton Center. She became a diplomate of the American College of Veterinary Surgeons in 2010, specializing in sports medicine and orthopedic surgery. In her free time, she enjoys riding her 14-year-old Thoroughbred, Jazz, schooling Third Level. She and her FEI-dressage-riding husband, Rob van Wessum, DVM, operate Equine All-Sports Medicine Center in Mason, Michigan. 

“Football players tear up their knees—it’s what they do. Hunters, jumpers and equitation horses are also athletes and they will get athletic injuries,” says Elizabeth Davidson, DVM, who focuses on equine sports medicine at the University of Pennsylvania’s New Bolton Center. In this article, Davidson explains how some common injuries happen, how they’re treated and how they could affect your horse’s career.

Any horse can get hurt at any time, of course. But hunter, jumper and hunt-seat equitation disciplines include demands that set horses up for certain injuries.

• Jumping stresses tendons and ligaments that support the leg during both push-off and landing. The impact of landing can also damage structures in the front feet. The bigger the jump, the bigger the stress.

• Speed increases the stress of jumping, so risks are higher for jumpers who are against the clock. Tight turns also raise the odds of a misstep that could lead to injury.

• Repetitive stress takes a toll. Many horses in these sports show year-round—and when they’re not showing, they’re schooling. “With repetitive stress, minor damage can build up in ligaments or other structures,” Davidson explains. “Then something tips it over the edge.”

What’s most likely to bench your horse? Hard statistics on injury rates in hunters, jumpers and equitation horses are limited, Davidson notes. “At any horse show you’ll see horses of different ages and breeds in different training programs and with riders at different skill levels. The variables make research difficult,” she says. Still, at a large referral clinic like New Bolton Center, many horses in these sports come in with problems in three areas that we’ll discuss below.

Suspensory Ligament Tears

The suspensory ligament acts like a sling, supporting the ankle joint as it sinks under weight and helping the joint return to normal when the weight is removed. Tucked behind the cannon bone, this ligament starts just below the knee (or hock), splits into two branches that pass around the back of the ankle and ends on the front of the long pastern bone below.

What happens: If the strain is too great, the tough fibers that make up the ligament may tear. “This is an area that undergoes repetitive stress, so it’s a common site for athletic injury,” Davidson says. “In horses that jump, both front and hind injuries occur.” Although fibers can tear at any point on the ligament, proximal (high) injuries are common. The injury may be mild with just a few torn fibers, but in severe cases, the ligament may rupture or even fracture bone as it tears away.

What you see: “Your horse may suddenly be lame, but usually damage has been building up as a result of recurring stress,” Davidson notes. “Identifying the problem as early as possible, before severe injury, gives the horse the best chance of recovery.” Early detection isn’t easy with high suspensory injuries, though. A horse with a mild injury may be barely off and because the top of the ligament is hidden under other structures, you won’t find heat, swelling or sensitivity at the site.

What to do: Your veterinarian can find the problem with local nerve blocks and a hands-on exam. An ultrasound scan will show the exact site and degree of injury to the ligament, and X-rays can show if bone is damaged. Magnetic resonance imaging (MRI) can also identify damage to the ligament. “MRI is often helpful in hind-limb suspensory injuries, when ultrasound can be difficult to interpret,” Davidson says.

Every case is different, so your vet will help you work out a treatment plan that suits your horse’s injury. Treatment usually includes these steps:

• Cool down. To reduce inflammation, your vet may prescribe cold therapy (icing or cold-hosing several times a day) and a nonsteroidal anti-inflammatory drug, such as phenylbutazone or Banamine® (flunixin meglumine).

• Stall rest to let healing begin. Your vet may advise standing wraps for the injured leg and the opposing leg.

• Hand-walking. Once inflammation is down, controlled walking encourages proper healing. Follow your veterinarian’s advice, starting with as little as 10 minutes a day and gradually increasing the time.

• Gradual return to exercise. Working closely with your vet, set up a program that eases your horse back into work over several months, using ultrasound exams to monitor the ligament and adjust the program as needed.

Your vet may suggest other therapies, such as shockwave treatments. Stem cells or platelet-rich plasma can be injected at the injury site with the goal of improving healing. Research into these new regenerative therapies is ongoing.

Surgery—neurectomy of the deep branch of the lateral plantar nerve and fasciotomy—is an option for hind-limb proximal suspensory injuries that are reluctant to heal, Davidson says. In the hind limb, a band of connective tissue traps the top of the ligament in a sort of compartment and swelling within the compartment causes chronic pain. The surgeon cuts the connective tissue (fasciotomy) and the deep branch of the lateral plantar nerve (neurectomy), relieving pressure and pain. This nerve branch serves only the top of the suspensory, so the operation doesn’t otherwise affect the horse. Your veterinarian can help decide if surgery might be the best option for your horse’s case.

What to expect: Ligaments heal slowly—anywhere from two to 12 months, depending on the location and extent of the damage. The process can’t be rushed. Re-injury is a risk even after healing because scar tissue that forms isn’t quite as strong as the original ligament tissue.

“Front proximal suspensory ligament injuries tend to heal well with treatment, but hind injuries often don’t respond so well,” Davidson says. “With conservative treatment only, less than 20 percent of horses with hind proximal suspensory ligament injuries return to previous levels. Surgery greatly improves the odds.” Keep in mind, though, that current rules bar horses from FEI competition after any neurectomy.

Sore Feet

The front feet take the brunt of landing after a jump and structures in the hoof capsule work together to handle the shock. The coffin joint—the meeting point of the small pastern bone, the navicular bone in the heel and the coffin bone in the toe—disperses the force. Ligaments that lash the joint together stretch then spring back. So does the deep digital flexor tendon (DDFT), which runs behind the joint and helps support the navicular bone.

What happens: The feet are designed to handle great forces, but jumping fence after fence takes a toll. Common problems include:

• Strains and tears in the DDFT or the ligaments in the foot

• Inflammation in the coffin joint or in the navicular bursa, a fluid-filled sac that helps cushion the navicular bone from the pressure of the DDFT

• Deep bone bruising, which can appear in any of the foot bones

• Inflammation and degeneration of the navicular bone

“Sometimes there are multiple problems,” Davidson says. “Again, these are injuries that occur through wear and tear—damage builds up until it hits the tipping point.”

What you see: “Because the injured structures are hidden by the hoof capsule, you don’t see swelling or other signs,” Davidson explains. “Often these problems are bilateral, involving both front feet, so the horse may not be obviously lame. He may begin to move with shorter strides, but the gait is still symmetrical.” Or the horse may be lame and improve with rest, but be sore again when he goes back to work. He may rest a front foot or shift weight from one foot to the other when standing.

What to do: A lameness exam and diagnostic nerve blocks will help the vet determine the general site of soreness. Often it’s in the heel, or caudal, region, where several key structures come together. But to treat the problem, you need to know which structures are injured.

X-rays can reveal bone damage, but they won’t show soft-tissue injuries. Ultrasound is great for imaging soft tissues in the leg, but it’s hard to get a clear ultrasound image in the hoof capsule. The best tool, Davidson says, is MRI. “With MRI we are able to look inside the hoof capsule and sort out these problems much better than in the past,” she notes. The results will help your veterinarian target treatment to fit the injury.

• A tendon or ligament injury needs a long period of rest, six months to a year. You’ll follow more or less the same program as you would with a suspensory injury with stall rest followed by a gradual return to work. The vet may recommend directed injections of platelet-rich plasma or stem cells.

• Inflammation in the coffin joint or the navicular bursa may respond to directed injections of corticosteroids, which are powerful anti-inflammatories, and hyaluronic acid, which is a natural component of cartilage and joint fluid.

• A bone bruise needs rest. This injury isn’t as serious as a fracture, but there is microscopic damage to the bone and fluid builds up within it. Healing can take three or four months depending on the degree of bruising.

• When the navicular bone is chronically inflamed, it responds by remodeling, losing mineral content in some areas and developing lumps of new growth in others. This pattern of inflammation and degeneration is often called navicular disease, and it doesn’t heal with rest.

