Equine asthma is a condition that can affect horses of all abilities, but is most frequently diagnosed in performance horses and racehorses, and is a common cause of poor performance. The term ‘equine asthma’ covers a broad range of inflammatory conditions of the lower airways, which can vary in their presentation and severity. Conditions that were previously referred to as ‘recurrent airway obstruction’, ‘heaves’, ‘inflammatory airway disease’, ‘chronic obstructive pulmonary disease’, and ‘summer pasture associated asthma’ are now all known as ‘equine asthma’.

When a horse has been diagnosed with, or is suspected of suffering from asthma, it is natural for us to want to provide them with relief. From a pharmaceutical standpoint, that can often mean the use of corticosteroids and, in many cases, clenbuterol (often sold under names such as Claire Gel, Broncopulmin, Airway Gel, Ventipulmin, Equipulmin, etc). While use of these medications may help relieve some clinical signs of asthma, they do not address the underlying causes of the condition and may also come with unintended health consequences. Unfortunately, these side effects are often overlooked, or simply not discussed.

Whilst clenbuterol may provide some initial relief in equine asthma, the use of this drug can contribute to a vicious cycle, potentially perpetuating the condition.

Clenbuterol has been demonstrated to deplete the amino acid taurine. Taurine plays a significant protective role in lung health by exerting powerful anti-inflammatory, antioxidant, and membrane-stabilising effects. It also helps to inhibit allergic responses, which can play a role in many cases of equine asthma. Reduced taurine levels may increase the severity of equine asthma and the likelihood of lung tissue damage as a result of ongoing airway changes. Taurine is also needed to promote healthy gut integrity and microflora: gut health is increasingly recognised as an important factor in respiratory conditions such as asthma.

Clenbuterol decreases levels of potassium and magnesium in the body—two key nutrients known to support respiratory health and reduce the severity of asthma. Potassium is essential for controlling airway smooth muscle tone and supporting respiratory muscle function.  Low potassium can increase airway reactivity and hamper breathing, further exacerbating clinical signs of asthma. Depleted potassium levels can also lead to cramping in susceptible horses. Magnesium acts as a bronchodilator (helping the airways relax) and helps reduce airway hyperactivity, spasms, and inflammation.

Long-term use of clenbuterol may also have negative impacts on immune function, further contributing to a self-perpetuating cycle of equine asthma.

An often overlooked side effect of clenbuterol is the influence it may have on temperament and behaviour in our horses. Clenbuterol belongs to a class of drugs known as beta-2 adrenoceptor agonists, which work by mimicking the effects of epinephrine (adrenaline) in the body. This results in a stimulating effect, which may lead to changes in behaviour, including increased excitability, reactivity or nervousness in some horses.

Helping a horse at risk of, or diagnosed with asthma, starts with good management practices. Identifying and appropriately addressing the factors that contribute to the underlying pathophysiology of equine asthma, meeting the individual horse’s nutritional requirements (which often differ from basic nutrient requirements due to medication use), and the judicious use of suitable herbal medicines can significantly support respiratory health, allowing a horse to remain healthy and perform at its best. There is much that can be done for the horse diagnosed with asthma, using approaches that not only support airway health and performance, but also promote overall wellbeing. If your horse has been diagnosed with asthma, or you suspect respiratory issues may be affecting performance or comfort, a tailored approach can make a significant difference. Get in touch with Optim Equine to discuss a personalised plan to your support your horse’s health and performance.

At Optim Equine, we regularly work with horses affected by respiratory conditions…

Optim Equine

Camilla Whishaw is a highly regarded, experienced horsewoman and naturopath, helping to holistically treat and manage a broad range of equine health conditions and injuries, with a passion for mare and stallion fertility.

As a world-renowned practitioner, presenter, author, and consultant in the field of Equine Naturopathy, Camilla shares her knowledge through keynote presentations, interviews, lectures, panel sessions, and workshop training.

Depending on the herb (or combination of herbs used) and their application, they can help to:

• reduce inflammation
• modulate immune function
• aid healing and tissue repair
• assist recovery from infections
• prevent and/or manage equine asthma
• soothe the gut lining and promote healing of both gastric and colonic ulcers
• reduce colic 
• support digestion
• assist fertility
• help regulate hormone levels
• calm nervous horses
• provide gentle pain relief
• promote healthy hoof growth and integrity
• help to reduce the severity of osteoarthritis and maintain joint health
• Aid in blood glucose control and assist in the treatment of insulin resistance, equine metabolic syndrome and laminitis

Whilst herbal medicines are incredibly versatile, they’re not magic. And they can’t replace a poorly balanced diet….

One of the biggest misconceptions I see is that herbs can fully meet a horse’s nutritional needs or correct nutritional deficiencies on their own. 

This is simply not true. 

The vast majority of herbs (with few exceptions) do not provide sufficient quantities of key minerals and vitamins our horses need for optimal health and functioning.

Take the calcium rich herb nettle (Urtica diocia) for example….

100 g dried nettle leaf (~4–5 cups) provides approximately 300–500 mg calcium.

For a 500 kg (1100 pound) horse, calcium requirements typically fall in the range of 20–40 g/day (depending on life stage, workload, and physiological status).

This means:

• 100 g nettle provides roughly 0.3–0.5 g calcium
• This equates to approximately 1/40 to 1/133 of daily calcium requirements

To meet calcium needs via nettle alone would require:

• 4–5 cups × 40–133 = ~160–665 cups per day

This is neither practical nor appropriate.

Whilst strategically employed herbal medicines can help to restore optimal gastrointestinal health and function in our horses (including digestion, absorption and metabolism)- which in turn, can aid in better nutritional status, herbs in and of themselves don’t provide enough levels of nutrients our horses needs to meet daily nutrient requirements.

Optim Equine

Camilla Whishaw is a highly regarded, experienced horsewoman and naturopath, helping to holistically treat and manage a broad range of equine health conditions and injuries, with a passion for mare and stallion fertility.

As a world-renowned practitioner, presenter, author, and consultant in the field of Equine Naturopathy, Camilla shares her knowledge through keynote presentations, interviews, lectures, panel sessions, and workshop training.

It seems almost impossible to read news reports and social media posts these days without coming across someone telling you how important it is to look after your microbiome. From managing our mood and our weight, to reducing the risks of any number of diseases, someone, somewhere, will make a link to the billions of bacteria living in you, or on you.

But a recent study, published in the open-access journal Nature Scientific Reports, made a new and extraordinary connection: a foal’s internal hitchhikers may affect how fast he runs. And not just that – they can predispose to, or protect from, a range of conditions that might even prevent him from racing at all.

The paper followed 52 foals, born between February and May 2018, from five Thoroughbred stud farms in the UK. These foals were followed as they entered training (dispersed between 29 different training yards) and through to the end of their 3-year-old season.

In the earliest part of the study, faecal samples were obtained from each individual on day 2 postpartum and at regular intervals up until one year of age. These samples were then analysed and the number, variability, and different types of bacteria in the samples were assessed and recorded. The study was prompted by increasing evidence that not only are there a range of non-communicable diseases in humans affected by the bacteria within the intestines, but also that babies with differing birth and early-life circumstances may be predisposed to certain conditions, because of differences in their microbiome. 

The clinical and racing histories of the foals were then compared to the results of the microbiological evaluations. 

The results were striking: the gut bacterial community in the first months of life could predict the risks of specific diseases and athletic performance in later life. Foals with lower diversity (i.e. fewer different species of bacteria in their samples) at one-month-old had a significantly increased risk of respiratory disease in later life. A higher diversity was associated with a decreased risk of orthopaedic disease. And, when athletic performance was assessed — judged by comparing official ratings, number of starts/wins/places, and prize money earned — positive effects were again seen in foals with a greater diversity of bacteria at one-month-old and could even be linked to the relative abundance of specific bacterial families.

Foals are born without a functioning microbiome and must acquire all of their gut bacteria from their dam and their environment. This early phase of development, where foals are born with an immune system that is yet to encounter external challenges, is sometimes referred to as a ‘critical window’ — essentially a period when the gut microbial community imprints immunity and future health outcomes onto a blank canvas. There is now a great deal of interest in humans as to how this might be contributing to a variety of diseases: from obesity, diabetes and allergies, to diseases of the circulatory system, bones and neurodevelopment disorders such as autism. 

