How HISA has affected the marketing and selling of equine supplements - What trainers need to know

Article by Ken Snyder

In 1834, Thomas Day of Day & Sons in the UK. introduced Day’s Black Drink, an elixir for horses to relieve colic, chills, “low condition” and something called “gripes.” There is no record of the ingredients, and that is probably something best left unknown.

Black Drink was the first known supplement, or product made from natural, not synthetic, substances, as this was the early 19th century. So, too, is heroin derived from a natural substance—poppies. (Created from morphine in 1874, its use on the racetrack was prevalent enough in the early 20th century to help fix races that “horse” became slang for the narcotic in recent history.)

Supplements today range from useless and quackery to many that are considered effective in horse health care by many trainers on the racetrack. In fact, the majority of  Thoroughbred trainers utilize supplements with feed.

Like therapeutic medications and illegal substances, dietary supplements are under the purview of the Horse Integrity and Safety Authority (HISA). Like their drug counterparts, HISA is instituting uniform regulations for supplements in all 50 states. The task falls specifically to the organization’s Horse Integrity and Welfare Unit (HIWU).

Good, bad, or indifferent, the intent of this organization, inarguably, is noble: to make racing safer and healthier for the horses. 

Supplements, however, are seemingly lost in the fog in the scrutiny and attention paid to perhaps the biggest problem in horse racing: medications.

There are potential hazards with supplements, however, and uniform rules across all U.S. racing jurisdictions are in place just as with medications. The key regulation that is now applicable in every HISA jurisdiction specifies that “orally administered vitamins“ and “unsupplemented isotonic electrolyte solutions by oral or intravenous administration” may be administered up to 24 hours prior to post time. This may differ from prior state regulations.

Alexa Ravit, director of communications and outreach for HIWU, outlined the objectives of this regulation and all HISA “regs” in response to an email:

“HISA’s supplements-related regulations (and in particular addressing ‘drug claims’) are intended to protect horsemen from 1) fraudulent or unproven claims of effect; 2) the unknown safety risk to horses in administering these products; and 3) products where the risk of contaminants or unknown components is high due to lack of independent quality controls.”

The task of monitoring and regulating dietary supplements is not nearly as challenging as that for medications, but it is no slam-dunk either. Also, while medications and new withdrawal times for permitted drugs might be a trainer’s focus, trainers should know that, while supplements by and large are safe, there are things to watch for with their use. 

In simplest terms, managing supplements for trainers under HISA/HIWU is following three steps: (1) reading labels (more on this below); (2) being careful in using dietary supplements in combination with approved medications; and (3) not accepting free supplements without understanding what’s on the label.

Mislabeled supplements, according to Rivet, are the major thing that can get a trainer and owner in trouble. She wrote, “If…the product’s labeling…includes a health or structure/function claim, the product is a drug, not a dietary supplement.” Also, drugs are FDA-approved and will carry that information on the label. Supplements won’t. 

In short, trainers need to look first to make sure the supplement does not say “FDA approved.” Supplement labels also should not make “structure/function” claims. HIWU lists these examples:

− Decreases or prevents exercised-induced pulmonary hemorrhaging (EIPH)

− Prevents or treats gastric ulcers
− Manages pain caused by osteoarthritis
− Controls inflammatory airway disease 

− Increases cardiac output
− Increases red blood cell production

The claims are definite, positive and apparently proven by results, warranting approval by the FDA.

Contrast these claims against what will be found for dietary supplements: 

− Sustains lung health
− Maintains gastrointestinal health
− Supports heart health
− Supports bone strength
− Promotes healthy metabolism
− Replenishes electrolytes lost through exercise and sweating

Labels on dietary supplements sound good but stop short of making a promise and, in a couple of instances, are vague at best. “Sustains lung health” and “maintains gastrointestinal health” are things you would want a horse to have after lung or gut issues are solved, and maybe skate closest to a claim like a drug. What supports heart and bone health and strength, respectively, is anybody’s guess. The same goes for promotes healthy metabolism. (Maybe the label will tell one how.) Replenishes electrolytes is a straight-up promise that evidently is achieved with dietary supplements and not drugs. (Gatorade for humans comes to mind.) 

To make another simple distinction, drugs are available only through a prescription from a veterinarian. If a trainer is getting them through another source, there’s potential trouble; but that’s for another story. Supplements are available in tack shops and/or online and do not require a veterinary prescription. 

Ravit, in response to how common it is to see supplements making drug claims contrary to regulations, only said, “It cannot be quantified.” That’s “Governmentese” for “It’s anybody’s guess.”

HISA/HIWU’s own definition of a drug, by the way, is this:

“Under the Federal Food, Drug, and Cosmetic Act, the term “drug” means a product intended for use in the diagnosis, cure, mitigation, treatment, or prevention of disease, and articles other than food intended to affect the structure or any function of the body.” That’s a mouthful to say it ought to work.; you should get results.

In case you’re wondering why supplements are not regulated by the FDA, the category name “dietary supplements” gives you the answer. The FDA defines them as a “dietary ingredient intended to supplement the diet.” Dietary supplements are not regulated for humans either.

Are they safe? You would think, given the absence of regulation, the answer would be an automatic “yes.” The FDA, however, can take action to remove supplements from the market if they are adulterated (unsafe) or misbranded (misleading). Let the buyer beware.

What a trainer can control are things to avoid, such as mixing supplements with drugs, administering too many supplements, or substituting supplements for drugs altogether. 

