By Margaret Evans

Whether or not to give supplements to horses has always been the topic of lively and enduring conversation. But, there is a growing community of riders and horse owners who choose to provide their horses with the supplemental balance of vitamins, minerals, and trace elements to help with health issues and augment the well-being of their animals.   

While some may think that the use of supplements is a trendy, contemporary approach to equine nutrition, in fact the history of supplements for horses goes way back.

In 1833, Thomas Day began manufacturing animal medicines at Wantage, Oxfordshire, UK, and expanded into London a year later. In 1834, he launched the first known equine tonic called Days’ Black Drink to relieve colic, gripes, chills, and low condition in horses. He sold Black Drink for 10 shillings for six bottles (there were 20 shillings in British pound). Day & Sons, which was established in 1840, billed itself as the largest veterinary supplier in the world and included a statement on the bottle’s label to caution against others selling imitations of their Black Drink.

In 1912, biochemist Frederick Hopkins (1929 Nobel Prize in Physiology for Medicine) published a paper that explained, through a series of animal feeding experiments, that proteins, carbohydrates, fats, minerals, and water alone do not promote growth, but other then-unidentified substances called “accessory food factors” were essential for animal growth and survival. Those accessory food factors turned out to be vitamins.

Over the subsequent decades, an industry in equine food and nutritional supplements took off. According to an article in the UK magazine Horse & Hound (October 2004), 1929 saw the launch of Equivite’s vitamin and mineral mix for horses; the first cod liver oil product for horses and ponies was launched in 1935; and, in 1958, the first “pony nuts” (pellets) appeared. Products to improve horse health developed steadily with the first herbal calmer (1986) and the first feed balancer in 1989. In 1995, the University of Guelph, Ontario, completed research that led to the first premium electrolyte for performance horses. In the past 20 years, horse owners have enjoyed an expanding selection of feeds, supplements, and balancers to choose from and the market continues to grow.

“There is a rise in owners searching for supplements,” says Shelley Nyuli with SciencePure Nutraceuticals Inc., in Abbotsford, BC. “However, their desire is for a supplement that they think is needed to aid in a specific symptom of a nutritionally unbalanced or environmentally-deprived horse.” 

Nyuli says that, since 1997, the most popular product is a joint aid formula for horses showing symptoms of osteoarthritis, joint stiffness, or short striding.

“Over the years we have noticed a drastic increase in horse owners using supplements on their horses, in particular joint supplements, not only for therapeutic use but also for maintenance,” says Trevor Watkin, co-owner (with brother Jason Watkin) of Purica in Duncan, BC. “From our experience, the most popular supplements are, of course, a good vitamin supplement but also supplements for joint issues.”

The interest in equine nutrition and the value of supplements is just as strong in the US.

“Over the last 30 years, we have seen a dramatic increase in equine nutrition interest,” says Dr. Scott Gravlee, equine nutrition consultant with Life Data Labs, Inc., in Cherokee, Alabama. “There has been an increase in the usage of supplements manufactured by Life Data Labs, Inc. every year. Although we cannot speak for all manufacturers, our primary customer focus has been on hoof, joint, and forage balancers.”

In Vernon, BC, veterinarian Dr. Dave Reed formulated supplements to use on his own equine breeding stock and in his veterinary practice, and now sells his products through feed dealers in the province.

“Our data indicates, yes, more horse owners are using supplements,” says Reed. “They are appreciating research now specific to horses, and have available many resources to read from and to listen to. Although the horse population is decreasing, the value of many of those being maintained is increasing, prompting their owners to seek the best possible for their animals.”

The most important component of the horse’s diet is fibre from pasture grazing or quality hay. Before adding a supplement, the horse’s diet should be assessed to determine what is needed to fill in the nutritional gaps. Photo: Thinkstock/AMCImages

In Abbotsford, BC, equine nutritionist Shelagh Bertrand, PAS with Foundations Equine Consulting Services agrees that there is a lot of growing interest in supplements. “A lot of people are interested in what they can feed their horse. Most popular I would say is probiotics, and the other one would be supplements to aid in comfort, joint supplements. Those are the big ones.”

Many ask if supplements work and, if so, how? But first it is important to understand the natural feeding instincts of horses, how they evolved in relation to their natural resources, and how or whether those same sources have changed today in nutritional quality.