This particular study did not examine the gut microbial profile of the mares delivering and rearing the foals. But the authors point out that the gut bacterial profile of human mothers is known to be a primary driver of gut colonisation in human infants. Indeed, in human medicine, there is increasing engagement of methods to optimise this ‘handover period’ in neonates. There is limited evidence for how feeding mares may influence foals in this early phase. But a recent study, that fed two groups of mares on the same stud farm separate and distinct rations, demonstrated a stark difference in failure of passive transfer — assessed by levels of IgG in the foals’ blood within twenty-four hours of birth — between the two sets. Other researchers have confirmed that the microbial population of foals varies between stud farms, most likely due to differences in management styles. Numerous studies in other species have demonstrated links between maternal nutrition and various measures of colostrum quality, and there is evidence that a pro-inflammatory profile is seen in colostrum produced by obese mares, along with reduced medium-chain saturated fatty acid levels (important as an energy source and in the development of gut microbiota and immunity).

So, what if the balance could be tipped back in favour of the newborn foal, simply by adjusting how the mare is fed? And what if this could also affect the vigour of our young athletes? The developmental origin of health and disease (DOHaD) — first advocated by David Barker in the early 1990s — seeks to understand how exposure to environmental factors during periods of high plasticity in the early stages of life (including the gestational period) influences the program for development and disease risk in the progeny, that extends well into adult life.

Before the middle of the twentieth century, the foetus was believed to be immune from the effects of the maternal environment. It is now understood that in laboratory animals and humans, which is where of course almost all of this research has been done, numerous external factors influence the health and development of the foetus before birth. Historically, the focus has been on those causing adverse effects, such as polycyclic aromatic hydrocarbons — found in vehicle exhaust fumes and cigarette smoke — alcohol, and certain notorious pharmaceuticals. Epidemiogical studies began to link certain aspects of development, some not immediately obvious at birth, with environmental factors that had not been appreciated earlier and may be influenced by microbiome effects. For example, having “furry pets” at home impacts meconium bacterial diversity, and children reared with domestic animals from infancy have reduced prevalence of allergic-related diseases; maternal consumption of artificial sweeteners produces profound metabolic changes and microbiome changes in mouse pups (with profiles similar to those seen in human obesity). ‘Barker’s theory’ on the foetal origins of adult disease considered three characteristics: latency, where the effects may not be apparent until much later in life; persistency, in which conditions affecting the foetus continue; and genetic programming, where specific genes are switched on due to the prenatal environment. Brief windows at the very start of development, when a small number of cells are dividing rapidly and vulnerable to a range of influences, drive the development program of the entire individual, all the way through to adulthood.

Much of the work on the transferability of a healthy microbial population from one individual to another was prompted by early observations, reported in 1958, that patients affected by a particularly unpleasant and intractable cause of severe diarrhoea showed drastic improvements following a novel treatment. Clostridioides difficile is an anaerobic bacteria (it thrives in low-oxygen environments), commonly found in the intestinal tract of normal people. It doesn’t cause any issues until it proliferates uncontrollably, and the commonest reason for this is when the other bacteria in the intestine ecosystem are knocked out, usually by the patient receiving antibiotics for another problem. ‘C. diff’ is the commonest cause of antibiotic-associated diarrhoea, and it is notoriously difficult to treat in some cases — it only responds to a select group of antibiotics, many cases remain refractory, and it has a fatality rate of up to 40%. Back in the 1950s, the doctors were utilising a therapy that had been written about in the fourth century: transplanting gut bacteria from a healthy individual into the affected patient. And they did so by taking faeces from those healthy volunteers and delivering it via an enema (the very earliest records describe it being given as a ‘soup’).

Faecal microbiota transplantation (FMT) is now used in cases of C. diff that do not respond to first-line treatments and is well established for this, with impressive success rates of 80-90%. It works because it restores the normal balance of gut microbes, which prevents the Clostridia from maintaining a hold on the intestinal environment and, basically, out-competes them for the resources available. But as well as this, restoring the regular bacteria found in a healthy gut revitalises the relationship between the host —  us, or the animal — and the trillions of single cell organisms we live with.

Estimates of the numbers of bacteria within the body vary, but it’s safe to say it’s in the tens of trillions. It’s also safe to say that in most people the bacteria outnumber the human cells, in some cases by an order of magnitude. Whether the same is true of horses isn’t known, but considering the horse has evolved to rely almost entirely on bacterial activity within the intestine for its existence, it’s almost certain that the numbers involved are even more impressive. But the bacteria (and other microorganisms such as viruses and fungi) don’t just provide the necessary enzymes to digest food — they have evolved with the host and are absolutely vital for the development and maintenance of other functions, particularly the immune and nervous systems. Even within the intestine, it isn’t just a matter of dissolving the food as it passes through for the animal to absorb: the microbes are fundamental to those pathways developing adequately and operating effectively, from the earliest stages of life to the very last day of it.

The most striking examples of the absolutely cardinal role of bacteria in health and development can be seen in laboratory animals. Mice can be born and reared in sterile conditions, so that they develop without any (or very few) microbes in their environment and without the normal gut colonies they would usually possess. These so-called germ-free, gnotobiotic, or axenic mice do not develop normally. They can be fed the optimum diet and housed comfortably but they do not thrive: their immune and digestive systems are stunted, they do not gain weight normally, and they are vulnerable to a wide range of diseases. Even if introduced to ‘healthy’ microbial populations found in conventionally-reared animals they do not recover, most likely because they have missed the aforementioned, once-in-a-lifetime, critical window. Interestingly, germ-free mice can live longer than their colonised compatriots (if reared very carefully), which has recently raised important questions over the role of the microbiome in ageing and its implications for humans. 

Mammals need microbes. So where does a new-born mouse, human, or foal get these essential organisms from and, knowing what we know about the dangers that some types of bacteria present, how do they get the right ones?

It is now established that babies born via caesarian rather than vaginal delivery are more at risk from a number of conditions, including inflammatory and neurodevelopment disorders, and diseases of the bowel, lungs and joints, so much so that the technique of ‘vaginal seeding’ has become a much-discussed technique. Much of the impact of surgical delivery has been attributed to alterations in the microbial community that the infant is exposed to in the very earliest stages of neonatal life. While caesarian delivery is a very much rarer event in horses, the effect of early exposure to the ‘correct’ microbiome (sometimes referred to as ‘pioneer colonisers’) has been demonstrated in other species. The hygiene hypothesis is a term used to describe the way that early exposure to particular microorganisms is protective, and that a lack of such exposure leads to poor immune tolerance. Unfortunately, this term has sometimes been misunderstood: it doesn’t mean hygiene is a bad thing — we all need protection from pathogens — and it certainly doesn’t imply that having more infections during early life is advantageous. But a broad exposure to a variety of certain microbes is an essential part of development.  

But this exposure may begin even earlier. For many years, it was considered incontrovertible that the foetal environment in utero was sterile and that exposure to bacteria and other organisms only began at birth. However, recent work has challenged this ‘sterile womb paradigm’ and a number of studies have demonstrated the presence of microbial material within placental and foetal tissues. The debate is still ongoing, not least around whether the presence of bacterial DNA actually represents viable bacteria or simply fragments of long-deceased organisms; even the ability to breed axenic animals (as mentioned above) suggests foetal microbial colonisation is unlikely. 

What is emerging is a general consensus that the products of bacterial life in the mother may well be influencing foetal development, and could be crucial to it. Maternal microbiota produce bioactive metabolites that can enter the maternal circulation and may be actively or passively transferred through the placenta.

We know that elements of the microbiome that affect offspring are transferable: for example, bacteria taken from the gut contents of obese mice and transferred to pregnant, normal-weight mice, lead to overweight offspring with altered inflammatory responses. Maternal obesity causes changes in microbiota correlated with altered foetal brain development, while maternal undernutrition in humans affects infant immunity by attenuating responses to vaccines in early childhood (among many other effects). There is a huge volume of data concerning nutrition, and its effects on offspring, across many species, and it’s beyond the scope of this article to go into direct nutrient effects. Nonetheless, work has shown that foals born to obese mares are more likely to be affected by osteochondrosis, and supports the hypothesis that maternal relative hyperinsulinaemia may be a contributory factor through its role in cartilage differentiation. Foals born to overweight dams also have evidence of systemic inflammation (higher levels of plasma SAA) which may also affect development through inhibitory effects on bone growth. Crucially, the impact on progeny may be different depending on the alignment of the disturbance: i.e. whether the mares were obese at conception or overfed during the early or later stages of gestation. Maternal undernutrition is much less likely to be a problem in commercial breeding operations, but when it is, mares may develop a syndrome close to gestational diabetes in humans, a condition widely recognised to have potentially very serious consequences to the neonate, and even beyond. Again, timing is crucial: studies of epidemics, famine, and war show that mothers and their children have different outcomes depending on at which stage, from preconception to early childhood, the crisis occurred. 

