Eco Trainers - converting manure to electricity

By Katherine Ford

Trainers at the main French training base, Chantilly, have gone green and are soon to be the envy of their contemporaries around the world with a ground-breaking manure-disposal project. Faced with piles of manure, the bane of all trainers' lives, Chantilly professionals are working together to launch a pioneering scheme which looks set to solve all their problems and at the same time reap both environmental and financial rewards. The 10-million euro project, which should be operational towards the end of 2009, is at the cutting edge of technology and consists of using a process of methanization to convert the waste into electricity which will then be sold to the EDF (French Electricity Board), and into heat which will be used locally.

With some 2500 Thoroughbreds currently in training in and around the towns of Chantilly, Gouvieux and Lamorlaye, the region is France's leading training center and among the most prestigious sites for preparing racehorses in the world. A further 700 polo ponies and 800 riding horses are stabled in the area to make a grand total of 4,000 equine inhabitants. Slightly less glamorous than the haul of Group 1 victories which the four-legged stars of Chantilly bring home each season is the waste they produce. Each horse creates one ton of manure per month. The muckheaps of Chantilly are overflowing and a solution is urgently needed.

Dual-purpose handler Richard Crépon was one of the first to react to the issue, and in early 2006 he became president of the Lamorlaye Bio-Resources Association. "We started to research ways to deal with our large quantities of manure and initially came up with the idea of converting it into compost, or incineration. Local farmers made a small contribution by spreading shavings-based manure on their land. But none of these systems were perfect and we realized that we needed to take control of the situation ourselves." It was then that the current CUMA (Co-operative for the Utilization of Agricultural Material) was born, again under the presidency of Crépon. All of Chantilly and the surrounding area's hundred or so license holders, as well as the towns' riding school, livery and polo proprietors, have been invited to invest the modest sum of 100 euros to join the co-operative which, as Crépon explains, "needs manure in order for our project to be feasible."

The CUMA'S methanization project offers a mutually-beneficial solution to a relatively new problem. Until recently trainers had been able to rely on the abundance of mushroom producers in Chantilly to dispose of their troublesome "by-product." The farmers had chosen Chantilly for its combination of an unending supply of the horse manure necessary for their fungus to grow, and the geological characteristics of the surrounding area. Chantilly is built on valuable limestone which has been excavated over the centuries, notably to construct the spectacular Grandes Ecuries and Chateau which give such charm to France's Classic racecourse. The quarrying left vast underground caves perfect for mushroom cultivation and thirty years ago the area was home to around 25 mushroom farms. "They used to pay us to take away our manure. Nowadays, the industry has largely moved to Eastern Europe, leaving only 4 mushroom producers in Chantilly. We have trouble to get anyone to empty our manure pits and it costs more and more." In Chantilly it now costs 15 euros per ton for trainers to dispose of their organic waste.

Aside from the purely practical inconvenience of evacuating the tons of waste produced weekly, fellow trainer Tony Clout, making a regretful gesture towards a steaming skip full of manure, comments, "we don't realize it, but we contribute to the greenhouse effect every day with all this manure." Clout is another board member of the French Trainers' Association who is an active player in the CUMA. Like all his trainer colleagues, he is primarily concerned by another form of pollution. "Horse manure is officially considered as a waste product and we are responsible for it until it has been completely destroyed. At the moment we have no control over where it ends up. In the current crazy situation, our manure is transported the length and breadth of France. It is always worrying to see piles of manure left standing in fields across the countryside, as they could easily have originated in our stables. There is a real risk that effluent from the waste will pollute the ground water in these instances and the trainer will be held liable and fined."

The increased environmental awareness on the part of the authorities, aside from making them more likely to take trainers to task for inadequate disposal of their waste, has another more beneficial side for the CUMA. "The timing has been ideal for us," explains Crépon. "We started to think about environmentally-friendly ways to recycle our manure at the same time as the government was creating grants and finance schemes for exactly this type of project." One such policy is that proposed by EDF, who pay a special tariff of 140 euros per megawatt hour (compared to usual rate 60 euros MW/h) for electricity produced by renewable sources. This price operates on the basis of a 15 year contract, which the CUMA has secured. "All this is possible thanks to our contract with EDF," states Clout.

Although the finer details have yet to be settled, the principle behind the Chantilly project is the same as that used in Germany by around 4,000 methanization plants for pig slurry. Nevertheless this will be the first time the technology has been used for horse manure. Bruno Battistini, consultant to the Lamorlaye Bio-Resource Association, explains, "We are setting a European and worldwide precedent. The pig manure operations are common in Germany and function in the same way as sewage processing plants as the slurry is highly-concentrated and in liquid form. However this is the first time anyone has attempted the process with dry matter, although it is similar to that used for household waste." In France there are two such plants, in Calais and Lille, for recycling household waste but there remain a number of unknowns concerning Chantilly's innovative project and the CUMA is still conducting research in conjunction with the INRA (National Institute for Agronomic Research) of Narbonne. "Our primary concern is to verify that our horse manure is compatible with the anaerobic breakdown process. We must also be sure of the levels and composition of the biogases produced, and finally that the equipment will stand the test of time." At the current time, around 18 months before the project is due to leave the starting stalls, Battistini and the trainers are certain that the process will work with straw-based manure and are expecting confirmation from the INRA that shavings will be able to be recycled in the same conditions.

Methanization is an anaerobic fermentation process through which the waste is decomposed by bacteria in an air-free environment. The manure will therefore be collected in giant sealed silos, where it will ferment to give off biogas consisting largely of methane and carbon dioxide. These gases will in turn be used to drive turbines which produce the electricity destined for EDF. "While EDF is our guarantee of income," explains Battistini, "we have a legal obligation towards them according to which, in order to benefit from their favorable rates, we must not waste potential energy." The latent heat generated during the methanization process therefore becomes a secondary resource. In addition to its utility in heating the plant's reactors, which need to be maintained at an operational temperature of 131°F, it will also be sold locally for heating purposes.

A 3 ½ acre site has been chosen for the plant, on land owned by the Institut de France and subsidized by France Galop. Its central location at Mont de Po, between the training centers of Chantilly and Lamorlaye, while being practical for trainers, is of vital logistical importance for the sale of the heat. Within just a few hundred meters of the site are the AFASEC jockeys' school and the Bois Larris Red Cross Hospital, the two major clients whose heating systems are to be supplied by the warmth created by the turbines. Their proximity means that a minimal amount of heat will be lost during transfer.  Another bonus with the location is that there is already a 20,000 volt cable running underground across the site to cater for the hospital, which means that no unsightly pylons will be required.

After the three-to-four-week methanization process has been completed, around 60% of the initial volume will remain as biologically stable residue. "Our profitability is also dependent upon the use we make of this residue," says Battistini. "The heat we sell to the hospital and the AFASEC will be running at 100% of its potential in December and January, however that will be reduced to 10% in the summer months. This seasonal issue will affect our global efficiency and in order to qualify for the subsidies on offer, we need to prove that we utilize at least 75% of the energy produced."  The solution to this final conundrum is to recycle the residue a second time to create fuel briquettes. The latent heat which is surplus to requirements over the summer will be used to dry, and then carbonize, the waste from the digestors at temperatures of up to 752°F. The resulting matter will be compressed into briquettes for use either in households or possibly by the AFASEC or the hospital if their boilers could be converted to use this type of fuel. The CUMA are also keen not to leave the remaining mushroom-growers in the lurch and are working together to determine whether the farms can make use of the residue.

The project is expected to cost in the region of 10 million euros. "We have yet to finalize a finance plan as we are still awaiting the various technical validations from the INRA. When we have these we will be able to make an accurate evaluation of the cost of the plant and then source funding for our operation." However Battistini does not have any concerns on this score. In addition to the EDF contract, a whole range of grants and support dedicated to the development of biomass projects and the recycling of waste are proposed on regional, national and European levels, including Grenelle Environment and Brussels. The scheme is supported by the government ministries of agriculture and environment as well as by Finance Minister Eric Woerth, who is Mayor of the prestigious racing town. Indeed the town of Chantilly itself, thanks to its status as a Pole d'Excellence Rurale (Center of Rural Excellence), is eligible for European money dedicated to this type of project. Another source of income could quite simply be a bank loan. This may be more simple than it first appears, as Battistini confirms, "According to a law which was passed five or six years ago, all the major French high-street banks offer loans called ‘Sofergies' which are dedicated to the financing of this type of equipment. The interest rate is negotiable but the real advantage of the idea is that banks must give priority to innovative projects such as ours which will produce renewable energy." In the future, carbon credits may be recuperated by the CUMA, although there is still work to do on this front as they are currently only available for porcine and bovine schemes. Battistini intends to change this state of affairs. "We are lobbying the CITEPA (Technical Interprofessional Center for the Study of Atmospheric Pollution) to convince them to change this ruling and hope to benefit from carbon credits within a year or two."

Richard Crépon and Tony Clout aim to have written off the cost of the factory within seven or eight years, whereas Battistini offers the slightly more conservative estimate of ten years. Whoever is right on this minor issue, the CUMA seems assured of success on both economic and ecological levels. "Once we have repaid the cost of the plant, the trainers, who are the shareholders in the CUMA, will reap the financial benefits," says Clout. "In the future we should be able to return to a situation in which trainers are paid for the removal of their manure, and not vice versa." While the renewable energy supplied to EDF and local services will make a small impact on country-wide electricity production, the project is also advantageous in cutting down on primary pollution which currently originates from the currently steaming muckheaps of Chantilly. The CUMA will seek to standardize manure storage for all the region's trainers so that all waste is kept in covered pits or containers prior to transportation to the plant's closed fermentors, thereby considerably reducing current methane emissions.

While the project is far from completion, the ensemble of favorable circumstances mean that the members of Chantilly's CUMA can be confident of a cleaner, cheaper future in which they will be in control of the manure their horses produce. Their progress will be followed with interest by trainers around Europe and the world.

The importance of warm-up and cool-down in the racehorse

Human athletes pay great attention to detail when warming up and cooling down for competition. Research studies have shown that warming up prior to competition is an important factor in preparation to enhance performance and potentially reduce injury risk. Both the physiological and psychological benefits have been investigated, although human physiologists are divided in their opinions as to the benefits of warming up.

When it comes to cooling down the research is more unified, showing that active cooling down is more beneficial than passive cooling down. There is limited research available into the benefits of the warm-up and the cool-down in horses and racing, and it is certainly an area that warrants further investigation.

The importance of a warm-up period before racing How a warm-up programme is developed depends on the sport. The main considerations in warming up prior to racing are how long before the race to start warming up, how long to warm-up for and the intensity of exercise. The two main reasons for warming up are to improve performance, and to reduce the risk of injury. A period of warm-up will have both physiological and psychological effects; with direct effects on the respiratory system, the cardiovascular system and the neuromuscular system. Warm-up consists of an activity or series of exercises that raise the total body temperature, preparing the body for vigorous activity. As well as raising temperature, muscle blood flow and oxygenation are also increased. This enhances the ability of the muscles to work aerobically and to reduce lactic acid build up. Therefore a good warm-up should delay the onset of fatigue due to lactic acid accumulation. However, there may also be some negative physiological effects that can be attributed to excessive warm-up, so too long spent on it can be just as detrimental as too little. Increasing muscle temperature over its working optimum can result in dehydration and electrolyte imbalance, as well as lactic acid production and therefore the onset of fatigue before the race. Warm-up can also increase the horse’s range of motion by lengthening the stride and improving gait coordination, resulting in a decreased likelihood of tears, sprains and strains. Warm-up should be adjusted depending on the environmental temperature. In cold weather it may take longer for muscles to reach their optimum working temperature than in hot weather.

Active warm-up prior to racing An active warm-up programme will begin with aerobic exercise such as walking and trotting, to raise heart rate (but to remain under 170 beats per minute) which will increase the muscle temperature. Most racehorses will routinely have an adequate period of aerobic warm-up prior to racing consisting of walking in the pre-parade and parade ring. This is followed by cantering down to the start which equates to the sports specific warm-up, and has the effect of preparing the muscles for the exercise ahead. Passive warm-up and products available Active warm-up is more beneficial than passive warm-up as it increases the heart rate. However, in some circumstances it may also be beneficial to use passive warm-up prior to active warm-up. Massage will increase the muscle temperature and will change the muscle tone. It will also have a relaxing effect, so it is important to get the timing right, and not to massage immediately prior to racing, although it does provide an opportunity to check that there is no muscle soreness that could have occurred during travel to the racecourse.

Massage is used extensively in human professional sports as part of warm-up, but there is very little research available into the effects of massage on injury prevention in the horse. However, there is some evidence from small studies that massage increases stride length and range of motion, and therefore potentially has a positive effect on performance. Stretching can be performed after massage (when the muscles are warm), but this is an area where research is available to show that although there are benefits from stretching, there are also some negative effects. New technology has recently been developed which uses the body’s own heat to enhanced physical performance and provide effective prevention and treatment of injuries.

For example, the Mirotec and Back On Track rugs can be used as a warm-up aid prior to exercise (and can also be used post-exercise to ease any muscle soreness), but are not a substitute for active warm-up. These rugs contain a heat reflective layer of metallic material, which can maintain body temperature and boost circulation. This is a relatively easy and cost effective way to warm up the muscles prior to any exercise, and may therefore a useful aid to warm-up, especially in colder climates. The aims of a cool-down period Active cooling down has been shown to be more beneficial than passive cooling down, therefore maintaining a slow trot or canter for a few minutes or so will have greater benefit than walking or standing still.

The aim of a cool-down period is a progressive reduction in exercise intensity allowing a gradual redistribution of blood flow, enhanced lactic acid removal from the muscles, and a reduction of body heat through convection and evaporation. If a horse is inadequately cooled after competing, any residual lactate in the system will affect performance if the horse is required to compete again within a short space of time. The application of cold water will result in heat loss by conduction from the skin to the water, thus reducing body temperature. The active cool-down will also result in an effective return to normal breathing and heart rate.

Actual post-race cool-down regimes These routinely consist of a slow canter back around the course to the exit, followed by a period of walking to where the saddle is removed. After this a horse will be washed with cold water and continually walked until heart rate and breathing return to normal. Shower systems are increasingly being used to aid quick and effective wash down. In hotter climate conditions the cool-down may include the application of iced water and iced blankets to ensure a return to normal body temperature in the shortest possible time. Products such as Equi-N-ice, cooling rugs and bandages are available to speed up cool-down. They use a combination of coolants and specialist fabrics to cool the skin and evaporate moisture more effectively. It is important that the horse is kept walking during the cool down period. When the horse is sufficiently cool many trainers will apply a cooling product to the legs before travelling home. The Zamar system is a portable system which provides thermostatically controlled cold therapy (or heat therapy) via insulated pipes to specially designed leg and body wraps. This particular product consists of a specially adapted refrigeration system that circulates a glycol liquid to produce the required temperature.

It maintains a pre-set consistent cold temperature for the required treatment time. The system also provides cyclical compression to the area treated. The application of Game Ready wraps after racing or a strenuous workout will minimise the inflammatory reaction and subsequent tissue damage that can result from strenuous activity. The technology behind this portable system is the continuous rapid circulation of ice water through circumferential wraps, thus providing ice treatment and compression. Post-race practical applications of these cold systems may be most effective when used on the tendons. The core temperature of tendons after racing is known to be over 40°C which can have a detrimental effect on the physiological function associated with the maintenance and repair of the tendons.

The immediate application of cold treatment can quickly and effectively cool the tendon core, returning the temperature to normal. The above mentioned cooling systems also have many other uses in the treatment of various injuries, and can provide more consistent colder temperatures than the application of ice or a cold hose, although these practices are still very popular and widespread within the racing industry. The combination of ice and compression causes capillary vasoconstriction and pressure on the connective tissue to restrict blood and fluid leakage from damaged tissue. The first 48 hours after injury are critical in the restriction of development of oedema or swelling. A simple but efficient way of applying immediate cold and compressive therapy post-race is to soak polo wraps in iced water before applying them.

