EARN CPD POINTS WITH ETN

ETN’s series of CPD features helps SQPs (Suitably Qualified Persons) earn the CPD (continuing professional development) points they need. The features have been accredited by AMTRA, and highlight some of the most important subject areas for SQPs specialising in equine and companion animal medicine.

AMTRA is required by the Veterinary Medicines Regulations to ensure its SQPs undertake CPD. All SQPs must earn a certain number of CPD points in a given period of time in order to retain their qualification. SQPs who read the following feature and submit correct answers to the questions below will receive two CPD points.

May 2019

The health of the digestive system

By Katie Williams M.Sc (Dist) RNutr.

It is now widely accepted that the digestive system is not just a means of providing nutrients to the rest of the body, it is also an important part of the immune system and what goes on in the gut can have a significant impact on mood, behaviour and general well-being.

The gastrointestinal tract provides a barrier against harmful organisms and substances and research increasingly suggests that when this barrier breaks down, problems such as Equine Gastric Ulcer Syndrome (EGUS) and laminitis occur.

Clearly it is important to maintain the integrity of the barrier to keep both the gut and the animal healthy. We therefore need to understand more about what the barrier consists of and the factors that contribute to its failure.

Figure 1 highlights the three components of gut health proposed by Conway (1994). All three factors interact with one another and in the healthy animal this interaction facilitates the digestion and absorption of feed as well as an effective immune function. The animal should then thrive and be able to perform at its best. We will look at each component to understand how we can feed and manage horses with gut health in mind.

Gut Tissue

In simple terms the gut tissue has to be permeable to nutrients and impermeable to anything harmful to stop it reaching the body and causing disease. The intestinal epithelium (lining) consists of a single layer of cells which are joined tightly together.

When the junctions between these cells are compromised the gut becomes more permeable or leaky and the term “leaky gut syndrome” is increasingly being used to describe this phenomenon.

Some of the factors thought to compromise the integrity of the epithelium include stress, disruption of blood flow to the gut tissue such as during exercise and increased acidity levels in the gut which is related to diet.

Exercise has been shown to divert blood away from the gut and send it to more active tissues such as the lungs and muscles. Ponies undergoing maximal exertion on a treadmill were found to have significant reductions in blood supply to the pancreas, small intestine, and colon, among other organs (Manohar, 1986).

More recently, researchers have found that performing exercise more than 4 or 5 days per week is a risk factor for Equine Glandular Gastric Disease (EGGD) (ulcers in the glandular region of the stomach) in racing Thoroughbreds (Habershon-Butcher et al, 2012) and show jumpers (Pedersen, 2015).

This lends weight to the belief that a contributing factor to EGGD is the disruption of blood flow to the stomach resulting in a breakdown of the natural protective mechanisms present there. Providing at least 2 rest days a week has a protective effect against EGGD which may be partly because the blood supply isn’t being diverted away from the stomach as often.

In the glandular region of the stomach there are 3 regions:

• Fundic - produces acid

• Cardiac - has no parietal cells (those that produce acid) but produces mucus and acts as a sensor - once acid reaches this area of the stomach a signal is sent to indicate enough acid has been produced.

• Pyloric – mucus secretion and also secretes the hormone gastrin

Levels of acidity in the whole of the equine stomach range from pH 1.6 to 6.5 with the more acidic conditions in the glandular region. Feeds containing higher levels of starch increase acidity in the stomach and so are not desirable when trying to reduce the risk of gastric ulcers. A low starch content compared with other similar feeds is one of the criteria required by the BETA approval mark for feeds suitable for horses and ponies prone to EGUS.

Microbial Population

The population of microorganisms in the gut varies due to factors such as diet, age, stress and environment. Fibre digesting bacteria tend to thrive in a less acidic environment – the volatile fatty acids (VFAs) produced from fibre fermentation are relatively weaker acids than the lactic acid produced when starch is fermented by bacteria.