Maternal stress during early pregnancy has been shown to reduce faecal bacterial diversity and alter taxa composition in pregnant mice and has been replicated in human studies. Conversely, severe maternal stress in the last trimester was associated with increased bacterial diversity in newborn babies. Maternal depression may alter the ratio of certain bacterial families in neonates, specifically by reducing numbers of Proteobacteria, a pioneer taxon which creates the environment for later anaerobic colonisation. 

A number of studies have identified known risk factors for infant severe respiratory tract infections, the leading cause of child mortality globally, including a carbohydrate-rich, fruit-/fibre-/vegetable-poor maternal diet, and/or never breastfeeding. In a 2023 study, researchers demonstrated that mice fed high-fibre diets produced a milk microbiota that increased infant gut propionate levels, leading in turn to increased production of specific cells in the bone marrow that confer protection against respiratory infections. Indeed, therapy with specific propionate-producing bacteria, and even propionate supplementation, were shown to act in a similar way. Fermentable dietary fibre favourably influences the gut microbiome resulting in the production of metabolites that modulate the immune system (particularly short-chain fatty acids — SFAs). It is widely accepted that SFAs play an important part in regulating intestinal barrier integrity, and there is now evidence that they have a role in placental structure and vascularisation. Breastmilk also contains regulatory cytokines, growth factors and oligosaccharides, all of which influence the developing infant. Metabolic disorders, such as gestational diabetes, affect the levels of SCFAs and other metabolically significant metabolites causing changes in the maternal immune system with knock-on effects for the developing foetus. The authors of this study suggested that the “manipulation of the maternal diet during pregnancy and during the pre-weaning period, or through the provision of defined tailor-made prebiotics and/or probiotics directly to infants, may present novel opportunities for enhancing resistance to inflammation-mediated diseases.” Other researchers have described the transport of even more molecules across the placenta, including lipopolysaccharides and other bacterial cell fragments. Preconception infections with some intestinal parasites can lead to maternal imprinting in mouse offspring, thereby suggesting that the transfer of immunity is not solely dependent on the passive transfer of antibodies. 

These metabolites may also exert an effect on the genetic material within cells. Epigenetics is the set of factors and molecules that modify gene expression while not changing the genome sequence itself. Only around 2% of mammalian DNA is associated with protein-encoding genes; the rest (non-coding DNA — what used to be referred to as ‘junk DNA’) modifies the links on the chain to switch genes on and off at crucial junctures. These modifications are commonly associated with environmental cues — good and bad — that can result in significantly different outcomes (phenotypic plasticity) for two genetically identical individuals. In one Danish study, children who exhibited allergic rhinitis at the age of six were found to have a distinct DNA methylation pattern (an epigenetic signature) in their nasal mucosal cells associated with reduced microbial diversity at one week of life. It was folate’s role in countering the development of neural tube defects that first pointed to the foetal nutritional programming hypothesis through epigenetic programming. And as the stage most susceptible to environmental stressors is embryogenesis, where DNA methylation is closely associated with optimal differentiation and growth, consideration of preconception dietary factors is fundamental (folate supplements are recommended when pregnancy planning, but gut bacteria produce significant amounts of folate in humans with a healthy microbiome).

While epigenetic changes do not change the base-pair sequences within the genome, they are heritable, meaning that future generations may inherit far more than just the A–T and G–C building blocks. It seems certain that different epigenetic mechanisms may partly explain why dietary factors at critical developmental stages might affect the susceptibility to diseases in adulthood. 

With microbes contributing 99% of all genetic information present in the body, maternal microbial transmission should be viewed as an additional and important mechanism of genetic and functional change in evolution. Horses are selected for characteristics such as temperament, strength, speed, and endurance. Although genetic selection tools have been developed to assist breeders in the choice of sires and dams, there is also a growing body of research reporting that the maternal environment modulates the genetic potential of the offspring. Under natural conditions, microbes that promote host fitness, especially in females, will simultaneously increase their odds of being transferred to the next generation. Under controlled breeding programmes, efforts to assist this beneficial effect should be encouraged: the trajectory of the young foal’s colonisation process has lifelong clinical implications. And being aware of its influence may not only improve the outlook for your foal, but your foal’s foals as well. 

Guest Author

Corticosteroids (such as prednisolone and dexamethasone), non-steroidal anti-inflammatory drugs (such as phenylbutazone, firocoxib, flunixin), gastric ulcer medications and antibiotics all impact gastrointestinal (GI) ‘gut’ health through several different mechanisms. These may include: irritating the sensitive tissue which lines the digestive tracts of our horses and ponies, potentially causing gastric ulceration and/or bleeding; causing GI dysbiosis (adversely impacting the delicate microflora populations within our horses’ and ponies’ GI tracts); and altering nutrient absorption and metabolism (the way our horses and ponies digest, utilise and excrete nutrients). 

Good gut health is central to the overall health and wellbeing in our horses. We know that beyond digestive health, gut health in our horses and ponies significantly influences: immune health; bone, cartilage and joint health; respiratory/airway health; metabolic health; reproductive health/fertility; hoof health; laminitis risk; and even behaviour and motor patterns in our horses.

These are just some of the reasons why it is important to use any medications judiciously- even ones that are routinely employed in many situations. In the case that these medications are required, strategic nutritional supplementation and in many cases, appropriately prescribed herbal medicines can help to address some of the nutrient depletions and side effects caused by these medications. Additionally they can help to return the digestive system to the best possible state of health.

Optim Equine

Camilla Whishaw is a highly regarded, experienced horsewoman and naturopath, helping to holistically treat and manage a broad range of equine health conditions and injuries, with a passion for mare and stallion fertility.

As a world-renowned practitioner, presenter, author, and consultant in the field of Equine Naturopathy, Camilla shares her knowledge through keynote presentations, interviews, lectures, panel sessions, and workshop training.

For the owner or rider considering taking on an OTTB, careful thought and planning should go into ensuring that the transition from the life of a racehorse to the next phase of the horse’s career is as smooth as possible. Some of the biggest considerations need to be given to changes in the horse’s diet, routine and optimising health parameters. Equipping yourself with knowledge and enlisting the help of suitably qualified professionals can help to realise your horse’s full potential.

Goals and Capabilities as a Rider/Handler

Before even inspecting an OTTB for potential purchase, clearly know what you are wanting in your new horse and your capabilities as a rider. Are you looking for a future show hack with impeccable conformation and looks? Are you looking for a pony club mount that needs to be calm and versatile? Are you looking for a horse with the potential to be a top-class eventer, thereby needing to be very sound, athletic and able to withstand high levels of training? Are you looking to get a cheap yet athletic horse to re-educate and sell on? Knowing the answers to these questions will quickly help to narrow down the horses you inspect for potential purchase and look to undertake a pre-purchase veterinary examination. By clearly knowing your goals, you can save yourself a lot of time and money and are far more likely to choose the most suitable horse.

When taking on an OTTB (particularly one that has come straight from a racing stable environment), honestly assessing your capabilities as a rider is critical. Are you confident and competent enough to safely and effectively manage and deal with an anxious, highly geared horse (whose temperament may or may not change significantly whilst in your care)? Or are you better suited to taking on a more relaxed OTTB or even one that has been off the track for some time and has spent time being re-educated with a different owner? One of the many beauties of OTTBs is that there are so many to choose from and at many different life and career stages- you are bound to find one that suits you perfectly! Be patient and choose wisely.

Vet Check

One of the first things to consider (and often most overlooked) when purchasing an OTTB is getting a thorough vet examination prior to purchase. Musculoskeletal soundness and airway health are two of the most significant considerations. Just like human athletes, racehorses’ bodies are put under strenuous physical demands, with the potential to develop injuries. Due to the hard galloping done by many young horses in training, considerable stress is put on bones, tendons and ligaments. This can lead to soundness issues. A thorough vet examination can help to identify previous injuries or any potential issues which may influence the ability of the horse to be suitable for its intended next career. On radiographic screening (x-ray), many racehorses will have some degree of osteoarthritic changes in their joints. With planning, sound dietary practices and the strategic use of appropriate supplements and management interventions, many of these conditions can be well managed. Furthermore, the fact that many OTTBs transition into their next careers at a relatively young age is advantageous. From a physiological perspective, when given suitable nutrition and support, their body is better able to repair and regenerate than an older horse. Referring back to your goals and what you intend to do with your OTTB is an important consideration here. A past injury in a racehorse which may prevent it from high-level eventing may pose no issues for a horse intended for general pleasure riding.