The application of immediate cold and compression will minimise post-race inflammation and swelling. Cold water hosing is a cheap and effective way of applying cold treatment to the horse’s body and legs, but although this method will provide cooling of the skin surface, the temperature may not be low enough to affect deeper structures. There are also many other ice gel packs and ice boots available for cold therapy, which often provide a cost effective and simple way to provide cold treatment to the tendons and other structures. The application of ice is a well researched and excellent treatment modality in the prevention of swelling and inflammation after exercise.

Massage to aid recovery after racing Muscle soreness often develops 24 to 48 hours after racing or strenuous exercise, and is thought to be largely due to microtrauma. Until this pain disappears, the muscle is in a weakened condition, predisposing it to injury. Massage and stretching can be used to release muscle tension and reduce soreness. It may be beneficial to treat the horse with massage immediately post-race (when sufficiently cooled and with heart and breathing rate returned to normal). This can then be followed up with further regular massage treatments to restore suppleness and range of motion. The next issue of European Trainer will feature more detailed analysis of how the application of ice and cold therapy affects the horse both pre and post-race, including its benefits and physiological effects.

Stabling and health specifically for racehorses

In looking at this subject, it is important to see the needs of the racehorse as being different from horses kept for any other sporting purpose. Its management, feeding, training and stabling are all critical and unique. For racing, all body organs must function efficiently and, in so much as these can be affected by stabling conditions, it might pay to take a critical look at the elements involved. Our discussion is particularly about the way stabling and stable management influence lowgrade or ‘sub-clinical’ disease. It is not about major diseases like flu or strangles, although aspects of stabling can affect the degree of illness as well as recovery times in these conditions too.

VARYING NEEDS Stabling standards differ from country to country and from season to season. Horses racing in a UK winter, for example, face more climatic fluctuations than in summer or than others might in warmer places, like Dubai, or Florida. Yet the principles of management are similar for all. The horse’s needs vary with prevailing conditions and change has to be recognised and accounted for. To limit infection, it is necessary to understand how organisms set up disease as well as how horses resist infection. In my lifetime, there has been a seachange in stabling ideas generally and it is appropriate to ask why and with what degree of logic. 1 An increased racehorse population from the Sixties onwards meant bigger yards, a movement towards barn-type buildings on economic grounds. The importance (and difficulty) of controlling temperatures and airflows was overlooked until problems arose and these were reflected in results on the track. 2 Condensation in old damp buildings, where water ran from walls and ceilings, was resolved by radically increasing ventilation. This reduced dampness – but the negative consequences brought an increase in lowgrade infection. 3 Vets treating horses with severe respiratory disease, like COPD, saw a need for more air. Bigger holes were made in stable walls, even between individual stables. No one asked if the fit racehorse, not being ill, might be unique in not tolerating this.

DEFENCE AGAINST THE ENVIRONMENT It is essential to the health of racehorses that their stables are clean, warm and draft-free. The defences against infection operate best when environmental conditions are stable and unchanging, when there is warmth to maintain body temperature without a need to burn-off stored energy to combat the cold. Consider that the stabled horse cannot generate heat from movement and cannot remove itself from unhealthy or unpleasant conditions. In fact, with certain variations, the horse’s resistance to infection runs very close to that of humans in similar conditions. Having a thick skin and hairy coat does not prevent disease; besides, we are obliged to clip coats, automatically reducing the insulating influences of fat through the training programme. Furthermore, warm clothing cannot compensate for drafty airflows and a cold horse loses weight as well as the fuel it needs for work. It also loses some of its ability to resist infection at a cellular level. Add to this how intensive training affects fluid balance and demands fine tuning of all body systems, and disease at even a sub-clinical level is easier to understand.

RESISTANCE Natural resistance in otherwise healthy horses decides the length of time from infection to recovery and this, with most known organisms, is never open-ended. Resistance is, in fact, a measure of normal health that can be lost through disease, malnutrition or age. While recovery from debilitating conditions may be slow, sub-clinical infections should be overcome in days rather than weeks. Where this is not the case, external influences are likely to be involved. Stabling factors are a common cause. In recent times, all sorts of ‘medicines’ have been used to bolster resistance, but with little effect – because the answer frequently lies in the stable, not the horse.

ANECDOTAL EVIDENCE In horse management generally, many ideas and accepted facts are anecdotal and always have been. That is, they have come by word of mouth, from the trial and error investigations of individuals rather than through scientific research. Racing history suggests our ancestors knew as much about the horse as we do today, that despite talk of new levels of fitness, modern training methods are superior to those of the past. Many old ideas came from people who relied on their horses for work, transport and enjoyment. They were never backed by science because it was never possible to do so. But poor science, based on assumption, is no better than anecdote and there has been much of that. Technology hasn’t helped either and we should never dismiss knowledge as ‘unscientific’ unless there is solid evidence against it. For example, some today keep their horses in Arctic-cold conditions while others speak of heating stables. Both cannot be right.

SUB-CLINICAL DISEASE The term ‘sub-clinical’ describes any disease condition where the symptoms are obscure, whatever the cause. In the main, it refers to viral and bacterial conditions where the affected animal is not obviously ill, but racing performance suffers. The organism, when isolated, might not be thought capable of causing disease. That it becomes so is a reflection of stress, something in the horse’s management that favours infection. There have been numerous examples in modern times. One reason acceptable research is lacking is because medicine has no fool-proof way of identifying sub-clinical infections, especially when the final measure is the racecourse. A negative laboratory finding is worthless if the horse runs badly and, in fact, no research into performance-related problems can ever be fruitful if lowgrade conditions are not accounted for. In the absence of science, of course, anecdotal evidence is all there is. But, to be acceptable, it must come from informed sources, from volume experience and the studied observation of people educated to see and know. It won’t come from those who interpret tests and machines, or from the experiences of those in non-racing areas.

DECISIONS ON BUILDING Stables are often built with cost a first priority, even with the comfort of humans put before horses. Then, when disease appears, questions are raised about whether or not building design might be a cause. Opinions have often been provided by individuals with no understanding of the elements involved. ‘Experts’ emerged from areas like pig management, which was novel. The needs of sedentary animals reared to produce fat are not the same as those in whom fat is distinctly unwanted. Ultimately, disease has to be dealt with by professionals. Any infection needs to be investigated to provide understanding and control. In an ideal world, organisms are isolated and identified. But, as we know, unexplained outbreaks – loosely described as ‘the virus’ - have ruined the careers of both horses and trainers. Their true cause might never have been defined, but a list of the victims contains some distinguished names as well as many who never got off the ground.

‘THE VIRUS’ In relating health and stabling then, we are addressing a problem that has plagued UK racing for years. Inevitably, busy yards are exposed to organisms that arrive from different sources and can cause disease at any time, sometimes leading to outbreaks that last long periods, belying accepted patterns. Mixed or sequential infections are a feature of this and one organism may simply follow another, or become re-activated, as appears to happen in herpes infections. Actually, the term ‘the virus’ means nothing specific. It can represent infection by a single virus, but more commonly reflects a lowering of resistance that gives opportunity to any organism going the rounds. The distinction between debilitating conditions and ‘the virus’ lies in the clinical effect. In a serious infection, a horse is sick and evidently so. With ‘the virus’, animals look healthy but are unable to show their form. A range of mild symptoms may be seen, but observers comment on how insignificant they are. Most eat and drink normally, look ‘big’ and well; others have dry coats, lose condition and seem to lack energy. The general view is that they are not sick, as trainers regularly insist. Some, that appear to work well, are only found wanting when raced. Looked at more closely, the lining membranes may be inflamed, lymph glands enlarged, there may be watery, or thicker, discharges from nose and eye. However mild, these are signs of disease. Lowgrade liver involvement may occur and is a serious impediment to racing. The horse will not return to form for months rather than weeks. Bleeding from the lungs is also more common in the presence of infection. It is likely to become chronic where the aggravating factors are not removed.

MEASURING FITNESS As a practising vet, I cut my diagnostic teeth on viral outbreaks that initially involved stud farms, then moved to racing with a view to defining the parameters of infection and monitoring horses as they returned from illness to full training. The task was to relate this to form on the course and, ultimately, to see if it was possible to diagnose with certainty and predict with any degree of accuracy. To do this, it was necessary to find a simple way of measuring health in a fully fit horse and to pit this against expectation, or effort on the track. An effective method had to give instant information, prove reliable and be consistent. It, ideally, needed to be effective the day before a race and would prove worthless if not accurate to a high degree. It was necessary, too, to recognise that a horse with no identifiable infection might have other physical problems, be unwilling or temperamental. So the exercise was complex and movement, for a racing animal, is as important as heart-beat or lung expansion. THE HEART An idea came after Roberto, an Irish Derby favourite trained by M. V. O’Brien, ran down the field; and the belief that such a performance had to be predictable through the heart’s action, which it would have been. While the technique doesn’t have a wide use, because of the complexity of issues and the difficulties of interpretation, it has proved extremely useful in evaluating management factors that influence health and stabling. The heart of a healthy racing animal is obliged to operate with ease and strength during work, the ability for which is best judged when at rest in the stable, preferably some hours after exercise. As training progresses, it adapts to its greater workload and strengthens; the resting beat-per-minute (bpm) rate also reduces. The sounds in a healthy horse are consistent and reliable, although there are many normal variations as well as changes that verge towards the clinical. They can, with experience, be interpreted to provide a reliable measure of health in a fit horse. There is a whole range of factors that might influence heart sounds, not just illness or infection, and the predictability of peformance relies as much on precisely how fit an animal is as on its state of health. The task of evaluating sounds is complex, too, and the variety of changes from normality is extensive. Any imposition on the heart’s working capacity (by infection, dehydration, anaemia) brings changes that are recognisable with a stethoscope, therefore open to interpretation; they can be related to performance capacity once all necessary information is included in the opinion. The extremes of heart function are heard in serious clinical infection (when the beat is usually loud and the bpm elevated) and with the least intrusive organisms (when changes are more subtle). The likely influence on peformance is often a fine judgment, especially so where infection is slight and the horse is overcoming it.

RESEARCH All this, of course, is subjective, therefore unlikely to satisfy scientists, but it works in the field and makes it possible to understand and differentiate between causes in a way that other systems cannot. Infection is probably the most common cause of performance disappointment. By using this kind of monitoring, it is possible to move affected animals from one stable to another and evaluate how they react and how quickly infection is overcome, the racecourse being a critical test of the decisions made. Thousands of horses in a variety of management conditions have provided private research facilities with material and are the basis of the opinions expressed here. Many horses were monitored on a daily basis, even through the course of a racing season. There are, sadly, no records, but the opinions have come from many years of working with both Flat and National Hunt animals, in yards that varied in size from a handful to a hundred-plus. As a general rule, no attempt was made to isolate organisms – mainly because of past problems with isolation and interpretation. At times, organisms were isolated which, on all the evidence, looked responsible for disease yet were considered at laboratory level to be insignificant. While this situation may have changed, the necessity clinically is to assess the situation and act; there is no time for delay. In most of my work, the diagnosis of infection was based purely on symptoms. Old and new yards were involved, old and young horses, old and modern buildings, barns as well as single-stable units. It proved possible to relate performance to specific conditions and origins. Once the complexity of the exercise was overcome, it was simple to assess infection and follow it through its course from start to return of full performance expression.

Distinguishing between the responses of horses kept in different stabling and environmental conditions became routine. Even in infected yards, some were kept racing while others about them were ill, as long as the management elements were understood and permitted it. The very successful jumps trainer Fulke Walwyn achieved great success at a time when very different attitudes pertained to today. Known as ‘a windows man’, it was common for him to be seen adjusting windows in an effort to control airflows as conditions and temperatures changed. His horses ran with great consistency, as did those of Tom Dreaper, who appears to have held similar principles, judged by pictures of Arkle in his stable. Perhaps both knew from instinct things we overlook now, or they may simply have followed the advice of their forebears without giving it too much thought. Finally, it needs to be stressed that this exercise was conducted on fundamentally healthy horses, to interpret and control performance on the track. For it to work, management generally has to be of the highest standard and that applies to everything that surrounds the life of a racing animal

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The Equine Heart - how it works to power a racehorse

Robert Keck

Exciting new advances in ultrasound image technology have provided a better understanding of both the anatomy and function of the heart at rest and during exercise. In the last 30 years many veterinary clinics and universities with equine departments that study equine physiology are able to study the heart of the equine athlete in their own sports performance laboratories, while exercising on a high-speed treadmill.

Considering that heart rate is one of the most frequently measured physiological variables in exercise tests, Thoroughbred racehorse trainers have largely failed to take advantage of the heart rate monitor as standard equipment. However, heart rate monitors are commonplace in eventing and sport horses. Understanding the heart’s function, and its response and adaptation to training, can provide trainers with a competitive edge.

ANATOMY AND FUNCTION

The heart of a Thoroughbred weighs about 1% of the horse’s bodyweight but can be as high as 1.3-1.4% in elite animals. Therefore an average 1000 pound horse has a heart weighing between 8-10 pounds. The horse has a proportionately larger heart per unit of body mass as compared to other mammals. The horse’s heart rate is 20-30 beats per minute at rest and may have a maximal heart rate of 240 beats per minute during maximal exercise. The fact that the horse is able to increase heart rate by nearly 10 times the resting heart rate is a contributing factor to their athletic superiority.

As in all mammals, the heart consists of four chambers with valves that open and close as the heart muscle relaxes and contracts to insure blood flows in the right direction. The two pumping chambers are the left and right ventricles, and the two receiving chambers are the left and right atria. The left ventricle is larger than the right ventricle.

Specialized cells within the heart conduct electrical activity that coordinates the muscles of the heart to contract in order to optimize blood pumping. Electrical impulses of both the atria and ventricles are isolated by a fibrous ring; preventing them from contracting simultaneously. The only point at which electrical activity can pass between the atria and the ventricles is via the Purkinje fibers found in the wall between the left and right ventricle. When the atria contract, blood is delivered to the larger volume ventricle that lies beneath. The right side of the heart receives unoxygenated blood from the body and pumps it to the lungs to allow the red blood cells to uptake oxygen. Oxygenated blood returns to the left side of the heart, and the left ventricle pumps it out the aorta to the rest of the body.The cardiac cycle consists of a contraction/ejection phase (systole), and a relaxation/filling phase (diastole). Stroke volume (SV) is the volume of blood pumped in each beat, and is influenced by the muscular contraction of the ventricles, their resistance to flow during systolic ejection, and their ability to fill during the diastolic relaxation. The structural integrity of various anatomic components of the heart such as the valves and septa between the chambers affect heart function.

Stroke volume in a 500 kg Thoroughbred is approximately 1.3 litres and can increase by 20-50% during exercise. Cardiac output (CO) is stroke volume (SV) multiplied by heart rate (HR); therefore CO = SV x HR. At rest the cardiac output is approximately 6.6 (25 litres) gallons per minute and increases to an amazing 79 (300 litres) gallons per minute in elite athletes during exercise.

A horse’s total blood volume is approximately 10 gallons, representing 10% of its body weight. At rest 35% of the horse’s blood volume is red blood cells, however they can amazingly increase their red blood cell count on demand to 65% of their blood volume during a race, with up to 50% of the total red blood cells stored in the spleen. The horse has a proportionally larger spleen per unit of body mass as compared to other mammals. The red blood cells are void of a nucleus and have the large protein haemoglobin that transports oxygen. The horse’s heart is able to handle the increased viscosity of the blood. During exercise blood is diverted away from internal organs such as the intestines and kidney to working muscles used in motion.

THE HEART AND VO2 MAX

The heart is a major determinant in VO2 max, a measure of aerobic capacity. VO2 max is the maximal rate of oxygen consumption that can be consumed by the horse. VO2 max is determined by cardiac output (stroke volume x heart rate), lung capacity, and the ability of muscle cells to extract oxygen from the blood. During exercise the oxygen requirement by muscles can increase to 35 times their resting rate. Sydney University studies have shown that training can increase a Thoroughbred’s VO2 max by 20% or more, with this improvement highly attributable to the heart’s pumping capacity.

