Photo courtesy Horses’ Haven

Adoptable Horse: Abby, a 19-year-old, 13.2hh grade mare
Organization: Horses’ Haven, Howell, Mich.

Get to Know Adoptable Horse Abby

With her striking grulla coloring and kind expression, Abby is the type of mare who effortlessly captures attention. Recently returned after spending the past three years as a cherished companion horse, she is now looking for her next forever home.

Abby is a non-riding companion mare with a sweet, calm personality. One of her volunteer grooms, who was new to horse care, described her as “a sweet girl with a calm personality” who was patient and forgiving while they learned. Abby walks nicely on a lead, stands quietly for grooming, and is the kind of horse that helps build confidence in the people around her.

Though mildly neurologic in the hind end, this doesn’t prevent her from receiving routine care, including farrier work and handling. In fact, it simply adds a little extra swagger to her step and makes her even more memorable.

Overall, Abby is a sweet and gentle girl who enjoys attention, companionship, and being part of a herd. She has been pastured with mares, geldings and mules in the past. She would be an excellent match for someone looking for a beautiful pasture companion, a friend for another horse, or simply a mare to love and spend time with.

Contact Horses’ Haven today about ASPCA Right Horse Adoptable Horse of the Week, Abby!

Photo courtesy Horses’ Haven

ASPCA Right Horse

ASPCA Right Horse is the online adoption platform of The Right Horse Initiative, a collection of equine industry and welfare professionals and advocates working together to improve the lives of horses in transition. A program of the ASPCA, their goal is to massively increase horse adoption in the United States. To find more adoptable horses and foster horses, visit www.myrighthorse.org. To learn more about The Right Horse, a program of the ASPCA, visit www.aspcarighthorse.org.

The post ASPCA Right Horse Adoptable Horse of the Week: Abby appeared first on Horse Illustrated Magazine.

While some horses receive adequate levels through fresh forage, others may require supplementation to meet their needs. Understanding vitamin E’s importance, sources, and proper supplementation can help ensure your horse is functioning at his best.

What is Vitamin E?

As many horse owners know, the world of supplementation is vast and overwhelming.

The choices are endless; how do we know which supplements our horses truly need? Vitamin E is a fat-soluble antioxidant that plays multiple roles in equine health, making it a key piece in the equine diet.

Its primary functions include:

◆ Muscle Maintenance and Function

Horses rely on strong, healthy muscles for movement, whether they are backyard pets or performance athletes. Vitamin E aids in muscle cell repair and reduces oxidative stress, which occurs during exercise. It helps prevent muscle fatigue and soreness, supporting overall mobility and endurance.

◆ Boosting the Immune System

A strong immune system is essential for keeping horses healthy and resilient against infection. Vitamin E enhances immune responses by supporting white blood cell function and aiding in the production of antibodies.

This is especially vital for foals, senior horses, and those exposed to frequent travel and competition stress.

◆ A Powerful Antioxidant

Oxidative stress damages cells and leads to inflammation. As a potent antioxidant, vitamin E neutralizes free radicals and protects muscles, nerves, and cells from damage. This function is crucial in preventing conditions like equine motor neuron disease (EMND) and exertional rhabdomyolysis (tying-up syndrome).

Best Sources of Vitamin E for Horses

Vitamin E must be obtained through diet, as horses cannot produce it naturally. There are several sources, but the most natural and bioavailable is green grass.

The simplest source of vitamin E is fresh green grass, but many horses aren’t able to graze at least 12 hours per day for six months a year. Photo by Margaret Burlingham/Adobe Stock

However, for horses to obtain sufficient levels of vitamin E for the year through grazing, this requires being turned out on pasture for approximately 12 hours a day, for at least six months out of the year. In many parts of our country, this isn’t a viable option.

Melissa Fenn, DVM, Dipl. ACVIM, and Internal Medicine Specialist at Littleton Equine Medical Center in Colorado weighs in on the alternatives.