Suboptimal hoof health is a common finding in the newly transitioning OTTB. This is often due to a combination of poor gastrointestinal (GIT) health (which influences nutrient absorption and the production of essential vitamins such as biotin needed for sound, healthy hooves). For more information on the role of GIT in overall health and the role of nutrition in hoof health see articles: Fibre, Chewing and Gastrointestinal Health; Ulcers in Horses: The importance of understanding how medications work; Hay, Stomach (Gastric) & Hindgut (Colonic) Ulcers; and Beyond Biotin: Optimising Horse Hoof Health.

Routinely being shod in race plates can also compound the problem of poor hoof structure and health. Many racehorses have contracted hooves with under-run heels, long toes and thin soles. Encouragingly, hoof health is an aspect that can readily be turned around in a period of around 8-12 months with appropriate dietary changes and good farriery. Including radiographs of the hooves as part of the pre-purchase examination may be a valuable investment in some horses: x-rays can help to demonstrate what is going on in the hoof and can aid the proactive farrier to trim, shoe and manage the hoof appropriately.

It is important to remember that often racehorses in training will initially go footsore when their shoes are removed and they are left barefoot during a spell. This is especially true of the front feet. Some farriers and owners will choose to keep their horses in shoes. In many cases however, it is advisable for the spelling horse to have an extended period of time being unshod: this helps to positively influence hoof shape and integrity and aids in proper circulation and blood flow to the hooves. Feeding the horse a diet which reduces inflammation, using nutritional supplements (nutraceuticals) and herbal medicine under qualified supervision, and potentially easing the transition to barefoot through the use of padded, removable boots are all beneficial strategies.

Another aspect of the pre-purchase examination should also include an upper airway scope. Respiratory conditions which may be evident when assessing an OTTB include a history of exercise-induced pulmonary haemorrhage (EIPH, more commonly known as bleeding), airway inflammatory disease, and laryngeal hemiplegia (roaring). The first two can generally be well managed with appropriate feeding and supplementation practices and adopting strategies to minimise the inhalation of air particulate matter and dust.

History

Where possible, finding out as much history about the horse as possible can help to make a smooth transition to the next phase of its career. For a horse coming straight off the track, contact with the trainer and/or stable manager can help provide you with valuable information as to any health or injury concerns with the horse, the dates it was last vaccinated and drenched (de-wormed), any medications and/or supplements it may have been receiving, its current diet and any quirks, habits or temperament considerations to take into account. Having said this, it is also important to remember that when a horse is put in a new environment, some of the aforementioned things may change! For example, a horse that was previously often irritable can become much calmer with a more natural diet and living environment. Similarly, horses which may have been very picky eaters whilst in training often become very good eaters once their GIT health has improved and the stress of the training environment has been removed.

Diet

The majority of diets fed to thoroughbreds in training are not conducive to optimal GIT health and function. Practices vary between trainers and stables, but most often, horses in training are fed two or three large grain and/or concentrate-based meals per day. Grass and/or lucerne hay are often provided in limited amounts. Many trainers do not have the luxury of turning horses out to graze. This puts the horse’s digestive system under strain and increases the likelihood of many health issues including ulceration throughout the GIT (gastric and colonic ulcers), colic, disturbances in the GIT microflora (bacterial balance of the digestive system), hindgut acidosis, suboptimal ability to utilise feed properly and nutritional deficiencies/insufficiencies. The addition of high cortisol levels produced by the horse in response to stress and high-intensity exercise further compromises GIT health and digestive function. To read more about the contributors and effects of stress in our horses see: Stress in Horses: Why it isn’t always obvious.

Horses, by nature, are designed to be constantly moving about and grazing high-fibre roughage. This is important as the stomach of the horse is relatively small in volume and has little capacity to expand. As a result, small amounts of feed which are consumed often are digested much better than the large volume feeds given a couple of times per day. The constant grazing a horse does in its natural environment also ensures that there is a physical buffer in the stomach to protect against the breakdown action of hydrochloric acid and digestive enzymes. These substances are constantly produced in the horse and are essential for proper digestion, as well as immune function. To read more, visit: Ulcers in Horses: The importance of understanding how medications work. Grazing and chewing also stimulate the production of saliva. Saliva serves many important functions in the horse, including releasing bicarbonate ions into the stomach (which also protects the stomach lining, another smart natural mechanism of the horse to protect against ulcers). To learn more about the benefits of grazing, visit: Why Basics Matter: The Importance of Chewing.

Sudden changes in feeding practices (even those that are beneficial to the horse) can increase the risk of colic and other complications. This is thought to be largely attributed to rapid changes in GIT microflora in response to the feed offered. Finding out the horse’s current diet prior to purchasing can help to make smooth transitions to a more fibre-rich feed, whilst ensuring the gut microflora change at an appropriate rate. It is advisable to make the transition of feeds gradual (over a period of 12-14 days) to help best facilitate this.

Whilst horses who come directly out of training will have been maintained on high-energy rations, their relative energy needs during their initial transition into an OTTB will be much lower. Furthermore, if GIT health is optimised as part of their transition (through feeding, management practices and appropriate supplementation), they will be better able to use fibre rich feeds (ie pasture and hay) as energy sources. This is made possible through bacterial fermentation in the hind gut (helpful microbes in the large intestine break fibre down into short-chain/volatile fatty acids, a high source of energy for the horse). It is important to remember that whilst a horse’s actual energy needs may be much lower than when they were in training, their need for specific minerals, vitamins and protein may remain relatively high. Without the excess demands of training and racing the body is in a prime position to help address and heal any niggling injuries, musculoskeletal damage or immune health challenges. To find out more about nutrient requirements and the role of protein for horses visit Nutrient Requirements for Horses: Fortified Feeds and the need for Supplementation; The Importance of Protein. These are commonplace in any athlete involved in demanding sports. To facilitate optimal healing and health, is essential to ensure that the OTTB receives at a minimum the recommended dietary intake of minerals and vitamins, in addition to good quality protein sources. A good quality balancer feed or supplement, in the addition to sufficient pasture, hay and lucerne hay (where appropriate) will help to meet these needs.

Some people find challenges in putting condition on their OTTB and/or the horse being picky with their feed. This is most often due to irritation of GIT, use of ulcer medications and non-steroidal anti-inflammatories (NSAIDs) such as ‘bute’ (PBZ), and the diet racehorses are commonly maintained on,. These factors can all significantly compromise gut integrity and health. Add to this the stress of a new environment and the change in the horse’s routine and it can take a little time for the horse to adjust. Whilst the prescription of appropriate nutritional and herbal supplementation can help immensely in these cases, basic management practices including turning the horse out to graze, the provision of sufficient roughage (hay, pasture), and keeping the OTTB  with a sensible paddock mate are all effective starting points owners are encouraged to implement. One of the most common mistakes that can be made when wanting to put weight on a newly acquired OTTB is to continually increase the ration of grain or high-energy concentrate feed, without the provision of sufficient roughage and fibre. This contributes to additional compromises in the integrity of the GIT lining and further shifting the hindgut microflora away from that which promotes the best utilisation of feed and energy. As a result, the cycle of struggling to gain weight is perpetuated, and often leads to frustration as the horse seems to take an extended period of time to ‘let down’ and gain condition. To read more about horse’s who struggle to put on condition, visit the article: HELP! My horse won’t put on body condition.

Down Time

One of the best things you can do as an owner of a newly transitioning OTTB is give it some much needed ‘down time’. The majority of racing stable environments are far removed from what is a natural for the horse. Like humans constantly under work deadlines, family demands and everyday pressures, horses too routinely experience stress. This stress is manifested in many forms, primarily driven by changes in levels of the stress hormone cortisol (which can lead to reduced immune function, high levels of inflammation, changes in temperament and behaviour, and reduced capacity to recover). Additionally, the constant physical demands of training and racing can lead to ongoing musculoskeletal ‘niggles’- aches, pains and minor injuries. A period of 4-8 weeks, turned out in the paddock, fed a fibre-rich diet, and not in the demands of work or being fussed with is one of the most beneficial things you can do to help the newly transitioned OTTB. It helps the horse to mentally wind-down, aids in the restoration of GIT health, gives any small niggles the chance to heal, and lets the horse settle into a new environment and freshen up. Just like humans, horses too need holidays. Simply giving them time out before asking new demands from them in their new career, can help them get off to the best start. 