HIWU’s language on dietary supplements is actually a bit scary:   

“It is…the responsibility of the manufacturer to ensure the product’s safety and to market the supplement in accordance with applicable law.“

The second part of the statement should give one pause. Yes, the manufacturer is responsible for the product’s safety, but it’s the trainer or trainer’s barn help that is the last person in the literal food chain for the horse. Once a supplement is in a trainer’s hands, he or she is on their own. The safe bet is a veterinarian’s assessment of any risks and/or benefits. 

HIWU addresses this in their literature: “Supplements can interact with some medication with adverse health conditions” advising trainers to “be vigilant and discuss administration [of a supplement] with your veterinarian.”

Ravit also responded with “no comment“ to whether there have already been instances of a supplement producing a positive test for an illegal or controlled substance.

Practicing veterinarians like Dr. Rick Fischer, who has been on the racetrack for 53 years, is, as one would expect, well-versed in the difference between a drug and a supplement. He presents another issue that threatens the health and safety of horses. He and other vets are not always gatekeepers with supplements for trainers. Laymen or salesmen will approach trainers directly promoting supplements. “Worse than that, they’ll give them away: ‘Here are two gallons of this. Use it and see if you like it.’ You really don’t know what the hell you’re getting,” said Fischer.

There are other words on supplements to be mindful of. HIWU’s website warns that “’natural’ does not mean safe, nor does it mean that a product is free of Prohibited Substances.  Neither do “seals of quality assurance” that guarantee a supplement is safe and effective. In short, even practicing veterinarians recommending supplements cannot guarantee safety or effectiveness.

Fischer said there have been instances where a supplement and an approved medication have produced positive tests for banned substances. 

 HIWU’s website advises, “It is crucial to have specialized knowledge from a chemical engineer or pharmacist in order to comprehend and forecast the resulting molecules, due to the intricate interplay between the chemicals involved.” 

 Fischer expounds on the “intricate interplay” thusly: “There’s been positive tests on things that I’ve never even heard of. It’s not something that anybody in their right mind would give a horse. But the chemical breakdown when they’re in combination…who knows? 

“They’ll give you a list of all the different ingredients. Most of it is Greek to these guys and some of it is Greek to me, and I’ve been practicing for more than 50 years.”

Fischer actually parroted HIWU language in saying it would take a chemical engineer or pharmacist to be able to tell “if this molecule matches up with this molecule and what it’s going to come out as.“

Good luck to any trainer looking for a chemical engineer or pharmacist on the backside. 

Dr. Day’s Black Drink, by the way, would not pass muster as a supplement as it claimed to treat colic. As for “gripes,” there is no supplement or drug for that. 

The use of probiotics as an alternative to antibiotics to reduce resistance in the gut

Article by Kerrie Kavanagh

The leading causes of horse mortality can be attributed to gastrointestinal diseases. Therefore, maintaining the balance of the gut microbiota and avoiding a shift in microbial populations can contribute to improved health status. The gut microbiota, however, can be influenced by countless dynamic events: diet, exercise, stress, illness, helminth infections, aging, environment and notably, antimicrobial therapy (antibiotics). These events can lead to gut dysbiosis—a fluctuation or disturbance in the population of microorganisms of the gut, which can contribute to a wide range of disease. The use of antibiotics in horses is thought to have one of the most notable effects on the gut microbiota (gut dysbiosis), which can lead to diseases such as colitis, colic and laminitis.

Antibiotics, which are antimicrobial agents active against bacteria, are important to equine medicine; and bacterial infections can be resolved quite successfully using antibiotics for antimicrobial therapy, but there are consequences to their use. An antimicrobial agent can be defined as a natural or synthetic substance that kills or inhibits the growth of microorganisms such as bacteria, fungi and algae. One of the consequences of antibiotic use is that of antibiotic-associated diarrhea, which can contribute to poor performance in the horse and even mortality. In antimicrobial therapy, the target organism is not the only organism affected by the antimicrobial agent but also the commensal microbiota too (the normal flora of the equine gut). Antibiotics can promote fungal infections and resistant organisms and impede or even eliminate the more sensitive organisms; and they can have both short- and long-term consequences on the gut microbiota composition and function. 

Research has indicated that antibiotic treatment may adversely affect metabolic function in the gut by decreasing protein expression responsible for biochemical pathways such as glycolysis, iron uptake, glutamate hydrolysis and possibly even more metabolic functions. The use of antimicrobial drugs directly impacts and possibly contributes to the most notable effect on the gut microbiota of the host, leading to gut dysbiosis; and certain antibiotics can have further-reaching consequences on the microbiota than others. The type of antibiotic and mode of action (bacteriostatic versus bactericidal) will differ in their influences on the gut microbiota composition, e.g., clindamycin operates a bacteriostatic mode of action by inhibiting protein synthesis and exerts a larger impact on the gut microbiota compared to other antimicrobials. These influential consequences that are imparted by the antimicrobial agent are relatively yet to be elucidated and may result in the manifestation of illness or conditions later in life. For example, the development of asthma in humans has been linked to antibiotic treatment in early childhood as a result of bacterial infections. It may yield interesting results if researchers were to examine the gut microbiome of horses suffering from chronic obstructive pulmonary disease (COPD) and other chronic respiratory illnesses and to establish if there is indeed a link with antibiotic therapy used in horses from an early age. 