“Horses are ‘hay burners,’” says Gravlee. “This means horses can convert cellulose (fibre) to energy in the pouches of their digestive systems. In their evolution, horses had the capacity to produce all the nutrients needed for survival by consuming water, minerals, plant materials, and cellulose. Bacteria in the hindgut use cellulose derived from hay and other roughages to produce energy. These same microbes also produce the building blocks to manufacture most of the essential nutrients that simple stomach animals, such as people, must ingest. Unfortunately, this ecosystem does not have the capacity to furnish the quantity of nutrients to compensate for the added work and stress of the modern horse. In addition, modern agriculture is producing grains (oats) and pasture grasses that have a different nutrient content than the forages from which horses evolved. And lastly, the mineral content of soil from which the grasses and grains grow has changed due to leaching from rainfall. We are faced with the nutrition challenge to fortify the horse’s ecosystem without producing nutrient excesses and/or deficiencies.”

So, do supplements work to meet the nutritional challenge?

“Whether a supplement works or not depends on many factors,” says Gravlee. “First, the assessment of the horse’s problems must be correct. For example, if the horse is exhibiting lameness due to a neuromuscular problem, a joint supplement is unlikely to help. Also, the quality of the horse’s current nutrition is a determining factor in whether additional supplementation will help. Not only is an adequate level of each necessary nutrient important, but the ratio of the nutrients to each other is often more important. The best-known correlation is between calcium and phosphorus; however, most other nutrients have correlations too. Over-supplementation with resulting altered nutrient ratios is a common problem facing the horse today. Other factors influencing the effectiveness of a supplement include the horse’s breed, occupation, genetics, age, etc.”

Bertrand stresses that it is important to always remember that the horse needs fibre. “Horses evolved to have a diet of fibre and they ferment it in the hindgut. They need small meals fed often and you need superior quality forage.”

Horses are non-ruminant herbivores and the best feeding regimen for a horse is continuous grazing in a grassy paddock. But when feeding forage, horse owners need to know how well the hay they are buying is providing the required nutrients. In addition to hay, beet pulp, some grains, and hay cubes (alfalfa or timothy/alfalfa cubes) all contribute to healthy hindgut function.

Throughout any one year, horses are often fed a variety of hay depending on where their supplier is buying it from. It is worthwhile to get an analysis of the hay to determine what the horse is eating. By understanding the nutritional value of the horse’s basic diet, it is easier to consult with an equine nutritionist to figure out what might be missing and supplement accordingly, if necessary.

According to Reed, horse owners are most frequently seeking a complete vitamin/mineral supplement to augment their non-complete hay/grain choices for broodmares, young horses, seniors and performance horses, and more recently for sugar sensitive horses. While there are some owners who do not feed complete feeds, those who do, depending upon the quantity being fed, may not need additional supplementation.

Joint supplements are popular, and the majority of horses receiving them are engaged in competition. A high performance horse is more likely to require dietary supplements to support his athletic endeavours than a backyard horse with a less demanding workload. Photo: Shutterstock/Diane Garcia

“[However], many supplements do work with visible results - sometimes very visible - surprisingly quickly,” says Reed. “If it is decided that supplementation is needed, there are many things to be considered. Our personal process has always been to seek advice from a professional nutritionist with a special interest in/knowledge of horses who has access to peers with similar interests. There is a huge variety of supplements addressing many needs. It has become a daunting adventure to choose the one for your horse. Firstly, I would say one wants to be comfortable with the quality of the source and the quantity of ingredients. Read the analyses and ingredients lists. For example, in our case the small amount of grain used for palatability and pelleting is 100 percent Canadian, non-GMO, and closely monitored for low moisture content upon arrival at the mill. A portion of our trace minerals are chelated/complexed and a portion of our selenium is organic. Research advises that both organic and inorganic sources of minerals play best in bio-availability. The small amount of oil in our products, for dust control, are non-hydrogenated vegetable oils supplying Omegas 3 and 6. Our products contain B vitamins - not all do - our choice to make immediate support for stressful situations the horse might experience. Our products contain Diamond V yeast culture which enhances digestion in the hindgut.”

Nyuli agrees that, by using a reputable brand, horse owners should see results in the first week, depending of course on the reason for supplementing in the first place. Owners, she says, have to be very clear in their minds as to what they expect from a supplement, adding that feed mixes may use oxide minerals which are not nearly as bio-available as protein bond (proteinated/chelated) minerals.