VO2 max expressed as millilitres of O2 per kilogram of bodyweight per minute (or second). At rest the horse absorbs 3 millilitres of oxygen per kilogram of body weight per minute. Maximal rates of oxygen intake vary within breeds and training state, but fit Thoroughbreds have a VO2 max of 160-170 ml./min./kg and elite horses can achieve 200 ml./min./kg. By comparison elite human athletes have a VO2 max of about half or 85 ml./min./kg. Pronghorn antelopes have a VO2 max of 210-310 ml./min./kg.
VO2 max is a high indicator of athletic potential, and has been found to be highly correlated with race times in Thoroughbred horses. A horse with a higher VO2 max had faster times (Harkening et al, 1993). The ability of the horse’s muscle mass to consume oxygen far exceeds the ability of the heart and lungs to provide oxygenated blood. Therefore cardiac output is a limiting factor in performance. Conditions that improve cardiac output positively impact VO2 max.

HEART RESPONSE TO TRAINING

The heart has two initial responses to exercise, a rise in blood volume pumped and dilation of the blood vessels. The heart rate increases, and beats stronger. The stroke volume may increase from 20-50% above resting rates. Through training the heart becomes more efficient at delivering oxygenated blood to exercising muscles.

Heart mass has been shown to increase with training. This hypertrophy (enlargement) in the heart comes in two ways, a thickening of the heart walls, and an increase in the size of the chambers, especially the left ventricle. Although the effects of training on the heart are not clearly understood, heart mass has been shown to increase up to 33% in 2-year old horses after only 18 weeks of conventional race training (Young, 1999). The increase in heart size results in increased cardiac output. Stroke volume has been shown to increase by 10% in as little as 10 weeks of training (Thomas et al, 1983).

Although not yet proved, it is likely that in addition to the strengthening, improved filling capacity of the pumping chambers when the heart is relaxed may contribute to the increases shown in stroke volume. Interestingly, maximal heart rate does not increase with training, and resting heart rates (unlike humans) do not decrease with training.

Training can improve VO2 max from 10-20% in the first 6-8 weeks of training, after which further improvement is limited. The relationship between VO2 max and velocity is highly correlated, but the differences found in speed and performance of two Thoroughbreds with equal VO2 max can be explained by differences in biomechanics and economy of locomotion.

Although the heart plays an important role in determining several physiological factors related to performance, it is merely one variable in the whole physiological equation that describes the equine athlete. Not only does the heart change and adapt with the rigors of training, but a myriad number of adaptations take place in the muscle fibers at the cellular level. As a result of training, oxidative enzymes in the muscles increase, along with the size and density ofmitochondria, the powerhouse of the cell. Enhanced oxidative capacity results in increased utilization of fat and less reliance on blood glucose and muscle glycogen, being an advantage at both submaximal and maximal exercise, because fat is a more efficient energy fuel.

An improved network in the number and density of capillaries provides more efficient blood flow and transit time to working muscles, which also become more efficient in buffering lactate in anaerobic exercise. Muscle, bone, tendons and ligaments modify their structure with the stresses of training. Depending on the event, the horse develops “metabolic specificity” and neuromuscular coordination for his chosen discipline.

EVALUATING THE HEART - ULTRASOUNDS

When evaluating the equine heart, ultrasound has become an extremely valuable non-invasive tool, revolutionizing equine cardiology. The heart’s anatomical structure and physiology can be readily determined as well as measurements in heart size, wall thickness, and identifying defective cardiac valve function. Findings can determine pathology of the heart and the cause of poor performance. The ultrasound examination of the heart (echocardiogram) is now considered an integral part of cardiovascular evaluation of equine athletes.

An ultrasound machine works by emitting a beam of high frequency sound waves (>20,000 Hz) from an ultrasound transducer into the body tissues. In general, the waves can penetrate to a maximum of 15 inches (40 cm) and they interact with various tissue types in different ways. The waves can be scattered, refracted or attenuated. The reflected waves are transmitted back to the ultrasound transducer. This information is interpreted by the ultrasound machine which produces a two-dimensional black and white image called a sonogram.

The frequency of the ultrasound waves emitted by the transducer markedly influences the quality of the image, depending on the depth of the tissues. Higher frequency ultrasound waves have a shorter wavelength and yield better resolution of small structures close to the skin surface. However, more energy is absorbed and scattered with high frequency, therefore high frequency transducers have less penetrating ability. Conversely, a lower frequency transducer will have greater depth of penetration but poor resolution. The transducer selected for echocardiography should be the highest frequency available that will penetrate to the depths needed to image the heart in its entirety. Frequencies generally used for veterinary echocardiography range from 2.25-3.5 Mhz for adult horses.

The three main types of ultrasounds available to veterinarians and researchers are the M-Mode, Two-Dimensional (2-D), and Doppler. Although M-Mode yields only a one-dimensional (“ice pick”) view of the cardiac structures, it can yield cleaner images of cardiac borders, allowing the researcher to obtain very accurate measurements of cardiac dimensions and critically evaluate cardiac motion over time. Two-dimensional echocardiography allows a plane of tissue, with depth and width, to be imaged in real time. This makes it easier to appreciate the anatomic relationships between various structures. 2-D echocardiography makes available an infinite number of imaging planes of the heart. Doppler echocardiography records blood flow within the cardiovascular system when blood moving toward or away from the transducer causes a Doppler shift. From this shift, it is possible to calculate the velocity of the moving blood.

ELECTRO-CARDIOGRAM (ECG)

An ECG (electrocardiogram) is another tool commonly used in evaluating the heart. It measures the heart’s electrical conductivity can identify a part that is not contracting properly. It is the tool of choice for diagnosing arrhythmias. The ECG provides information to the researcher about the quality and rhythm of the heartbeat. The appearance of the ECG changes dramatically from rest to exercise.

Cardiac contractions are the result of a well-orchestrated electrical phenomenon called depolarization. In the myocardium are specialized fibers that are very conductive and allow rapid transmission of electrical impulses across the muscle, telling them to contract. There is uniformity in the sequence and force of both the filling and ejecting chambers, relying on a single impulse initiated by the sinoatrial (S/A or sinus) node. Another node is the A/V node (atrioventricular node) situated between the two chambers.

The ECG measures electrical activity from the P-Wave, QRS, and T-Wave. The P-Wave represents the electrical impulse measured across the atria, whereas the T-Wave measures the repolarization of the ventricles. The QRS represents the electrical impulse as it travels across the ventricles. Measurements between these impulses include the PR and ST segments and the PR and OT intervals, all of which can reveal abnormal heart function.

Electrodes are placed in strategic positions on the skin surface to pick up the heart’s electrical activity. In clinical practice, 12 leads may be used in a diagnostic ECG, but usually there are three standard leads, I, II and III, placed at different areas around the ribcage and chest. Placement of the electrodes are critical, and can change the size and shape of the ECG.

HEART MURMURS AND ARRHYTHMIAS

Vascular diseases in horses, such as atherosclerosis, which contributes to strokes and heart attacks, are rare. Two of the most common heart abnormalities are heart murmurs and arrhythmias. A heart murmur is the sound of turbulent blood flow, usually caused by an abrupt increase in flow velocity. This turbulence is caused by increased velocity due to a leak or obstruction in one of the heart valves or because of abnormal communication between different parts of the heart. Heart murmurs, which are fairly common, occur in horses of all ages. They are called “innocent” when they are soft, short and variable without any other cardiac pathology. One study detected cardiac murmurs in 81% of 846 Thoroughbred racehorses (Kriz, Hodgson, and Rose 2000).Congenital heart defects are abnormalities that are present at birth, the most common being ventricular septal defect (VSD) where a hole is found between the two ventricles.

Oxygen-rich blood from the higher pressure left ventricle passes through to the lower pressure right ventricle and pulmonary artery during ventricular systole. Because some blood bypasses the lungs, it is not fully oxygenated and will have an adverse effect on cardiac function. Depending on the size of the hole, the horse may be fully capable of moderate activities without fatigue or shortness of breath. VSD is usually detected on the right side of the chest over the cranial part of the heart, and can be fully diagnosed with 2-D ultrasound and Doppler echocardiography.

Atrial fibrillation is an electrical disorder of the heart rhythm, also know as an arrhythmia. Associated with diminished performance, the normally regular, organized atrial waves become irregular, disorganized and chaotic, and the atria fail to contract normally, leading to an unpredictable and irregular heartbeat. Accurate diagnosis using an electrocardiogram can determine type and severity, and often an oral or injectable drug such as quinidine can be administered to establish a normal rhythm. An arrhythmia can sometimes be caused by myocarditis, where part of the heart muscle tissue has died due to an infectious disease such as strangles, influenza or an internal abscess. Toxic damage to the heart muscle may occur from a severe deficiency of vitamin E or selenium.

The most commonly recognized acquired structural heart disorders are degenerative valvular deformities. These defects, involving a thickening and deformity of the valve leaflets, cause inefficiency of one or more heart valves, resulting in dilation of the chambers trying to handle the regurgitated blood on either side of the damaged valve. If the leak is severe enough, the pressure in the veins leading to the affected side of the heart increases until fluid accumulation (edema) occurs.

HEART SIZE AND PERFORMANCE

For centuries, owners, breeders and trainers have been captivated by the idea that the horse’s heart may be the proverbial “Holy Grail” to understanding athletic performance, and predicting the future elite racehorse.

The large hearts found in elite human athletes are well-documented. In the 1920’s the “Flying Finn” Paavo Nurmi, who won 12 Olympic medals in track including 9 Golds and set world records from 1500 meters to 20 kilometers, had a heart three times larger than normal (Costill). At postmortem, the legendary 7-time Boston Marathon winner Clarence De Mar was shown to have an enlarged heart and massive coronary arteries (Costill).

In 1989, it was believed that Secretariat, American Triple Crown winner of 1973, had a heart weighing over 10 kg (22 lbs.), and may have had a VO2 max of 240 ml./kg./min. Autopsies showed that the great Australian racehorse Phar Lap had a heart weighing 6.4 kg. (14.1 lbs), 20% larger than normal, and Key to the Mint, American champion 3-year old of 1972 and excellent broodmare sire, had a heart weighing 7.2 kg (15.8 lbs). Secretariat’s rival and runner-up Sham had one of the heaviest hearts recorded, weighing in at 18 lbs. (8.2 kg).

Some of the first studies that scientifically attempted to correlate heart size with race performance were conducted in the 1950’s and early 60’s. The Heart Score concept was first discovered and developed by Dr. James D. Steel, a professor of veterinary medicine at the University of Sydney in Australia in 1953. Using ECG (electrocardiography) to studying herbivores, he began studying the occurrence of heart disease in racehorses. His examinations led him to the development of the “Heart Score” which was his term to describe the correlation between the QRS (intraventricular conduction time) complexes and the performances of several elite versus average racehorses at the time. He believed that the higher heart score number based on the QRS duration using the standard bipolar leads must be correlated with the larger heart size and weight found in superior racehorses.

Steel developed a ranking system that placed male horses with a heart score of 120 or more (116 or more for fillies and mares) in the large heart category, between 103-120 in the medium to normal category, and 103 or less in the small heart category. His conclusion was based on the assumption that the QRS represents the time required for the electric wave to spread and depolarize the ventricular mass. He believed that the QRS interval corresponds to the beginning and end of ventricular depolarization. As the ventricular muscle mass increases, a longer time will be necessary for the ventricular depolarization to take place. Therefore, he believed the higher the heart score the larger the heart mass (and size) Unfortunately, Steel was wrong!

Steel’s conclusions seemed logical at a time when equine cardiology was in its infancy. But in the horse (and hoofed mammals) the depolarization process differs from that of small animals because of the very widespread distribution of the Purkinje network. These fibers extend throughout the myocardium and ventricular depolarization takes place from multiple sites. The electromotive forces therefore tend to cancel each other out; consequently, no wavefronts are formed, and the overall effect of the ventricular depolarization on the ECG is minimal. (Celia 1999) Today, we know that ECGs provide little or no information about the relative or absolute sizes of the ventricles. An ECG cannot measure heart size and cannot be used to correlate its size and / or mass. In several studies, heart score showed a relationship neither with body weight nor with ventricular mass, as determined by echocardiograph. Heart score did not correlate with heart size and cannot be regarded as an index for predicting potential performance (Lightowler et al 2004). Although a study using Danish Standardbreds showed a correlation between heart score and Timeform ratings, using these scores to determine heart size has largely been disproved.

HEART SIZE AND PERFORMANCE

Current research in the field of equine exercise physiology continues to investigate the heart and cardiac output. The size of the heart is a key determinant of maximal stroke volume, cardiac output and therefore aerobic capacity, and several new studies have proved this relationship.

A recent breakthrough study demonstrated a significant linear relationship between British Horseracing Board Official rating or Timeform rating and heart size measured by echocardiography in 200 horses engaged in National Hunt racing (over jumps)  (Young and Wood, 2001). It is the first study that positively correlates heart size to performance.

Additionally, a significant strong relationship has been found between left ventricular mass (and other measurements of cardiac size) and VO2 max in Thoroughbred racehorses exercising on a high-speed treadmill. (Young et al 2002).

Interestingly, no such relationships have been reliably been found when horses employed in flat racing were examined, suggesting that, as might be expected, VO2 max and heart size are more important predictors of performance for equine athletes running longer distances.It must be emphasized that these research studies were conducted on older racehorses that were already racing and training, very different from an untrained yearling.

CONCLUSION

Understanding the equine heart and its role in equine physiology will remain of great interest to breeders, owners and trainers. Future use of heart rate monitors and heart evaluations using ultrasound technology to identify heart pathology and abnormality will undoubtedly contribute to future breakthroughs in training and racing. The equine heart still remains just one variable in the elusive equation that makes for a great racehorse. 

Should Horsewalkers be Round or Oval?

By David Marlin

Horsewalkers (electro-mechanical devices that allow multiple horses to be exercised simultaneously in a controlled fashion) are used extensively in the management and training of horses. They permit controlled exercise of horses at walk and trot. They are less labour intensive than most other forms of controlled exercise, such as walking in-hand, lunging, riding, swimming or running horses on treadmills.

The exception might be ride and lead, but this is not a widely used technique, except perhaps in polo. Horsewalkers may be used for a variety of reasons including warming-up or cooling down prior to or following ridden exercise, as a way to relieve boredom in stabled horses, for controlled exercise as part of a rehabilitation programme and to supplement ridden exercise. Horsewalkers are often also used where ridden exercise is not desirable or possible, such as in preparation of young animals for sale or in animals that may have injury to the back and therefore cannot be ridden. The majority of horses can be trained to accept being exercised on a horsewalker within a short period of time. Any form of exercise carries a risk of injury and whilst there does not appear to be any objective information on the safety of this form of exercise, it would generally be considered that the horsewalker is a very safe form of exercise.


Until recently, horsewalkers have been exclusively of a round design in which the horse is constantly turning on a circular track. The radius (tightness) of the turn is determined by the diameter of the walker - the larger the walker, the more gradual the turn. At present commercial round horsewalkers vary from around 10 to 30 metres in diameter (i.e. 5-15 metres in radius). The conventional design is of a centre post from which radiate arms that support the moving dividers that separate the horses but also encourage them to walk as the centre post rotates, in turn moving the dividers. Other designs do not incorporate dividers but horses are hitched to arms radiating from the centre post. Whilst the majority of walkers can operate in either a clockwise or anti-clockwise direction, on the walker the horse is still turning constantly. 


Exercising at walk or trot on a circle for prolonged periods of time must be considered to a large extent unnatural for a horse. Horses at pasture, whether grazing or exercising, move in all directions and never in one continuous direction. The same is true of ridden exercise. No rider would work his or her horse continuously for 30 minutes on a circle, even when working in a confined area. For example, a Dressage test incorporates many changes in rein and exercise in straight lines as well as on turns.