“It’s important to consider that commercial feeds, especially those designed for performance horses, often contain vitamin E,” she says. “But these are synthetic formulas, and don’t appear to contribute to their overall vitamin E intake. While hay provides many essential nutrients, the vitamin E content declines significantly after harvest and storage. Within a few months, stored hay loses nearly all its vitamin E content, making supplementation necessary for horses without consistent pasture access.

Hay loses vitamin E rapidly as it is dried, baled, and stored for long periods. Photo by filmbildfabrik/Adobe Stock

“For horses that don’t have regular pasture turnout, diets can be supplemented with vitamin E,” Fenn continues. “These supplements come from either natural or synthetic sources. Synthetic products are labeled dl-alpha-tocopherol, all racemic, or all-rac vitamin E, and I would not recommend using them. Supplements made from natural sources contain 100 percent RRR-alpha-tocopherol. They may also be labeled as d-alpha-tocopherol. Studies have shown that the natural formulations successfully raise vitamin E levels in horses, and I would always support using them for supplementation over synthetic products.

“There’s a lot of misinformation out there,” says Fenn. “Natural formulations can either be in water-soluble (tocopherol) or powdered/pellet forms (tocopheryl). The main difference between the two is how quickly you should expect to see a clinical response in your horse. It’s fast with water-soluble formulations—you can see a difference in as little as 24 to 48 hours. In comparison, the powdered/pellet formulations can take up to eight to 10 weeks before you might notice a change.”

You may need to add vitamin E to your supplement lineup if your horse doesn’t graze enough to get adequate levels of this important nutrient. Photo by Dusty Perin

Vitamin E Deficiency

Horses that do not receive enough vitamin E can develop serious health issues. Symptoms of vitamin E deficiency include muscle weakness and stiffness, poor performance and prolonged recovery times, neurological issues, muscle fasciculations (twitching), poor body condition, weight loss, muscle atrophy and lethargy, and weakened immune response.

These can all be brought on by limited access to pasture, changes in climate, and modern equine management practices.

Long-Term Effects of Deficiency

“There are three primary disorders associated with vitamin E deficiency in horses,” says Fenn. “Vitamin E responsive myopathy (VEM), equine neuroaxonal dystrophy/equine degenerative myeloencephalopathy (eNAD/EDM), and equine motor neuron disease (EMND).

“Although all three are associated with the same deficiency, they have different clinical presentations and manifest at different ages in affected horses,” she continues. “VEM and EMND cause neuromuscular disease, which presents as an insidious onset of poor performance, muscle weakness, and sometimes even muscle atrophy and fasciculations (twitching). eNAD/EDM affects the central nervous system of young to middle-aged horses, causing limb incoordination (ataxia), an abnormal stance, behavioral changes and occasionally loss of conditioning. Of the three disorders, horses with VEM respond remarkably well to appropriate vitamin E supplementation and can make a complete recovery. Unfortunately, EMND has a much more guarded prognosis, even with supplementation. There is no treatment available for eNAD/EDM.

“Understanding the different forms of vitamin E and planning supplementation appropriately is currently our only approach to preventing these diseases.”

When choosing to supplement your horse, there are several variables to consider: type of supplement, dose, length of treatment, and any clinical signs associated with a deficiency. A simple blood test performed by your veterinarian can measure the current levels of vitamin E and help answer some of the above questions to determine the best course of treatment for your horse.

Measuring Your Horse’s Vitamin E Levels

If you want to make sure your horse is consuming adequate amounts of this critical nutrient, here are some recommended daily intake levels from the National Research Council (NRC):

◆ 500-1000 IU per day for maintenance horses

◆ 800-1,000 IU per day for performance horses

◆ 1,500-5,000 IU per day for horses with muscle disorders or neurological conditions.

“The NRC requirements do not discriminate between natural and synthetic sources,” Fenn cautions. “They don’t factor in if your horse has a deficiency, increased performance demands, or medical conditions. Horses in consistent training, those with medical conditions, or those in geographic areas with no access to pasture typically require higher doses under veterinary guidance.”