Supplements for Joint Issues

Of all the supplements purchased by horse owners, those that address joint issues, specifically osteoarthritis (OA) and discomfort, disability, or some loss of function, are among the most popular. Understandably, most of the horses being administered this form of supplement are engaged in competition.

A study done by nutrition scientists at Kentucky Equine Research (KER) in Versailles, Kentucky, focused on the effectiveness of joint supplements. KER maintains a herd of about 40 research horses on their 150-acre farm. The researchers point out in their report summary dated June 1, 2017 that the quality of joint supplements can vary markedly depending on the ingredients and manufacturer.

“A multimodal approach to managing OA currently involves the use of nonsteroidal anti-inflammatory drugs like bute, corticosteroids, and joint supplements, among others, depending on the horse and the work asked of it,” says nutritionist Dr. Kathleen Crandell in the report summary. “Products containing glucosamine, chondroitin sulfate, and hyaluronic acid continue to reign among the most popular supplements. Studies show that these ingredients help decrease inflammation through multiple pathways and provide molecular precursors to cartilage cells to help build new, healthy cartilage in arthritic joints.”¹

Many studies are done on horses with joint issues and results understandably differ according to the horse’s health condition, level of exercise, and the parameters set for each specific test. “Performance horses require increased levels of many different nutrients when compared to a horse that is not ridden often, simply because of the increased metabolic load required for intense and prolonged effort,” says Watkin. “Just like human athletes, who often supplement to help prevent wear and tear, to relieve pain and spasm, and to reduce inflammation, the same is appropriate for horses. Like people, each horse will present its own physical weaknesses and limitations, and there is plenty of scientific evidence to suggest both potent preventative and therapeutic effects from a wide range of supplements and nutraceuticals (plant medicines).”

Supplements for Digestion

The most important component of any horse’s diet is fibre in the form of pasture grazing or quality hay. The sheer act of eating and the intake of forage stimulate the good bacteria in the gastrointestinal tract, and most of the digestion of fibre takes place in their enormous hindgut where the bulk of nutrients and fluids are absorbed. It is here where all those good bacteria (microflora) digest the fibre to release nutrients. Providing quality forage is the foundation of every feeding program.

Along with forage, water is the next most critical component. A 450 kilogram horse (1,000 lbs) eating nine kilograms (20 lbs) of food a day needs 30 litres of water to process it all. And that is before water is required for thirst, heat, sweat after exercise, or any other trigger.

“Live grass grazing is not only higher in the essential minerals as baled grass hay, it is far easier on the horse’s stomach and mind,” says Nyuli. “That is the traditional thought. However, with ground nutrient depletion and weather changes causing rapid sugar increases, grazing horses have to be watched for daily changes in temperament and heat in the feet. Ideally, alternate pasture grazing and unlimited hay feeding is best for the equid digestive system given that the stomach holds forage for only 15 to 30 minutes before passing it on to the small intestine. If the stomach is empty for too long (two hours) and fermentation continues as it always does, the small stomach fills with gas and could create gastric colic and gastric ulcers. Eating small meals more often, or constant grazing, is the way the digestive system is designed and we cannot change that.”

Water, a critical component of every horse’s diet, is necessary for digestion and thermoregulation. Free-choice water of appropriate temperature should be provided at all times. Photo: Shutterstock/Sari ONeal 

Nyuli suggests that the very first supplement any performance horse should have is salt, and the second (and perhaps equally important) supplement should be based on any nutritional deficiencies in the horse’s forage. The microbial analysis will provide information on the hay’s sugar content, critical if the horse has a metabolic syndrome issue, as well as calcium, phosphorus and other minerals.

At KER, research was done earlier this year to explore the value of using a high-algae supplement to fight or prevent equine gastric ulcer syndrome (EGUS). Some forms of algae contain high levels of minerals, especially calcium, which can buffer stomach acid and aid in healing. The researchers gave ten horses diagnosed with EGUS an algae supplement containing 32 percent organic calcium for 30 days. Ulcers are graded on a scale of 0 to 4 and the horses had ulcers averaging scores of 2.2. After 30 days, they all showed significant improvement. Seven of them had a zero score and two had a score of one. However, in their press release, the researchers cautioned that while these results are encouraging, not all supplements are safe and effective and some algae products can even be dangerous. 