Lunging is another mode of controlled, unridden exercise that is commonly used by horse owners or trainers. Lunging may be used in place of ridden exercise or to train riders or as a warm-up for the horse prior to it being mounted and ridden. Lunging may also be used in situations where a horse requires to be exercised but where fitting a rider and saddle is not desirable, for example, in the case of a sore back. However, prolonged lunging is not advisable and in addition, as with circular walkers, changing the rein frequently is common practice.

Continual turning may be deleterious to the musculoskeletal system  (muscles, bones, tendons, ligaments and joints). For example, it is widely recognised that signs of lameness are exacerbated in horses exercised on a circle. This is commonly used by veterinary surgeons in lameness investigations. It is also suspected that sharp turns may contribute to injury of distal limb structures (i.e. those structures furthest from the body such as the foot). This implies that turning exercise changes the
weight distribution through the limbs. The surface on which a horse is lunged may also determine whether lameness is apparent or not; a horse may not exhibit lameness when lunged on a soft surface but may do so when lunged on the same size circle on a firmer or uneven surface. 
Most research into how horses move has been concentrated in horses walking and trotting in straight lines, or on treadmills, and there are only a limited number of studies relating to horses turning on a circle.

Only one kinematic (movement) study has evaluated the effects of turning a corner on the distal joint motions. Horses turning in a sharp (1.5m diameter) left circle showed a shorter stride length, but stance duration (the amount of time the foot is on the ground) was longer. This work also showed that the lower leg and foot rotate as the weight of the horse moves over the limb. 
Research from Australia showed that the outside edge of the cannon bone is not loaded significantly during exercise in a straight line on a flat surface. The same group of researchers also showed in a separate study that surface strains on the cannon bone vary between inside and outside forelimbs during turning. On the inner surface of the cannon bone, compression of the bone is greatest in the outside limb, and stretching of the bone is greatest on the inside limb. On the outer surface of the cannon bone, both compressive and tensile peaks are largest on the inside limb, which also showed the largest recorded strains in compression. On the dorsal (front) surface of the bone (where bucked shins occur in young horses), compressive strains were largest on the outside limb, and were greater on larger circles. They concluded that turning exercise is required to maintain normal bone, in that low-speed exercise in a straight line only loads the outer edge of the cannon bone. 
In 2006 workers from the USA studied the effect of trotting in a circle on the centre of mass of the horse. The centre of mass is a point within or on the body at which the mass of the body is considered to act. The centre of mass may vary according to gait, speed and direction of travel. The location of the centre of mass affects the distribution and size of the loads on the limbs. These researchers showed that in horses trotting on the lunge on a 6m diameter circle at a speed of ~2 metres/second, all horses leaned inwards at an angle of ~15°. The speeds attained by these horses at trot on a circle are lower than those typically seen for horses on a straight line. As the speed was slower, the implication is that stance proportion was increased (i.e. the weight bearing phase of the stride was longer on a circle than would be expected in a straight line). Furthermore, the researchers pointed out that “horses may behave differently when turning clockwise versus counter-clockwise due to asymmetries in strength, suppleness and neural programming…”. Thus, whilst it is often assumed that an equal amount of exercise on each rein on a circular horsewalker should be applied, this may not be the case for many horses and may actually be counter-productive.

The potential negative impact of circular exercise has also been highlighted with respect to the muscular system: “Especially in the initial stages of a return to work avoid lunging, horse walkers, or work in tight circles, as well as hill work”; a quote from veterinary surgeon and muscle specialist Dr Pat Harris from the Equine Studies Group at the WALTHAM Centre for Pet Nutrition, UK.

Exercising on a circle also requires more effort than exercising in a straight line (Harris, Marlin, Davidson, Rodgerson, Gregory and Harrison (2007) Equine and Comparative Exercise Physiology, in press). For example, being lunged on a 10 metre diameter circle was around 25% more work than being ridden on a large oval track in an indoor school. In addition, being lunged on a 5m circle was around 12% more work than being lunged on a 14 metre diameter circle. Even accounting for the weight of the rider, lunging is harder work than ridden exercise, which is most likely due to the continual effort required by the horse to balance itself on a continual turn.

Oval walkers are a new concept. The premise of using oval walkers is that continual exercise on a small circle is unnatural for horses and could even lead to injury and that a walker incorporating both straight line and turning exercise would represent a more appropriate form of controlled exercise. As so little information exists on turning in horses, a study was designed by us [Dr David Marlin (Physiologist) and Paul Farrington (Veterinary surgeon)] to investigate turning stress in horses in more detail. The work was undertaken in collaboration with Dr Bob Colborne (a specialist in Biomechanics) at Bristol University, UK.

A SUMMARY OF THE RECENT RESEARCH ON TURNING


The purpose of this study was to record the forces acting on the lower limb as horses walked in a straight line, on a 14 metre diameter circle, and on a 10 metre diameter circle to provide insight into the horizontal forces transmitted up the limb during locomotion in a straight line and whilst turning.

Three fit, sound Thoroughbred horses, ages 3, 5 and 12 years of age were used in the study. Horses were walked across a force-plate (a metal plate placed on the ground that measures the force with which the horses’ foot is placed on the ground) both in a straight line and on a 10 and 14 metre diameter turn. For the turns the horse was always walking on a left-turn.

The results showed that the coffin joint had the greatest degree of abduction (movement of the limb away from the body), adduction (movement of the limb towards the body) and axial rotation (twisting movement) and that these movements were greatest at the time of impact and break-over. The first point of contact with the ground has a significant influence on the line of stress through the foot and up the limb, as does the position of the body at the same moment. On a turn the horse abducts the inside forelimb away from the body towards the line of the circle with rotation of the foot in the direction of the turn. The stride length is dictated by the tightness of the turn, as is the stance time (when the foot is on the ground). As the horse then moves forward the horse’s body moves towards the inside limb increasing the loading on the limb. The results showed that on average the forelimbs tended to behave asymmetrically (i.e. the two front legs did not behave the same) on a circle so that the forces and 
movements differ to produce different torque effects (twisting forces). The hind limbs tended to behave more symmetrically except  when the size of the circle was reduced from 14 to 10 metres in diameter.

IMPORTANCE OF HORSEWALKER SURFACES


The walking surface will likely have an effect on the stresses experienced by a limb. If the surface allows reasonably free twisting of the hoof when weight bearing, the stresses between the hoof and ground will be small. However, any ground surface that holds the hoof and impedes this horizontal rotation will probably impart higher loads to the joints of the lower limb. Large turning forces should be avoided when the limb is vertically loaded (i.e. when the weight of the horse’s body is over the limb and the limb is on the ground). It is also important that the walking surface is level to avoid tilting of the hoof during weight-bearing. A walking track that is worn in the middle and that causes rotation of the joints in the foot is likely to cause larger and uneven forces to the lower limb joints and associated tendons and ligaments.

IMPLICATIONS FOR OVAL VERSUS ROUND HORSEWALKERS


Our recent research and a review of other scientific studies show that turning is not equivalent to exercise in a straight line. Turning exercise is harder than exercise in a straight line and loads the bones in a different way. Furthermore, on small turns the inner and outer limbs may not behave in the same way as on larger circles. This may have implications for horses with pre-existing musculoskeletal injuries. The potential advantages of an oval walker is that it combines straight line and turning exercise that more closely mimics the exercise that a horse will do when being ridden or when free at pasture. 
The results of our small study have shown that the hind limb patterns were quite different on the tighter radius turns, indicating a different strategy for turning, and supporting the notion that both straight line and turning exercise should be recommended for overall loading patterns that are healthy for maintaining bone that can withstand loading forces in a variety of directions. 
The results also make clear that small diameter round walkers (~10 metre diameter or less) are less desirable than round walkers of 14 metre diameter or greater. Small diameter round walkers increase the loading and asymmetry and increase the work compared with larger diameter walkers. 
In conclusion, there appear to be significant advantages to using a walker of an oval design as opposed to a round design, as exercise on an oval loads the limbs with a combination of straight and turning movements, as would be experienced during riding or in free movement.

Reinventing the Wheel - the Kurt Equine Training System

​By Niki Sweetnam

The combined forces of Italian trainer Daniele Camuffo and the enigmatic Turkish businessman Mehmet Kurt have brought to fruition a project first dreamt up by Kurt himself more than a decade ago. 

The Kurt Equine Training System has been endorsed by some of the world’s leading veterinary surgeons and research groups, and the results of horses trained on it are already beginning to speak volumes for its future potential. From 12 juvenile runners this season, 3 have raced and all have won or placed, showing no signs of physical or mental stress at any stage.

A specialist equine vet for more than 30 years, it was Italian Marco Astrologo who introduced Kurt to the then Rome-based trainer Camuffo, knowing that Kurt was looking for a good trainer with an open mind to come and work with him in Turkey and turn his 10 years worth of research, investment, development and modification on his invention into reality. The Kurt stable had won 2 Turkish Derbys, on both occasions with European trainers (1993 with the aptly named The Best and in 1999 with Bartrobel); Camuffo had come to the realisation that there was no longer much of a living to be made out of training in Italy as costs spiralled, owners thinned and prize money levels swung. Born in 1963 and a licensed trainer since 1989, a disillusioned Camuffo travelled to Turkey on the invitation of Kurt and loved the opportunity he saw. A blank page, top class facilities at his private base near Istanbul, the chance to work with Kurt and break new ground in the application of science to the art of training thoroughbreds.

 “I’m a traditionalist” Camuffo announces, contradictory to what one may think. “I don’t like the idea of training horses by machine. Human intervention is critical, the human eye makes training an art, not a science, but in the development of his skill an artist should avail of the most modern techniques, the most high-tech instruments, the newest chemical mix of powders, resins, oils, water, in order to achieve perfection.” Since Camuffo’s move out to Turkey less than 2 years ago, the pair have modified and fine-tuned Kurt’s brain-child to perfection. Knowing precisely what they wanted to achieve, and having a dedicated team behind them has allowed them to overcome numerous minor technical and practical problems, and the fact that the invention has been funded entirely by Kurt himself has eliminated bureaucracy and red-tape. In short, the Turkish inventor’s dream has become the Italian trainer’s reality.

It is clear that the driving force between Team Kurt is Kurt himself, who has invested his cotton fortune in his passion for horses. Kurt, Astrologo, and Camuffo work closely together on the horses with the back-up of the Kurt Group office team which is overseen by Kurt’s daughters. They are joined by a small but diligent Turkish workforce at the training centre and the former Portuguese dressage trainer Jorge Almeida. “In Turkey, as elsewhere, good jockeys are hard to come by. The Kurt Training System alleviates this problem and provides a more consistent work-out for individual horses at the same time as eliminating many of the risks associated with working young thoroughbreds at high speeds. Of course we are not aiming to substitute jockey for robot, it is all about the achievement of maximum fitness with minimum risk. Our young horses do not have a different rider on board each morning, are not subject to variances in human mood, smell, handling, do not pull, do not take off, do not develop uneven muscle tone due to rider imbalance, do not work outside their ideal heart rate zone. As you can imagine, this vastly reduces both physical and mental stress for them. Consequently, when a jockey does get on board a couple of times a week, the horses are infinitely more manageable, better balanced, and thus less prone to injury. As a trainer this takes a good 80% of the risk out of the job.” explains Camuffo, leaving the obvious unsaid, that his own physical and mental stress as a trainer is consequently reduced to a minimum. In his experience, the Kurt horses are also better ‘do-ers’, stomach ulcers being one of the main manifestations of stress in a racehorse. The light-framed Camuffo keeps to a sensible riding weight as horses work typically four days per week on the system, are ridden two days and rest a day.

Whilst it may be hard to see the Kurt Training System’s acceptance in traditional European racing circles for some time to come, there has already been significant interest from the Arab Emirates and America. Given the initial level of investment required (and the fact that it is equally suitable for training camels!), this is not surprising. Indeed many of Kurt’s business contacts are in the States and word there is spreading fast, so much so that daily enquiries come into the Kurt Group office, requests for visits to Turkey so see the machines in action from vets and trainers alike.

Doctor Wayne McIlwraith from Colorado State University is one such recent visitor to Istanbul. He sites a number of uses for the Kurt Training System. The safe training of young horses up to relatively fast work with decreased need of exercise riders was the primary reason behind Kurt’s development of the system. McIlwraith goes on however to explain from a veterinary viewpoint its beneficial role in the musculoskeletal conditioning of young horses. Weanlings have been worked on the machine on an early conditioning programme to build muscle and strengthen bone with the aim of reducing injuries once they went into full training. Furthermore, McIlwraith highlights its potential use as a post-operative rehabilitation tool, decreasing the need for in-hand walking and providing a safe, consistent environment for the gentle, controlled exercise required for optimum recovery after surgery. All this can happen on a more natural training surface than that of the traditional treadmill.

Professor David Evans from the University of Sydney is another who sees multiple advantages in the use of both the rail (multiple) and single vehicle training systems. In particular he is excited about the single vehicle’s potential as a diagnostic tool. “This kind of ‘mobile laboratory’ has really opened up new opportunities for research. With racehorses, the performance limiting factors that we need to monitor generally occur only at high speed. The advent of the single vehicle training system allows us to assess accurately and in a safe environment the reasons behind poor performance in an individual because horses can work safely up to racing speed. At this speed they can be endoscoped, have pressure sensors attached to under their hooves, we can measure their oxygen uptake, lactic acid production, heart rate, and study the mechanics of their movement ie length, regularity and freedom of stride.” Such measurements also provide the trainer with the basis for an individual’s fitness programme, ensuring that each horse is neither over nor under-trained, that they work within the correct heart rate zone and don’t tie-up, data which Camuffo has at his fingertips on a daily basis to use to his advantage.

From Rome to Istanbul, Camuffo has adapted easily. Istanbul is a bustling, cosmopolitan city like any European capital and English remains the common language for international business, although a basic grasp of Turkish is helpful. There is not a strong tradition of thoroughbred racing in Turkey, the 24 founding members of the Jockey Club back in 1950 have grown to some 120. From its Istanbul headquarters it organises the racing programme in 6 racecourses nationwide as well as the Jockey Club Stud in Izmit. The Istanbul racecourse features a 2020  metre / 10 furlong turf track, a 1870 metre / 9 furlong dirt track and a separate dirt training track of 1720 metres / 8 ½ furlongs and hosts the majority of Turkey’s major races. Breeders have been able to avail of stallions such as Sri Pekan, Common Grounds, Manila, Eagle Eyed and Strike the Gold as the country has opened up to investment in the thoroughbred sector and the importation of foreign mares that meet strict quality control criteria. 
 
Last year Kurt, whose racing stock are all home bred, invested heavily in the breeding stock sales at Goffs and Tattersalls, buying mares in foal to leading European sires such as Acclamation, Dansili and Daylami. He has whittled down the 90 horses that Camuffo found upon his arrival to 70, split between mares, yearlings and horses in training all with the emphasis firmly on quality. Of these, 29 are in training, well, Camuffo is superstitious about the number 8 so he told me to write 29. When he is not training the Kurt string or avoiding the number 8, Camuffo enjoys sailing and for the immediate future is happy with his lot in Turkey. The Romans may have invented the wheel, but the formidable Kurt-Camuffo team have gone one step further!
 
THE KURT TRAINING VEHICLE

A single training vehicle in a horse-shoe shape with a driver’s cab behind. Horses are neither “pushed” nor “pulled” , the crescent being closed behind by two padded panels behind and the horse restrained by safety cables that support, contain and correct the horse’s forward movement allowing for correct carriage at the various speeds and stages of training. The vehicle is then driven around the track at speeds of up to 60km / 35 miles per hour while cameras monitor its occupant from several angles.