What to expect: A horse with a mild injury has the best chance of recovery, but Davidson notes that rehabilitation can be challenging. “In sporthorses, significant pathology in the foot doesn’t have a good outlook. When the horse goes back to work, he stresses the same structures—so reinjury is likely,” she says.

Good trimming and shoeing are essential to keep the horse comfortable, regardless of what structures are involved. It’s important to keep the hoof trimmed at the correct angle, so the bones are properly aligned and the foot breaks over easily. Wedge pads or bar shoes can help take pressure off the heels. When problems persist, though, the horse may have to switch to a lighter work program.

Joint Problems

Elite horses are especially prone to joint problems. “Jumping a lot of big jumps—and jumping every weekend—stresses joints and eventually triggers degenerative joint disease (DJD),” Davidson says. Common sites include the hocks and ankles, but DJD can develop in any joint that comes under stress when the horse works.

What happens: Chronic inflammation in the joint from injury or simple wear and tear sets off a destructive chain of events. The viscous fluid that fills the joint becomes thin and watery, so it doesn’t lubricate the cartilage that cushions the working surfaces so well. Under pressure, cartilage starts to wear away and the joint stiffens. There’s more concussion on the bones, which respond by remodeling. Lumps of new bone growth appear in the joint.

What you see: Joint problems often creep up gradually. At first your horse may be mildly sore or stiff or just seem less fluid or less forward, especially at the start of work. The soreness may improve with rest, but it returns. Over time it worsens and begins to affect his performance over jumps. You may find heat or swelling in the affected joint.

What to do: Your vet can perform a lameness exam and other tests to diagnose DJD. X-rays can show damage to bone and cartilage, but by the time this damage shows up the destructive process is well under way. Damage to the joint can’t be reversed, but you may be able to slow the progress of the disease by managing inflammation. Anti-inflammatory medications like phenylbutazone can help the horse weather a flare-up, but for long-term management there are other options.

Management Options

Regardless of which modalities an owner and veterinarian elect to use when approaching equine joint health, it’s important to approach DJD or osteoarthritis (OA) not just as a cartilage or even a joint issue but, rather, a “whole-horse disease.”

Non-Steroidal Anti-Inflammatory Drugs (NSAIDs): These ubiquitous drugs, such as phenylbutazone (Bute), help keep horses with inflamed joints comfortable and are widely used as part of the approved multimodal treatment approach to OA. In older horses who do little to no work, NSAIDs can help control comfort and maintain quality of life. In performance horses, however, experts agree that NSAIDs should not be the base of your treatment program.

“I think that NSAIDs can have a place in performance horse management,” says José M. García-López, VMD, Dipl. ACVS, ACVSMR, associate professor of large animal surgery at the University of Pennsylvania’s New Bolton Center. “These can safely be used at a low dose and while monitoring the overall health of the horse, either during conditioning or rehabilitation from an injury.”

Intra-Articular Therapies: In lieu of relying on NSAIDs to help maintain joint health, veterinarians often use intermittent intra-articular therapies to control joint discomfort in performance horses. In a recently published survey, 407 equine veterinarians provided information regarding some of the more popular therapies currently being used in performance horses. Based on that survey, corticosteroids—primarily triamcinolone and methylprednisolone—are still one of the first-line, intra-articular therapies. Practitioners frequently co-administer hyaluronic acid with those intra-articular corticosteroids.

Despite these tried-and-true articular therapies, Kyla Ortved, DVM, PhD, Dipl. ACVS, ACVSMR, assistant professor of large animal surgery at New Bolton Center, says the tides are changing.

“I think using orthobiologics early in the disease process is better because they are designed to prevent further damage and promote healing,” she said. “If I have a horse with lameness or pain attributable to a particular joint, I won’t hesitate to use orthobiologics in the early stages of disease. And I feel more comfortable using these before jumping to steroids as I think they are more protective of the cartilage.”

Other Intra-Articular Therapies: Another intra-articular product available for horses is Polyglycan®, which is essentially a synovial fluid replacement product. “I use Polyglycan®, which is made of a patented formulation of hyaluronic acid, chondroitin sulfate and N-acetyl-D-glucosamine, at the end of any elective arthroscopic procedure and also as my hyaluronic acid fluid replacement product of choice,” said García-López, citing a 2009 study out of Colorado State University that showed Polyglycan® to have the potential to have both symptom- and disease-modifying effects.

Polyacrylamide hydrogels are also available for horses with OA and gaining popularity. Polyacrylamide gels are synthetic products, not orthobiologics, injected into the joint to provide lubrication and shock-absorbing properties. In one study of a 2.5% polyacrylamide hydrogel product, researchers reported that 83% of treated horses were lame-free at four, six and 12 weeks following administration.

Despite study findings, García-López believes more unbiased research is needed on these products.

“There is subjective evidence that these gels can create fibrosis of the synovium and granulation tissue formation that, in turn, can affect the composition of the synovial fluid, which is the main source of nutrition to the cartilage in adult articulations,” he said. “This family of gels could be considered in end-stage cases of OA but maybe not in early or moderate cases of OA.”

Intramuscular Therapies: It’s important to keep in mind that OA management is multimodal, and intramuscular (IM) polysulfated glycosaminoglycan (Adequan®) is still recommended by veterinarians.

“I like to use Adequan® in performance horses,” Ortved said. “I generally recommend 500 milligrams IM every four days for seven treatments every six months or at time of injury.”

García-López agrees with Ortved, adding, “In horses that have either early signs of joint inflammation or OA without significant morphologic changes, I like to place them on a course of IM Adequan® for the one dose every four days for seven treatments. This has shown good objective evidence for helping restore the ‘steady state’ between production and destruction of cartilage components. Basically, it is quite helpful to keep what is good, good.”

Physical and Alternative Therapies: Many other therapies can help round out a performance horse’s joint management plan. “Physical therapy is a huge part of management and something we need more data on and help from specialists integrating into practice,” Ortved noted.

Examples of such physical therapies include postural exercises and exercises designed to improve coordination and proprioception, target muscle atrophy/weak muscles (potentially secondary to joint discomfort and disuse) and increase joint stability through conditioning. Additional therapies you might consider to help keep your performance horses’ joints comfortable include extracorporeal shock wave therapy (ESWT), laser and acupuncture/electroacupuncture.

Oral Joint Health Supplements: Many owners give their horses joint supplements, making these products one of the most popular types of equine supplement on the market. Of the studies performed in horses, evidence does support the use of some ingredients, such as (but not limited to), glucosamine hydrochloride, chondroitin sulfate and avocado-soybean unsaponifiables (ASU). Glucosamine is believed to play a role in the formation and repair of cartilage, chondroitin sulfate helps give cartilage its elasticity, and hyaluronan helps lubricate joints and form the matrix of articular cartilage. Some studies also suggest that ASU may reduce inflammation and protect cartilage.

But García-López cautions that data regarding the use of oral nutraceuticals in horses is lacking. “Nutraceuticals should not replace treatment with other products such as Adequan®, Legend®, Polyglycan® or intra-articular therapy, whether it is with an orthobiologic or corticosteroid,” he noted.

Nutraceuticals are not required to meet the same standard for Food and Drug Administration approval as drugs are, and so their efficacy has not been studied as extensively. However, equine and human research suggests that some of these substances have protective effects. Your veterinarian can help you decide what’s best for your horse.

Appropriate Conditioning: Adjusted work levels can help. Moderate exercise is good for joint health, but too much can trigger inflammation. Increase the horse’s turnout, give him longer warm-ups and let him be your guide in how much work you do. As long as he stays comfortable, you’re probably on the right track.

“Conditioning cannot be overlooked,” adds García-López. “Equine athletes have their entire weight, which biomechanically increases exponentially during exercise, transferred through one or two limbs at a time. They need to be properly conditioned in order for all musculoskeletal components, including muscle, tendon, ligament, bone and cartilage, to share the load adequately.”