In comparison to the vast wealth of human studies conducted so far, the volume of equine studies falls disappointingly far behind, but that is changing as researchers focus their interest on developing and filling this gap of knowledge. One such study, which examined the effect of antibiotic use on the equine gastrointestinal tract, demonstrated a significant reduction in culturable cellulolytic bacteria (>99%) from equine feces during the administration period of trimethoprim sulfadiazine and ceftiofur in a study comparing responses to antibiotic challenge. That reduction was still evident at the end of the withdrawal period when compared to the control group. In other words, there was a significant reduction in the ‘normal’ bacteria of the gut. The ability of antibiotics to modulate the gut microbiota was evidenced by the proliferation of pathogenic Salmonella and Clostridia difficile (commonly associated with diarrhea in horses) in the antibiotic challenged horses. This trend of reduction in cellulolytic bacteria associated with antibiotic use was also mirrored in a relatively recent study conducted in 2019, where a short-term reduction in culturable cellulolytic bacteria was combined with a progressive increase in amylolytic bacteria. The heavy reliance on cellulolytic bacteria in the role of equine digestion (without these types of bacteria the horse cannot break down their food) may, therefore, adversely affect the dietary energy available from forage during antimicrobial therapy and may therefore impact performance.

Another study that compared the effect of penicillin, ceftiofur and trimethoprim sulfadiazine (TMS) on the gut microbiota in horses using next-generation sequencing showed that TMS had the most profound impact on the microbiota, in particular the phylum verrucomicrobia. This same study also reported a significant decrease in bacterial richness and diversity of the fecal microbiota. A reduction in bacterial diversity is certainly a trend that is commonly seen in gastrointestinal disease in horses. The restoration of the normal gut microbiota after completion of antibiotic treatment can take up to 40 days, but the organizational structure of the bacterial populations can take many years to re-establish the original structure map that was laid out in treating the pre-antibiotic gut. 

Equine studies certainly show similarities to human studies, indicating the consequences of antibiotics that can be seen across more than one species. Human studies have reported long-term consequences of antibiotic treatment on the human microbiota. One such human study investigated a seven-day clindamycin treatment and monitored the patients for two years. The impact on the human microbiota remained evident two years post-treatment, where a reduction in bacterial diversity and detection of high-resistance to clindamycin were detected. 

Interestingly, no resistant clones were detected in the control group over the two-year sampling period. Another study focusing on the effects of antibiotic treatment for Helicobacter pylori showed findings mirrored in similar studies of that field. The findings demonstrated the rapidly reducing bacterial diversity (one week) after antibiotic treatment and found that disturbances in the microbiota and high levels of macrolide resistance were evident four years post-treatment. Human studies may predict that equine studies will find similar trends with equine antimicrobial therapy. These studies highlight the impact of antibiotic use and the long-term persistence of antibiotic resistance remaining in the intestinal microbiome, which is a concern for both humans and animals. 

Antibiotics can lead to the selectivity and proliferation of resistant bacteria, which is evidenced by the long-term effects observed on the gut microbiota harboring drug-resistant encoded genes. Horizontal gene transfer (HGT) commonly occurs in the gut (can be up to 25 times more likely to occur in the gut than in other environments). HGT can be attributed to the close proximity of the microbiota in the gut, allowing the transfer of genetic material via routes such as plasmids and conjugation; in other words, the bacteria in the gut have developed a pathway to transfer antibiotic-resistant genes from one generation to another. Resistance to antibiotics is now a global issue for the treatment of many diseases. 

With the unfavorable association tied to Clostridium difficile infections (CDI) and the onset of colitis, particularly in mature horses treated with β-lactam antibiotics (commonly used for equine infections), the incidences in which antimicrobial therapy is considered should be minimized and only used if entirely necessary. The use of broad-spectrum antibiotics in recurrent presentations of symptoms of disease such as urinary tract infections in humans or diarrhea as a result of CDI in both humans and horses is promoting drug resistance. The antibiotics, by disrupting the gut microbiota (which act as a defense against the establishment and proliferation of such pathogenic bacteria) are allowing the opportunity of growth for these multi-resistant microorganisms such as C. difficile, vancomycin-resistant enterococci (VRE), and multi-resistant Staphylococcus aureus (MRSA). The organism C. difficile and its antibiotic resistance has been demonstrated in the treatment of CDI for both humans and animals. The introduction of vancomycin (a glycopeptide antibiotic) in 1959 for the control of CDI remained effective until the 1990s when a more virulent form of C. difficile emerged. This new form of C. difficile with reported broad-spectrum antibiotic resistance resulted in chronic conditions and increased human mortality. C. difficile is most noted with human hospital-acquired infections. C. difficile BI/NAP1/027 has been shown to have resistance to fluoroquinolone antibiotics, moxifloxacin and gatifloxacin, which was not seen in historical genotypes. As C. difficile infections are found to cause gastrointestinal disease in horses as well as humans, this is certainly of concern.

Alternative therapies to antibiotic therapy to restore or modulate the gut microbiome after a gut dysbiosis event could be considered in certain circumstances where antibiotics are no longer effective (e.g., CDI), if they’re not the best course (presence of extended-spectrum -β-lactamase (ESBL) producing  organisms) or if they’re not essential for example, when the diagnosis of the bacterial cause is uncertain. The rationale to using probiotic treatment along with antimicrobial treatment is that the antibiotic will target the pathogenic bacteria (e.g., C. difficile) and also the commensal microbiota of the gut, but the probiotic bacteria will help to re-establish the intestinal microbiota, and in turn, prevent the re-growth of the pathogenic bacteria in the case or residual spores of C. difficile surviving the antibiotic treatment. Alternative therapies such as fecal microbiota transplant (FMT) or probiotic solutions can reduce the risk of proliferation of antibiotic-resistant bacteria and also have fewer implications on the gut microbiome as evidenced by antibiotic use. 