THE KURT MONORAIL SYSTEM

This is a train of box cars on an electric locomotive that is hauled along an overhead track which can be assembled to suit any shape or length of training track. Up to 50 horses can be trained simultaneously on this system. Both prototypes were engineered by Roush Technologies, a British company specialising in vehicle design, engineering and development, in full collaboration with the Kurt Group.

THE SILICONE SADDLE

Silicone saddles of various weights and mouldings have also been developed in conjunction with the Kurt Training System in order to accustom the horse to carrying a jockey’s weight.

Equine Exercise Physiology - understanding basic terminology and concepts

By Robert Keck

Equine exercise physiology is defined as the study of the horse’s body systems in response to exercise. A relatively new scientific field, equine exercise physiology provides an incredible amount of information that can be used to maximize performance, and extend the health and longevity of the athletic horse.

Understanding basic terminology and concepts that researchers commonly use in measuring equine performance, the modern trainer can design a training program that enables the horse to reach the limits of its genetic potential.

The study of equine exercise physiology can be divided into several broad categories including:
• the cardiovascular and respiratory systems
• the muscular system and energenics
• biomechanics and gait analysis
• Thermoregulation
• hematology
• nutrition

The Heart and Lungs


 
The horse’s heart weights between 4-5 kg., or about 1% of their body mass. At rest the horse heart beats 30-40 beats per minute. At full speed however, the maximal heart rate (HR max) in a 2-3 year old racehorse can reach 240-250 beats per minute. The heart pumps .8-1.2 liters in each beat. Cardiac output is calculated by multiplying heart rate (HR) x stroke volume (SV). At rest the heart cardiac output is approximately 25 liters per minute and increases to an amazing 300 liters per minute in elite athletes during exercise. Therefore, a horse’s heart is capable of pumping a 55 gallon barrel of blood per minute!

A horse’s total blood volume is approximately 40 liters, and accounts for 10% of a horse’s body weight. At rest 35% of the horse’s total blood volume is red blood cells, however they can amazingly increase their red blood cell count, on demand, to 65% of their blood volume during a race, with up to 50% of the horse’s total red blood cells stored in the spleen. The red blood cells are void of a nucleus and have the large protein hemoglobin that transports oxygen. The horse’s heart is able to handle the increased viscosity of the blood. During exercise blood is diverted away from internal organs such as the intestines and kidney to working muscles used in motion.

The combination of the horse’s powerful respiratory and cardiovascular system, enable the horse to have a tremendous oxygen consuming capability. The normal ventilation rate at rest is about 80 liters of air per minute at rest, and at a fast gallop can reach up to 1800 liters, with a ventilation rate of 150 breaths per minute.
Because horses are only able to breath through their nostrils, they must have a clear upper airway with little air resistance. Partial paralysis of the muscles that abduct the larynx reduces airflow, therefore justifying the reliance and importance of pre-sale endoscopic examinations.
Termed as respiratory-locomotory coupling, a horse’s breathing is in synch with their stride, taking one breath per stride when at a canter or gallop. Therefore, stride length and frequency is highly correlated with oxygen intake.

Aerobic and Anaerobic Power

During exercise oxygen is supplied to working muscles at the cellular level to produce energy for the muscles. Aerobic work is performed at a heart rate below 150 beats per minute (BPM), and includes low intensity activities such as walking, trotting and slow galloping. In the Epsom Derby run over 1 ½ miles about 80% of the energy would be aerobic, with the remaining 20% being derived anaerobicly, achieving a high cruising speed and accelerating at the finish in the last few furlongs. When exercising aerobically carbohydrates, fats and protein are used as fuel and broken down into energy in the form of adenosine triphosphate (ATP) in the presence of oxygen.

Anaerobic work is performed at heart rates above 150 BPM and involves explosive power such as short sprints, acceleration, and fast galloping. A Quarter horse running 2-furlongs would be deriving energy 60% anaerobicly and 40% aerobically. The primary anaerobic fuel source is glycogen without the presence of oxygen. Typically a horse can perform purely anaerobic work for a short duration.

Muscles and Structure

Horses have 700 individual muscles, and in thoroughbreds, muscles make up as much as 55% of the horse’s total body mass. The skeletal muscle consists of bundles of long spindle shaped cells called muscle fibers that attach to bone by tendinous insertions. The blood vessels and nerves that nourish and control muscle function run in sheets of connective tissue that surround bundles of muscle fibers. Each nerve branch communicates with one muscle fiber at the motor end. The nerve and all muscle fibers that it supplies are together termed a motor unit. Each time that a nerve is stimulated all of the muscle fibers under its control will contract. One motor nerve will supply from 10-2000 muscle fibers.

A muscle’s unique ability to contract is conferred by the highly organized parallel, overlapping arrangement of actin and myosin filaments. These repeating contractile units or sarcomers extend from one end of the cell to another in the form of a myofibril. Each muscle fiber is packed with myofibrils that are arranged in a register giving skeletal muscle a striated appearance under a microscope. Muscle contraction occurs when the overlapping actin and myocin filaments slide over each other, serving to shorten the length of the muscle cell from end to end and mechanically pulling the limb in the desired direction. The sliding of the filaments requires chemical energy in the form of ATP.

Muscle Fiber Types

The horse has three basic muscle fiber types: Type 1, Type 2A, and Type 2B. These fibers have different contractile rates and metabolic energy characteristics.
Type 1 fibers, also known as “slow twitch” or “red fibers” and have high oxidative capacity and are resistant to fatigue in part related to their high density of mitochondria which can utilize fuels aerobically and have the highest oxidative capacity. Mitocondria are the small organelles in the muscle cells that convert fuels (fats and glycogen) into ATP. They have the highest lipid stores, highest densities of capillaries, and the lowest glycogen stores. They have the lowest glycolytic enzyme capacity of the three fiber types.   
Type 2A are the “intermediate fibers” in terms of both contractile speed and metabolic properties between Type 1 and Type 2B. These fibers are aerobic, but also use a combination of glycogen and fat for energy generation. The thoroughbred has a high percentage of these “intermediate” fast twitch oxidative fibers that can produce speed and still utilize large amounts of oxygen and resist fatigue.
Type 2B “fast twitch” fibers have the fastest contractile speed, the largest cross-sectional area, the highest glycogen stores and glycolic capacity. They are ideally suited to short fast bursts of power. They have a low aerobic capacity and tend to depend on anaerobic glycolysis for energy generation.
Genetics determine muscle type and composition and is 95% inheritable in humans, and is thought to be highly inheritable in horses (Snow and Guy). In evaluating the fiber type distribution in a number of breeds of horses, heavy hunters had a very large proportion of Type 1 fibers, while Thoroughbreds and Quarter horses had few Type 1 fibers and a large number of the faster contracting 2A and 2B types. The percentage of each fiber type that a particular breed has in its muscle depends on the type of performance the breed is selected.
Thoroughbreds have the highest number of the highly aerobic 2A fibers, illustrating the importance of oxygen utilizing pathways in the thoroughbred racehorse. Researchers also found that thoroughbred stayers have a high number of Type 1 fibers than either sprinters or middle distance horses. Unfortunately, within a breed, the spread in fiber type distribution is so small that fiber typing as a predictor of performance is probably of limited value.
Muscle strength, size and shape can be predictive of muscle fiber ratios. Although each muscle may have a fiber type mix, generally a higher percentage of the “fast twitch” (Type 2) fibers are found in the horse’s hindquarters providing power, whereas the “slow twitch” (Type 1) are found in the forelimbs providing stride, rhythm and a weight bearing role.

VO2 Max

VO2 Max is a measure of aerobic capacity. VO2 Max is the maximal rate of oxygen consumption that can be consumed by the horse. VO2 Max is determined by cardiac output (stroke volume x heart rate), lung capacity, and the ability of muscle cells to extract oxygen from the blood. During exercise the oxygen requirement by muscles can increase to 35 times their resting rate.

VO2 Max is a high indicator of athletic potential, and has been found to be highly correlated with race times in thoroughbred horses. A horse with a higher VO2 Max had faster times (Harkening et al, 1993). Training increased VO2 Max. (Evans and Rose, 1987) VO2 Max is determined by measuring oxygen during exercise as increasing speed and/or incline of a high-speed treadmill incrementally increases the workload. VO2 Max expressed as milliliters of O2 per kilogram of body weight per minute (or second). At rest a horse absorbs 3 milliliters of oxygen per kilogram of body weight per minute. Maximal rates of oxygen intake vary within breeds and vary with breed and training state, but fit thoroughbreds have a VO2 Max of 160-170 ml./min./kg. By comparison elite human athletes have a VO2 Max of about half or 80 ml./min./kg. Pronghorn Antelopes have a VO2 Max of 210-310 ml./min./kg. 
When VO2 Max is determined, the speed at which VO2 Max is achieved is also measured. Comparing two (2) individuals with the same VO2 Max, one individual will have a higher speed at which the VO2 Max is achieved. VO2 Max calculations enable researchers to evaluate the fitness of a horse and its ability to utilize oxygen for energy.

Anaerobic Threshold

Anaerobic threshold (also know as lactate threshold) is the level of effort usually expressed as a percentage of VO2 Max at which the body produces more lactate than it can be removed. Anaerobic work is performed at a heart rate approximately above150 BPM and at intensities above 70% VO2 Max. At Lactate threshold the cardiovascular system can no longer provide adequate oxygen for all exercising muscle cells and lactic acid starts to accumulate in those muscle cells (and subsequently in the blood as well).

Lactate threshold research has recently focused on blood lactate threshold (LT) as a refection of an individual’s level of training. There are always certain cells within muscles that are relatively deficient in oxygen and are therefore producing lactic acid, but at levels small enough to be quickly metabolized by other cells that are operating on an aerobic level. At some point the balance between the production of lactic acid and its removal by body systems shifts towards accumulation. 
Lactate threshold is usually slightly below VO2 Max, and will improve with training. Horses with increased LT not only experience less physical deterioration in muscle cell performance but also use less glycogen for ATP production at any level of performance.

Training Responses

Thorough training physiological changes take place in most of the horse’s systems. Major training responses take place in the blood, heart, muscles, and cardiovascular, neuromuscular and skeletal systems.
The first 2-4 months of training, increases the total amount of blood volume, red cell count, and hemoglobin concentrations and creates a more efficient circulatory system. Increased blood plasma in the first weeks of training contributes to improved thermoregulation and sweating capacity. After training for 3-6 months, an improved network in the number and density of capillaries provide more efficient blood flow and transit time to working muscles.

After 4-6 months of training a multitude of adaptations take place at the cellular level. Oxidative enzymes in the muscles increase along with the number, size and density of mitochondria in the muscle cells. The enhanced oxidative capacity results in increased utilization of fat and less reliance on blood glucose and muscle glycogen, being an advantage at both submaximal and maximal exercise, because fat is a more efficient energy fuel. 
Training regimens that include speed work, and increased acceleration at intensities close to VO2 max will also result in the increase of glycolic enzymes needed for anaerobic energy production. Training at these higher anaerobic levels will improve the buffering capacity in the muscle cells. Buffers are chemicals that limit lowering of pH when lactic acid accumulates. The clearing and removal of lactic acid and wastes also becomes more effective.

Heart mass has been shown to increase with training. Hypertrophy (enlargement) in the heart physically comes in two ways, a thickening of the heart walls, and an increase in the size of the chambers, especially the left ventricle. Heart mass has been shown to increase up to 33% in 2-year old horses after only 18 weeks of conventional race training (Young, 1999). The increase in heart size results in increased cardiac output. Stroke volume has been shown to increase by 10% after as little as 10 weeks of training (Thomas et al, 1983). A study has also shown that heart size is also correlated with VO2 Max using an ECG (Young et al, 2002).

VO2 Max increases from 10-20% in the first 6-8 weeks of training after which further improvement is limited. Although, the relationship between VO2 Max and velocity is highly correlated, the differences found in the speed and performance of two thoroughbreds with equal VO2 Max values can be explained by differences in biomechanics, and economy of locomotion. Horses with a high VO2 Max and efficient gait will use less energy to attain the same speed. As fitness progresses, the horse will be able to attain a higher speed before reaching VO2 Max. An example would be a lightly trained thoroughbred hitting VO2 Max at 25mph, but after beginning a training program, the same horse would eventually be able to go 30 mph before reaching the limit.

Although improvements in VO2 max and aerobic capacity occurs early in the training stages, it’s not until 4-6 months that improvements are seen in bone and ligaments. This physiological mismatch is often the cause of many bone and soft tissue injuries.

At maximal exercise levels, such as a gallop, increases are seen in bone density, and mass. Bone density, shape and internal composition are related to strength. Medium tissues such as tendons and ligaments become thicker and more elastic. The modeling response of bone is stimulated by fast work, fortunately only short durations are necessary (Firth et al, 1999). Training at the trot or canter results in minimal changes in bone mass and density. Therefore, the trainer must gradually add speed work into the training plan with the goal of developing bone density.

The peak time of bone development occurs between 2 and 3 years of age, with 50% of their primary structure replaced by their 3-year old year. The ability of bone to adapt decreases with age, with some researchers believing that bone becomes more brittle with age, and young horses actually remodel bone more quickly and easily, and are at less risk than horses started later (McIlwraith). This idea is further supported by other researchers that found that tendons grow and adapt to the stresses of training more successfully prior to their 2-year old year (Smith, Birch, Patterson, Kane et al, 1999).

Contrary to common belief, most current research indicates that early training may not only enhance bone and tendon development, but reduce the incidence of injury during training and racing, prolonging racing careers.

Performance Measures

For over 30-years high speed treadmills have revolutionized the study of equine exercise physiology. Today many veterinary clinics and universities with equine departments are able to study the equine athlete in their own sports performance laboratories.

The treadmill can easily evaluate the athletic potential of an equine athlete by standardizing variables used in an exercise test.  A high speed treadmill can answer various questions relating to speed, ventilation, heart rate, VO2 max, blood lactate, substrate (fuel) use, gait analysis, and endoscopic examination of the upper airway. The high speed treadmill will run at speeds in excess of 35 miles per hour, can be inclined at a 3-3.5% grade to simulate ground resistance and a rider’s weight. Treadmills equipped with a respiration calorimeter are used to measure gas exchange. Using indirect calorimetry, a loose fitted, padded face mask is attached to a motorized pump that monitors and analyses air breathed in each breath. The suction created by the pump ensures that expired air is collected and not re-breathed by the horse.

The research team can design an exercise test tailored for a desired performance measures. The test can be designed as an incremental test, where horses are asked to perform and ever increasing high speed until reaching maximal exertion, or a longer endurance test. During a standard exercise test fitness can be monitored using heart rate, with a heart rate monitor. Heart rate is one of the most frequently measured physiological variables measured in exercise tests.  Measurements of blood lactate, glucose concentrations, free fatty acids and pack cell volume can be taken throughout the test not just before and after. Knowing the horse’s weight is necessary in order to make calculations, and the horse is weighed prior to testing. During the test the airflow rate is measured in liters / minute. Both Oxygen (O2) intake and exhaled carbon dioxide (CO2) is measured. These measurements provide information to calculate VO2 (volume of oxygen), VO2 max (maximal oxygen intake), and VCO2 (volume of carbon dioxide).  VO2 max provides information on aerobic capacity, and the speed at which VO2 max is achieved. Being equipped with a heart rate monitor, the speed at which maximal heart rate achieved is also known.

The relationship between running speed, heart rate and oxygen consumption is linear up to VO2 max. Two commonly used variables that are used to describe the relationship between heart rate and velocity are V140 and V200. There is a high correlation between V200 (velocity at 200 beats per minute) and VO2 max. These variables are simply used to describe speeds attained at different heart rates. Numerous graphs and charts can be generated to display a horse’s athletic progress over time. Similarly, the speed at which blood lactate reaches certain levels is also measured. Lactate levels at different speeds are used to measure anaerobic capacity. Onset of blood lactate accumulation (OBLA) is recorded as VLA4. This is the speed achieved when blood lactate concentrations reach 4 mmol./l. Elite thoroughbreds can tolerate lactate concentrations as high as 30 mmol/l.