Several of the general rules of feeding relate to the impact that diet and feeding management can have on the microbial population. For example:

• Make changes gradually - the microbial population needs time to adjust to a new diet to be able to digest it efficiently

• Feed little and often – large meals of cereal based feeds can’t be digested and absorbed fully in the small intestine and so reach the hind gut where the majority of the microbial population reside. The starch is broken down quickly and creates a very acidic environment which the bacteria don’t like

A study by Respondek et al (2007), investigated the effect of feeding short-chain fructo-oligosaccharides (scFOS) also known as prebiotics to healthy horses. The stomach was the region of the digestive tract where the effect of the scFOS was greatest with a higher number of total bacteria present and a higher pH meaning the stomach was less acidic. By stimulating the bacteria that utilise the stronger lactic acid, the scFOS appeared to help regulate acidity.

Some feed materials may also help to regulate acidity as they contain minerals and other substances that buffer or neutralise acidity. Lybbert et al (2007) found that the inclusion of alfalfa compared to Bermuda Grass hay reduced the severity of ulcers in horses. It is believed that the relatively abundant levels of calcium and amino acids in alfalfa are what act as buffers in the digestive system.

Diet

The role of diet in promoting gut health is clearly an enormous topic but an area of recent interest is the importance of fibre and its impact on the mucus layer. It is important to stress that research to date is largely in other species. One such study by Schroeder et al (2017) explored the functional interactions between dietary fibre, the gut microbiota and the mucus barrier in the colon. The study was investigating human health using mice that had been inoculated with a human microbial population in their digestive systems.

The results showed that if insufficient fibre was supplied over the short and long term, the microbiota resorted to using the mucus lining the gut as a nutrient source, resulting in the reduction of the mucus barrier in the colon. The researchers suggested that the damage to the mucus layer potentially allows harmful bacteria greater access to the gut tissue and therefore more opportunity to cause harm or disease. In the horse, the reduction in the mucus layer brought about by a low fibre diet may increase the risk of leaky gut syndrome.

Clearly this study can only provide an indication as to the potential importance of fibre in the equine gut but as further research is carried out it may identify even more reasons to ensure horses are fed high fibre diets.

References:

Celi, P. Cowieson A.J., Fru-Nji F., Steinert, R.E., Kluenter, A-M. and Verlhac, V. (2017)
Gastrointestinal functionality in animal nutrition and health: New opportunities for sustainable animal production. Animal Feed Science and Technology 234 (2017) 88–100
Conway, P.L., 1994. Function and regulation of the gastrointestinal microbiota of the pig. In: Souffrant, W.B., Hagemeister, H. (Eds.), Proceedings of the VIth International Symposium on Digestive Physiology in Pigs. EAAP, Publication, Dummerstof, pp. 231–240.
Habershon-Butcher JL, Hallowell GD, Bowen IM, Sykes BW. Prevalence and risk factors for gastric glandular disease in Thoroughbred racehorses in the UK and Australia (Abstract). J Vet Int Med. 2012; 26:731
Lybbert, T, Gibbs, P., Cohen, N., Scott, B. and Sigler, D., (2007), Proceedings of Annual Convention of the AAEP, Orlando, Florida, 2007.
Manohar, M. (1986) Blood flow to the respiratory and limb muscles and to abdominal organs during maximal exertion in ponies. Journal of Physiology. 1986; 377:25–35.
Pedersen S, Windeyer C, Read E et al. Prevalence of and riskfactors for gastric ulceration in showjumping warm-bloods. J Vet Intern Med. 2015; 29:1239
Respondek, F.,Goachet, A-G., Rudeaux, F. and Julliand, V. (2007) Effects of short-chain fructo-oligosaccharides on the microbial and biochemical profile of different segments of the gastro-intestinal tract in horses. Pferdeheilkunde 23 (2007) 2. 146-150
Schroeder et al., (2017) Bifidobacteria or Fiber Protects against Diet-Induced Microbiota-Mediated Colonic Mucus Deterioration, Cell Host & Microbe https://doi.org/10.1016/j.chom.2017.11.004
Stieler Stewart, A, Pratt-Phillips, S. and Gonzalez, L.M. (2017) Alterations in Intestinal Permeability: The Role of the “Leaky Gut” in Health and Disease. Journal of Equine Veterinary Science 52 (2017) 10–22

A low starch content compared with other similar feeds is required by the BETA approval mark for feeds suitable for horses and ponies prone to EGUS.