Probiotics have been defined by the Food and Agricultural Organization (FAO) and the World Health Organization (WHO) as “live non-pathogenic microorganisms that, when administered in adequate amounts, confer a health benefit on the host.” The word probiotic is Greek in origin, meaning, “for life”; and the term was coined by Ferdinand Vergin in 1954. While the mechanisms of action of probiotics are complex and require a deeper knowledge of the modulations of the gastrointestinal microbiota, and the health benefits due to their use are the subject of some debate, there is no doubt that probiotics are considered by many as a vital resource to human and animal health.   

The use of probiotics in animal production, particularly in intensive swine and poultry production, has increased in recent years, primarily as an alternative to the use of antimicrobials in the prevention of disease. The problem of antibiotic resistance and antimicrobial residues in food-producing animals (the horse is considered a food-producing animal), as a result of historical antibiotic use with the corresponding reduction in antibiotic efficacy in humans, leads to having to look at more sustainable options, such as probiotic use, to combat disease. Probiotics in horses are predominantly used as a treatment modality in the gastrointestinal microbial populations to combat illnesses such as diarrhea—to prevent diarrhea (particularly in foals) or help improve digestibility.  Shifts or fluctuations in the microbial populations of the equine gastrointestinal tract have been associated with diseases such as laminitis and colic.  

Gut dysbiosis, as mentioned previously, is a fluctuation or disturbance in the population of microorganisms of the gut. It is now being recognized as a cause of a wide range of gastrointestinal diseases; and in horses, it is one of the leading causes of mortality. The ability of probiotics in conferring health benefits to the host can occur via several different mechanisms: 1) inhibiting pathogen colonization in the gut by producing antimicrobial metabolites or by competitive exclusion by adhering to the intestinal mucosa, preventing pathogenic bacteria attachment by improving the function and structure; 2) protecting or restabilizing the commensal gut microbiota; 3) protecting the intestinal epithelial barrier; 4) inducing an immune response.

It is known that there are a wealth of factors that will adversely affect the gut microbiome: antibiotics, disease, diet, stress, age and environment are some of these compounding contributors. To mirror one researcher’s words, echoing from an era where antibiotics were used as growth promoters in the animal industry, “The use of probiotic supplements seeks to repair these deficiencies. It is, therefore, not creating anything that would not be present under natural conditions, but it is merely restoring the flora to its full protective capacity.” In the case of using concurrent antibiotic and probiotic treatment, this strategic tweaking of the microbiota could be used as a tool to prevent further disease consequences and perhaps help improve performance in the horse.

The benefits of probiotic use in horses have not been investigated extensively, but as mentioned previously, they are now being focused upon by researchers in the equine field. The most common bacterial strains used in equine probiotic products are Lactobacillus, Bifidobacterium, Streptococcus, Enterococcus, Bacillus and yeast strains of Saccharomyces. Lactobacillus, Bifidobacterium and Enterococcus strains typically account for less than 1% of the microbiota’s large gastrointestinal populations. Regulation is lacking regarding labeling of probiotic products, often not displaying content with clarification and quality control (such as confirmed viability of strain[s]) not excised with over-the-counter probiotic products. There is evidence to suggest that host-adapted strains of bacteria and fungi enjoy a fitness advantage in the gut of humans and animals.  Therefore, there may be an advantage in using the individual animal’s own bacteria as potential probiotics. Probiotics and antibiotics used concurrently could be the way to minimize the introduction of antibiotic-resistant bacterial strains in the gut, and in turn, protect future antibiotic efficacy. 

Racehorse Bone Health: From a Nutritional Perspective

Strong, healthy bones are the foundation for racehorse soundness, but unfortunately skeletal injuries are an issue that every trainer will face. There are many factors involved in the production of strong bones; however, two key factors that we can influence are training and nutrition. 

By Louise Jones

Every trainer knows how important exercise is to ‘condition’ the bones, and we are constantly striving to improve training programmes so that sufficient strain is applied to signal an increase in bone development, whilst not straining the bones to the point of fracture; this is a difficult balancing. Perhaps more fundamental to this is the role of diet in supporting bone density, strength and repair.  Even minor nutrient deficiencies or imbalances can mean that the horse doesn’t receive the nutrients it requires for healthy bones and thus increases the risk of potential problems down the track.

Understanding how bone is formed and adapts in response to training, alongside the critical role optimal nutrition plays in these processes, can help to ensure skeletal soundness and minimise the risk of bone-related injuries.

Bone formation & remodelling

Bone formation occurs by a process of endochondral ossification; this is where soft cartilage cells are transformed into hard bone cells. Bone consists of three types of cells and an extracellular matrix. This extracellular matrix is made mainly from the protein collagen, which makes up to 30% of mature bone and is a key element in connective tissue and cartilage. The three types of cells in bone are:

• Osteoblasts: These are the cells that lay down the extracellular matrix and are responsible for the growth and mineralisation/hardening of bone.

• Osteoclasts: These cells are involved in the breakdown of bone, so that it can be replaced by new stronger bone. 

• Osteocytes: These cells work to maintain and strengthen when a bone requires modelling or remodelling.

Bone mineral content (BMC) is a measure of the amount of mineral in bone and is an accurate way of measuring the strength of a bone. Interestingly, about 70% of bone strength is due to its mineral content; calcium being the most notable and accounting for 35% of bone structure. A horse’s bones do not fully mature until they are about 5-6 years old. So, whilst a horse will have reached 94% of their mature height when they are a yearling, they will have only reached 76% of their total BMC. 