Temperament

A significant (and often highly variable and unpredictable) consideration in the OTTB is temperament. This can be a challenge when acquiring a new horse, as it is difficult to know exactly how much is ingrained behaviour and the horse’s natural tendency, compared to how much it is a result of the environment the horse has been in, the feeding practices and GIT health. An important consideration to note is that 70-80% of the neurotransmitters (the chemicals which influence mood, temperament, behaviour and learning) are produced in the GIT. There are clear links between GIT health and levels of anxiety, mood changes and behaviour. This is useful to take into account: an OTTB which has struggled with compromised gut health in training and may be nervous, edgy or readily spook can change significantly when GIT health is addressed. A combination of appropriate supplementation and feeding, combined with appropriate ‘down time’ can really significantly impact the behaviour of an OTTB for the better. It routinely plays a role in why many horses that are temperamental/nervy/anxious in training become more relaxed away from the stable environment. Keep in mind too, that the actual environment the horse is kept in also plays an important role.

Monitoring and Progress

From a basic health standpoint, once the new OTTB has arrived and settled, it is wise to measure temperature, respiratory and heart rates at roughly the same time each day for a week to establish what is ‘normal’ for your horse. Record these and keep on hand (using the notes section on your mobile phone can be great, otherwise written on a whiteboard or somewhere easily accessible). This information is incredibly helpful in the instance that your horse may become unwell: you know what is ‘normal’ and healthy for your horse, helping to implement appropriate strategies in a timely fashion.

Taking photos of your horse from the side and back (safely), on a fortnightly or monthly basis is a simple tool to monitor body composition changes and progress. The same thing can be done with their hooves front and side-on, in addition to picking the hoof up and taking pictures of the sole and frog. It can be incredibly rewarding to look back over a 4-6 week period and notice the subtle improvement in body condition. Horses can make significant progress in gradual increments, which may be missed when you are seeing the horse on a daily basis. By having photo evidence on hand, you are able to make a more objective assessment. Keep in mind that changes in hoof shape and quality will be much slower to notice: front hooves take a full 8-12 months to grow from the coronary band to the toe.

The majority of horses in training are maintained on a routine drenching (deworming) schedule. Given our current state of understanding in relation to resistance to worming products, it makes sense to adopt a strategic drenching approach. In order to implement this safely and effectively, taking routine faecal samples to be sent off for testing are encouraged. Doing this at the commencement of ownership can help to provide guidance to the most effective drenching requirements of your horse. For more information on drenching/deworming visit the article Drenching/Deworming with Panacur.

Conclusion

Like most worthwhile things in life, effectively transitioning a racehorse to an accomplished OTTB takes time and patience! Knowing your capabilities as a rider and having clear goals as to what you want to achieve with your new mount are important starting points. Enlisting the expertise of suitably qualified professionals and equipping yourself with the knowledge of best practices can help make for a smooth and rewarding journey. Choosing an OTTB can make for one of the most gratifying experiences as a horse owner and rider. Careful consideration, planning and attention to detail can ensure you give your horse every chance to excel in its new phase of life.

Optim Equine

Camilla Whishaw is a highly regarded, experienced horsewoman and naturopath, helping to holistically treat and manage a broad range of equine health conditions and injuries, with a passion for mare and stallion fertility.

As a world-renowned practitioner, presenter, author, and consultant in the field of Equine Naturopathy, Camilla shares her knowledge through keynote presentations, interviews, lectures, panel sessions, and workshop training.

The smell of our horse’s breath isn’t something we generally give much thought to. Yet if you’ve ever smelt the breath of a horse or pony with halitosis (bad breath)- then it becomes something hard to ignore. So why do some horses and ponies have bad breath and is it something to be concerned about?

Many factors can contribute to bad breath in the horse or pony: the most common being bacterial overgrowth in the mouth, decreased saliva, dental plaque, periodontal disease, cracked teeth and tooth abscesses. Yet the causes of bad breath aren’t just limited to the mouth alone. Infection in the respiratory tract and poor digestion can all contribute to bad breath. The side effects of some medications may also contribute to halitosis.

Oral Contributors

Halitosis can arise due to a lack of saliva production. The major salivary gland in our horses, the parotid gland, only secretes saliva when a horse chews. When our horses or ponies go long periods of time without grazing or consuming fibrous feeds such as hay, there are significant periods of time when there is little saliva in the mouth. The horse fed one or two concentrated/hard feeds daily, with little hay or grazing in between producing much less saliva than nature intended them to. Saliva has a multitude of functions in relation to our horse’s health, one of these being important antimicrobial activity through naturally occurring antibodies it contains. Lack of saliva production due to lack of chewing creates the perfect breeding ground for high levels of specific bacteria to build up in our horses’ mouths. This results in malodour. The effect is compounded by feeds that are high in sugar and/or starch, which can further ‘feed’ these ‘bad’ bacteria.  Furthermore, a dry mouth and lack of chewing fibrous feeds can also contribute to increased volumes of plaque on the teeth, giving rise to bad breath. Saliva helps rinse away tiny particles of food debris that may otherwise settle on the teeth and cause dental plaque. For more information on saliva and the importance of chewing in our horses visit the article: Why Basics Matter: The Importance of Chewing.

Gingivitis (gum inflammation) and periodontitis (where the inner layer of the gum and bone pull away from the teeth and cause pockets of air between the gums and teeth) affect horses in a similar way to humans. Gingivitis usually precedes periodontitis and begins when bacteria in the mouth proliferate around the teeth and gums. The build-up of large numbers of bacteria that attack the gingiva or gums leads to inflammation and malodour. It’s important to note that as the disease progresses and the gums become swollen and bleed, bacteria are able to enter a horse’s bloodstream and travel around the body. The effects of periodontal disease extend far beyond the mouth: it may be associated with reproductive problems in our horses and other undesirable conditions. Gum disease can contribute to loosened teeth, tooth loss and infections in the bone surrounding the teeth.

Poor Digestive Function

Hydrochloric acid (HCl) is an essential component of healthy digestion in our horses and ponies. It is produced by specialised cells in the stomach called parietal cells. One of the many functions of HCl is to help keep bad bacteria and opportunistic micro-organisms in check. When HCl production is reduced or shut down (as is the case with the use of ulcer medications) a perfect environment is created for opportunistic bacteria to flourish (for more information on the way ulcer medications work and their effects, visit the article: Ulcers in Horses: The importance of understanding how medications work). These bacteria produce compounds that result in a foul odour. Another crucial role of HCl is facilitating proper digestion and breakdown of food. Without sufficient HCl to help initiate normal digestion and maintain an acidic pH in the stomach, feed can ferment in the gut- resulting in the production of malodorous gasses. For these reasons, bad breath can be an indication to look at digestive health beyond the mouth. 

Medication Side Effects

A wide variety of medications commonly used in horses and ponies may contribute to halitosis through differing mechanisms. Some antibiotics, anti-fungals, anti-histamines, diuretics, sedatives, bisphosphonates and dimethylsulfoxide (DMSO) may all cause or contribute to bad breath in equines.

Respiratory Tract Infections

Sinusitis (inflammation of the lining of one or more of the sinuses) and upper respiratory tract infections can also contribute to bad breath in our horses. These are generally accompanied by mucoid (whitish, yellowish) nasal discharge out of one or both nostrils. Clinical signs may also include swelling or bulging of the facial bones, decreased appetite, lethargy and weight loss.

Nutritional Deficiencies/Insufficiencies

Beyond the type of feed our horses consume and how frequently they are fed, many key nutrients play important roles in oral health. Insufficiencies and/or deficiencies in protein, vitamin A, vitamin D, zinc and impaired production of B group vitamins and vitamin C may all be implicated in compromised oral health, leading to bad breath.

Conclusion

There are many causes and contributing factors to bad breath in horses and ponies. Whilst poor dental and oral health are obvious cases of bad breath, diet, medications, gastrointestinal and respiratory system function may all play important roles. Foul smelling odours from the nostrils and/or mouth warrant further investigation by suitably qualified professionals. Properly identifying and addressing the cause(s) of halitosis help to promote overall health in your horse or pony, as well as helping them to have a non-offensive smelling breath!

Optim Equine

Camilla Whishaw is a highly regarded, experienced horsewoman and naturopath, helping to holistically treat and manage a broad range of equine health conditions and injuries, with a passion for mare and stallion fertility.

As a world-renowned practitioner, presenter, author, and consultant in the field of Equine Naturopathy, Camilla shares her knowledge through keynote presentations, interviews, lectures, panel sessions, and workshop training.

What is Protein?

Protein is a crucial macronutrient in a horse’s diet and is comprised of long chains of building blocks called amino acids. There are 21 amino acids. The specific order and combination of amino acids determines the structure and function of each protein. Insufficient dietary intake of specific amino acids limits the production of key proteins essential in our horse’s bodies. For more in-depth information on protein quality see the article: Soy: The Good, Bad and Confusing.