Grain-based concentrates have their values but they can also have their issues with respect to the release of blood glucose and a surge in insulin hormone levels. Concentrates should be fed at no more than 0.4 percent body weight per feeding, or 1.8 kg (4 lbs) per 450 kg horse.

A sudden change in diet, stress from travel, competition, or a change in routine can upset the normal digestive flow of food and endanger the population of the good bacteria in the horse’s gastrointestinal tract. Many horse owners consider giving probiotic supplements that contain microorganisms, fungus, and yeast, and they are all designed to stimulate good bacteria to aid digestion. 

Supplements for Hoof Growth

Hoof supplements are huge business and there are many products on the market. Hoof wall problems present as cracks, chips, brittleness, white line disease, thin sole, and a variety of conditions that may have their roots in the breed genetics of the horse, the degree of work, or in a dietary deficiency.  

One of the most devastating hoof conditions is laminitis. In 2014, researchers with the Biomin Research Centre in Tulln, Austria, published results of a study in the journal Toxins, in which they showed the value of using milk thistle and silymarin, an extract of milk thistle, to combat bacterial endotoxins (LPS) that compromise hoof lamellar tissue. Milk thistle and silymarin both have anti-inflammatory and antioxidant properties and can be found in some hoof supplements.  

“Milk thistle and silymarin were not only able to neutralize endotoxins but [were] also capable of reducing LSP-induced lamellar separation,” the report states. “Hence, MT [milk thistle] and silymarin might be used to support the prevention of laminitis through direct neutralization of endotoxins and inhibition of LPS-induced effects on the lamellar tissue.”

The researchers cautioned that further studies are necessary on endotoxins and how they contribute to laminitis. More investigation is also needed on the action of milk thistle and silymarin as to how they neutralize LPS.

“Supplements are ideal to fill in nutritional gaps found in most feed sources today,” says Watkin. “Whether it be selenium, magnesium, or any other nutrient that can be deficient in the diet, or the need to increase levels of vitamin C to account for oxidative stress of prolonged high intensity equine sport, supplements improve performance by optimizing nutrient status and helping to prevent damage from occurring.”

The enthusiasm to use supplements should be balanced with the knowledge that the products do not come under the regulations of the Canadian Food Inspection Agency and it is a largely unregulated industry. The best pathway to success is to consult with your veterinarian or an equine nutritionist on the most appropriate course of action to effectively provide your horse with the specific supplements needed.

¹*Kilborne, A.H., H. Hussein, A.L. Bertone. 2017. Effects of hyaluronan alone or in combination with chondroitin sulfate and N-acetyl-d-glucosamine on lipopolysaccharide challenge-exposed equine fibroblast-like synovial cells. American Journal of Veterinary Research. 78(5):579-588.

A Word About Electrolytes

Electrolytes are minerals dissolved in the blood and tissues of the horse’s body. They carry a positive or negative charge and, when combined with another ion, they make salt. Electrolytes help to maintain the correct balance of fluids and they are involved in muscle function and the processing of waste material.

Photo: Shutterstock/Art Studio

When horses sweat, they lose more than water. Horse sweat contains the electrolytes chloride, sodium, potassium, calcium, magnesium, and other trace minerals. The two electrolytes lost in the highest amounts are sodium and chloride, or salt. During training or competition, electrolyte loss can be considerable especially in hot, humid weather. A 500 kg horse can lose 10 litres of sweat during a two-hour exercise routine and that would include 60 grams of chloride.

“Electrolytes don’t stay in one place,” says Barbara Socha who owns Equiwinner in Arizona. “Electrolytes move around, in and out of cells, while transmitting electrical impulses along nerves for muscle function such as your horse’s beating heart or muscle contractions to allow him to run. And they manage all your horse’s bodily fluids.”

Socha says that research has shown that simply providing electrolytes to horses does not necessarily guarantee they will work properly and abnormalities in electrolyte activity have been linked to non-sweating and tying up. Signs of electrolyte deficiency include a dull coat, sunken eyes, listlessness, poor performance, and dark urine.

Providing an electrolyte balance may include the use of certain supplements or, alternatively, the use of an electrolyte patch placed on the horse’s rump. Advice from your vet or your equine nutritionist is recommended prior to using electrolytes or, equally important, knowing when to use them in relation to your horse’s water intake. 

More by Margaret Evans

Main photo: Shutterstock/Mila Supinskaya Glashchenko