Although it may seem like mature bone is inert, it is in fact a highly dynamic tissue, and BMC is constantly adapting in response to exercise and rest by a process called remodelling.zBone remodelling is a complex process involving several hormones and nutrients. Essentially when mature bone ages or is placed under stress, such as exercise, small amounts of damage occur. This results in the osteoclast cells removing the old or damaged bone tissue. In turn, this triggers osteoblasts and osteocytes to repair the bone by laying down collagen and minerals over the area, thus strengthening the bones. It’s estimated that 5% of the horse’s total bone mass is replaced (remodelled) each year. It should be noted that during the remodelling process, bone is in a weakened state. Therefore, if during this period, the load applied to the bones exceeds the rate at which they can adapt, injuries such as sore shins can occur.  

Bone strength & exercise

When galloping, a horse places up to three times its body weight in force on the lower limbs. The more load or pressure put on a bone, the greater the bone remodelling that will need to take place. Ultimately, this will result in new, stronger bones being formed. 

Studies have shown that correct exercise can increase bone density in the cannon bone, the knee and sesamoid bones; and this can help reduce the likelihood of skeletal injury. However, the intensity of training is key; low intensity exercise (trotting), whilst essential for muscle development, has been shown to only result in small change in cannon bone density. Whereas training at high speeds for a short amount of time (sprinting), rather than repetitive slow galloping, has shown to result in a significant increase in bone density. This is highlighted in a study using a treadmill where short periods of galloping at speeds over 27mph (43 km/hour) were associated with a 4-5% increase in the density of the cannon bone.

Whilst exercise clearly plays a pivotal role in bone density, doing too much too soon can be disastrous and result in issues such as:

• Sore/buck shins: This is a common injury in young racehorses. It is caused by excessive pressure on the bones resulting in tiny fractures on the cannon bone, which may not have fully mineralised (strengthened and hardened). This results in the periosteum (a fibrous membrane of connective tissue covering the cannon bone) becoming inflamed. 

• Bone chips: Another common skeletal injury in racehorses, mostly seen in joints, particularly in the knee. This is when a tiny fracture occurs in the joint, weakening the bone and ultimately resulting in a ‘chip’ of the bone becoming separated. 

When trying to maximise skeletal strength, periods of lower intensity exercise or rest are just as important as gallop work, as they give the bone a chance to remodel. However, prolonged rest will have a negative effect on skeletal health.  Research has looked at the loss of BMC in the cannon bone when horses were placed on box-rest (with 30 minutes on the walker) and found overall BMC was reduced. Therefore, even horses returning to work after a short period of 1-2 weeks of box-rest could potentially have a significant decline in bone density and thus be at increased risk of skeletal injury once exercise recommences. 

It’s also important to bear in mind that when a young horse starts training, it is normally coming from a 12–24-hour turnout. This is where the horse has the ability to gallop and play. However, once training begins, they are typically stabled from long hours with short intervals of low intensity training. Consequently, bone demineralisation can occur. In addition, during this early stage of training, bone will undergo a significant degree of remodelling in response to exercise. Initially this process makes the bone more porous and fragile before it regains its strength. As a result, research has shown that horses can have reduced bone density during the first few months of training, with bones being at their weakest and the horse more prone to issues such as sore shins between day 45–75 of training. 

It should be noted that even when training is carried out slowly, conditions such as sore shins can still happen as bone remodelling occurs at different rates in every horse and is influenced by factors such as track surface and design. While there is some information on exercise and bone development from which to make inferences, a definitive answer as to the perfect amount of exercise to support optimal bone development has not yet been found.

Nutrition & bone health

Exercise is essential to bone health, but nutrition plays an equally important role. Bone is continuously being strengthened, repaired and replaced. And if we can aid bone remodelling with good nutrition, we can decrease the likelihood of skeletal injury. The essential nutrients for bone health are protein, minerals and vitamins, including calcium (Ca), phosphorus (P), zinc (Zn) copper (Cu), vitamins A, D and K. 

Protein: Collagen is a protein and forms the bony matrix on which minerals are deposited. Feeding sufficient high-quality protein, rich in essential amino acids such as lysine and methionine, is therefore a key factor in the development of strong healthy bones. When selecting an appropriate feed for horses in training, both the level and quality of the protein it provides should be carefully considered; not all protein is equal.  

Calcium & Phosphorus: It is well documented that these essential minerals are the foundation of strong and healthy bones, making up 70% of the BMC. The ratio of calcium and phosphorus in the diet is also very important for bone mineralisation. This is because imbalances in the Ca:P ratio can result in the removal of calcium from the skeleton and may lead to bone demineralisation. The minimum Ca:P ratio in the diet should be 1.5:1, with the ideal ratio being at least 2:1 for young horses. It is important to note that adding other feedstuffs such as chaffs or cereals to the horse’s feed can alter the Ca:P ratio in the overall diet. For example, adding oats, which are high in phosphorus, will reduce the calcium to phosphorus ratio and this may adversely affect calcium absorption. On the other hand, including some alfalfa, which is high in calcium, can help to increase the Ca:P ratio if required. 