No matter which strategies you and your veterinarian ultimately integrate into an athletic horse’s joint-health plan, as a team you must critically evaluate and reevaluate that plan regularly to make sure you’re optimizing each individual horse’s treatment to his particular needs, balancing equine ability with fragility.

Keep Him Sound

“Injuries happen because of what these horses do,” Davidson says. You can’t eliminate the risk entirely and you can’t stop the clock when it comes to aging. “Most of us have one horse and we invest a lot of time, energy and money in that horse,” she notes. “We ask horses to be athletes, but we forget sometimes that they can’t keep performing at the same level forever.”

Still, many factors that increase the risk of injuries are in your control. Take these steps to help your horse stay sound for many years to come:

• Don’t overtrain or overface him. Keep his work within his ability and be sure he’s in shape for what he’s asked to do. “Fitness—respiratory, cardiovascular, muscle, tendon, ligaments and bone fitness—helps avoid injuries,” Dr. Davidson says.

• Keep up with shoeing. Long toes and low heels put stress on the feet and on the joints, ligaments and tendons in the legs. Be sure feet are trimmed regularly so toes are kept short and use shoes with rolled toes to ease breakover if necessary.

• Use good sense on bad footing. If horses are sliding around in the ring, ask yourself: Is this class or this schooling session worth the risk?

• Stay alert for subtle trouble signs. Do a daily hands-on leg check, comparing opposite legs to detect heat, swelling or sensitivity. Watch for shortened strides and other markers of soreness. Give the horse a few days off if you suspect a problem. If the signs return when he goes back to work, ask the vet to check him out. A mild problem can blossom into a career-limiting condition if it’s ignored.

This article originally appeared in the June 2016 issue of Practical Horseman, but was updated in 2025.

These vital signs have a normal range for a healthy horse at rest. Unusual fluctuations in these values can be an indication of illness, infection or other problems. Being familiar with what’s normal for your horse can alert you to any potential issues and prompt you to contact your veterinarian to evaluate your horse’s health.  

To check your horse’s vital signs, you will need a thermometer and a watch or mobile phone to track time. A stethoscope is also a helpful tool to measure vital signs accurately. Follow the guidelines below to check your horse’s vital signs and monitor them regularly. Be sure to wait at least 20 minutes after exercising your horse to get accurate readings at rest.

Temperature

The normal resting temperature for an adult horse is between 99-101°F . To take your horse’s rectal temperature, dip the thermometer into a small amount of lubricant, such as Vaseline^®, and gently insert it into your horse’s rectum. Leave the thermometer in long enough to avoid a false low-temperature reading. Most digital thermometers will beep when the temperature reading is finished. If you use a glass mercury thermometer, you will need to wait at least three minutes to get an accurate reading. Hold the thermometer in place or clip a string attached to the thermometer to your horse’s tail. 

When taking a horse’s temperature, be sure to take it before giving any medications. Nonsteroidal anti-inflammatory medications are fever reducers, and other medications can also affect a horse’s temperature. 

A horse with an elevated temperature between 101-102°F may be able to be monitored without needing a vet visit, but call your vet if the fever persists or your horse has a temperature of 103°F or higher. The fever could be an indication of illness or disease.

Pulse 

An adult horse’s pulse, or heart rate, at rest is typically 28-44 beats per minute. You can take your horse’s pulse by using a stethoscope to listen to the heart on your horse’s left side directly behind his elbow in the girth area. The lub-dub sound made by a horse’s heart should be counted as one beat. If you don’t have a stethoscope, you can take the pulse from the lingual artery, which is a cordlike structure that crosses where the cheek and jawbone meet on the underside of the jaw. Count the beats for 15 seconds then multiply that number by four to determine your horse’s pulse in beats per minute. 

When taking a horse’s pulse, make sure that you are not double-counting the heartbeats, or counting the lub and dub sounds separately, because you’ll get an incorrect pulse. Also, be sure to take your horse’s pulse when he’s calm. A nervous horse’s heart rate can be significantly higher than his normal resting heart rate. 

An elevated heart rate at rest can be a sign of pain, such as from colic.

Respiration

Respiration involves a horse’s breathing, or respiratory rate. One breath is the combined inhale and exhale taken by a horse. An adult horse’s normal resting respiratory rate is 10-24 breaths per minute. You can measure your horse’s respiratory rate by watching his flank move in and out, watching his nostrils flare with every breath or using a stethoscope on his flank to listen to his breaths as the air passes through his lungs. To take your horse’s respiratory rate, count the number of breaths for 15 seconds and multiply that number by four to determine the rate in breaths per minute. 

Make sure your horse is relaxed when taking his respiratory rate, as it can increase significantly if he’s nervous. Also, avoid letting your horse sniff your hand while measuring his respiratory rate because he will sniff more quickly than his normal breathing rate. 

An elevated respiratory rate can be a sign of respiratory issues, such as equine asthma, or another indicator of a fever.  

Mucous Membranes

The mucous membranes line a horse’s mouth and gums, and they should be moist and have a healthy pink color. You can check your horse’s mucous membranes by gently pulling up his upper lip to inspect his mouth. Pale white or grayish gums can indicate illness, while bright red gums can be a sign of dehydration, infection or toxin ingestion. 

Capillary Refill Time

Capillary refill time refers to the amount of time it takes for a horse’s gum color to return to pink after being pressed with a finger. The normal capillary refill time for a horse is two seconds or less. To check your horse’s capillary refill time, pull up his upper lip and gently press your thumb against his gums directly above a tooth. Release your thumb and count how many seconds it takes for the gums to return to their original color. If the color doesn’t return quickly to the gums, the horse’s circulation may be affected by a health issue. 

Gut Sounds

As a horse digests food, his gut will make rhythmic gurgling, gas-like growls and occasionally roaring sounds. You can check your horse’s gut sounds by placing your ear or a stethoscope against both sides of his abdomen—high and low. A healthy horse’s gut will make the routine digestive sounds, but prolonged silence could indicate an abnormality or colic.

Become familiar with your horse’s resting vital signs by checking them once or twice a month, so you can recognize when you need to call your vet for a possibly critical health issue.

Practical Horseman thanks Caitlin Rothacker, DVM, DABVP, for her technical assistance in the preparation of this article. Rothacker is a partner at Grand Prix Equine in Newtown, Connecticut. Her interests include lameness and diagnostic imaging, purchase exams as well as routine preventive care.

This article originally appeared in the summer 2025 issue of Practical Horseman.

Intense heat and humidity can lead to overheating, heatstroke and dehydration in horses which can cause poor performance, lethargy, colic, kidney damage, collapse and even death. Meanwhile, flies bite and pester our equine partners and also spread diseases like pigeon fever, vesicular stomatitis, equine infectious anemia and influenza. Additionally, they can trigger allergies, dermatitis and eye ailments, and constant stomping can contribute to joint issues and other impact-related injuries and even weight loss.

To protect your horse from intense heat and menacing insects and ensure he stays happy, healthy and performing his best throughout the summer, follow these savvy management tactics and veterinary advice.

Beat the Heat & Keep Your Horse Hydrated

August of 2024 was the hottest month ever recorded, according to both NASA and the National Oceanic and Atmospheric Administration—and higher than average temperatures are predicted for much of the U.S. this year. When the weather heats up, it’s crucial to ensure your horse doesn’t get over-heated or dehydrated.

How Horses Cool Themselves

Besides humans, horses are one of the few mammals who cool themselves through perspiration in hot weather and during exercise or times of stress. Duncan Peters, DVM, MS, former head of the Hagyard Sport Horse program at Hagyard Equine Medical Institute in Lexington, Kentucky, explains that when your horse’s core temperature rises above its normal range (99 to 100 degrees F), his brain sends signals to the sweat glands to start pumping out sweat. As the sweat evaporates, it carries heat way from his skin, reducing his body temperature. During intense exercise, your horse can lose 3 to 4 gallons of fluid per hour via sweat and water vapor as he exhales.