If your horse has been diagnosed with a deficit by your veterinarian, a natural water-soluble (not powder/pellets) form of vitamin E at 10 IU per kilogram of body weight is recommended. Periodic rechecks are equally important to help guide long-term treatment.

Signs of Over-Supplementation

Over-supplementation of fat-soluble vitamins (A, D, E and K) is possible, since excess cannot be excreted in the urine like with water-soluble vitamins (vitamin C and the B vitamins), and can lead to potential health risks.

Moderation and veterinary consultation are critical when adjusting vitamin E levels to avoid unintended health complications. Signs of excessive vitamin E intake include coagulopathy, in which the blood’s ability to coagulate (form clots) is impaired, and diminished bone mineralization.

Despite the vast array of choices and marketing that accompany the world of equine supplements, vitamin E is a foundational pillar for equine health. Don’t let deficiencies take root, and make sure this key element is reaching your horse at sufficient levels in his diet.

This article about vitamin E for horses appeared in the July/August 2025 issue of Horse Illustrated magazine. Click here to subscribe!

The post Vitamin E for Horses appeared first on Horse Illustrated Magazine.

Photo courtesy Happy Trails Farm Animal Sanctuary

Adoptable Horse: Flying Comet, a 23-year-old, 15.1hh Standardbred gelding
Organization: Happy Trails Farm Animal Sanctuary, Ravenna, Ohio

Get to Know Adoptable Horse Flying Comet

Meet Comet, a wonderfully behaved Standardbred who’s ready to squeeze his way into your family.

Comet is an absolute gem. He is kind and always eager to please. This sweet soul enjoys long, leisurely walks down grassy roads and a quiet plod around the trails once or twice a week. He’s patiently waiting to begin his next chapter and start a new career. He tacks up very quietly and has plenty of “old-man energy” under saddle.

He’s the kind of horse you can let sit for months and come back to just as you left him. He’s steady, dependable, and full of heart. Keeping him moving, but still respecting his aging body will be the perfect combo for this boy.

With his gentle eyes and genuine personality, Comet has already stolen the hearts of those at Happy Trails… And now he’s ready to steal yours, too.

Please note that Comet is currently getting 1 tab Equioxx daily to help with his arthritis

Contact Happy Trails Farm Animal Sanctuary today about ASPCA Right Horse Adoptable Horse of the Week, Flying Comet!

ASPCA Right Horse

ASPCA Right Horse is the online adoption platform of The Right Horse Initiative, a collection of equine industry and welfare professionals and advocates working together to improve the lives of horses in transition. A program of the ASPCA, their goal is to massively increase horse adoption in the United States. To find more adoptable horses and foster horses, visit www.myrighthorse.org. To learn more about The Right Horse, a program of the ASPCA, visit www.aspcarighthorse.org.

The post ASPCA Right Horse Adoptable Horse of the Week: Flying Comet appeared first on Horse Illustrated Magazine.

Photo courtesy West Virginia Horse Network

Adoptable Horse: Dakota, a 20-year-old, 14.2hh grade mare
Organization: West Virginia Horse Network, Elkview, W.Va.

Get to Know Adoptable Horse Dakota

Dakota is a 20-year-old grade mare who is broke to ride and is an amazing trail horse that is up for any level of trail.

She has a very big trot and a smooth canter that would look nice in the arena as well. She is a little forward and needs more miles, so Dakota is not suitable for a beginner but not hard to handle.

Dakota stands to be groomed, bathed and great for the farrier. She loads on the trailer without a fuss and backs off the trailer. She has been exposed to multiple obstacles and handled them like a dream.

West Virginia Horse Network can’t say enough nice things about Dakota. Once she bonds with you, she is an extremely sweet girl that loves attention.

Dakota is much happier in a pasture environment and is a little higher in the pecking order but not mean to other horses. She can be a challenge to catch, but once you have her, she relaxes and is easy for all necessary care and handling.