Protein is Needed for Growth, Maintenance and Repair of Tissue

We commonly only think of this as important when we are trying to increase muscle mass in a horse. For instance, building top-line on our ridden horse, or conditioning a thoroughbred yearling for sale. Yet protein is absolutely essential for normal growth and development of the young horse, and recovery from riding and training in active horses. Insufficient protein in the diet can therefore increase risk of illness and injury in our horses. Times of illness and injury also increase protein requirements in order to help recover from the illness or heal from the injury. Providing insufficient protein to a sick or injured horse during their recovery can significantly delay and/or impair their healing and adversely impact their future athletic potential.

Protein Facilitates Biochemical Reactions

Enzymes are a specific type of protein that aid in the normal biochemical reactions that take place in a horse. Specific enzymes are needed to facilitate proper digestion (therefore helping to promote optimal gut health and utilisation of feed); energy production (helping a horse to perform); normal metabolism (helping to regulate weight and temperature in a horse); blood clotting; and muscle contraction. Insufficient protein in the diet can lead to digestive problems- a critical consideration given the heightened focus on gastrointestinal (GI) health. A common mistake is to restrict protein intake in the overweight horse: this can further slow metabolism (compounding the problem) and compromise overall health.

Protein is Required for Proper Communication in the Body

Hormones are chemical messengers that aid in communication between a horse’s cells, tissues and organs. They are needed for everything from normal growth, metabolism, reproductive function and digestion. Amino acids are also an important component of neurotransmitters: the chemical messengers which play a crucial role in a horse’s mood, temperament, learning and behaviour.

Protein Provides Structure

Different types of protein are essential for the formation of healthy bones, tendons, ligaments, muscles, skin and hooves. Depending on the type of protein, they aid in providing structure, strength, elasticity and rigidity to specific tissues. Insufficient protein in the diet can make a horse more susceptible to injury to muscles, tendons, bones and ligaments. They may also have poor skin and/or hoof quality.

Protein Helps to Maintain pH Balance in the Body

Proteins act as a buffer system, helping a horse’s body to maintain proper pH values of the blood and other bodily fluids.

Protein Helps to Balance Body Fluid Levels

Albumin and globulin are two important proteins found in a horse’s blood. They help to maintain the body’s fluid balance by attracting and retaining water. If a horse’s diet has consistently has low quantities of quality protein, the levels of albumin and globulin eventually decrease. This can result in swelling or oedema as these proteins can no longer keep blood in the blood vessels, forcing the fluid into the spaces between cells. The irony is that protein is often blamed for causing swelling in horses- with the reverse often being the cause!

Protein is Needed for a Healthy Immune System

Protein is absolutely essential for white blood cell production and the formation of immunoglobulins (antibodies) needed to fight infection in our horses. Insufficient protein in the diet can leave a horse more susceptible to bacterial, viral and fungal infections.

Protein Aids in the Transportation and Storage of Nutrients

Transport proteins carry substances in our horse’s blood streams- into, out of and within cells. The substances transported by these proteins include nutrients such as vitamins and minerals, blood sugar, cholesterol and oxygen. Whilst we often think of iron as being a key driver in helping oxygen delivery to the body’s tissues, protein plays a paramount role- yet is often overlooked. Specific proteins also have a storage role: ferritin is a storage protein that stores iron.

Problems with Excessive Protein: Myths or Facts?

So now we can see that protein is absolutely vital in keeping our horses healthy, yet is there a downside to this nutrient? And can we feed too much? Like most things, the answer is relative to the situation and the individual horse.

Excess Protein

To overly simplify, horses are unable to store excess protein that they consume in their diet for later use. The metabolism of excess protein increases levels of nitrogen end-products, such as ammonia and urea. A diet containing excess protein will increase the horse’s water requirements and urine output as the ammonia and urea are flushed out of the body. If a horse is kept out at pasture, is only in light work and has free access to plenty of fresh water, this generally isn’t a problem. It is an issue however where horses are stabled. Exposure to this strong urine can cause lung irritation and other respiratory problems. Extra urination means extra wet bedding, which equates to more mucking out.

Metabolism of Protein Produces Heat

Protein digestion and metabolism is a heat generating process. A horse that is on a high protein diet that is burning a lot of protein as an energy source will sweat more to help get rid of the heat. It is important to remember that the body has a preference for using carbohydrates and fats over protein as an energy source, and will only use protein as a significant energy source when these other two nutrients don’t meet their requirements. Protein fed in appropriate amounts to meet a horse’s needs will not contribute greatly to heat production or sweating. Feeding excessive amounts of protein however, particularly to horses in hot and humid climates, or those undertaking moderate to heavy work, can contribute to dehydration and heat stress.

Protein Causes Poor Behaviour/ Hot Horses: MYTH

Protein is often blamed for making horses ‘hot’, nervy or spooky. This is turn can cause some owners to avoid including quality sources of protein in their horse’s diet. Protein has not been shown to cause behavioural issues in horses. Diets which are high in energy and excessive to a horse’s energy needs which are also high in protein can contribute to a horse being hyperactive or silly. The problem here is the overall energy intake, not the protein!

Kidney and/or Liver Damage: MYTH

In healthy horses, high protein diets have not been demonstrated to cause kidney and/or liver damage. In horses that have pre-existing liver or kidney problems, then protein intake may need to be restricted- ensuring that intake is still sufficient to meet a horse’s daily requirements but does not exceed them.

Take Home Message

As a general rule, I see far more horses in clinical practice with insufficient protein intakes compared to those with excessive protein intakes. Insufficient protein in the diet may leave a horse more susceptible to illness and/or injury and delay or impair their recovery. Including adequate, quality protein in the diets of our horses is absolutely essential in order for them to be healthy, perform and recover at their best.

Optim Equine

Camilla Whishaw is a highly regarded, experienced horsewoman and naturopath, helping to holistically treat and manage a broad range of equine health conditions and injuries, with a passion for mare and stallion fertility.

As a world-renowned practitioner, presenter, author, and consultant in the field of Equine Naturopathy, Camilla shares her knowledge through keynote presentations, interviews, lectures, panel sessions, and workshop training.

Heat stress occurs when a horse’s thermoregulatory system cannot adequately dissipate heat. It is most common when exercising in hot, humid conditions, as exercise results in the generation of heat. Heat dissipation relies on evaporation of sweat: sweat cools the skin down and the blood flowing through it by evaporation. In hot, dry air, sweat evaporates very quickly but as the humidity increases, the speed at which sweat evaporates becomes less effective. Overweight and/or unfit horses are less effective at dissipating heat, increasing their risk of heat stress.

As a horse’s sweat levels increase, so does their loss of essential electrolytes. Horses are able to sweat faster than any other animal (thereby helping to cool themselves). Additionally, the electrolyte content of horse sweat is highly concentrated. The most significant electrolyte lost in sweat is salt. Salt must be supplemented in the horse’s diet to meet their daily sodium requirements- this is true even when horses sweat minimally. Processed horse feeds do not contain sufficient salt for basic daily requirements. Grass, hay and other feeds also do not help to meet our horse’s salt requirements. If electrolytes aren’t adequately replaced in the diet, insufficiencies/deficiencies and imbalances in electrolytes can occur in our horses (horses cannot make their own electrolytes). These imbalances and deficiencies in turn increase the likelihood and/or severity of poor performance. They may also be implicated in exertional rhabdomyolysis (tying up) and synchronous diaphragmatic flutter (thumps).

Dehydration is a risk factor in many horses. As they can sweat at such high rates, fluid losses are accentuated. Dehydration can increase the risk of several health conditions, one of the most common being colic. Dehydration can slow the passage of food material in the gastrointestinal (GI) system and make faeces much drier and firmer- resulting in impaction colic.

Respiratory health complications can also arise from dehydration. Respiratory tract irritation, inflammation and infection may all be consequences of dehydration. In a dehydrated horse, the mucus in the airways of the lungs increases in viscosity (thickness) and moves slower- resulting in accumulation of matter in the lungs.

Hot and/or humid weather can cause horse feed to go off much quicker than usual and can change the nutritional content of processed feeds. High fat feeds and oils will quickly go rancid in hot weather (it is important to note that this can occur without the feed or oil smelling ‘off’). This can lead to a horse consuming less feed than normal. Dehydration can also result in reduced appetite.

Some minerals and vitamins in different feeds also deteriorate in quality with heat, further compounding health issues. Reduced feed intake and/or changes in metabolic rate associated with hot and humid environmental conditions, can lead to weight loss in the horse.

