Pastern Fractures - Split Pasterns, the injury that gets worse before it gets better

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THIS ARTICLE FIRST APPEARED IN - EUROPEAN TRAINER MAGAZINE ISSUE 45

Vitamins - as easy as ABC?

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North American version: issue 30 Fall/Winter 2013

European version: issue 43 Autumn 2013

Breaking the silence: The impact of sound and hearing

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THIS ARTICLE FIRST APPEARED IN - EUROPEAN TRAINER - ISSUE 41

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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Forage - so much more than just a filler

Too often thought of as just a ‘filler’, or occupational therapy to while away the time between hard feeds, forage is worth so much more than that. Simply feeding an inadequate quantity of forage, or choosing forage that has an inappropriate nutrient profile, or is of poor quality can have a negative impact both on health and performance in racehorses. Inappropriate choice of forage and its feeding can easily lead trainers down the slippery slope towards loose droppings and loss of condition.

Forage can also have a significant impact on the incidence and severity of both gastric ulcers and respiratory disease, including inflammatory airway disease (IAD) and recurrent airway obstruction (RAO).

When choosing forage the main elements to consider are

• Good palatability to ensure adequate intake • Adequate digestibility to reduce gut fill

• Fitness to feed to maintain respiratory health

• A profile of nutrients to complement concentrate feeds

FORAGE CAN ONLY BE GOOD WHEN PALATABLE

Palatability is a key issue, as even the best forage from a quality and nutritional standpoint is rendered useless if the horses do not eat sufficient quantities on a daily basis. Palatability is a somewhat neglected area of equine research and so we largely have to draw on practical experience to tell us what our horses like and what they don’t. Some horses appear to prefer softer types of hay, whilst others prefer more coarse stemmy material. Many horses readily consume Haylage, whilst some trainers report that other horses prefer traditional hay. Apart from the physical characteristics, the sugar content of hay or haylage may affect its palatability. Forage made from high sugar yielding Ryegrass is likely to have a higher residual sugar content compared with that made from more fibrous and mature Timothy grass. Some interesting research carried out a few years ago by Thorne et al (2005), provided some practical insight into how forage intake could be increased in the reluctant equine consumer.

This work reported that the amount of time spent foraging (which will increase saliva production), was increased when multiple forms of forage were offered to horses at the same time. From a practical viewpoint this can be easily applied in a training yard and it should help to increase the amount of forage consumed. For example, good clean hay could be offered together with some haylage, and a suitable container of alfalfa based chaff or dried grass all at the same time.

A Healthy Intake Racehorses in training often eat below what would be considered to be the bare minimum amount of forage to maintain gastrointestinal health. Whilst sometimes this is due to the amount of forage offered being restricted, in other instances it is because the horses are limiting their own intake. This may be due to either their being over faced with concentrate feed, or due to unpalatable forage being fed. Establishing a good daily intake of forage during the early stages of training and then maintaining the level through the season is important. Typically the absolute minimum amount of forage fed should be about 1% or 1.2-1.5% of bodyweight for hay or haylage, respectively.

This equates to 5kg of hay or a rounded 7kg of haylage for an average sized horse (500kg). The weight of haylage fed needs to be greater than that of hay due to the higher water content of the latter. Intake of haylage needed to achieve a similar dry matter intake to 5kg of hay Moisture Dry Matter Weight of forage % Increase above hay Hay (Average) 15% 85% 5kg Haylage 1 30% 70% 6kg 20% Haylage 2 45% 55% 7.5kg 50% The dry matter of haylage needs to be consistent to allow a regular intake of fibre and reduce the likelihood of digestive disturbance or loose droppings.

Ideally trainers should be aware of any significant change in dry matter, so that they can adjust the intake accordingly. Forage intake is restricted in racehorses to firstly ensure that a horse consumes adequate concentrate feed to meet their energy needs and requirement for vitamins and minerals within the limit of their appetite. Secondly, the amount of forage fed is restricted in order to minimise ‘gut fill’ or weight of fibre and associated water in the hindgut, as this will restrict their speed on the racetrack. BUT… inadequate amounts of forage in a horses’ diet has such a negative effect on health that the minimum amount fed must be kept above recognised ‘safe limits’.

Choosing an early cut forage that is less mature and with more digestible fibre means that the ‘gut fill’ effect is lessened. In addition, horses can always be fed more forage during training with the daily quantity being reduced (within the safe limits) in the few days before racing where this is practical.