Dakota had to have an eye removed recently but she is adapting fine.

Again, Dakota isn’t for a beginner and will need at least an intermediate adopter. She is used to being ridden in a hackamore.

West Virginia Horse Network is able to allow potential adopters to speak to both Dakota’s current foster as well as her previous adopter to give additional perspective and answer any questions. Dakota is currently fostered in Maryland.

Contact West Virginia Horse Network today about ASPCA Right Horse Adoptable Horse of the Week, Dakota!

Photo courtesy West Virginia Horse Network

ASPCA Right Horse

ASPCA Right Horse is the online adoption platform of The Right Horse Initiative, a collection of equine industry and welfare professionals and advocates working together to improve the lives of horses in transition. A program of the ASPCA, their goal is to massively increase horse adoption in the United States. To find more adoptable horses and foster horses, visit www.myrighthorse.org. To learn more about The Right Horse, a program of the ASPCA, visit www.aspcarighthorse.org.

The post ASPCA Right Horse Adoptable Horse of the Week: Dakota appeared first on Horse Illustrated Magazine.

Photo courtesy Wild at Heart Horse Rescue

Adoptable Horse: Jax, a 22-year-old, 14.1hh American Quarter Horse gelding
Organization: Wild at Heart Horse Rescue, Lancaster, Calif.

Get to Know Adoptable Horse Jax

Meet Jax, a sweet gelding who is ready to find his soft landing. This handsome gentleman is looking for a companion home or a family who would love to welcome him as a cherished pet.

Jax has the kind, steady presence that makes him a wonderful barn buddy. He would thrive in a home where he can enjoy turnout time with other horses, soak up attention, and simply be loved for who he is. Whether he’s keeping another horse company or greeting you at the gate for scratches and treats, Jax is happiest when he’s part of the family.

At this stage of his life, Jax deserves a peaceful environment where he can relax and enjoy his days. He would be perfect for someone wanting a low-pressure horse to dote on, groom, and share quiet moments with.

If you have room in your heart and pasture for a deserving gelding who just wants to be someone’s special boy, Jax is waiting to meet you.

Contact Wild at Heart Horse Rescue today about ASPCA Right Horse Adoptable Horse of the Week, Jax!

ASPCA Right Horse

ASPCA Right Horse is the online adoption platform of The Right Horse Initiative, a collection of equine industry and welfare professionals and advocates working together to improve the lives of horses in transition. A program of the ASPCA, their goal is to massively increase horse adoption in the United States. To find more adoptable horses and foster horses, visit www.myrighthorse.org. To learn more about The Right Horse, a program of the ASPCA, visit www.aspcarighthorse.org.

The post ASPCA Right Horse Adoptable Horse of the Week: Jax appeared first on Horse Illustrated Magazine.

Just a few strands of mane or tail hair can open the gateway to facts about your horse you couldn’t otherwise know. So then the question arises: Just because you can DNA test your horse, should you? What are the insights you could hope to gain, and are they worth the cost of the test?

DNA tools have been used by breed registries for decades to verify the parentage of a new foal. But there are other potential benefits of performing an equine DNA test—and the resulting useful information that can fall into four basic categories.

Close-up of individual mane hairs pulled from the root that contain enough cells to send in for DNA testing. Photo by Daniel Johnson

Color Information

A DNA test can provide very reliable results concerning your horse’s coat color genetics. This is because horse coat colors rely on simple inheritance, with some very specific genes and modifiers are directly responsible for visible results.

What you can’t visibly see from looking at your horse are the nuts and bolts of his dominant and recessive coat color traits. For instance, a black mare might have the hidden ability in her genes to produce, say, a chestnut foal if the stallion also carries that gene.

DNA tests can also easily identify modifiers like dilute, roan, and gray. Knowing your horse’s coat color genetics is helpful when considering future breeding plans, as it will give you an understanding of what color the resulting foal might be. Additionally, coat color genetics are just plain fascinating, and can help explain your horse’s precise color.