A sprint test on a thoroughbred may be run at supramaximal intensity of 115% VO2 max for a 2-minute period, near maximal heart rate, whereas an endurance horse such as and Arabian may be expected to run at 35-40% VO2 max for 90-minutes. Interestingly, Arabians have been found to use more fats as fuel than thoroughbreds (Kentucky Equine Research, Pagan). Using RQ (respiratory quotient) researchers can determine whether the horse is using fat or carbohydrate as a fuel source. Unlike oxygen, carbon dioxide varies tremendously with substrate (fuel) use. The RQ (respiratory quotient) is calculated by dividing VCO2 by VO2. An RQ of 1.00 indicates that carbohydrates are being used as fuel, and an RQ of .7 indicates that fats are being used.

Designing a Training Plan

By understanding the basics of equine exercise physiology, a racehorse trainer has the advantage of understanding how various physiological systems adapt and respond to training. In designing a comprehensive training plan for each horse the intensity, frequency, duration, and volume of the work is determined. The plan must also incorporate rest and recovery, and avoid overtraining. Each new level of training is maintained until the body has adapted to the added stress, after which further increase in training load can be applied. Alternating periods of increased workload, with a period of adaptation is known as “progressive loading.” Training should be specific to the event in order to train the appropriate structures and systems, doing work that is similar to racing which elicits neuro-muscular coordination. Horses “learn” how to do the event. This principle of conditioning is known as “metabolic specificity.”

Most training programs are divided into three phases. Phase I is the long slow distance (LSD) phase, Phase II is focused around strength work, and Phase III involves sharpening and speed work. (Marlin and Nankervis, 2002)
In Phase I, the primary focus is on long slow distance (LSD) and builds the foundation on which all other work is based. In their first year of training, Phase I may last from 3-12 months, with improvements in aerobic capacity seen in the first 6-8 weeks. Long slow distance is performed at slow canters at heart rates below 130-150 beats per minute. Even after this phase is completed LSD may comprise of 3-5 sessions per week lasting 20 minutes. Phase I improves cardiovascular fitness and trains musculoskeletal structures decreasing the future risk of injuries. This phase also helps the horse’s mental attitude toward daily training. Phase I is primarily done at low intensities of aerobic levels.

Phase II is the strength phase, where horses are trained with intensities from 150-180 beats per minute, and above 70% VO2 Max. Horses are usually working from a canter to a gallop over distances up to 1-1/2 miles. This phase can be accomplished in 60-90 days. Aerobic and anaerobic systems are trained, with horses reaching anaerobic threshold levels during their workouts. These workouts over time will increase the time and speed at which lactate threshold is reached. Strength work may be performed 2-days a weeks with adequate rest between sessions. Often in Europe hill work is added at this stage, increasing the intensity, without increasing the speed. Hill training strengthens the hindquarters, and working horses downhill strengthens the pectorals, shoulder, and working against gravity, the quadriceps in the hindquarters, become balanced.

Phase III is the sharpening phase, where speed work is performed at heart rates and intensities at close to race speed, often reaching V200 and VO2 max levels. Usually, depending on intensity, this type of work is performed only once every 1-2-weeks. Fast work can be performed as either continuous or interval training. K Continous training performed at the racetrack involves distances from ¼, ½ mile, and 1-mile or more, usually with the last quarter at race speed. Interval training involves using multiple exercise bouts separated by relatively short recovery periods where the heart rate drops below 100 beats per minute. Although each phase has a focus on training specific medabolic systems, a trainer must plan.

Conclusion

Understanding basic equine exercise physiology and the metabolic systems of the horse not only benefits trainers, but owners, breeders and agents in training, breeding and buying a future thoroughbred athlete.

Nasal Strips - increasing performance, reducing EIPH

By Bill Heller

Nasal strips’ future in Thoroughbred racing seemed limitless in the fall of 1999. Just two weeks after longshot Burrito won a race at Keeneland wearing one, 29 of the 101 horses competing in the 1999 Breeders’ Cup at Gulfstream Park November 6th had the 4-by-6-inch strip affixed 1.5 inches above their nostrils.

More importantly, three of the eight winners wore them, including Cat Thief, who captured the $4 million Classic at odds of 19-1 under Pat Day, who was sporting a human equivalent, himself.
 
The image of both Cat Thief and Day posing in the winner’s circle with nasal strips was a powerful one. Cat Thief’s victory was the second that day for Hall of Fame trainer D. Wayne Lukas, who earlier saddled 32-1 longshot Cash Run to win the $1 million Breeder’s Cup Two-Year-Old Juvenile Fillies. She, too, wore the non-invasive strip designed to reduce an exercising horse’s airway resistance and decrease exercise-induced, pulmonary hemorrhaging (EIPH).

The nasal strips received enormous national publicity after the Breeders’ Cup. Wouldn’t almost everyone in North America emulate Lukas? Stan Bergstein, the executive vice-president of Harness Tracks of America and a columnist for the Daily Racing Form, postulated long ago that if a horse wearing a blue balloon tied to his tail won a race, you’d see dozens of horses with blue balloons tied to their tails in the paddock the next day.
Lukas, however, preached caution regarding the role of nasal strips in Cash Run and Cat Thief’s surprise Breeders’ Cup victories. Regard-less, Lukas and trainer Bob Baffert spoke at a meeting of the California Horse Racing Board Medication Committee meeting, January 12th, 2000, in support of nasal strips. According to a CHRB press release, CHRB Commissioner Marie Moretti expressed hope that using the strips could lead to the decreased use of bleeder medication for some racehorses. That never happened, as Lukas proved prophetic. He saddled three horses in the 2000 Kentucky Derby, two with nasal strips, and none of them finished higher than 12th.


According to Equibase, between October 23rd, 1999, and April 24th, 2000, 8,402 Thoroughbreds wore the strip and 1,077 won, nearly 13 percent. Apparently that wasn’t high enough. Less and less trainers used them, though Lukas still does.

By the end of 2000, there was a story on the Internet site www.suite101.comentitled “The Demise of Nasal Strips.” Published December 12th, 2000, the article began, “The rise and fall of nasal strips was short and sweet.” Noting that the Daily Racing Form had originally listed the nasal strip in past performance lines for all tracks and that by mid-June was only listing them at Hollywood Park, the story concluded, “As quick as they appeared in the spotlight, they vanished.” The obituary was more than a bit premature.
Miesque’s Approval won the 2006 Breeders’ Cup Mile at Churchill Downs wearing a nasal strip for trainer Marty Wolfson, who uses them on all of his 30 horses. “I’ve been using them on all my horses for two years,” Wolfson said in mid-March. “I use them on myself. I run and they help me when I run. I breathe easier. The only time I couldn’t use one was when Pomeroy was in the 2006 Forego Handicap at Saratoga.” Pomeroy won that stakes. He was denied the nasal strip at Saratoga because the New York Racing Association mysteriously banned nasal strips, a day after the New York State Racing and Wagering Board approved them for both Thoroughbred and harness racing.

Currently, New Jersey is the only other state which doesn’t allow them, while Pennsylvania allows them for Thoroughbreds but not for Standardbreds.

According to nasal strip co-inventor and president of Flair Nasal Strips Jim Chiapetta, some 15,000 nasal strips are sold world-wide each year: 9,000 in the United States, 3,500 in Europe, 2,000 in Australia and New Zealand and 500 in Dubai. He said they were used mostly on horses in eventing, then on Thoroughbreds, Standardbreds and Quarter Horses.
Should they be used more often? Are they a realistic alternative to the powerful diuretic Lasix, which is now used by roughly 95 percent of all Thoroughbreds in the U.S., though the rest of the horse racing world bans Lasix and all other race-day medications? Lasix, which is used ostensibly to reduce EIPH, can improve a horse’s performance dramatically the first and/or second time it is used, if for no other reason that its diuretic properties. Horses can lose 10 to 20 pounds through urination after Lasix is injected. That alone improves most horses’ performance. Think about it. If there is an apprentice jockey with even a modicum of ability, trainers scramble for his services just to decrease the weight his horse is carrying by five pounds.

The efficacy of nasal strips can be judged in comparison to Lasix or by itself. “Lasix and nasal strips work in very similar ways,” said David Marlin, a consultant who worked for the Animal Health Trust in Newmarket, England, and co-authored Equine Exercise Physiology. “From scientific studies, they seem to be equally effective in reducing bleeding.”
Breathe Right strips were invented in 1987 by Bruce Johnson, who suffered from allergies. By the early 1990’s, they were being used for colds, allergies, snoring and athletic performance. They work by reducing the partial collapse of the soft tissues of the nose when it is under pressure because of the vacuum caused by the lungs during exercise. The mechanical, spring device maintains optimum air flow. Humans have an option for breathing: nose or mouth. Horses do not. They breathe only through their nostrils. Could nasal strips benefit horses?

That’s a question Jim Chiapetta and his partner Ed Blach decided to explore. They had become friends at the Littleton Large Animal Clinic in Littleton, Colorado.
Chiapetta, 48, returned to his clinic in Shakopee, Minnesota, to finish law school at William Mitchell College of Law. Blach, a former veterinarian who is now an animal products consultant, called Chiapetta in 1996 to discuss a possible equine version of a nasal strip.
“We talked to a bunch of people and they said it wouldn’t work for horses, but I told Ed I think it could,” Chiapetta said. “We went ahead and made some prototypes.”
Then they consulted Monty Roberts, the horse whisperer. “Ed used to be Monty’s resident veterinarian,” Chiapetta explained. Roberts was interested enough to have them test the strip at a track at Roberts’ farm north of Santa Barbara in California. “We didn’t have the adhesive done right,” 
Chiapetta said. “The riders were coming back and saying, `This horse felt better, more relaxed.’ So we figured there was something there.”

Having breakfast one morning with Roberts, Chiapetta and Bloch came up with a name. “I was thinking about flaring nostrils, then I was thinking about air, and we came up with the name Flair,” Chiapetta said.
Next, they consulted with CNS, the Minnesota company which manufactured Breathe Right. “They agreed to license it if it showed it reduces bleeding,” Chiapetta said. “They funded a study at Kansas State University.”
That study and a majority, but not all, of a handful of subsequent studies - all involving a standard small sample of horses - showed positive results from nasal strips. “The nasal strips seem to help,” Dr. Howard Erickson of Kansas State University, a co-author of one of the studies, said last February. “We’ve done studies here. There have been studies in Kentucky, California and Florida. In most of the studies, it decreases the bleeding by 50 percent and it also decreases the airway resistance.”
He believes that most horses would benefit from both, because he believes almost all horses suffer from EIPH: “I think it’s nearly 100 percent that have some degree of bleeding for the movement of fluid from the capillaries to the airway. For some, it may be negligible. Quarter Horses will respond the same way. Standardbreds, too. You see it in rodeo horses and barrel horses.”

That sentiment is shared by David Marlin, who has worked with researchers at Kansas State. “The bottom line is that all horses will break blood vessels in a race,” he said. “It happens with camels; it happens with humans, it happens with greyhounds.”
Marlin also believes that nasal strips may be a more preferable treatment than Lasix. “It’s less complicated and you can’t build up tolerance,” he said. “If you think about a diabetic who uses insulin, he develops tolerance and needs more of it. Do horses develop tolerance of Lasix? Generally, when you use drugs repeatedly, there’s a chance of adaptation to it. The nasal strip is different because it’s a mechanical device.”
Then why aren’t trainers around the world, and especially in the United States, using them?

Ironically, Chiapetta believes that the success of Cash Run and Cat Thief in the 1999 Breeders’ Cup is a major reason why. “It was the worst possible thing that could have happened,” he said. “We were on the front page of the New York Times Sports Section, the Wall Street Journal and Sports Illustrated. I think horsemen said, `Hey, this will make us win.’ So they strapped them on. And when they didn’t win, they took them off.”
Some, not all.
“They’re expensive ($7.95 per strip),” Wolfson said. “Some people don’t want to spend the money, but I think it’s worth it.”

Day, the retired Hall of Fame jockey, knew they worked on him. “I found them to be quite helpful when I was riding a number of races back to back,” he said. “It seemed that I was less fatigued because I believed I was getting much more air into my lungs. I would have thought that would be more helpful to horses than riders. Horses only breathe through their noses. They cannot or will not breathe through their mouths. If you can open up the nasal passages, open the airways, you would think it would be beneficial to the horses.”
At the Havemeyer Foundation Workshop investigating EIPH, March 9th-12th, 2006, in Vancouver, Canada, Dr. Frederick Derksen, of the Department of Large Animal Clinical Sciences at Michigan State University, spoke about the role of airways in EIPH. He said, “A series of studies demonstrated that the use of a nasal strip decreases the number of red cells in bronchoalveolar laverage fluid after exercise. In horses, the majority of inspiratory resistance to airflow is located in the upper airway. The nasal valge region, located just cranial to the nasoincisive notch is a high resistance region, not supported by bone or cartilage. These characteristics make this region particularly susceptible to collapse during inhalation. Application of the nasal strip in this region prevents nasal collapse and decreases upper airway resistance during exercise. This in turn is expected to reduce negative alveolar pressure during inhalation and decrease transmural capillary pressures.”

The nasal strips are certainly a hit in New Zealand, especially with harness horses. After reading about the use of nasal strips in the 1999 Breeders’ Cup, Brian McMath, a committee member of the New Zealand Standardbred Breeders Association, imported a few samples. After the strips were approved by Harness Racing New Zealand, several trainers began using them and many had success, including Jim and Susan Wakefield’s Glacier Bay, who won the $105,000 PGG Sales Series Final at Alexandria Park in April, 2000, for trainer Cran Daigety. Eventually, Thoroughbred trainers began using the strip, too. By the end of 2004, more than 700 winners in both harness and Thoroughbred racing won wearing the strip.
“I have a technology background in chemistry and engineering, and what convinced me the strips work was basic physics,” McMath said. “It’s all about windpipe pressures and how a simple mechanical device like the springs in the nasal strip can beneficially alter these pressures.”
The reception in Europe, at least for Thoroughbreds, was decidedly cooler. In an April 11th, 2000, letter, Peter Webbon, the Chief Veterinary Adviser to the British Jockey Club, noted that the senior veterinary surgeons from the European Horserace Scientific Liaison Committee (Britain, France, Italy, Germany) considered the question of nasal strips and decided to recommend to their racing authorities that their use should be banned for the following reasons:

1  “Other `gadgets’, such as tongue ties, which are allowed, are intended to address a specific clinical entity. Nasal strips are seen by trainers as a non-specific way of improving performances.
2 “If they improve performance, they should be banned, in line with performance enhancing medication.
3 “If they are ineffective, they should be banned because they give the impression that we condone practices that are intended to improve performance.
4  The manufacturers claim that they reduce the frequency/severity of EIPH. The EHSLC veterinarians felt very strongly, for the sake of the breed, that horses should run on their merits. What would be the effect on the Thoroughbred in the long term if a horse won the Derby, wearing a nasal strip,that without the strip was unable to win a selling race?”

To this day, they are banned throughout Europe for racing but allowed for training.

Two years ago, Chiapetta met with Webbon and his assistant in Newmarket. “He said, `It reduces fatigue, which improves performance,’” Chiapetta related. “I said, `If you shoe them, do they run better? If you feed them, do they run better? If you train them, do they perform better? Where do you draw the line?’”

Event horses are allowed to use them throughout the world because they were approved by the International Federation for Equine Sports (FEI).On June 26th, 2006, Horse & Hound  wrote that nasal strips “are becoming commonplace on the noses of top event horses,” and noted that Andrew Hoy’s Moon Fleet won the Badminton, a premier cross-country event in England. “I started using them two years ago,” Andrew Hoy said. “I’d seen them being used on horses and humans, and discussed their use with a vet. I had used a human one myself when I had a cold, and it seemed to help. I now use them on my horses at top events to give them every opportunity.”
The story said that another eventer, Francis Whittington, uses them on his “advanced” horse Spin Doctor. “I tried the human version and noted the difference,” he said. “I believe it makes it easier for him to breathe so he can last the distance.”