Signs and symptoms to look out for that may be indicative of detrimental effects of heat and/or humidity in the horse include:

• Increased rectal temperature
• Poor performance
• Poor recovery post exercise
• Panting (fast, shallow breathing)
• Blowing excessively for a prolonged period of time after exercise
• Lethargy (often accompanied by the appearance of being unsteady on their feet)
• Muscle spasms
• Feeling very hot to touch
• Dark and/or reduced urine
• Nostril flaring
• Decreased appetite and/or thirst
• Irregular heart beat
• Thumps (synchronous diaphragmatic flutter)
• Dark mucous membranes
• Very prominent blood vessels on the skin

Helping to prevent heat stress and/or the consequences of high temperature and humidity takes a multi-faceted approach. Heat acclimatisation (when important competitions/events take place in the heat) is an important consideration. Horses, like humans, can become acclimated to heat. This generally takes 2-3 weeks, and requires them to be sensibly exercised in the heat and/or humidity on a daily basis. It is important to take into account that even fit, well acclimated horses may experience reduced performance in hot and/or humid weather conditions. Quite contrastingly- if you enjoy riding during hot weather (but are not competing in events that take place in the heat) then exercising your horse in the coolest parts of the day is an effective strategy.

Post exercise, adequately cooling down and hosing off your horse is important. In cases where a horse is extremely hot, hosing for 10-15 minutes with cold water may be necessary. Its best not to scrape the water off your horse in this case: water which sits on the skin will evaporate and help to contribute to the cooling process.

Ensure clean drinking water is always provided to your horse and don’t withhold water before or after exercise. Offering water immediately after exercising is recommended, as this is the time when a horse’s thirst is strongest. Try to avoid ice cold water, but don’t restrict intake. Giving water to a healthy horse post exercise is not associated with causing colic. With increased sweating rates, horses have increased fluid requirements- so expect and allow them to drink more.

The daily provision of adequate salt and the appropriate use of electrolytes are important to help maintain normal physiological processes in the body.

Exercising horses in hot and/or humid weather can pose some challenges, but sensible management and riding practices can help to minimise these. Keeping our horses properly hydrated, cooling them effectively post exercise, and ensuring we meet their dietary requirements are important factors in keeping them healthy in hot, humid weather.

Optim Equine

Camilla Whishaw is a highly regarded, experienced horsewoman and naturopath, helping to holistically treat and manage a broad range of equine health conditions and injuries, with a passion for mare and stallion fertility.

As a world-renowned practitioner, presenter, author, and consultant in the field of Equine Naturopathy, Camilla shares her knowledge through keynote presentations, interviews, lectures, panel sessions, and workshop training.

For the purpose of this article, we will focus on soy bean meal and feeds containing processed soy- not soy oil or soy bean hulls- as these components alone have significantly different nutritional value and properties.

Pros

Soy is one of the more widely fed significant sources of protein in a horse’s diet. It is a common misconception that protein is only needed to promote weight gain, muscle condition or the development of topline. Whilst it is important in these instances (in combination with appropriate exercise and training), protein is absolutely essential for a multitude of functions in all horses at any life stage and exercise level: it is a critical component of normal immune function; facilitates proper growth and repair of the musculoskeletal system; and is needed for the majority of metabolic processes in the horse. Even horse’s who aren’t in heavy work and/or actually need to lose weight need sufficient protein in their diet.

Protein is comprised of smaller units called amino acids. Horses require 21 amino acids, 12 of which a horse can synthesise (produce) themselves. The remaining nine (and in the case of illness or injury- potentially ten) amino acids must be present in a horse’s diet. These are known as ‘essential amino acids’. In addition to all essential amino acids being present in the diet, they must be present in appropriate quantities- so a horse has enough of each of them to facilitate various bodily functions. If they fall short of any essential amino acids then health, normal development, performance and recovery may be compromised.

With the exception of oils, practically all horse feeds, grains and forages contain SOME protein- Depending on the exact feed source, the actual amounts of protein contained in these feeds will vary. Different sources of protein are comprised of different sequences of amino acids. This influences how useful they are to a horse. Some high protein feed sources are actually of little value to a horse, as they lack decent amounts of essential amino acids that a horse needs, or they are unable to be properly digested and absorbed by a horse.

So how does all this relate to soy? Soy is one of the best dietary sources of lysine for our horses and ponies. Lysine is a very important essential amino acid in the equine and it is generally one which is lowest in our horse’s diets. Lysine is absolutely essential for normal muscle growth and turnover, helps to promote collagen integrity (important for healthy bones, skin, muscles, tendons and ligaments), is critical for proper immune function, and may further help bone health through improving calcium absorption and utilisation. Animal studies have also shown that diets low in lysine may be associated with anxiety. Thus, a diet low in lysine may be one of many potential contributing factors in some cases of horses with an anxious tendency.

For horses competing in endurance events, optimising hydration pre-event is an important consideration. Commercial soy feed products which require soaking before being fed, can help to increase fluid intake in horses. It’s important to keep in mind that there are other feeds which can be used for this same purpose. Soy is not the only option.

Being a low starch and protein rich feed, processed soy meal can aid in stabilising blood glucose levels- thus helping to prevent rapid spikes in insulin levels. High insulin levels are a driving factor of equine metabolic syndrome and are commonly implicated in many cases of laminitis. Horses with Pituitary Pars Intermedia Dysfunction (PPID) (also commonly referred to as ‘Cushings’) and Polysaccharide Storage Myopathy (PSSM)- a component in many cases of ‘tying up’, may also particularly benefit from a diet low in starch and containing adequate quantities of quality protein.

The phytoestrogen content of soy is an important, yet often misunderstood concept. Soy is unique in that it contains a high concentration of isoflavones, a type of plant oestrogen (phytoestrogen) that is similar in function to the hormone oestrogen but with much weaker effects. Soy isoflavones can bind to oestrogen receptors in the body and can either increase or decrease oestrogen levels in the body. Research has demonstrated that when oestrogen levels in the body are naturally low, then ingestion of phytoestrogens may help to increase the body’s levels.  When oestrogen levels in the body are naturally high, then consuming phytoestrogens may help to reduce oestrogen levels, as they bind to some of the receptor sites that naturally produced oestrogen may bind to.

Potential Cons

The phytoestrogen activity of soy may also potentially be a drawback of this feed. Excessively high intakes of phytoestrogens have the potential to decrease testosterone levels, an important consideration in stallions and colts. Soy certainly isn’t the only source of phytoestrogens commonly found in horse diets: clover grass is rich in phytoestrogens. Before attributing potential positive or negative effects of phytoestrogens in a horse’s diet, the total quantity of all phytoestrogen rich food sources needs to be taken into account.

Soy is commonly attributed to causing allergic symptoms in horses- everything from itchiness and skin irritation, colic and digestive disturbances, to overly-reactive behaviour and respiratory issues. Whilst soy is a common allergen in humans, the same has not yet been demonstrated in horses. Diagnostic tests for equine food allergies are difficult to carry out, time-consuming and often unreliable. In clinical practice, I find that the majority of horses with allergy related symptoms (whether these be environmental or food related) improve significantly when overall nutritional status and specific components of both immune and gut health have been therapeutically addressed. Generally something which may appear to cause allergic symptoms in a horse is not the real culprit.

A significant valid concern with soy is the fact that it is one of the most commonly genetically modified (GM) crops. Whilst this is only an issue in some parts of the world, it is certainly worth taking into consideration. Animal studies with GM foods indicate that they may cause some common toxic effects such as hepatic, pancreatic, renal, or reproductive effects and may alter blood parameters and immune function.

Soy is high in omega six fatty acids. Whilst these types of fatty acids are an essential component in our horse’s diets, they are generally present in higher than desirable amounts. Of further importance is the percentage of omega six fatty acids in proportion to omega three fatty acids. High levels of omega six fatty acids with accompanying low levels of omega three fatty acids are known to promote inflammation. Adding large amounts of soy products to a diet already high in omega six fatty acids further accentuates the shift towards a pro-inflammatory tendency. This can  have wide-ranging effects from impairing recovery from training, competition and exercise; compromising immune function; and exacerbating already existing inflammatory conditions such as osteoarthritis, desmitis, placentitis and laminitis to name a few.

Uncooked or even inadequately cooked soybean meal has some anti-nutritional factors. Trypsin inhibitor is the most significant one. Trypsin is an essential enzyme which helps horses to properly digest protein, allowing for absorption and metabolism of the amino acids which make up the protein. Trypsin inhibitor found in uncooked soybean prevents trypsin from being able to properly break down proteins. This means that in the presence of trypsin inhibitors a large percentage of all protein from all sources a horse is consuming is unable to be properly digested, absorbed and metabolised.