Fluid loss can also depend on climate conditions; on hot, dry days, sweat can evaporate almost as quickly as it forms. “So be aware that even if you don’t see sweat pouring off your horse, he could have lost a large amount of fluid in dry conditions,” Peters said. “Horses can also be slow to replace that fluid, because the nature of their sweat delays their thirst response.”

When humans sweat, we lose mostly water, he explains. That water loss leaves us with an electrolyte imbalance that triggers thirst. Horses’ sweat, however, contains a higher concentration of electrolytes (key minerals like sodium, chloride, potassium, calcium and magnesium). Therefore, it takes longer for them to develop an electrolyte imbalance and feel thirsty.

Unfortunately in extremely hot and humid climates, sweating and the cooling effects of your horse’s breathing may not be enough to offset his temperature. This may not be too detrimental if the heat stress is brief; for example, if you exercise him for short period of time and he has ample time to cool off afterward. But Peters says if the stress is prolonged during intense exercise like cross country or hauling long distances in hot weather, the heat can began to build up in a horse’s body. Humidity can further exacerbate heat stress because when the air is saturated with moisture, sweat can’t evaporate fast enough to dissipate your horse’s body heat. He’ll keep sweating, but it won’t help cool him down.

Prevent Overheating

• Limit exercise in hot and humid weather.
• Pay attention to the Heat Index. This measure combines air temperature and relative humidity to estimate how hot it actually feels. (You can the find the National Weather Service heat-index calculator here.)
• Exercise your horse during the coolest time of the day—early mornings or evenings, depending on where you live.
• Always give your horse a thorough cooldown with lots of walking, cold baths and fans.
• During turnout, ensure he has access to shade or turn him out at night. If you horse is sensitive to bugs and needs a fly sheet, be sure to choose one made out of lightweight mesh with ample ventilation.
• During the hottest parts of the day, keep him stalled with ample air flow and fans.
• Encourage your horse to hydrate. Peters notes that even a 3% hydration loss is enough to affect your horse’s performance. Always off clean, cool free-choice water. At shows, offer him water at least every hour.
• Be mindful of your horse’s general behavior. Pay attention to his attitude, body posture, appetite, willingness to move freely (when turned out) and the relaxation of his muscles to determine if might be experiencing heat-related stress.
• As horses gain fitness, they become better at regulating their body temperature during exercise. As their bodies adjust to use energy more efficiently, Peters says, they produce less heat, sweat more readily and their sweat becomes less concentrated so they lose fewer electrolytes.

Heat Danger Signs

For any horse, a buildup of body heat leads to fatigue and can have serious health consequences. The combination of prolonged hard work and hot, humid weather can be particularly deadly.

If your horse isn’t able to regulate his body temperature, he’ll overheat and may even suffer heat stroke. (In heat stroke, your horse’s sweating mechanism fails, and his temperature rises quickly to 106 to 110° F.) If he sweats excessively he will be at risk for dehydration, which disrupts key functions like circulation and digestion and can damage organs. In extreme cases, dehydration can be fatal.

Here are five signs that your horse might be in danger of overheating:

• He’s breathing hard—and continues to. Peters says rapid, shallow breathing is common after exercises in hot weather, but it should slow fairly quickly to a normal resting rate, which is 20 breathes or below for most horses. If your horse’s breathing rate remains high, he might even pant to cool down.
• Prolong high temperature. A horse’s temperature can reach 106° F during intense work, but you should be concerned if it doesn’t drop a degree or two within 20 to 30 minutes.
• He seems exhausted or depressed. He might go off his feed. When dehydrated, horses generally don’t eat, but they usually will go for water. Horses, however, who are severely dehydrated may refuse to drink.
• His skin lacks resiliency. Test by pinching a fold of skin in three places–at midneck, high on his shoulder and low on his shoulder. If he’s well hydrated, the skin will snap back promptly; if fluids are low, it will stay folded up for a few seconds and then slowly flatten.
• His gums are dry and pale or white. (They should be moist and pink.)
• His eyes and/or flanks appear sunken.
• His gut is quiet. You should hear bubbles and gurgles; little or no noise indicates trouble. Your horse’s intestines typically contain a large amount of water that his body draws on as a reserve. When he gets dehydrated, gut motility slows, which can lead to digestive concerns.

If your horse is showing any of the above signs or you suspect he’s overheated:

• Hose your horse down with cold water. The water helps bring their core temperatures down to normal and provides overall relief from the heat. After bathing your horse, be sure to use a sweat scraper to thoroughly remove excess water and allow him to completely dry either under shade or in the barn with a fan before turning him back out in the sun. Otherwise, even a thin layer of water on his coat, especially in humid climates, can act as an insulator and trap body heat.
• Keep air moving as much as possible with fans and misters. When temps really soar and there is little to no access to breeze or shade outside, keep your horse stalled during the day with at least one fan for air circulation. Moving air carries heat away from your horse’s skin. If feasible, you might also consider installing misters or a misting fan for heat relief. Misters add water vapor to the air to lower its temperature.

• Always provide access to clean, cool water. Hydration is essential to prevent overheating, so encourage your horse to drink as much as possible. Peters says you won’t hurt him by giving him some water after exercise. It’s practically always safe to let your horse drink a small amount–up to a gallon–walk him for a few minutes and offer water again, he notes. If you let him drink intermittently, a gallon at a time, you may stay ahead of dehydration.
• Replenish lost electrolytes. Electrolytes are available in pellets, powder and paste form and can help replenish any vitamins or minerals lost through sweat, which can help protect him from dehydration and regulate muscle function and other body processes. Electrolyte supplementation can also encourage your horse to drink more water, which will help rebalance his fluids and ensure proper digestion.
• Offer salt: Adult horses need at least one ounce of salt per day. Since hay, grass and grain provide very little salt, horses are often lacking in this key mineral. Salt is essential for healthy nerve and muscle function. It also helps keeps fluids balanced and encourages hydration, especially in hot climates. You can add table salt to your horse’s grain (although, some horses aren’t keen on the taste of plain salt) or at the very least provide a salt block. Most horses, however, don’t get adequate amounts of salt from blocks or licks. If your horse isn’t keen on the taste, there are flavored salt supplements that many horses find palatable. 

When to call your veterinarian?

It depends on the severity of the signs and your horse’s general attitude. Peters says if his vital signs are improving and he’s alert, drinking water and interested grass or hay, you can probably handle the situation. If he seems dull or disoriented, turns down food or water or hasn’t cooled down despite your efforts, it’s smart to call your veterinarian. He can assess your horse’s condition, administer fluids by stomach tube or intravenously, and provide other supportive treatment as necessary.

SMART FLY CONTROL

Unfortunately, flies are a part of managing horses, and you’re not going to be able to eliminate them all. But there are several effective management strategies and fly-control measures you can utilize to minimize their impact on your horse.

Management: First Line of Defense

Keeping areas clean and dry is one tactic to help manage flies. Flies are drawn to wet areas, where they drink and breed. Eliminate standing water in low-pasture areas and any containers with stagnant water. It’s also important to create effective drainage around your barn, repair any plumbing leaks and ensure stalls are dry. Additionally, moist, decaying leftover feed is an ideal breeding site for stable flies and houseflies. Ensure your feed room is dry and place waterers in well-drained areas and away from places where horses are fed. Properly dispose of all garbage and keep grain, supplements, and other feeds sealed under air-tight lids. 

Cleanliness in stalls and pastures also helps keep flies at bay. Manure is the housefly’s meal of choice and the more manure around your barn, the more flies you’ll attract. Remove manure from stalls every day and from paddocks at least once a week. If possible, move it to an off-site location or cover with a heavy tarp and treat on-site for later removal. Also, replace your horse’s stall bedding once a week and opt for shavings and sawdust. Straw tends to attract more flies. 

Several other barn hacks can help deal with flies. Prevent flies from entering the barn by positioning fans for downward and outward airflow. For stalled horses, large fans can deliver blasts of air to knock flies off their targets; for horses kept on pasture, make sure to provide access to open, breezy spaces. Adding screens around your feed and tack rooms, as well as stalls, can greatly cut down on flies, and residual insecticides specifically made for wall, ceiling and rafter application (versus products designed for use on horses) can deter bugs from the barn. You can also set up traps around the barn that use fly bait to lure flies onto a sticky surface or into a receptacle where they’re trapped and die.  