That’s the whole point. “Some people may think that more oxygen makes them run faster,” co-inventor Blach said. “That’s not the case. Rather, horses perform at their optimum level for a longer time so they can do what they’re made to do over the long haul. Maybe it’s too simple. It’s based on very simple physics that if you maintain the size of an opening, you’re going to maximize what goes through it, in this case air.”
Asked if nasal strips help horses, Blach said, “Absolutely.” Perhaps the most confounding question about nasal strips is that even the single negative clinical study about them said that they do not reduce EIPH, but offered no tangible downside to their usage. Asked if there is a downside, Marlin said, “I think, as far as anyone knows from a scientific point of view, there is no evidence that there is.” Referring to that study, Chiapetta said it showed that horses using them “certainly weren’t less healthier. I don’t think there’s any downside to it.”

Dr. Ted Hill, the New York Racing Association steward for the Jockey Club, said on April 11th, “Our only downside was how to regulate it. If a horse comes to the paddock and it falls off, what do we do? Do we treat it as equipment? We can’t put it back on. The significant problem we had originally was it possibly being an aid to bleeders, and relaying that to the public. That came up in an international meeting at a round table in Tokyo last October. It did not receive wide acceptance because it has some efficacy.”
So Japan does not allow them. Australia allows them for Standardbreds, but not for thoroughbreds. Yet, nasal strips are allowed for Thoroughbreds in Dubai and Singapore, as well as New Zealand.
“It’s probably been embraced more in other countries than here, but in Thoroughbred racing here, furosemide (Lasix) is so embedded,” Kansas State’s Erickson said. “Furosemide reduces weight. It certainly reduces bleeding. But maybe we have to look for something better.”
Maybe something better has been out there for eight years.

Horsewalkers - should they be round or oval?

Horsewalkers (electro-mechanical devices that allow multiple horses to be exercised simultaneously in a controlled fashion) are used extensively in the management and training of horses. They permit controlled exercise of horses at walk and trot. They are less labour intensive than most other forms of controlled exercise, such as walking in-hand, lunging, riding, swimming or running horses on treadmills. The exception might be ride and lead, but this is not a widely used technique, except perhaps in polo.

Horsewalkers may be used for a variety of reasons including warming-up or cooling down prior to or following ridden exercise, as a way to relieve boredom in stabled horses, for controlled exercise as part of a rehabilitation programme and to supplement ridden exercise. Horsewalkers are often also used where ridden exercise is not desirable or possible, such as in preparation of young animals for sale or in animals that may have injury to the back and therefore cannot be ridden. The majority of horses can be trained to accept being exercised on a horsewalker within a short period of time.

Any form of exercise carries a risk of injury and whilst there does not appear to be any objective information on the safety of this form of exercise, it would generally be considered that the horsewalker is a very safe form of exercise. Until recently, horsewalkers have been exclusively of a round design in which the horse is constantly turning on a circular track. The radius (tightness) of the turn is determined by the diameter of the walker - the larger the walker, the more gradual the turn. At present commercial round horsewalkers vary from around 10 to 30 metres in diameter (i.e. 5-15 metres in radius). The conventional design is of a centre post from which radiate arms that support the moving dividers that separate the horses but also encourage them to walk as the centre post rotates, in turn moving the dividers.

Other designs do not incorporate dividers but horses are hitched to arms radiating from the centre post. Whilst the majority of walkers can operate in either a clockwise or anti-clockwise direction, on the walker the horse is still turning constantly. Exercising at walk or trot on a circle for prolonged periods of time must be considered to a large extent unnatural for a horse. Horses at pasture, whether grazing or exercising, move in all directions and never in one continuous direction. The same is true of ridden exercise. No rider would work his or her horse continuously for 30 minutes on a circle, even when working in a confined area. For example, a Dressage test incorporates many changes in rein and exercise in straight lines as well as on turns. Lunging is another mode of controlled, unridden exercise that is commonly used by horse owners or trainers.

Lunging may be used in place of ridden exercise or to train riders or as a warm-up for the horse prior to it being mounted and ridden. Lunging may also be used in situations where a horse requires to be exercised but where fitting a rider and saddle is not desirable, for example, in the case of a sore back. However, prolonged lunging is not advisable and in addition, as with circular walkers, changing the rein frequently is common practice. Continual turning may be deleterious to the musculoskeletal system (muscles, bones, tendons, ligaments and joints). For example, it is widely recognised that signs of lameness are exacerbated in horses exercised on a circle. This is commonly used by veterinary surgeons in lameness investigations. It is also suspected that sharp turns may contribute to injury of distal limb structures (i.e. those structures furthest from the body such as the foot).

This implies that turning exercise changes the weight distribution through the limbs. The surface on which a horse is lunged may also determine whether lameness is apparent or not; a horse may not exhibit lameness when lunged on a soft surface but may do so when lunged on the same size circle on a firmer or uneven surface. Most research into how horses move has been concentrated in horses walking and trotting in straight lines, or on treadmills, and there are only a limited number of studies relating to horses turning on a circle. Only one kinematic (movement) study has evaluated the effects of turning a corner on the distal joint motions. Horses turning in a sharp (1.5m diameter) left circle showed a shorter stride length, but stance duration (the amount of time the foot is on the ground) was longer. This work also showed that the lower leg and foot rotate as the weight of the horse moves over the limb. Research from Australia showed that the outside edge of the cannon bone is not loaded significantly during exercise in a straight line on a flat surface. The same group of researchers also showed in a separate study that surface strains on the cannon bone vary between inside and outside forelimbs during turning.

On the inner surface of the cannon bone, compression of the bone is greatest in the outside limb, and stretching of the bone is greatest on the inside limb. On the outer surface of the cannon bone, both compressive and tensile peaks are largest on the inside limb, which also showed the largest recorded strains in compression. On the dorsal (front) surface of the bone (where bucked shins occur in young horses), compressive strains were largest on the outside limb, and were greater on larger circles. They concluded that turning exercise is required to maintain normal bone, in that low-speed exercise in a straight line only loads the outer edge of the cannon bone. In 2006 workers from the USA studied the effect of trotting in a circle on the centre of mass of the horse. The centre of mass is a point within or on the body at which the mass of the body is considered to act.

The centre of mass may vary according to gait, speed and direction of travel. The location of the centre of mass affects the distribution and size of the loads on the limbs. These researchers showed that in horses trotting on the lunge on a 6m diameter circle at a speed of ~2 metres/second, all horses leaned inwards at an angle of ~15°. The speeds attained by these horses at trot on a circle are lower than those typically seen for horses on a straight line. As the speed was slower, the implication is that stance proportion was increased (i.e. the weight bearing phase of the stride was longer on a circle than would be expected in a straight line). Furthermore, the researchers pointed out that “horses may behave differently when turning clockwise versus counter-clockwise due to asymmetries in strength, suppleness and neural programming…”. Thus, whilst it is often assumed that an equal amount of exercise on each rein on a circular horsewalker should be applied, this may not be the case for many horses and may actually be counter-productive. The potential negative impact of circular exercise has also been highlighted with respect to the muscular system: “Especially in the initial stages of a return to work avoid lunging, horse walkers, or work in tight circles, as well as hill work”; a quote from veterinary surgeon and muscle specialist Dr Pat Harris from the Equine Studies Group at the WALTHAM Centre for Pet Nutrition, UK. Exercising on a circle also requires more effort than exercising in a straight line (Harris, Marlin, Davidson, Rodgerson, Gregory and Harrison (2007) Equine and Comparative Exercise Physiology, in press).

For example, being lunged on a 10 metre diameter circle was around 25% more work than being ridden on a large oval track in an indoor school. In addition, being lunged on a 5m circle was around 12% more work than being lunged on a 14 metre diameter circle. Even accounting for the weight of the rider, lunging is harder work than ridden exercise, which is most likely due to the continual effort required by the horse to balance itself on a continual turn. Oval walkers are a new concept. The premise of using oval walkers is that continual exercise on a small circle is unnatural for horses and could even lead to injury and that a walker incorporating both straight line and turning exercise would represent a more appropriate form of controlled exercise.

As so little information exists on turning in horses, a study was designed by us [Dr David Marlin (Physiologist) and Paul Farrington (Veterinary surgeon)] to investigate turning stress in horses in more detail. The work was undertaken in collaboration with Dr Bob Colborne (a specialist in Biomechanics) at Bristol University, UK. A

SUMMARY OF THE RECENT RESEARCH ON TURNING

The purpose of this study was to record the forces acting on the lower limb as horses walked in a straight line, on a 14 metre diameter circle, and on a 10 metre diameter circle to provide insight into the horizontal forces transmitted up the limb during locomotion in a straight line and whilst turning. Three fit, sound Thoroughbred horses, ages 3, 5 and 12 years of age were used in the study. Horses were walked across a force-plate (a metal plate placed on the ground that measures the force with which the horses’ foot is placed on the ground) both in a straight line and on a 10 and 14 metre diameter turn. For the turns the horse was always walking on a left-turn. The results showed that the coffin joint had the greatest degree of abduction (movement of the limb away from the body), adduction (movement of the limb towards the body) and axial rotation (twisting movement) and that these movements were greatest at the time of impact and break-over. The first point of contact with the ground has a significant influence on the line of stress through the foot and up the limb, as does the position of the body at the same moment.

On a turn the horse abducts the inside forelimb away from the body towards the line of the circle with rotation of the foot in the direction of the turn. The stride length is dictated by the tightness of the turn, as is the stance time (when the foot is on the ground). As the horse then moves forward the horse’s body moves towards the inside limb increasing the loading on the limb. The results showed that on average the forelimbs tended to behave asymmetrically (i.e. the two front legs did not behave the same) on a circle so that the forces and movements differ to produce different torque effects (twisting forces). The hind limbs tended to behave more symmetrically except when the size of the circle was reduced from 14 to 10 metres in diameter.

IMPORTANCE OF HORSEWALKER SURFACES

The walking surface will likely have an effect on the stresses experienced by a limb. If the surface allows reasonably free twisting of the hoof when weight bearing, the stresses between the hoof and ground will be small. However, any ground surface that holds the hoof and impedes this horizontal rotation will probably impart higher loads to the joints of the lower limb. Large turning forces should be avoided when the limb is vertically loaded (i.e. when the weight of the horse’s body is over the limb and the limb is on the ground). It is also important that the walking surface is level to avoid tilting of the hoof during weight-bearing. A walking track that is worn in the middle and that causes rotation of the joints in the foot is likely to cause larger and uneven forces to the lower limb joints and associated tendons and ligaments.

IMPLICATIONS FOR OVAL VERSUS ROUND HORSEWALKERS

Our recent research and a review of other scientific studies show that turning is not equivalent to exercise in a straight line. Turning exercise is harder than exercise in a straight line and loads the bones in a different way. Furthermore, on small turns the inner and outer limbs may not behave in the same way as on larger circles. This may have implications for horses with pre-existing musculoskeletal injuries. The potential advantages of an oval walker is that it combines straight line and turning exercise that more closely mimics the exercise that a horse will do when being ridden or when free at pasture. The results of our small study have shown that the hind limb patterns were quite different on the tighter radius turns, indicating a different strategy for turning, and supporting the notion that both straight line and turning exercise should be recommended for overall loading patterns that are healthy for maintaining bone that can withstand loading forces in a variety of directions. The results also make clear that small diameter round walkers (~10 metre diameter or less) are less desirable than round walkers of 14 metre diameter or greater. Small diameter round walkers increase the loading and asymmetry and increase the work compared with larger diameter walkers. In conclusion, there appear to be significant advantages to using a walker of an oval design as opposed to a round design, as exercise on an oval loads the limbs with a combination of straight and turning movements, as would be experienced during riding or in free movement.

Does artificial lighting benefit the conditioning of a horse?

By Paul Peacock

The claims of manufacturers of light therapy equipment for equines vary from the scientifically proven, through the scientifically dodgy to the downright bizarre. Trainers need to be able to sift through the advice and make financially viable judgements and weigh up the various proposed benefits against costs.

There is also the question of animal welfare to consider, comparing proposed benefits against the possible inconvenience of treatment. Certain forms of so-called light therapy, involving crystals and projected rainbows lie outside the remit of this article as much the same conclusions apply as in other forms of alternative treatment for equines.

However, there are many scientifically proven and highly practical uses for light therapy with thoroughbreds. Research by H. Kolárová, PhD, D. Ditrichová, MD, J. Wagner, PhD at three universities in the Czech Republic has conclusively shown that light penetrates skin tissues and there are a number of light receptors in the skin. These receptors have various functions including the production of more than one set of hormones and vitamins.

Mares at stud

Research in the USA showed that the day-length stimulated the pituitary gland to produce follicle stimulating hormone, thus bring the mare into season. This response is linked to the onset of spring, which in the natural world would bring the mare to foal at the appropriate time. However, this is not usually good enough to meet the cycle of yearling sales, especially in the US (much less so in Europe) and artificial light is used in the autumn and winter months to bring mares into season prematurely early. Up to 70 days of enhanced light, using medium intensity day-glo lighting, either in bulb or fluorescent form, is usually sufficient. More recent research has reduced this figure to les than a month with the use of the drug Sulpiride.

Implications of day length

Clearly, if the pituitary gland can be stimulated using artificial light, other benefits might be available to the horse if the onset of spring is artificially induced. These included increased energy, healthier immune system response, quicker and better recovery from injury and the vague yet important increased interest in life and work. This simple conclusion has led to a growing industry which in some cases uses pseudo science to market benefits that are simply not true.

The science

As far as it is currently understood, light has a number of effects under the skin, i.e. nothing to do with the eye. These effects are not fully understood, and consequently, in order to sell equipment, many companies resort to little understood, pseudo science in order to enhance the effects of light therapy equipment.
There are some compelling and intriguing reasons for looking in to light therapy, but there are not, as yet, any ‘double blind’ scientific studies to actually back up current claims.

Vitamin D

There are light receptors under the skin, but the production of this important vitamin does not need them. It is impossible for any mammal to get all its vitamin D from food sources. One of the many cholesterol molecules is broken down by a specific frequency of light to the vitamin. This only takes place under ultra violet B, and so ordinary bulbs and fluorescents do not produce the required frequency.
The effects of vitamin D deficiency used to be thought to be quite plain. However modern research has shown there to be a lot of problems directly or indirectly associated with lower amounts of the substance.
These can include depression, seasonal affective disorder, heart disease, rheumatoid arthritis, poor coat quality and other skin problems, periodontal disease and inflammatory bowel disease.
Consequently, Vitamin D being such an important molecule, the exposure of horses to an adequate amount of UVb light either in daylight or artificial form is important.

Endothelial light receptor cells

The science that might be at work in the other forms of light therapy shown by advertisers is detailed below, but these ideas are not particularly highlighted by many of the companies themselves. Usually you get the statement, “healing at the cellular level” or the “light heats up cells thus increasing their metabolism” or “the extra energy given to cells allows oxygen to become more available”. None of these statements can be attributed to factual evidence. However, current and possible areas for research include the following.
Horse skin, as in almost all mammals, contains a lot of light receptors. These use light to create a number of interesting effects.

First of all, nitric oxide synthatase (NOS), an enzyme which produces nitric oxide, is found more readily at higher light activity. This releases nitric oxide into the tissues which stimulates blood flow and has an effect on the nerves in the area. The interruption of morphine receptors can be initiated by nitric oxide, among other substances, thus providing an element of pain relief. In circumstantial evidence there does seem to be an increased immune system response directly associated to light receptors receiving extra incident light. This might be associated with oestrogens and their interaction with NOS, nitric oxide itself, and other as yet unknown substances.  In particular, wound repair and the healing of operation scars is becoming an interesting area of study which has been one of the favourite claims for using light therapy, particularly cold laser treatment.