Copper & Zinc: Copper is an important mineral for bone, joint and connective tissue development. Lysyl oxidase is an enzyme that requires copper. It is responsible for cross-linking of collagen, and therefore copper plays an important role in the formation of new bone which requires a collagen matrix. Similarly, zinc is integrally involved in cartilage turnover; and research has shown that horses supplemented with zinc, as part of a complete mineral package, have increased bone mineral density compared to horses fed an unsupplemented diet. Copper and zinc are frequently found to be low in forage and therefore must be provided in the form of a hard feed or supplement. 

Vitamins: A number of vitamins play essential roles in skeletal health. For example, vitamin A is involved in the development of osteoblasts—the cells responsible for laying down new bone—whilst vitamin D is needed for calcium absorption. More recent research has also shown that feeding vitamin K improves the production of osteocalcin, the hormone responsible for facilitating bone metabolism and mineralisation. Furthermore, research in two-year-old thoroughbreds suggests that feeding vitamin K may help increase bone mineral density and thus potentially be beneficial for decreasing the incidence of sore shins. Although standard feed manufactures include vitamin A and D in their feeds, a few also now include vitamin K.

Supplementation for bone health

Young horses in training, those recovering from injury or returning to work following a rest will benefit from additional nutritional support targeted at maintaining improving bone health. In these situations, supplementing with elevated levels of calcium and phosphorus will help improve bone health. Look for a supplement containing collagen, which is rich in type I and II collagen, proteoglycans and glycosaminoglycans—all of which aid the bone remodelling process and help to maintain bone health. Choosing a supplement that also contains chelated copper and zinc, as well as vitamins A and D, will also help support bone mineralisation. 

In summary, skeletal injuries have a huge adverse effect on the racing industry and are a common cause of lost training days. Undoubtedly, adapting our training regimes, modifying our gallops and improving our management practices will all help to reduce the risk of bone-related injuries. Equally, the role of nutrition in bone health should not be overlooked. A balanced diet, rich in nutrients, minerals and vitamins, can contribute significantly to bone density and strength. Proper nutrition is an essential parameter of skeletal health, participating in both the prevention and treatment of bone diseases.  To achieve a strong, sound skeleton, you must feed the bones.

The Importance of forage testing

Forage (hay/haylage) is an important source of nutrients for horses in training. However, the levels of minerals such as calcium, phosphorus and copper present can vary enormously and depend on factors such as the species of grass and the land on which it was grown. It is recommended that you regularly test the nutritional value of your forage. This will highlight any mineral excess/deficiencies and allow for the ratios of certain minerals such as calcium and phosphorus to be assessed. In most cases, any issues identified can be corrected through using an appropriate hard feed and/or supplement.

The Balancing Act - feed - supplement

By Catherine Rudenko

Key considerations when reviewing what you feed and if you should supplement

With so many feeds and supplements on the market, the feed room can soon take on the appearance of an alchemist’s cupboard. Feeding is of course an artform but one that should be based on sound science. In order to make an informed decision, there are some key questions to ask yourself and your supplier when choosing what ingredients will form your secret to success.

QUESTION #1: What is it?

Get an overview of the products’ intended use and what category of horse they are most suited for. Not every horse in the yard will require supplementing. Whilst one could argue all horses would benefit from any supplement at some level, the real question is do they need it? Where there is a concern or clinical issue, a specific supplement is more likely warranted and is more likely to have an impact. A blanket approach for supplements is really only appropriate where the horses all have the same need (e.g., use of electrolytes).

QUESTION #2: Is it effective?

There are many good reasons to use supplements with an ever-increasing body of research building as to how certain foods, plants or substances can influence both health and performance. Does the feed or supplement you are considering have any evidence in the form of scientific or clinical studies? Whilst the finished product may not—in a branded sense—be researched, the active components or ingredients should be. Ideally, we look for equine-specific research, but often other species are referenced, including humans; and this gives confidence that there is a sound line of thinking behind the use of such ingredients. Having established if there is evidence, the next important question is, does the feed or supplement deliver that ingredient at an effective level? For example, if research shows 10g of glucosamine to be effective in terms of absorption and reaching the joint, does your supplement or feed—when fed at the recommended rate—deliver that amount?

There is of course the cocktail effect to consider, whereby mixing of multiple ingredients to target a problem can reduce the amount of each individual ingredient needed. This is where the product itself is ideally then tested to confirm that the cocktail is indeed effective.

QUESTION #3: How does it fit with my current feeding and supplement program?

All too often a feed or supplement is considered in isolation which can lead to over-supplementing through duplication. Feeds and supplements can contain common materials, (i.e., on occasion there is no need to further supplement or that you can reduce the dose rate of a supplement). Before taking on any supplement, in addition to your current program, you first need to have a good understanding of what is currently being consumed on a per day basis. This is a different matter of comparing one feed tag or supplement pot to another one. Such ‘direct’ comparisons are rarely helpful as dose rates or feeding rates differ, and the manner in which units are expressed is often confusing. Percentages, grams, milligrams and micrograms are all common units of measure used on labeling. The unit chosen can make an inclusion sound significant when perhaps it is not. For example, 1g could be expressed as 1,000mg. Looking at the contribution, any feed or supplement made on an as-fed basis is the only way to know the true value for the horse. There are many categories of supplements in the market with the greatest cross-over existing around use of vitamins or minerals, which appear in both feeds and supplements. Occasionally feeds can also be a source of ingredients used in digestive health supplements or joint supplements. The contribution of your chosen feed(s) is the base from which you decide what, if any, of those matching nutrients or ingredients should be added to. Common areas for cross-over include vitamin E, selenium, B vitamins, iron, magnesium, calcium, phosphorus, zinc and copper. Duplication may also occur around use of vitamin C (antioxidant), FOS (prebiotic), MOS (pathogen binder), yeast (prebiotic) and occasionally maerl (marine algal calcium source).