A DNA test revealed that this colt’s base color is black, modified by one creme/dilute gene and one roan gene. Photo by Daniel Johnson

Health Information

Many equine health issues are unique to the individual horse and his environment. For example, genetics aren’t at play if a horse contracts a tick-borne illness.

But many equine diseases are genetic or have genetic ties. DNA testing can indicate whether your horse possesses the genes that could lead to that disease. It doesn’t necessarily mean your horse will ever display symptoms of the disease, but that the potential exists.

Other times, a horse is a carrier of a genetic disease, and while they’ll never actually develop the disease, they could pass it on to their foals. Sometimes a genetic disease is breed-specific; for example, you might test an Arabian horse for severe combined immunodeficiency (SCID), which can lead to foals with weakened immune systems. Quarter Horses may be carriers of the gene for hyperkalemic periodic paralysis (HYPP), a muscle disorder. These are but two examples; you can test for many genetic equine diseases.

Breed Information

In the case of a grade horse with no pedigree information available, a DNA test can potentially determine the breeds of his ancestors, giving you at least a rough idea of what general mixture of blood he carries. While interesting, this information might not be all that helpful in some situations.

For one thing, it’s probably fairly apparent just from looking at your horse what might be in his background. A draft appearance, an Arabian flair, pinto markings, height, bone, head shape—all of these already provide clues to his unknown heritage. A DNA test might give you some more precision in this area, but the success of the DNA test in this manner hinges on the size and samples available in the testing lab’s database.

Additionally, many horse breeds have influenced others across history, such that equines as a whole share a lot of “horsey” DNA, making these tests challenging to interpret.

Fun Information

Finally, some DNA tests provide you with a dose of entertainment. Some DNA testing services offer “family” matching, where it might be possible to identify close relatives of your horse—cousins, aunts, uncles, et cetera.

Other DNA tests may offer performance information, such as indications of a horse’s potential athletic abilities, or whether they’re capable of a special gait like pacing or a running walk.

How Does DNA Work?

You don’t really have to understand how DNA works to see the benefits of a DNA test, but a basic grasp of the topic can be helpful.

DNA is a long chain of molecules inside every living cell, made of sugars, nitrogen, and phosphates. The exact arrangement of these molecules on the DNA chain determines how a living thing constructs proteins, so DNA can literally be thought of as a code or an alphabet that contains the directions to build a living creature.

Every cell in an animal’s body contains a complete set of instructions for building that individual. Different small segments of DNA—the genes—affect different physical characteristics.

These segments are inherited from each parent, so DNA tests can be used to identify relatives. Genes can be complicated, as there’s not always a single gene associated with a single trait, and the environmental factors that affect your horse throughout his life can play a big role in shaping who he is. So while DNA tests can teach us a lot about our horses, they aren’t crystal balls, either.

Key Takeaway

So, is there value in these tests? Absolutely—if the information is useful or entertaining to you. There is value to be had in color information, as it is highly accurate and can be helpful to breeders.

Genetic disease information can help you plan for your horse’s future. Insights into your horse’s heritage or even the geographic regions his ancestors lived in can be fun, though perhaps less useful. It’s mostly up to your curiosity level and your budget.

This article about equine DNA tests appeared in the July/August 2025 issue of Horse Illustrated magazine. Click here to subscribe!

The post DNA Tests for Equine Genetics appeared first on Horse Illustrated Magazine.

Photo courtesy Houston Humane Society

Adoptable Horse: Raven, a 26-year-old, 14.0hh grade Standardbred-cross mare
Organization: Houston Humane Society, Houston, Texas

Get to Know Adoptable Horse Raven

This sweet, older black Standardbred-cross mare is a gentle soul with a quiet, steady personality. Raven came to the Houston Humane Society as part of a cruelty case but has shown remarkable resilience. She has been steadily gaining weight and improving in condition, proving that with proper care, she will thrive.