Treatments

Cold laser treatments are supplied in hand held form in a little box. You simply shine the light at the treatable area for a short while. A number of companies say that this treatment works by somehow transferring energy to and from ADP to ATP. This claim is nonsense. However, the non-science of the claims does not have to mean that the treatment doesn’t work. Hand held lasers are expensive, possibly out of the reach of many small yards. LED infra red diode therapy is where a string of infra red diodes are attached to the affected part. There are receptors in the skin which respond to infra red energy, normally to increase blood flow to remove the heat from the area. This can, therefore, have some benefit at the local level, but it is not conclusively shown. Furthermore many companies suggest using this equipment at the acupuncture points on the animal, causing the prospective user to weigh up the relative pros and cons of alternative therapies too, something beyond the scope of this article.
 


SAD adjustments, as described earlier, are possibly the best use of light therapy. It has to be said that the best and most cost effective light source is the sun, and stables need to be as light and airy as possible. However the simple use of daylight bulbs or fluorescents is sufficient to compensate for day length initiated disorders, keeping the animal in general good health. There are companies that sell booths with banks of lights on them. You can alternate these lights for infra red banks which create a warm radiance on the animal. They are frequently advertised with benefits such as shortening warm up / warm down times, and drying the animal after exercise or otherwise. Trainers will have to make up their own minds about these benefits.  There are no studies which detail the combined effect of heat and light on the health response of horses, yet common sense might provide some hints to their possible use.

Un-synchronised fluorescent lighting

Some horses. Like a small but significant number of humans, respond negatively to fluorescent lighting that is un-phased. Older, or cheap, fluorescent lights can have a flicker associated with them which can affect some thoroughbreds. Examples of crib biting and walking and kicking have been eased by simply changing the lighting.

Conclusion

There is plenty of anecdotal evidence that light therapy has some basic scientific truth about it. However the studies to completely show benefits are few and far between. Particularly, trainer will have to make up their own minds whether expensive equipment justifies the proposed benefits. Perhaps the very best light therapy can be obtained by simply changing the indoor lighting to daylight bulbs and the maintenance of a fourteen hour regime of daylight type radiation in the yard.

The benefits of long reining - enhancing a horse's physical and emotional well-being

By Bolette Petersen

Lunging and long reining may seem like old fashioned, basic disciplines for working horses. However by the end of this article, I hope to remind you that these disciplines, when incorporated into your horse’s work routine, can really enhance their physical and emotional state. 

After twenty years of working on the ground with yearlings and racehorses, I have seen how these simple methods have produced many successful racehorses. 

Used on a regular basis, these disciplines will strengthen your horse’s body so that he will go from being a front wheel drive machine to a four wheel drive machine with extra power behind. As well as becoming stronger, he will be more confident and willing in his work. You will notice how he will respond better to his handler, due to them spending more time together as a team whilst being lunged and long reined.

 I find that it is safer and easier to lunge a horse in a closed round pen. When lunged correctly, your horse will become more balanced in his work, his muscles will become stronger and have a more rounded feel to his body shape. Always put on over reach boots and brushing boots to protect the front legs. Some horses will need brushing boots behind too. I find the key bit a wonderful device for horses of all ages because it teaches them to accept the bit, as well as helping to soften their mouth, which eventually gives them a suppleness through their neck, resulting in an overall improved movement throughout their body. Even when they are older and still in training.  

Many horses will initially rush into the round pen and immediately start cantering until they settle. It is very important to teach horses to walk around the pen first, allowing them to relax and warm up their muscles. Horses are more prone to injuries at a canter, so it is imperative that you teach your horse to trot at a collected pace, making sure his hind feet fall into the foot prints of his front feet. You will see that this is the natural rhythm for your horse, allowing his muscles to work properly, and keeping injuries to a minimum. At this pace he will put less pressure on his fetlocks, tendons and knees, as well as less concussion going through his shoulders and withers. Trotting a horse at this pace can also strengthen weaknesses through the legs. I have noticed on many occasions, improvements in horses that are back at the knee because the shoulder and chest area strengthen, tightening everything up.  

Your horse should trot the same amount of time each side, and for most horses, trotting each way five to ten minutes every other day will produce significant results in his overall fitness. The day in between can be used for relaxation, long reining, walking or riding out, depending on what routine you are in.  

Incorporating side reins after a week or two will help the horse learn to use his hind quarters and hamstrings to a greater degree, they will also strengthen his back muscles, in particular his longissimus dorsi, and neck muscles: the rhomboid muscle along the top of his neck, the complexus muscle, the longissimus, capitus and atlantis muscles. These muscles will take on a much more pronounced, rounder shape to them.  Your horse‘s body will work almost like a concertina effect, this creates deeper strength throughout his body, strengthening his buttocks, and hamstrings which really power him forward towards his shoulders and neck. He will then start to drop his head into the bit, rounding his neck, working deeper. His muscles along his backbone (longissimuss dorsi) will start becoming even stronger, providing a better platform for the saddle and rider, thus helping to protect the back bone.

 Some horses will never have had side reins on before, so it is important to start with the reins quite long and then gradually shorten them over time. The ideal length allows the horse unforced give in his mouth and neck so that he attains a natural curve to his head (as seen in photo). Again after a couple of weeks you will notice his muscles changing shape, becoming more curved, in particular the rhomboid, longissimus capitis and atlantis muscles. Over time you can shorten the side reins to build the muscles up even more. Never have them too tight though as this may cause your horse to have a sore mouth and he may start to go against the lunging.

Incorporating long reining into your horse’s weekly routine is also beneficial for general fitness and well being. It is a difficult discipline, and should only be attempted by the more experienced horseman. I really enjoy taking my horses up the road, out of the farm and into the woods, but I always make sure that I do this route a few times in advance, leading in hand first, so that they are familiar with their surroundings. By leading them in the roller and side reins, they learn to abide by your voice and get to see different objects like rubbish bins, cars, tractors and barking dogs. It is good for them to come into contact with these different objects, because they will be so much calmer when in training. The side reins make it easier to control them too, so you don’t have to use a chiffney all the time.

It is easier to get the horse used to the long reins whilst lunging in the round pen. Lunge your horse in two lunge reins, attached to each side of the bit, through the middle holes of the roller, on each side for a couple of days until he gets used to them against his sides and flapping around his legs. Then, at the walk bring yourself around behind your horse, making sure you are not too close because he may kick out. Be prepared for your horse to take off which can happen sometimes if he is a little nervous. Help to avoid this by keeping your hands down by your knees so that your horse drops his head, rounding his back, and get him to walk on around using a calm reassuring voice to keep him calm and controlled. The side reining will have prepared him for this contact to his mouth, so he should be more receptive. If you can get someone to walk at your horse’s head for the first week, it will make it easier and safer.

 After a few days of practicing circles with the long reins, in the round pen, you can then try walking your horse out onto the road. The aim of this discipline is to get your horse out into the woods walking around the trees. This is particularly good for breaking in yearlings because not only will they become braver and more independent, you will notice how their mouths and neck will be much more pliable and their body more balanced. Keeping your hands down by your sides will help coax your horse to bring his head down, making him work forward with more strength from his hindquarters. Please make sure you wear leather gloves at all times, to give your hands greater protection in case your horse pulls hard.  

Long reining is also extremely beneficial for horses in training and resting racehorses. The older horses really enjoy learning new things. You may find that they sometimes lose interest in their work because they have become bored with the same routine. Therefore, I find that by incorporating lunging in side reins and long reining you will notice that they immediately change their attitude to their normal work, becoming more positive towards everything they do. 

I have worked with many horses that just need a change to freshen them up and just turning them out doesn’t seem enough. That’s why horses come here, to my farm for ‘working holidays’, not only to relax, but to do different things, and learn new disciplines.

 One such horse is Zorn, and he really is my inspiration for all the work that I now do with horses that come here for a rest during their training career. We bred him so he had been through all the basic education with me before he went into training. Unfortunately after four unsuccessful years in training and a few injuries, we took him home. I began schooling him with a view to having him as a dressage horse. Lunging in side reins came easy to him because he remembered what he had been taught as a youngster, as was long reining, and it didn’t take him long to become more balanced, rounded and stronger behind.

 He did this work for eight months with quite a lot of dressage thrown in. He became so fit, that we decided to send him back into training. A couple of month’s later he won his first race! He had become a stronger horse for all the work he had done at home and it had paid off.  Seeing him win on several occasions after that has been extremely rewarding for everyone involved.  

He has been home every summer for his ‘working holidays’, and always returns to a winter all weather campaign, winning a few races every year.

It is not just Zorn who has been successful after his ’back to basics’ schooling. Horses like Captain Rio, Torrid Kentavr, Distant Prospect and Shatin Venture, amongst others, have all been educated here in the same way, they have all been through these basic disciplines as youngsters and have since done extremely well on the racecourse

 Lunging and long reining may seem like old fashioned, basic disciplines for working horses. However by the end of this article, I hope to remind you that these disciplines, when incorporated into your horse’s work routine, can really enhance their physical and emotional state. 

Weighing Racehorses - how regular monitoring can provide vital information

 As racing has slowly embraced the technological era, so horsemen's lore has been reinforced or refuted by scientific advance. One area of increased awareness is the importance of monitoring the weight of the racehorse. From stud to stable, weighing machines have augmented, and even supplanted, the empirical judgment of the eye. Applications range from gauging the development of the weanling to assimilating the optimal fighting-weight of the performance horse to monitoring the effects of transportation.

Eliciting the comments of a diverse cast of trainers from the Flat and National Hunt communities on the use of weighing machines precipitates several common themes. There are two main areas where the use of weighing machines have proved illuminating: in establishing the weight that a thoroughbred is at its most athletically efficient, and in monitoring the systemic stress of competition and its attendant recovery rate. On the first topic, it is clear that a good deal of experience is required in interpreting the data which weighing the thoroughbred over a significant period yields. It is accepted that the thoroughbred develops physically until the age of five, yet there is no corresponding linear relationship with its mean weight. Fatty tissue is gradually replaced by muscle, so the racehorse gets bigger but leaner. This results in its weight varying considerably with factors such as pedigree, training, feeding and environment. Judging optimal performance weight is, therefore, far from being an exact science. "A lot of my horses weigh the most at the age of two.

Russian Valour, for instance, is the heaviest successful horse of any age I have trained," Mark Johnston said before the smart juvenile won last year's Norfolk Stakes at Royal Ascot. Dermot Weld, another qualified vet, is said to believe that the weight of his top Flat horses varies little between two and three years old, again perhaps due to the alliance between training technique and the variance in tissue type. The brilliant Irish trainer is therefore in a strong position to formulate a relationship between weight and performance. Eric Alston has been weighing racehorses for 15 years and is a strong advocate of the practice as a training aid. "The key is appreciating that horses are individuals and building up a pattern of how their weight varies with age and time," he says. "The eye is still very important, but weighing gives you that extra bit of confidence in your judgment of when a horse is right." Some equine giants range up to 570kg, but the majority fit within the range 470-515kg. When you consider that some can lose more than 25kg (roughly 5% of their bodyweight) through a single race, it is clear that monitoring recovery rate is vital to continued wellbeing and performance level. A thoroughbred at peak fitness should put back the lost weight within three to four days if all remains well with them, though individual rates vary and some even make a full recovery within 24 hours.

Leading National Hunt trainer Henry Daly believes that weighing horses has an important role to play in the analysis of post-race recovery. "I find that horses lose between 7.5kg and 25kg post-race," he says. "Travelling is a major factor. In my experience, the distance a horse races from its home base is roughly proportional to its weight loss, all other factors being equal." "This is especially true of the young horse, first time out. A novice can appear to win without having a stressful time, for instance, but when you get it back home it has experienced a significant weight-loss and your training must be adjusted accordingly."

William Bedell, whose company The Horse Weigh is a market leader in manufacturing weighing equipment, reports that the demand for weighing machines has mushroomed across the thoroughbred industry. "Our weighing units are constantly under development and the feedback from training yards - which constitute 40-50% of our business - is vital in development," he says. "The new-age trainer is soon on the phone if he believes he is missing an important aid to maintaining or improving his position." One of Bedell's most valued clients is the Shadwell Stud in Norfolk, whose manager Johnny Peter-Hoblyn is effusive about the importance of the equipment to one of the world's leading thoroughbred nurseries. "Weighing is an essential part of Shadwell's monitoring techniques, " he says. "Aberrant weights enable us to pick up potential problems before they are apparent to the naked eye, and before they become more serious. Weight loss can be the sign of the onset of viral problems, but just as important to us is controlling weight gain. "If a foal picks up more than 1.5kg a day, the extra burden on its young joints can lead to developmental problems. Having quality tools at our disposal, such as the weighing machines we have here, is crucial to the stud's success."

Weighing machines are also in use by racehorse transporters whose customers are sensitive to monitoring the physical stress of getting their horses to the racecourse. James Paltridge of International Racehorse Transport (IRT) has vast experience of travelling horses round the world, notably to events such as the Breeders' Cup and Melbourne Cup. "Obtaining reliable readouts can be difficult, as weighing machines seem to be calibrated differently. For this reason we have our own at either end of the journey when we fly horses to Australia," he says. "A horse can lose up to 30kg on a long-haul flight, mainly as a result of dehydration. Getting a horse to drink in a rarefied atmosphere is difficult, particularly if it is travelling from a winter climate to warm weather." "IRT uses weighing machines in order to provide the customer with information about weight loss. This is also of great benefit to the company liability-wise." Now comes the thorny issue. If knowledge of a horse's weight is so useful within the various enclaves of the thoroughbred industry, should it not be placed in the public domain on race days?

After all, the image of the sport is dependent to a significant extent on transparency, particularly in the aftermath of the blow to its integrity delivered by the Panorama and Kenyon Confronts programmes two years ago. Rupert Arnold, chief executive of the National Trainers' Federation, sums up the position of his members towards trackside weighing. "We discussed the topic at most of our regional meetings last autumn," he says. "So long as weighing was carried out at a convenient position and with minimum disruption - and we believe that it can - that is not a significant concern. "The main issue in the trainer's mind is the misinterpretation of the information in sensitive cases. Weights can vary significantly through natural variation, and isolating it as a central factor in the performance of a horse is far from straightforward. "Integrity is an important issue to trainers, but it is not very clear that weighing racehorses would improve matters. We are all for expanding information sources, but even the more sophisticated punter is more likely to be misled than enlightened by racehorse weights."

British horseracing already has a model available if it is considering publishing weights. With integrity issues always to the forefront of its considerations, the Hong Kong Jockey Club introduced the practice three years ago. According to one professional punter, however, the information has been subject to various degrees of interest. It is far from evident that winner finding nor performance interpretation has been made easier as a result. Newmarket trainer Luca Cumani experienced mandatory weighing when sending Falbrav over to win the Hong Kong Cup last December "I had no problem whatsoever with having Falbrav weighed before the race. Anything which is helpful, useful or interesting to the racing public is a service which should be offered. There is little disruption to the horse." Cumani has no qualms about the practicalities of weighing but does doubt its efficacy in providing novel information. "I used to weigh horses in training but gave it up because it was adding nothing to my judgment. After a couple of years of recording and analysing the data, I came to the conclusion that I could judge a horse's weight within 5kg on the vast majority of occasions. "Of course, this is a personal opinion, but every experienced trainer should be able to do the same, if he lives with his horses every day."

It is far more important for those clamouring for technological improvements to focus their attentions on sectional times rather than weights, for British horseracing is screaming out for better time information in order to market itself better to the rest of the world. Racehorse weights are of considerable use to the professional horseman who has all the facts at his disposal with which to interpret the information correctly, but it is doubtful they would be anymore than interesting to the public. As far as integrity issues are concerned, it is possible that a mature horse reappearing after an absence could be checked to ensure it is not carrying more than a reasonable amount of excess weight. However, establishing what constitutes a reasonable variation, and dealing fairly with cases which are judged to be outside normal parameters, makes for extremely difficult policing.