Vitamins and Minerals An often-seen addition to the feed program for Thoroughbreds are bone supplements—providing relevant minerals such as calcium, phosphorus, zinc and copper. Whilst unquestionably important for sound skeletal development these nutrients are also present in feed, albeit at slightly varying levels by brand. Below is a typical profile of a bone supplement with the information as seen per kilogram on the feed label. Calcium and phosphorus are given as percentages on labels and require converting to grams when looking to calculate the amount of nutrients consumed. In this example, the calcium content is 20%, equivalent to 200g per kilogram.

The feeding rate is 31⁄2oz per horse per day. …

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Thoroughbred nutrition past & present

By Catherine Rudenko

Feeding practices for racehorses have changed as nutritional research advances and food is no longer just fuel but a tool for enhancing performance and providing that winning edge. 

While feeding is dominantly considered the content of the feed bucket, which by weight forms the largest part of the horse’s diet, changes in forage quality have also played a role in the changing face of Thoroughbred nutrition. The content of the feed bucket, which is becoming increasingly elaborate with a multitude of supplements to consider, the forages—both long and short chop and even the bedding chosen—all play a part in what is “the feed program.” Comparing feed ingredients of the past against the present provides some interesting insights as to how the industry has changed and will continue to change.

Comparing key profiles of the past and present 

The base of any diet is forage, being the most fundamental need of the horse alongside water. Forage quality and form has changed over the years, particularly since haylage entered the market and growers began to focus specifically on equine. The traditional diet of hay and oats, perhaps combined with mash as needed, provided a significantly different dietary intake to that now seen for horses fed a high-grade haylage and fortified complete feed. 

Traditional Diet

• 7kg Oats

• 1kg Mash – comprised of bran, barley, linseed and epsom salt

• 0.5kg Chaff

• Hay 6% protein consumed at 1% of bodyweight

Modern Diet – medium-grade haylage

• 8kg Generic Racing Mix 

• 0.5kg Alfalfa Chaff

• 60ml Linseed Oil

• 60g Salt

• Haylage 10% protein consumed at 1% of bodyweight

Modern Diet – high-grade haylage

• 8kg Generic Racing Mix 

• 0.5kg Alfalfa Chaff

• 60ml Linseed Oil

• 60g Salt

• Haylage 13% protein consumed at 1% of bodyweight

Oats field

The traditional example diet of straights with bran and hay easily met and exceed the required amount of protein providing 138 % equirement. When looking at the diet as a whole, the total protein content of the diet inclusive of forage equates to 9.7%. In comparison, the modern feeding example using a high-grade haylage produces a total diet protein content equivalent to 13.5%. The additional protein—while beneficial to development, muscle recovery and immune support—can become excessive. High intakes of protein against actual need have been noted to affect acid base balance of the blood, effectively lowering blood pH.1 Modern feeds for racing typically contain 13-14% protein, which complement forages of a basic to medium-grade protein content very well; however, when using a high-grade forage, a lower protein feed may be of benefit. Many brands now provide feeds fortified with vitamins and minerals designed for racing but with a lower protein content. 

While the traditional straight-based feeding could easily meet energy and protein requirements, it had many short-falls relating to calcium and phosphorus balance, overall dietary mineral intake and vitamin intake. Modern feeds correct for imbalances and ensure consistent provision of a higher level of nutrition, helping to counterbalance any variation seen within forage. While forage protein content has changed, the mineral profile and its natural variability has not. 

Another point of difference against modern feeds is the starch content. In the example diet, the “bucket feed” is 39% starch—a value that exceeds most modern racing feeds. Had cracked corn been added or a higher inclusion of boiled barley been present, this level would have increased further. Racing feeds today provided a wide range of starch levels ranging from 10% up to the mid-thirties, with feeds in the “middle range” of 18-25% becoming increasingly popular. There are many advantages to balancing starch with other energy sources including gut health, temperament and reducing the risk of tying-up. 

The horse with a digestive anatomy designed for forages has limitations as to how much starch can be effectively processed in the small intestine, where it contributes directly to glucose levels. Undigested starch that moves into the hindgut is a key factor in acidosis and while still digested, the pathway is more complex and not as beneficial as when digested in the small intestine. Through regulating starch intake in feeds, the body can operate more effectively, and energy provided through fibrous sources ensures adequate energy intake for the work required.

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All about tying-up

By Catherine Rudenko

Tying-up or ER (exertional rhabdomyolysis) is a problem that every yard will encounter at some point in time with reports of 5-7% of the Thoroughbred population being affected. ER is the general term used to cover two main forms of tying-up, acute or recurrent. ER by definition relates to the breakdown of striated muscle fibers following exercise. These fibers connect to the bone allowing movement of the skeleton. Damage causes anything from mild stiffness to the inability to move.

With much still unknown about the condition, the focus falls on reducing risk and ongoing management of those affected with recurrent form. The main area for intervention and management relates to feeds and feeding practices—an area that can be directly controlled by the yard and adjusted as needed for the individuals most affected.

Acute Exertional Rhabdomyolysis

The acute form is typically caused through factors external to the muscle rather than there being an intrinsic muscle defect.

It is most commonly seen when the horse is adapting to a new level of work, and the intensity or duration is too strenuous. Where speed work is concerned, the most likely cause is a depletion of cellular high energy phosphates, the muscles’ energy supply, combined with lactic acidosis. Where endurance work is concerned, depletion of intracellular glycogen—the stored form of glucose often combined with over-heating and electrolyte imbalances—is the common cause.