Relatively abundant levels of calcium and amino acids in alfalfa are believed to act as buffers in the digestive system.

AMTRA CPD explained

• AMTRA (the Animal Medicines Training Regulatory Authority) is an independent body whose task it is to ensure that the marketing and distribution of animal medicines in the UK is undertaken in a responsible manner by AMTRA qualified persons.

• AMTRA maintains registers of qualified persons, including Suitably Qualified Persons (SQPs), authorises training centres for course provision, provides information and advice for registered persons, monitors and accredits continuing professional development (CPD) for SQPs and regulates professional conduct.

• SQPs are permitted under the Veterinary Medicines Regulations to prescribe and supply medicines classified as POM-VPS and NFA-VPS.

• For more about AMTRA and becoming an SQP www.amtra.org.uk

April 2019

Understanding electrolytes

by Dr David Marlin

Electrolyte use can be a confusing area for customers. There are many opinions and many myths. Electrolytes are required for almost all bodily functions including nerve function, digestion and muscle contraction. The major electrolytes are sodium, potassium, chloride, calcium and magnesium. Electrolytes always exist as mixtures of more than one chemical e.g. sodium chloride; more commonly known as table salt, which is a compound of sodium and chloride, denoted by the chemical formula NaCl. Another example is magnesium aspartate – an electrolyte combined with an amino acid. Electrolytes are necessary for urine production and so are lost on a daily basis in urine, as well as in faeces. If a horse is exercising and sweating then electrolytes are also lost in sweat. Around 9g in total of sodium, potassium, chloride, calcium and magnesium are lost in each litre of sweat. Sweat is made up of around 55% chloride, 32% sodium, 11% potassium and 1% calcium and a small amount of magnesium. Sweat also contains a protein called latherin which makes sweat foamy and helps it to spread out over the coat and evaporate more efficiently to help keep the horse cool. As horses get fitter their sweat becomes more watery and less foamy.

It is very common for horses not to be receiving enough electrolytes. Electrolyte deficiency and imbalance usually takes weeks or months to become a problem and can take weeks or months to put right. Signs of electrolyte deficiency or imbalance can include poor performance, slow recovery after exercise, muscle problems (such as tying-up), reduced sweating, increased risk of fracture and “thumps” (synchronous diaphragmatic flutter), which is most common in endurance horses but can occur in any horse. It is very unusual for horses to be fed too much electrolyte, provided that you stick to manufacturers’ recommendations. Signs that you are feeding too much electrolyte could include feed refusal, excessive drinking (more than 4 buckets per day), a very wet bed and/or loose droppings.

Hard feeds and forage do contain electrolytes but will usually not replace what a horse in work uses up each day, especially in warmer weather. Horse diets in general are usually high in potassium but deficient in sodium. Forages (grass, hay, haylage) are low in sodium. Sodium is the most important electrolyte when it comes to regulation of thirst. A number of studies have shown that horses do not regulate their salt (sodium chloride/NaCl) consumption to match their needs from free choice salt when provided in the form of blocks or licks. A 500kg horse would typically benefit from the addition of 1 x 25ml scoop of table salt to the diet per day. The best strategy for feeding electrolytes for horses in work is to feed the same amount every day and allow the horses kidney to work out what it needs and allow it to excrete what it doesn’t and not just on harder work days or when competing.

The stomach and small intestine are major sites of electrolyte uptake into the body. Not all of the major electrolytes are absorbed as efficiently. For example, most of the sodium and potassium taken in are absorbed but only around 50-60% of the potassium, calcium and magnesium taken in are absorbed. Horses can store electrolytes but if you feed excess then they will drink more and excrete the excess in the urine. Electrolytes can irritate the stomach and contribute to gastric ulcers and can cause pain if horses have gastric ulcers. Think of rubbing salt in an ulcer on your hand. Sugar is not needed for absorption of electrolytes but can help with palatability.