Some concerns exist that soy can have a negative effect on thyroid function and can alter the levels of thyroid hormones. Whilst the majority of data is from human studies, it is unlikely that regular consumption of small amounts of soy containing foods have significant impact on thyroid function in healthy subjects. In cases where hypothyroidism already exists (keeping in mind that diagnosis and true cases of hypothyroidism in horses is rare), then reviewing the appropriate feeding of soybean containing products is warranted.

Conclusion

Processed soybean meal and feeds containing this product can be a valuable inclusion in the diets of many horses. Factors which may caution against the feeding of soy to some horses include specific health concerns and where in the world the soy is grown and produced. Soybean meal MUST be properly heat treated to prevent trypsin inhibitor from interfering with protein digestion. The quantity of soy products fed and the overall diet of the horse are crucial factors to take into consideration.

Rarely is anything inherently good or bad: the same may be said of soybean products. The most important consideration is that one size doesn’t fit all: feed the individual horse in front of you!

Optim Equine

Camilla Whishaw is a highly regarded, experienced horsewoman and naturopath, helping to holistically treat and manage a broad range of equine health conditions and injuries, with a passion for mare and stallion fertility.

As a world-renowned practitioner, presenter, author, and consultant in the field of Equine Naturopathy, Camilla shares her knowledge through keynote presentations, interviews, lectures, panel sessions, and workshop training.

In barn settings, ammonia is produced when the urea in urine hydrolyses (breaks down) through the action of the enzyme urease. Urease is a protein found in bacteria associated with faeces and stable flooring materials that have been fouled with faeces.

Ammonia can cause inflammation and irritation of both the upper and lower airways and can lead to the development of pulmonary oedema. Horses which are stabled have demonstrated more signs of respiratory inflammation than horses turned out at pasture.

Ammonia sets up an inflammatory cascade in the respiratory tract: increasing mucous production; interfering with the action of cilia (microscopic hairs which line the airways and help to prevent dust and debris from going further down the respiratory tract); and adversely affect immune function and health in the horse.

The negative effects of ammonia are further compounded by poor ventilation in the barn, dust and other particulates inhaled by the horse.

The good news is there are many practical strategies which can be employed to help reduce ammonia build-up in the stable:

• Provide excellent barn ventilation and where possible, avoid closing up the barn.
• Ensure stalls are cleaned once or twice daily to remove all urine-soaked bedding. Ensure stalls are stripped at least twice weekly.
• Ensure horses are removed from stalls whilst mucking and cleaning to minimise exposure to ammonia gases that are stirred up with pitching the bedding and raking.
• Use highly absorbent bedding materials.
• Mix an ammonia-neutralising product with clean bedding.
• Provide good drainage in stables and barn aisle ways to facilitate exit of urine. If matting is used in stalls, regularly clean under the mats when possible.
• Open windows where possible.
• As much as possible, keep horses outside or turn them out regularly to offer a clean air environment.

Treating horses with specific therapeutic herbs and nutrients can help to reduce inflammation and mucous production, in addition to supporting immune function. The most effective results are obtained however, when therapeutic intervention is used in conjunction with addressing the causative factors (such as ammonia and environments high in dust and other particulates). If the cause(s) is/are not addressed, then the initiating factor(s) of the irritation remain….

Optim Equine

Camilla Whishaw is a highly regarded, experienced horsewoman and naturopath, helping to holistically treat and manage a broad range of equine health conditions and injuries, with a passion for mare and stallion fertility.

As a world-renowned practitioner, presenter, author, and consultant in the field of Equine Naturopathy, Camilla shares her knowledge through keynote presentations, interviews, lectures, panel sessions, and workshop training.

Stables are full of tiny particles that can infiltrate and subsequently irritate their respiratory system. Barn air quality is difficult to visually assess: the particles that irritate the airways are generally microscopic in size.

Fortunately, there are many feeding, management and supplemental strategies which can help prevent the narrowing and spasms of the air passages (bronchoconstriction and bronchospasm) and excessive mucus production associated with Equine Asthma Syndrome.

Before or in addition to the use of strategic supplementation, there are three super simple steps any stable can implement to improve the respiratory health of their horses:

• Only muck stalls out when horses are not in the barn
• Avoid the use of blower vacs in barns.
• Only sweep the barn when horses are out.

Doing these things whilst the horses are out (working and/or turned out) and allowing at least half an hour after completing the above tasks before the horses are brought back in will help to reduce the particulates they inhale. The result? Healthier, less irritated airways and horses who are better able to perform.

Optim Equine

Camilla Whishaw is a highly regarded, experienced horsewoman and naturopath, helping to holistically treat and manage a broad range of equine health conditions and injuries, with a passion for mare and stallion fertility.

As a world-renowned practitioner, presenter, author, and consultant in the field of Equine Naturopathy, Camilla shares her knowledge through keynote presentations, interviews, lectures, panel sessions, and workshop training.

Equine asthma (EA) is a common cause of poor performance in racehorses and performance horses. Yet, the side effects of a drug commonly used to help mange clinical signs in the condition may play a significant role in anxious, worked-up, stressed, irritable behaviour in some horses.

Two commonly used medications in EA are Claire Gel and Airway Gel. The active ingredient in these products is the drug Clenbuterol. Clenbuterol is a beta-2-adrenoceptor agonist. Beta-2 adrenoceptor agonists work by mimicking the effects of epinephrine (adrenaline) in the body.

It is widely known that the use of this drug has been exploited due to its ability to burn fat whilst preserving lean muscle tissue. Sadly, this practice can severely compromise the horse’s health.

Clenbuterol, being highly stimulating, can adversely affect the temperament and behaviour of the horse. It has also been shown to deplete the body’s levels of taurine and potassium- which may lead to cramping (amongst other undesirable side effects). Additionally, animal studies have demonstrated that the drug depletes zinc levels and causes irreversible damage to cardiac tissue.

Negative effects upon stallion fertility have also been postulated. The drug has been shown to permanently damage the Sertoli cells in the testes-these are the cells where sperm is produced.

In the case of preventing and managing airway disease- there are many steps which can be taken to reduce the need for the drug. These include practices during feeding and stable management which reduce airway irritation and inflammation in the horse. The strategic use of several permissible nutritional supplements can help to alleviate airway inflammation, spasm and mucous production.

For a horse not currently in competition, correctly prescribed herbal medicine provides many therapeutics to support immune function, reduce mucous production, thin mucous and treat respiratory tract infection- all which may help to rectify breathing difficulties in the horse..

Optim Equine

Camilla Whishaw is a highly regarded, experienced horsewoman and naturopath, helping to holistically treat and manage a broad range of equine health conditions and injuries, with a passion for mare and stallion fertility.

As a world-renowned practitioner, presenter, author, and consultant in the field of Equine Naturopathy, Camilla shares her knowledge through keynote presentations, interviews, lectures, panel sessions, and workshop training.

Whilst iron deficiency in humans is an all too common problem, in our horses it is fairly rare. When it occurs, it is not usually due to an insufficient intake of iron in the diet. Instead it generally occurs due to low-grade, longterm blood loss (the causes of which deserve to be written about in a separate post). Losing large amounts of blood in an acute injury/health complication are also a cause.

One of the most commonly seen scenarios I see in practice is when trainers and riders give horses iron supplements in response to a horse performing poorly or a horse which has had an infection (viral or bacterial).  Iron is perhaps the most important micronutrient required for bacteria to proliferate and cause disease. Viruses also depend on iron in order to efficiently replicate.

It is important to remember too that iron is needed by inflammatory cells. Any condition a horse has where there is significant inflammation (Equine Asthma, placentitis, sesamoiditis, ligament or tendon damage, endometritis- just a few examples!) could be further worsened by iron supplementation.

Takeaway messages:

• By supplementing iron in the poor performing horse/horse that has a ‘virus’ or infection, or any significant inflammatory process, chances are you are making the condition worse.
• ‘Natural’ supplements aren’t always safe/appropriate/indicated
• Get professional advice to help identify and address the cause(s) of the poor performance/challenging health condition in your horse.

Optim Equine

Camilla Whishaw is a highly regarded, experienced horsewoman and naturopath, helping to holistically treat and manage a broad range of equine health conditions and injuries, with a passion for mare and stallion fertility.

As a world-renowned practitioner, presenter, author, and consultant in the field of Equine Naturopathy, Camilla shares her knowledge through keynote presentations, interviews, lectures, panel sessions, and workshop training.