You can also combat flies outside the barn with fly parasites. These tiny, low-flying wasps use the fly pupa as a host to kill developing flies before they hatch thus preventing new generations from maturing. Simply release eggs near manure piles, water sources and other fly-breeding sites, and they’ll emerge as active wasps in about five days. (They don’t bite or sting people, horses or pets.) And, if at all possible, don’t pasture horses near cattle or other livestock. Cow manure, in particular, attracts more vicious horn and face flies.  

Fly-Control Arsenal

In addition to savvy barn management, beef up your fly-defense artillery to keep these health adversaries as far from your barn’s front lines as possible. Protective barriers like fly sheets, masks and boots provide external protection from insects and are made out of lightweight mesh fabrics for ventilation to help keep your horse cool throughout the warm fly season. Sheets protect horses from withers to rump and many also offer neck, chest and belly protection, which is especially beneficial for horses prone to sweet itch from biting gnats (See “The Main Offenders,” below). Fly masks protect crucial facial areas and some have ear and muzzle covers, and fly boots—also typically made out of a lightweight mesh—protect sensitive skin on the lower legs and can be helpful combatting stable flies that love to chew on horses’ legs. 

Topicals are another essential ammunition to combat flies. In addition to fly spray, these are also available in roll-on and wipe form and contain natural and synthetic insecticides to knock down or deter flies on contact. There are also insecticide-free products that use citronella, essential oils and other plant-based ingredients to deter bugs. Newer sprays combine tried-and-true ingredients like pyrethrin and permethrin with fatty acids to overwhelm flies’ sense of direction, so they’re less likely to land on your horse. 

Feed-throughs can provide another line of defense. They contain ingredients that pass through a horse’s system into manure to prevent larvae and pupa from developing and hatching. Typically given with a horse’s grain ration from early spring to late fall, these work best when used in conjunction with fly traps and topicals. Keep in mind, however, that feed-throughs won’t be effective if they’re not administered in the correct dosage to all horses at your facility. 

Formulated with ingredients like garlic and apple cider vinegar, supplements help deter bugs by making your horse less appealing as fly food. Some also contain diatomaceous earth, which passes through the horse’s system into manure where it creates an inhospitable environment for fly larva. 

The Main Offenders

Several hundred species of flies plague horses, but the following six are the most prevalent:

• Bot fly: Bot flies lay sticky eggs on a horse’s coat, muzzle, jaw, lips, throat and insides of legs. Larvae hatch in horse’s mouth and migrate to the stomach and intestines. They can cause a number of health issues and even death, so, call your veterinarian if you suspect bot flies.
• Face fly: Females feed on secretions around a horse’s eyes and nostrils and on blood from insect bites and wounds. They have sandpaper-like tongues that abrade eye-area tissue to stimulate tears, which can cause infection and even blindness.
• Gnat: Also known as “no-see-ums” or “midges,” gnats are most bothersome at dusk and dawn. They produce painful bites that can cause sweet itch (persistent skin breakouts that result in intense itchiness) in some horses. The resulting sores can be painful and cause horses to rub.
• Horn fly: These flies pierce a horse’s skin to suck blood like the stable fly. They prefer cattle but also attack nearby horses and can fly up to 10 miles.
• Housefly: Houseflies have sponge-like mouths and primarily feed on manure, garbage or bodily secretions. They don’t bite, but like to suck up secretions around wounds, eyes and nostrils.
• Stable fly: These flies bite by piercing the flesh to feed on your horse’s blood. They’re attracted to horses’ legs, resulting in stomping and tail flicking.

For More on Heat and Flies:

• For more summer turnout tips to beat the heat and advice on finding the right fly sheet, mask and boots for your horse, click here.
• You can find tips for managing horses with anhidrosis during extreme heat here.

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.

Here, we look at what causes sweet itch, how to spot the signs that your horse might be gnat food and offer tips on how you can protect him from these miniscule, mighty-mouthed foes. Plus, we look at a study that confirmed horses can inherit a susceptibility to sweet itch.

Sweet Itch: At A Glance

Definition: Technically known as equine insect hypersensitivity (EIH), sweet itch is an allergic reaction to the saliva of biting insects, most often the Culicoides species of midges and gnats.

Signs: Intense itchiness, wheals and swelling, primarily on the neck (under the mane), face, shoulders, withers, belly and rump (over the tail). The skin may be rubbed until it is crusty, weepy, raw and hairless. Location of the lesions may depend on the specific species of gnat; most prefer to bite on the neck and along the topline, but some target the chest, belly, tail and groin.

Diagnosis: Skin scrapings and cultures may be needed to distinguish EIH from other causes of itchy dermatitis, such as mites, lice and fungal infections.

Treatment: Antihistamines or corticosteroids may help ease the itch and inflammation, providing relief to the itchy horse; antibiotics or antimicrobial shampoos can help prevent secondary infections. Pentoxifylline can be used to decrease skin reactivity, and in some cases allergy serum is worth trying.

Of Note: The condition is usually at its worst during the spring and summer when insects are most active, and it may subside during the winter. Less than 10 percent of horses in the United States develop sweet itch. Most horses won’t begin to show signs until they are 2 to 4 years old, and the condition is more common among Shires, Welsh Ponies and horses imported from Iceland, but it can occur in any breed.

Protect Your Horse

Research is underway to develop a reliable immunotherapy treatment for sweet itch. In the meantime, veterinarians may prescribe antihistamines and corticosteroids to help relieve the signs of the condition. But steroids carry a low but real risk of serious side effects, including laminitis. So, if your horse is susceptible to sweet itch, you’ll want to reduce his exposure to the insects that cause it. Here are steps you can take:

1. Stable your horse during peak biting hours. Culicoides spp. are most active at dusk and dawn, so bring your horse into a stall during those hours. For additional protection, install ultrafine screens in stall windows and set up fans to provide a continuous breeze over stabled horses. Gnats are weak flyers and even a slight breeze will keep them away. You might also consider applying a spray repellent designed for use on stall walls and other surfaces inside the barn.

2. Keep your horse covered. One way to reduce bites is to keep a fly sheet on your horse during insect season. Made of fine mesh and equipped with closures to keep out bugs, clothing designed specifically for horses with sweet itch has extensions to cover the neck, belly and tail, the areas where Culicoides spp. are most likely to bite. A fine-mesh mask may also be needed to protect the horse’s face and ears.

3. Use fly-control products. The most potent products combine repellents with pesticides. Look for ones labeled for use against gnats and midges. You’ll need to be diligent about applying the sprays and wipes as often as the manufacturers’ instructions allow.

4. Restrict your herd’s access to marshy areas. Gnats breed in marshy, shady ground with rotting vegetation. If possible, move your horse to a pasture in a drier, more exposed location away from boggy terrain. Around your barn, clear up standing water in ditches and gutters and keep them free of leaves and other debris. Place manure and compost piles as far away from the horses as is feasible.

5. Try over-the-counter products. You’ll find a number of products for horses with sweet itch, from feed supplements formulated to reduce inflammation, to topical preparations meant to soothe itchy, inflamed skin. Thick, oily or sticky ointments are messier but may keep gnats from landing on the horse’s skin. They may also help keep bugs from getting to the skin to bite. Anecdotal evidence suggests that these products offer some relief, at least in some horses. When trying a new topical product, start by applying it to a small area to make sure it will not further irritate sensitive skin. Be careful with tea tree oil, lavender and other herbals—they are soothing to some horses but can irritate the skin in others.

More Tips & Tricks

Here are a few home remedies recommended by riders to help prevent or reduce your horse’s exposure to the gnats that cause sweet itch:

• Apply Avon’s Skin So Soft bath oil to the most vulnerable areas.
• Add apple cider vinegar and/or garlic powder to your horse’s feed to make his sweat’s smell less attractive to gnats. (There are also supplements available that contain both apple cider vinegar and garlic.)
• Apply menthol products like Vick’s VapoRub to susceptible parts of your horse’s body.
• Rub a scented dryer sheet over his body.
• Apply baby oil to the roots of your horse’s mane and tail head; gnats can’t seem to get a grip on the skin to feed.