Raven is broke to ride and has a calm, sensible demeanor under saddle, making her an enjoyable partner for relaxed riding. She appreciates a quiet, confident handler and does best with a steady routine. She loves grooming and is beginner-friendly, making her a wonderful choice for someone looking for a kind and forgiving partner.

In the meantime, she enjoys calm handling, consistent routines, and quiet time in turnout.

Raven would do best in a safe, kind home that can continue supporting her recovery and provide a comfortable, consistent environment. With the right care, she promises to be a loving, reliable companion for someone looking for a calm, steady partner to share her golden years.

Contact Houston Humane Society today about ASPCA Right Horse Adoptable Horse of the Week, Raven!

Photo courtesy Houston Humane Society

ASPCA Right Horse

ASPCA Right Horse is the online adoption platform of The Right Horse Initiative, a collection of equine industry and welfare professionals and advocates working together to improve the lives of horses in transition. A program of the ASPCA, their goal is to massively increase horse adoption in the United States. To find more adoptable horses and foster horses, visit www.myrighthorse.org. To learn more about The Right Horse, a program of the ASPCA, visit www.aspcarighthorse.org.

The post ASPCA Right Horse Adoptable Horse of the Week: Raven appeared first on Horse Illustrated Magazine.

Photo courtesy Lollypop Farm

Adoptable Horse: Stephan (Real Sly), a 20-year-old, 16.1hh Thoroughbred gelding
Organization: Lollypop Farm, Fairport, N.Y.

Get to Know Adoptable Horse Stephan

Stephan (Jockey Club name Real Sly) came to Lollypop Farm with high praises. This sweet boy was loved on by his previous owner for most of his life, but due to unfortunate circumstances in the owner’s life, he is looking for another caring family to call home.

As a non-riding, companion only horse, Stephan gets to enjoy the rest of his life as a pasture pal. But he still deserves praise for how much he has done in his life — he raced, showed, trailered often, and has adjusted well to different homes. He is non-rideable due to conformational issues, including a club foot.

Stephan has been great for grooming, handling, vet, farrier, you name it! He is uitable for a beginner-intermediate handler.

His adoption fee is $300, or he is also eligible for the C.A.R.E Program.

Contact Lollypop Farm today about ASPCA Right Horse Adoptable Horse of the Week, Stephan!

Photo courtesy Lollypop Farm

ASPCA Right Horse

ASPCA Right Horse is the online adoption platform of The Right Horse Initiative, a collection of equine industry and welfare professionals and advocates working together to improve the lives of horses in transition. A program of the ASPCA, their goal is to massively increase horse adoption in the United States. To find more adoptable horses and foster horses, visit www.myrighthorse.org. To learn more about The Right Horse, a program of the ASPCA, visit www.aspcarighthorse.org.

The post ASPCA Right Horse Adoptable Horse of the Week: Stephan (Real Sly) appeared first on Horse Illustrated Magazine.

Photo courtesy February Star Sanctuary

Adoptable Horse: Trip Sevens (Ace), a 5-year-old, 16.0hh Thoroughbred gelding
Organization: February Star Sanctuary, Knoxville, Md.

Get to Know Adoptable Horse Trip Sevens (Ace)

Who doesn’t love a gorgeous gray? Trip Sevens, known around the barn as Ace, is a 5-year-old, off-track Thoroughbred that came to February Star Sanctuary from Aftercare Charles Town.

Ace is as sweet as he is handsome. He loves being around people, is a big fan of getting attention and affection, and is both calm and curious — he’ll probably be the first to greet you at the barn. Being the softy that he is, he can get spooked, so February Star thinks he’ll be best with an experienced, confident adopter who can help him learn groundwork and manners. He’s in the process of healing from an injury that will take about one year to properly heal, so at this time, he’s available as a companion horse. February Star does believe that with patience and correct management, he could eventually be a light trail rider.