FITNESS TO FEED

Quality of forage, in terms of its mould, yeast and mycotoxin load, can have a major impact on respiratory health. A recent Australian report (Malikides and Hodgson 2003) highlighted the cost of inflammatory airway disease (IAD) in horses in training, in terms of loss of training time and of potential earnings, together with the associated cost of veterinary treatment. They estimated from their study group that in Australian racing up to 33% of horses in training can have lower airway inflammation, yet show no overt clinical signs. Type and therefore quality of forage, as well as the quality of ventilation were singled out as the most significant risk factors in the development of IAD.

Forage is potentially a concentrated source of bacteria, mould spores and even harvest mites. Hay that has heated during storage, or that has been bailed with a high moisture content is likely to provide a greater load of these undesirable agents that can harbour substances that promote airway inflammation, such as endotoxin. Purchasing good quality and clean forage from a respiratory perspective will certainly reduce the pressure placed on young racehorses’ respiratory systems.

However, how does one achieve this?

• Microbiological Analysis – the price paid for a microbiological analysis of a prospective batch of hay is a worthwhile cost when the consequences of poor hay are considered.

Assuming the analysis is favourable, purchasing a larger batch for storage gives further peace of mind and spreads the cost further, providing of course that the storage conditions are appropriate. Interpretation of the microbiology results as CFU/g (colony forming units/gram) for moulds, yeasts and Thermophillic actinomycetes is not difficult. As a rule of thumb the lower the CFU count the better. Whilst a very low mould or yeast count (<10-100) should not usually cause concern, more consideration of the merits of a batch of forage should be triggered by a CFU count that reaches 1000-10,000. Certainly if any Aspergillis species of mould are identified the alarm bells should be ringing.

Aspergillis Fumagatus has particular association with respiratory disease including ‘Farmers Lung’ in humans.

• Storage –A suitably sized storage area will allow storage of a good-sized batch of your chosen forage giving consistency through the season. It makes financial sense for the welfare of racehorses to make adequate provision for a good-sized storage area. Third party storage is also sometimes an option where this is not available on site.

• Forage merchant or farmer - A good working relationship with one or more farmers or forage merchants is essential to be able to consistently buy good hay. They need to know what you want to buy and you need to be able to rely on them to provide a high quality product through the season. Newmarket based forage merchant Robert Durrant stands by the principle that “A good forage merchant should be able to supply a trainer with the same high standard of hay for much if not all of the season”. He adds that in his opinion “American hay English hay or haylage are all good options when they have been made well and the quality is high, but the quality of the American hays are consistently more reliable.”

PRO’S AND CON’S

Hay from colder climates e.g. UK, Ireland commonly used quality can be variable usually palatable economical Haylage. Usually clean dry matter can be variable Fermentation inhibits mould growth Need to feed more than hay Feed value often higher May need to adjust hard feed Usually palatable Beware of punctured bales Newmarket trainer James Eustace has used big bale haylage for many years he says “I found it increasingly difficult to reliably source good clean English hay. I am very happy with the haylage, as it is pretty consistent and it provides the dust free option that I wanted.”

Hay from warmer climates e.g. USA / Canada usually very clean May need to adjust hard feed Feed value often higher Premium price Usually palatable Newmarket trainer Ed Dunlop appreciates the advantages of using more than one forage source he says, "American hay gives us the consistent good quality that we need and the horses eat it well. Feeding it alongside other forage gives us the flexibility needed for different horses throughout the season." Alfalfa (High temperature dried or sun dried)

Good adjunct to forage (e.g 1-2kg) High intakes can oversupply protein and calcium Can be used as chaff Leaf fragments can add to dust High feed value & digestibility Less gut fill Many of Forage merchant Robert Durrants clients choose sun dried alfalfa as an extra treat for the horses he says “the horses get a large double handful daily as a treat and they love it.”

NUTRITIONAL CONSIDERATIONS

The nutritional contribution made by forage should complement that made by the concentrate feed. Most racing rations are high in energy, high in protein and low in fibre. Therefore a suitable forage needs to be contrastingly high in digestible fibre with a limited level of energy and protein. However, where you have sourced early cut hay or haylage that is more digestible and higher in energy and protein, the concentrate feed intake should be adjusted to account for this. This will help to avoid the issue of over feeding of energy or protein. An excess of energy can result in undesired weight gain or over exuberance, whilst an excessive intake of protein at the very least increases the excretion of ammonia, which is a respiratory irritant.

Whilst it is important to know the calcium and phosphorus content of forage, the trace mineral content is less significant as the concentrate feed will meet the majority of the horse’s requirement. The exception to this, however is where a batch of forage is identified as having a severe excess of one particular element, e.g. Iron which can reduce the absorption of copper. Much emphasis is placed on finding an optimum concentrate feed and associated supplements, to enhance the diet of horses in training. The same emphasis should ideally be placed on a trainer’s choice of forage. Forage can so easily make or break the best thought out feeding plan.