Genetic Connection for Sweet Itch?

A long-term study from the Czech Republic confirms that horses can inherit a susceptibility to the allergic skin condition known as “sweet itch,” which is technically known as insect bite hypersensitivity (IBH). The study focused on Old Grey Kladruber horses, a native warmblood breed, at the National Stud in Kladruby and 10 private breeding facilities.

The same person visually inspected the horses over a period of 13 years, from 1996 to 2009, scoring the severity of any signs of IBH at each observation. A total of 1,209 observations were entered in a database, along with information about each horse, including location, age and pedigree.

In statistics, the degree of a trait’s heritability is expressed on a 0 to 1 scale, with 0 meaning that none of the variability of the trait among individuals is the result of genetics and 1 meaning that genes are responsible for all the variability. The Czech researchers found the heritability of sweet itch susceptibility among the study horses ranged from 0.305 to 0.626, depending on the factors considered in the calculations. These numbers, the researchers say, indicate the heritability of sweet itch is “medium to high, so there is a possibility to reduce the prevalence of IBH by selection.”

Reference: “Genetic parameters of insect bite hypersensitivity in the Old Grey Kladruber horse,” Journal of Animal Science, January 2017

For More:

• For more tips on how to protect your horse from pesky and disease-carrying insects this summer and for our shopping guide on protective fly gear—including fly sheets designed specifically for sweet-itch protection—click here.
• Learn how to avoid the top-three summer equine health issues here.

One day there was a menacing blue manure bucket in the corner that Rio was sure contained a variety of monsters. Another time, two geese outside the arena got into a honking contest, and the gelding ran for the hills. Most offensive, however, was a lesson following a Halloween-themed show. The three straw bales and small scarecrows that comprised a jump were more than Rio could handle and resulted in a snorting, pawing bucking hissy fit.

To ensure there weren’t any underlying health issues going on, including his eyesight, Neth had her veterinarian out, who gave Rio a clean bill of health. Occasionally, she and her trainer tried giving him a calming paste, but didn’t see much of a difference, so after hearing about cannabidiol (CBD) products for horses, she decided to give it a try.

While the results weren’t instantaneous, Neth said within a few weeks, she did start to see a noticeable difference in her gelding. Every once in awhile, something out of the ordinary still startled him, but overall Rio seemed much happier and more chill about situations that would normally have set him off.

You’ve probably heard about the benefits of CBD for humans and dogs, but in recent years a number of companies have focused their research on CBD in horses. As a result, it’s gained popularity as an alternative or complementary treatment for a variety of equine issues, particularly those involving pain, inflammation and anxiety. Researchers, however, are still working to fully understand how CBD works in equines.

To help you determine whether a CBD-based product might be beneficial for your equine partner, we’ll explain how it affects horses’ physiology, the best modes of administration and the various types of products on the market.

Cannabis Connection: What Is CBD Exactly?

Holistic veterinarian Joyce Harman, DVM, a leading authority on equine acupuncture and alternative medicine, explains that CBD is derived from cannabis plants, a genus cultivated around the world for thousands of years. Archeological evidence suggests that cannabis plants, which originated in Asia, were used by humans as early as 2800 BCE.

There are two main species of cannabis, and many strains within those related species. Hemp-type cannabis includes varieties traditionally cultivated for their fiber (rope, twine, etc.), seeds (for food) and oils. Other types of cannabis, classified as marijuana strains, have been used for centuries for ritual, medicinal and recreational purposes.

The active ingredients in all these plants are chemicals called phytocannabinoids. The marijuana strains of cannabis plants are cultivated to produce high levels of tetrahydrocannabinol (THC), a psychoactive (mind-altering) phytocannabinoid. By contrast, the hemp strains, which contain cannabidiol (CBD), are not considered psychoactive. Studies in people and animals suggest that cannabidiol can relieve anxiety, reduce inflammation and provide pain relief. It’s also prescribed to treat some types of epilepsy.

“The difference between hemp and a marijuana plant is the amount of THC,” Harman said. “The plants we want for our animals are hemp plants. They have been selected and cultivated for high CBD and little to no THC.” 

After the 2018 Agriculture Improvement Act removed industrial hemp from the definition of marijuana in the Controlled Substances Act, hemp was legally separated from its psychoactive cousin and new uses of the plant became economically feasible. Nonetheless, regulations governing CBD are constantly changing, with states taking different approaches to the sale of CBD products, so be sure to stay up to date on your state and local laws.

Benefits of CBD for Horses

Calming Effects:

One of the primary claims made about CBD centers on its calming effects. But unlike the psychoactive “high” produced by THC in marijuana, CBD is believed to soothe stress or anxiety. “Many horse owners and veterinarians have seen positive responses with CBD in animals that have been through stressful periods,” Harman said. “It helps with mental equilibrium.”

CBD interacts with the body’s endocannabinoid system, which regulates many physiological functions, including appetite, mood, pain sensation and immune response. By binding to certain receptors in the endocannabinoid system, CBD can help modulate these functions.

“CBD doesn’t make horses ‘stoned’ like THC would. The brain is still functioning normally,” Harman explained. “The horse is calm but if there is cause to be alert, the horse is still capable of being alert.”

It’s important to note, however, that these calming effects have not been proven in clinical studies, but Harman believes horses are excellent candidates for CBD trial therapies because modern equine management practices tend to put horses at risk of chronic stress. As we know, horses are designed to roam and constantly graze, but unfortunately many horse owners don’t have that option. The United States Department of Agriculture estimates that 6,000 acres of the country’s open land are lost every day due to the increasing demand for urban and suburban development, which translates into real-world hardships for many equestrians and horse owners.

“Equine athletes are sometimes confined in small spaces, separated from their social groups and asked to do things that don’t come naturally to them,” Harman noted. “Many horses are on edge all the time. When we get on them, they spook at everything. CBD can help them stay calm and ‘forgive and forget.’”

Inflammation and Pain:

CBD also shows promise for treating chronic pain in horses. Harman says it may be beneficial for helping with laminitis, insulin resistance, musculoskeletal pain, skin disease, chronic ulcers, uveitis and even Lyme disease.

“Cannabinoids have action in both acute and chronic pain by modulating pain signals in the central and peripheral nervous systems and acting similarly to an anti-inflammatory,” Harman wrote in her 2020 Innovative Veterinary Care Journal article. “CBD can also act as an antioxidant and support immune function.”

While CBD is rarely the only treatment a horse receives, it may offer pain relief without the potential side effects of long-term use of conventional anti-inflammatory drugs like phenylbutazone (bute). CBD’s effectiveness against chronic pain has yet to be scientifically proven and it appears to vary greatly among individual horses. But Harman advocates trying CBD, particularly when traditional treatments have failed to alleviate pain.

Types of CBD for Horses

CBD products for horses are available in pellets, powders and oils. Powders and pellets can easily be distributed in your horse’s grain rations. For powders, Harman advises selecting a product that is 100% hemp with nothing else added; while pellets often contain alfalfa or added mold inhibitors.

CBD oils are extracted from the hemp plant and then mixed with an oil base. “Any type of safe, healthy oil is fine to dilute it in—usually hemp seed oil or MCT oil from coconuts—to get an amount you can measure in a dropper for feeding,” she said.

While some people claim that rubbing the CBD-infused oil into a horse’s gums is the fastest delivery method to get cannabidiol into his system, Harman says it’s often more practical to add CBD to his feed, especially as recent studies suggest that it’s better absorbed when administered with food.

CBD Dosage for Horses

The amount of CBD needed to achieve the desired effects in horses varies, as individuals responds differently to the compound. However, it’s always important to follow the specific manufacturers’ feeding directions.

Fortunately, Harman notes that CBD has a relatively solid safety record in many species and also seems to be well tolerated by horses in preliminary studies. “One thing we know about CBD is that the parts of the brain it works on will not be adversely affected by overdose,” she said.