Contact February Star Sanctuary today about ASPCA Right Horse Adoptable Horse of the Week, Trip Sevens (Ace)!

Photo courtesy February Star Sanctuary

ASPCA Right Horse

ASPCA Right Horse is the online adoption platform of The Right Horse Initiative, a collection of equine industry and welfare professionals and advocates working together to improve the lives of horses in transition. A program of the ASPCA, their goal is to massively increase horse adoption in the United States. To find more adoptable horses and foster horses, visit www.myrighthorse.org. To learn more about The Right Horse, a program of the ASPCA, visit www.aspcarighthorse.org.

The post ASPCA Right Horse Adoptable Horse of the Week: Trip Sevens (Ace) appeared first on Horse Illustrated Magazine.

“These insects make their appearance in the spring and become sparse in the cold winter months, but generally they remain active year-round, especially in places like Florida, contributing to the chronic causes of allergic skin disease in some horses,” says Caitlyn Henderson, DVM, of Peterson Smith Equine Hospital in Ocala, one of Florida’s largest equine clinics.

The condition is often seasonal with chronic relapses, but horses in warmer climates may be affected year-round.

Photo by Bob Langrish

Clinical Signs of Insect Bite Hypersensitivity in Horses

Horses suffering from IBH often present with recurrent hives and/or chronic itching (pruritus). Clinical signs of IBH can include:

◆ Circular areas of crusting caused by inflammation (bacterial folliculitis)

◆ Blisters (papules)

◆ Hair loss (alopecia)

◆ Raised, hard, thickened areas of skin

◆ Broken hairs with sores in mane and tail head

◆ Self-trauma from rubbing

◆ Pigmentary alterations

◆ Behavioral changes due to discomfort

“Signs can often start as very subtle, especially when under the mane or at the tail head,” says Henderson. “Broken hairs are easy to miss in the beginning.”

Intense itching can cause allergic horses to rub bald spots and sores into their manes and tails. Photo by Christiane Slawik

Skin lesions develop where insects feed. This is typically along the horse’s ventral chest and abdomen, under the mane, along the withers and back (dorsum), tail base, and inguinal areas (between the hind legs), as well as on the face and ears.

“These lesions all come with a degree of itching, which feeds the cycle of lesion development, eventually causing severe scarring, permanent hair loss, and depigmentation,” says Henderson.

Why It Happens 

With IBH, a half-ton horse can’t hold his own against tiny insects.

The horse’s immune system is triggered by proteins and enzymes in the insects’ saliva as they feed. The horse’s body identifies those salivary enzymes and proteins as foreign, which causes the allergic response.

“The immune system releases antibodies, specific immune cells, and inflammatory mediators that drive inflammation and cell migration to peripheral tissues near the bite site, which then drives itching and swelling,” says Henderson. “Histamine is also released from mast cells sent by the immune system at the bite site, and they release more enzymes that irritate nerves nearby, further driving the urge to itch.”

It’s a nasty cycle that will only continue unless the horse is treated and the cause addressed.

Diagnosing Insect Bite Hypersensitivity

Because IBH is often bundled with other environmental allergies, there isn’t a single test to definitively diagnose the condition.

 Veterinarians base their diagnosis on the horse’s history (including travel, exposure, housing, and environment), clinical signs, duration, severity, and frequency of those signs, previous treatment, and diagnostics. The goal is to rule out other skin diseases and determine the best response to treatment.

“Many practitioners will still reach for intradermal allergen testing to support their diagnosis, which is helpful if clients are looking for a more direct approach,” says Henderson. “Serum allergy testing has proven to be of little benefit for horses with their broad range of allergen exposure. It’s like sending your kiddo to daycare for the first time and then testing them to see what germs they picked up while they were there.”

Treatment Protocol 

There is no one-size-fits-all protocol. Medical treatment can soothe the irritated skin and provide relief, but fly control or insect avoidance is considered the mainstay of both treatment and prevention.