The other key factor for an acute episode is dietary energy intake being excessive to the current level of work. The use of high-starch feeds to supply energy for horses in training is a common practice with grains (traditionally oats) forming the basis of such feeds. In the early stages of fitness work, an over-supply of energy relative to need, particularly when starch forms a large part of the diet, is a risk factor.

Recurrent Exertional Rhabdomyolysis

This form of ER—where episodes are frequent and often seen even at low levels of exercise—has led to the suggestion that much like humans, there is an inherited intrinsic muscle defect. Such defects would predispose the horse to ER. Documented defects relevant to Thoroughbreds include a disorder in muscle contractility or excitation contraction coupling, whereby muscle fibers become over-sensitive, and normal function is disrupted.  

Risk factors for ER in horses with the recurrent form include stress or high excitement during exercise, periods of jogging (10-30 minutes), infrequent exercise, and over-feeding of energy in a high-starch format relative to need.

Dietary Considerations for ER

The amount of energy fed and the type of energy fed are important considerations whether looking to avoid an acute feed-related episode or considering the management of a horse with the recurrent form.

Other nutrients often talked about when managing ER include vitamin E, selenium and electrolytes. Historically the inclusion of vitamin E and selenium were considered important for the prevention of further episodes; however, there is no evidence to support such use. A case of deficiency in either of these nutrients may well put the horse at a disadvantage and could perhaps create a state where occurrence is more notable; however, with the advent of fortified and balanced complete bagged feeds, such nutrients are normally supplied in more than adequate amounts. Their role as antioxidants, which function to “mop-up” damaging free radicals generated through training, is where their use can benefit any horse at this level of work. The use of additional vitamin E is also recommended when increasing the fat content of the diet—a common practice when feeding horses with recurrent ER.

Electrolytes do play an important role in normal muscle function, and any deficiency noted in the diet should be corrected. Identifying a need in the diet is more easily done than determining if the individual horse has a problem with absorption or utilisation of the electrolytes. A urinary fractional excretion test (FE) will highlight issues, and subsequent correction through the diet to return the horse to within normal ranges may offer some improvement. However, it is important to note that for horses with recurrent ER, where an intrinsic muscle defect is present, the research to date has shown no electrolyte imbalances or differences between such horses and unaffected horses.

Quantifying “Low-Starch and High-Fat” Feeding

The recommended practice for management of ER is a reduction in starch and an increase in fats. This practice has two ways of benefiting the horse: a reduction in “spookiness” or reactivity and a positive effect on muscle damage as seen by lower CK (creatine kinase) levels following exercise.

Positive effects on lowering CK levels were found when a higher proportion of the energy fed came from diets higher in fats and lower in non-structural carbohydrates (starches and sugars). The effect was noted when fed at 4.5kg/day—an amount easily reached and normally surpassed when feeding horses in training. The beneficial diet provided 20% of energy from fats and only 9% from starches and sugars, compared to the more traditional sweet feed diet providing 45% of energy from starches and sugars and less than 5% from fats.

Finding Fats

Top dressing of oils will increase fat in the diet—with a normal intake of up to 100 mls per day. Although the horse can digest higher amounts, palatability usually restricts a higher intake. Pelleted or extruded fat sources are increasingly popular as alternatives to oils for their convenience of feeding and palatability. Straight rice bran and blends of materials such as rice bran, linseed and soya are available from most major feed companies. Oil content will typically range from 18-26% providing 180g-260g of oil per kilogram as fed.  

Racing feeds will also provide oil in the diet; content is quite varied, typically from 4-10% providing 40g-100g per kilogram as fed. Hay and haylage also contains oil at a low level, typically 2% providing just 20g per kilogram on a dry matter basis.

Choosing Carbohydrates

Traditional feeding based on oats and other whole grains will have a higher starch content than feeds using a combination of grains and fiber. Levels of starch found in complete feeds and straights have a broad range from as low as 8% in a complete feed—specifically formulated to have a low-starch content—and up to in excess of 50% for straights such as barley and naked oats.

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Does nutrition factor in injury, repair and recovery?

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Published in North American Trainer, Winter 2017.

Lost training days through injury or infection are problematic for trainers, both practically and commercially. It is a stark fact that 50% of Thoroughbred foals, bred to race, may never reach the racecourse.  In young Thoroughbreds, musculoskeletal problems have been cited as the most common reason for failure to race, and this appears to continue to be a major issue for horses in training.  

An early study carried out in 1985 in the United Kingdom reported that lameness was the single biggest contributor to lost days of training, and subsequent research 20 years later found that this was still the case, with stress fractures, which involve normal bone being exposed to abnormal stress, being cited as a significant underlying cause.  Perhaps not surprisingly, two-year-olds were more susceptible to injury than three-year-olds.  

While there are of course many other reasons – including muscular issues such as tying up, respiratory problems, and viral infection – why horses may fail to train, in this survey medical issues accounted for only 5% of the total training days lost.

Balance between damage and repair processes are imperative

There are many factors that affect the chance of injury in Thoroughbreds in training, including genetic predisposition, conformation, and training surface.  Style and type of training, in terms of frequency and intensity and how this is balanced through recovery protocols, is also likely to be a significant factor in the incidence of injury.  The nature of training means that a balance between damage and repair processes are imperative.  Physiological systems need to be put under stress to trigger a suitable training response, which inevitably involves a degree of micro-damage.

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