Still, it’s wise to be cautious about giving your horse too much CBD. Research has shown that higher doses of CBD can change liver enzyme levels in people and animals—although this may not be a problem, according to recent studies. But again, be aware that there aren’t specific studies in horses.

Harman advises to establish the smallest effective amount of CBD for your horse and stick with that. “I recommend starting at about 25 milligrams for about a week or 10 days. If you aren’t seeing improvement in the condition you’re trying to help, then double the amount (50 milligrams) for a while,” she said. “If that’s still not working, you can go higher until you find the level that works in that particular horse. But it’s always best to follow the manufacturer’s instructions as the quality or concentration can vary considerably.”

When administering CBD to combat inflammation and discomfort, Harman says a large loading (initial) dose might be helpful. “You might start at 50 milligrams for a week and increase it if necessary—on up to 200, if need be, and stay there for a few weeks or a month,” she noted. “If the horse becomes sound and is no longer in pain, you could back down until you find a comfortable level.”

If maximum doses of different CBD products don’t produce the desired results in your horse, it’s time to look for other alternatives. Regardless of the hype, Harman stresses that CBD isn’t a cure-all, and it won’t help every horse.

Potential Downsides

The potential benefits of CBD are clear. But there are also possible downsides. One of those concern comes from the fact that rules and regulations governing CBD products are often unclear and still evolving. Although the Food and Drug Administration (FDA) has approved a CBD prescription medication for treatment of certain types of seizures, the agency has declined to issue rules for other CBD products.

“It’s not apparent how CBD products could meet safety standards for dietary supplements or food additives,” said FDA Principal Deputy Commissioner Dr. Janet Woodcock in a statement explaining the decision. “The use of CBD raises various safety concerns, especially with long-term use. Studies have shown the potential for harm to the liver, interactions with certain medications and possible harm to the male reproductive system. CBD exposure is also concerning when it comes to certain vulnerable populations such as children and those who are pregnant.”

The FDA is calling on Congress to establish a regulatory structure to ensure the safety and efficacy of CBD products.

Regulatory Gaps

Until those regulatory gaps are bridged, Harman advises sticking with CBD products offered by well-established companies that are transparent about their ingredients and production standards. “When you see inexpensive CBD products, consider that there is often a reason they are so inexpensive,” she warned.

And especially if you compete with your horse, keep in mind that most equine sports’ organizations prohibit anything that might alter or enhance performance, including CBD. That means horses may be tested for CBD along with other prohibited substances.

To stay in compliance with competition rules, Harman suggests administering CBD between events. “We don’t know yet what a safe withholding time would be for all horses,” she noted. While it’s generally recommended to withdraw a horse from CBD seven days prior to competition, it can vary by individual.

Horses who compete less often, as well as those in rehab or on a break from competition, may benefit from CBD administered during down periods. “Then, if your horse is functioning in a calmer way, you may have improved the condition of his endocannabinoid system,” Harman said.

CBD Shopping Tips

As with any supplement, it’s best to purchase CBD supplements only from well-regarded manufacturers. “Reputable companies use organically grown hemp for their CBD products, but certification of organic status has only recently been granted to the hemp industry,” Harman pointed out. “Some products are grown responsibly, using organic methods, but are not certified as organic yet because the process is expensive and can take several years for a farm to obtain.”

Certificate of Analysis

A reputable company selling CBD products will also publish a certificate of analysis (COA) for each product on its website, verifying that it has paid to have these products tested. The COA lists everything in the product: the cannabinoids, any terpenes (other beneficial plant compounds), any solvent contamination, heavy metals, other chemical residues and microbiology—as well as any molds or bacteria.

It’s also smart to consider how a product was processed. “CBD can be safely extracted using carbon dioxide (CO2) or high-quality, organic ethanol,” Harman explained. “The cheap way is to use nasty chemicals like benzene. Your local gas station or convenience store might sell CBD, but you may be getting other chemicals along with it.” The COA will tell you whether there are residues left over from processing and whether the plants were grown in soils free of heavy metals or other contaminants. It will also tell you the strength (actual amount) of CBD in  the product.

THC Content

In addition, you want to verify that the product contains little to no THC, which can occasionally be present in trace amounts. The legal amount of THC to be in a CBD product is 0.3% and that amount will have no psychoactive effect. While Harman says that THC might be helpful in horses with cancer, dogs are highly sensitive to it, and researchers don’t know enough about THC to recommend its use in otherwise healthy horses.

For More:

SmartPak Equine commissioned a study on the safe use of their CBD ingredient at Louisiana State University School of Veterinary Medicine that was published in the Journal of Equine Veterinary Science, a  peer-reviewed scientific journal. You can read more about it, here. 

About Joyce Harman, DVM

Joyce Harman, DVM, has more than 30 years of experience in holistic veterinary medicine. She is the founder and owner of Harmany Equine Clinic in Flint Hill, Virginia. After receiving her veterinary degree from the Virginia-Maryland Regional College of Veterinary Medicine in 1984, Harman decided to explore alternative approaches to animal health. Over the years, she has incorporated a variety of holistic modalities into her practice, including acupuncture, herbal medicine, homeopathy, CBD and chiropractic care. Her website contains educational material, and she is currently working on an online nutrition and holistic health course. Harman is the author of The Horse’s Pain-Free Back and Saddle-Fit Book and is a sought-after speaker on veterinary topics around the world.

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. 

But after keeping him on a strict diet and trying to get him back in shape with plenty of exercise, he hasn’t shed any weight and still has noticeable fat deposits on the crest of his neck and tail head. Once your veterinarian takes some blood samples, she diagnoses your equine partner with Equine Metabolic Syndrome (EMS).

While you may be concerned, EMS is more common than you might think, and by working closely with your veterinarian and making some key changes to your horse’s lifestyle, you can get him back to a healthy weight to ensure he stays healthy for years to come and is able to perform his best.

What Exactly is EMS?

EMS is a disorder characterized by insulin dysregulation, or the inability to metabolize carbohydrates and regulate blood insulin levels correctly. (In the past, the clinical signs of this disorder have been known as hypothyroidism, pre-laminitic syndrome, peripheral Cushing’s disease, or “syndrome X.”)

As you might recall from biology class, insulin isa hormone secreted by the pancreas after a meal. It is released into the bloodstream after carbohydrates are broken down into glucose during digestion, causing the blood glucose (blood sugar) levels to rise.

One of insulin’s primary functions is to enable the transfer of that glucose from the blood into the body’s cells, where it is used to create energy. Once that transfer occurs, the blood glucose levels drop back down, and insulin’s job is done until the next meal.

Unless, that is, something goes wrong in the regulation process. In what is called insulin resistance, the fat deposits in affected horses release hormones that adversely affect the ability of the body’s tissues to respond normally to insulin. This causes a buildup of excess glucose in the blood and prompts the release of more and more insulin, often overwhelming the pancreas.

In humans, this kind of abnormal response can lead to type 2 diabetes. In horses, the result is what we now call Equine Metabolic Syndrome.

1. Breed, Environment and Other Factors Affecting EMS Susceptibility

Several genetic, environmental and physiological factors can contribute to EMS. Some breeds or types of horses are inherently prone to this disorder. These include Arabians, Morgans, Paso Finos, Saddlebreds and warmbloods. Donkeys and ponies are also at high risk. However, any “easy keeper” that becomes obese on very little feed can develop EMS. The classic trigger is a diet high in sugar—too much grain or forage high in nonstructural carbohydrates (NSCs). This, combined with a lack of regular exercise, can set the stage for EMS. The condition generally appears between the ages of 5 and 15 years.

As you’ve no doubt guessed, typical signs of EMS include increased appetite, excessive weight that can’t be lost and those characteristic fat deposits (although not every EMS horse is fat). Repeat instances of laminitis and other metabolic issues—occasionally at the same time—are other possible clues that your horse has EMS. So is an unusual amount of fatigue. If your horse is a breeding animal, infertility can be another sign.