“No amount of bathing, fish oil, and cetirizine in the world will help a horse with IBH if we aren’t trying everything we can to reduce the insect population in their environment,” says Henderson. “It doesn’t matter how much Benadryl you give your child after playing in an ant pile if you don’t get them out of the ant pile first.”

Limiting places where flies can make contact with a horse through use of fly sheets, masks, and boots helps sensitive horses enjoy outdoor time. Photo by Christiane Slawik

She advises horse owners to prioritize reducing the insect population and limiting insect-horse contact. This includes:

◆ On-horse insect repellent containing 2% permethrin

◆ Fly masks with ear covers

◆ Fly sheet

◆ Fly boots

◆ Automatic fly spray systems in barns

◆ Fly traps (including sticky traps)

◆ Bug zappers

◆ Strong indoor fans

◆ Keeping horses stabled during peak insect feeding times

◆ Eliminating standing water in paddocks and barn area

◆ Diligent manure management and removal 

Strong indoor fans discourage flies from landing on horses. Photo by Terri Cage/Adobe Stock

Bathing the horse with medicated shampoo is recommended. Look for products that contain ingredients that support healthy coats and reduce dryness, as well as ketoconazole and chlorhexidine to reduce bacterial and fungal growth in the skin that can contribute to itching.

“Many veterinarians want to reach for systemic glucocorticoids, such as dexamethasone or prednisolone, and antihistamines,” says Henderson. “There is little research that supports the efficacy of these drugs for horses with IBH, but anecdotally they show promise in limiting the itch-inflammation cycle. Cetirizine (Zyrtec), another antihistamine, also has little research supporting efficacy against itching and clinical signs associated with IBH, but it is considered safer for horses than systemic glucocorticoids. Regardless, your veterinarian should consider your horse’s general health, risk factors, and clinical signs when starting therapy.”

If you want to try an oral supplement, omega-3 fatty acid supplements have been shown to improve skin lesions, but don’t help with itching.

Diligent manure removal takes away fly breeding grounds. Photo by Christiane Slawik

Secondary Infections 

IBH lesions disrupt the skin’s protective barrier and the population of healthy microbiota. When this happens, opportunistic bacteria and pathogens sometimes infect deeper tissues, causing secondary infections.

“Now, instead of just controlling the itch and giving the skin time to heal, you have to eliminate the bacterial infection before the itching resolves and the healing can finally begin,” says Henderson.

Skin lesions develop where insects feed, such as under the mane, and may not be noticed until the hair is rubbed out. Photo by Christiane Slawik

Immunotherapy

People get allergy shots, but do they work on horses?

Henderson says allergen-specific immunotherapy (ASIT) has shown promise in horses when administered over a period of two years, but so far treatment protocols have not been standardized, so results vary.

“ASIT is especially beneficial for horses who cannot avoid their allergens or who are exposed to their allergens for extended periods, often resulting in further hypersensitization of the allergic response,” says Henderson. “Horses in Florida, for example, are exposed to mosquitoes and biting insects nearly year-round, so those horses that have moderate to severe IBH even in our peak ‘winter’ are good candidates for ASIT.”

It typically takes three to six months to see if the horse will have a positive response to treatment. In some cases, immunotherapy has resulted in remission of the allergy. Your veterinarian can determine if your horse is a good candidate for immunotherapy.

“Immune-modulating therapies, such as Cytopoint (lokivetmab), Apoquel (oclacitnib), and allergy shots are still undergoing safety and efficacy studies in horses,” says Henderson.

Finally, don’t subject your horse to the questionable suggestions you may find when searching for home remedies for IBH. Applying used motor oil, bacon grease, or similar concoctions to your horse’s mane, tail, or coat won’t cure the condition, and can end up increasing skin irritation. 

This article about insect bite hypersensitivity in horses appeared in the May/June 2025 issue of Horse Illustrated magazine. Click here to subscribe!

The post Insect Bite Hypersensitivity in Horses appeared first on Horse Illustrated Magazine.