2. Importance of Prompt Diagnosis

Early diagnosis of EMS is essential for the best possible outcome. So, if your horse is an “easy keeper” and overweight despite your best efforts to keep him trim—or if he has unusual fatty deposits or a nagging, unexplained lameness in a forelimb—it’s wise to get him professionally evaluated for this disorder.

Your veterinarian may screen for EMS by measuring blood insulin and glucose concentrations from samples taken first thing in the morning, after your horse has been fasted for six to eight hours. This is the best way to diagnose moderate to severe cases of insulin dysregulation.

Dynamic Tests: Dynamic tests that assess the body’s responses to a “glucose challenge” may be necessary to diagnose EMS in horses whose metabolic signs are not yet pronounced enough to detect the usual way. In one of these challenges, the Oral Sugar Test (OST), the horse is fasted for three to 12 hours and then given an oral dose of corn syrup. Blood samples are collected prior to and 60 to 90 minutes after corn syrup administration. The blood samples are tested for insulin to determine the horse’s response to a large increase in blood glucose concentration. EMS horses will demonstrate a large spike in blood insulin levels after corn syrup administration, while normal horses will not exhibit a pronounced spike in blood insulin concentration.

An insulin tolerance test (ITT) can also be performed to measure the ability of your horse’s tissues to take up glucose (insulin sensitivity). This involves comparing the glucose concentration of a baseline blood sample to that of a sample taken half an hour after a dose of insulin is administered.

Rule out PPID: When screening an older horse it’s important to rule out an age-related endocrine disorder called Pituitary Pars Intermedia Dysfunction (PPID, or equine Cushing’s disease). Unfortunately, the two can coexist, with PPID believed to worsen insulin dysregulation in horses also affected by EMS.

3. Treatment Options and They Can Help

Treatment of EMS is important, even if your horse is more “pasture ornament” than athlete. Why? Left untreated, this disorder can lead to painful complications. One of the most serious of these is laminitis, which can be crippling and even fatal.

For individuals who are “easy keepers” and obese (as most EMS horses are), simple changes in management can encourage weight loss. This should improve insulin sensitivity and help control the disorder.

But here’s the thing: Merely cutting your horse’s rations may not be enough. It is the restriction of carbohydrates that is critical to decreasing his body’s glycemic and insulinemic responses. Even if your horse consumes only forage, limiting his grazing is especially important in the early spring and autumn, as well as in the afternoon, when pasture grass is richest in natural sugars. (Grazing muzzle to the rescue!)

Hay can be an issue, too; consult your veterinarian about the most appropriate types to feed and consider having each load tested for NSC content. Ration balancers or complete feeds designed for horses with insulin dysregulation may also be useful.

If these dietary tweaks aren’t enough to reduce your horse’s weight, additional exercise may be prescribed.

Finally, if management changes don’t work, your veterinarian might suggest medical therapy with drugs like thyroxine or metformin to help stimulate weight loss and regulate insulin responses. Your veterinarian may also recommend that you add a metabolic supplement to your horse’s regimen.

4. Preventive Measures

To help prevent EMS—particularly in those high-risk, “thrifty” breeds—it’s best to feed using an ideal body condition score as your guide rather than just “eyeballing it.”

Keep in mind, too, that horses who are predisposed to this disorder will always need low-carbohydrate hay or pasture grass. That means their hay should ideally be tested for NSC levels. Their access to pasture should also be limited during periods of high sugar content (early spring and autumn), with early morning grazing preferred.

And don’t forget regular exercise! It’s just as important for horses as it is for humans.

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Equine odontoclastic tooth resorption and hypercementosis (EOTRH) is a dental disease characterized by tooth resorption (loss of dental tissue) and hypercementosis (overgrowth of dental tissue). In some cases, the surrounding bone may be destroyed (lysis). EOTRH can affect all teeth (incisors, canines, premolars and molars). The condition causes pain, with affected horses exhibiting noticeable signs, such as difficulty eating or refusing to be haltered or bridled.

EOTRH was first identified in 2004, and it typically affects horses over the age of 15. The disease is progressive, so the effects cannot be reversed. But with proper monitoring and treatment, affected horses can continue to live active, healthy lives.

Causes of EOTRH

The cause of EOTRH is unknown. While geldings seem more predisposed to the disease, there are several factors that may contribute to EOTRH, including:

• past overly aggressive dental procedures by improperly trained individuals,
• bacterial infection, 
• endocrine disease, 
• genetics, 
• horses who are not allowed to graze (i.e., kept on a drylot),
• interaction of autoimmune response, 
• masticatory (chewing) forces, and/or
• the presence of certain types of bacteria or other microorganisms in the mouth.

Another theory suggests that the increasing angulation of the incisors as horses age negatively affects the periodontal ligament that holds the teeth in place. The strained ligament causes chronic inflammation in the gums, which may affect the teeth. 

Signs

In the initial stages of EOTRH, there may be no visible signs. Over time, redness, swelling and recession develop in the gums of the affected teeth. Then, gingival ulcerations, heavy plaque and fistulae (draining tracts) with discharge may be observed. As EOTRH progresses, the teeth may loosen or fracture. Some teeth may develop a rough, bulbous appearance. Other signs may include:

• bad breath,
• head shyness or head shaking,
• refusing to be haltered or bridled,
• difficulty grazing, 
• reluctance to bite into apples
  or carrots,
• decreased appetite,
• weight loss, and/or
• irritation to tapping or manipulation of the incisors.

Diagnosis

If you see signs of infection or suspect that your horse has EOTRH, call your veterinarian to perform a complete sedated oral examination. She will look for fractured or loose teeth, pustules or draining tracts around the teeth, receding and/or swollen gums. In addition, dental radiographs must be taken to determine the location and severity of the condition below the gumline. 

Treating EOTRH

Regular oral and radiographic examinations can help monitor EOTRH in its early stages. As it progresses, the only treatment is to extract the affected teeth. Your vet will determine when or if extraction is needed based on clinical signs as well as examination and radiographic findings. Teeth will need to be extracted if they have deep pockets or severely receded gums around them, pustules or draining tracts, radiographs showing resorption into the sensitive dental tissue and/or are fractured or loose. 

Your vet may opt to remove only a few teeth at a time using regional and local anesthesia. However, in severe cases, a horse may need to have all incisors extracted at once, usually with standing sedation and regional nerve blocks. General anesthesia is rarely required.

After surgery, if the extraction sites are left open, gentle lavage with saline may be needed. If the sites are sutured, no flushing is required. Antibiotics are often prescribed as well as oral nonsteroidal anti-inflammatory medications. Most horses experience immediate relief after the extraction of the painful teeth, and their appetites and demeanor improve quickly. But they should not be ridden with a bit until the extraction sites are fully healed.

Horses generally cope well without incisors and quickly learn to use their tongue, gums and lips to pick up feed and grass. However, modifying their diets to include softer senior feeds may be necessary. Horses’ tongues may protrude from their mouths at rest or at work once their incisors have been removed.

Prevention

Since the cause of EOTRH is not understood, prevention of the disease is challenging and speculative. Work with your vet to perform regular oral examinations. Aggressive dental floating may accelerate the disease process. Good horse management to address issues, such as bacterial infection and endocrine disease, in a timely manner is important to a horse’s overall health and may be beneficial to slow the development of EOTRH. Also, one theory suggests that horses grazing daily with their heads down for many hours may protect their teeth by constantly bathing them with saliva. While more research is needed, ample grazing time may help prevent EOTRH. 

For more on equine dental care and common issues, click here.

Practical Horseman thanks Edward T. Earley, DVM, Dipl. AVDC-Eq, Dipl. AVDC-NSS/SA, for his technical assistance in the preparation of this article. Earley is the Associate Clinical Professor, Dentistry and Oral Surgery, at Cornell University College of Veterinary Medicine in Ithaca, New York. His clinical interests include tooth resorption, surgical extraction techniques, and sinus disease associated with dental diseases.

This article originally appeared in the Spring 2025 issue of Practical Horseman.