It is a myth that horses cannot store electrolytes, but you cannot and should not try to “load” horses by giving them a large amount of electrolytes on the day of a competition. This will not correct a long term deficiency and you risk putting the horse off its feed or upsetting the hindgut, and the horse will simply excrete the majority in faeces and urine. Blood electrolyte levels are a very poor indicator of electrolyte status except in the case of very sick or very deficient horses. The body attempts to maintain “normal” blood levels even if the levels in tissues and organs are low. For example, blood calcium level may be normal because the horse is breaking down bone to maintain the blood levels which in the long term can increase the risk of a fracture.

The only sure way to know exactly if you have your electrolytes right is to do a full diet analysis and then ask your vet to collect paired blood and urine samples. You can then tailor your electrolyte management for each individual horse. You will probably need to repeat this over 2-3 months. This is usually only required for high performance horses, horses that don’t respond normally to supplementation or horses with ongoing problems such as tying-up.

Excessive feeding of electrolytes can increase water intake and may also lead to gastric ulceration, worsening of ulcers if they are already present and hindgut disturbance (loose droppings to scouring) but in my experience this is very rare. Most horses are likely to be under supplemented. An excess could be supplementing more than 100g per day in cool months when the horse is in light work, or more than 200g per day in the summer when the horse is in hard work.

It is much better to feed a slight excess of electrolytes and allow the horse to regulate to what it needs by excreting what it doesn’t need. This of course requires sufficient water to be available. If you feed too little the horse can try to conserve electrolytes, but only for so long. Eventually an imbalance will occur or the “normal” levels will not be able to be maintained.

It is commonly advised not to give electrolytes to a horse that isn’t drinking. If a horse has worked hard and has lost a lot of electrolytes in sweat, then if they are not drinking this is not a good sign. If they continue not to drink this can increase the risk of impaction colic. Giving a concentrated electrolyte paste may stimulate a horse to drink and is safe provided they have access to water. It is often said that electrolytes draw water into the stomach and this is why they should not be given, but this is what actually activates the horses thirst mechanism.

Supplementing only around the time of competition or changing how you supplement around the time of competition would probably be considered undesirable for a two main reasons. Firstly, a negative effect on palatability. If your horse is not used to the taste of salt in his feed, then supplementing before competition could put your horse off eating. Secondly, you are highly unlikely to have much impact on whole body electrolyte status by starting feeding electrolytes or feeding extra electrolytes around the time of or during competition. There is also the risk that a sudden increase or change in electrolyte supplementation around the time of a competition could cause disturbance to the hindgut.

What a horse needs in terms of electrolytes will be determined by a combination of diet, work, breed, fitness, weather and also how well it absorbs the different electrolytes.

November 2018

Understanding forage

By Clare Barfoot RNutr, research and development manager at Spillers.

Forage should make up the majority of the horse’s diet. However, with the UK’s swelteringly hot, dry summer following hard on the heels of a cold, wet winter, some of your customers may be struggling to find a healthy source of forage over this coming winter.

But horse owners don’t need to panic if there is a winter hay shortage, because there are plenty of forage alternatives to choose from.

You can be a big help to your customers if you have the facts and figures about fibre and forage at your fingertips and it could help boost sales too.

Forage: the key facts

Fibre provided by forage is the mainstay for equine digestive health. It is made up of structural carbohydrate and it is this that horses need to keep their gut and the microbes that colonise it happy.

Every horse or pony should have a minimum fibre intake of 15g/kg bodyweight (dry matter) per day, which is approximately. 9kg of hay or 10.5kg of haylage for a 500kg horse. Ideally horses should be fed fibre ad lib, unless on a specific restricted diet.

Why horses need fibre

Horses are herbivores, meaning they have evolved to digest a vegetarian herbaceous diet. The horse has formed a very special symbiotic relationship with the microbes that live in its hindgut. The job of these microorganisms is to ferment and break down fibre to produce volatile fatty acids, which are used as a form of energy for the horse.

If a horse doesn’t receive enough fibre there are many negative consequences including an increased risk of gastric ulcers, colic and weight loss. Mental wellbeing can also be affected if horses are unable to forage and chew for around 16-18 hours a day as they have evolved to do.

Hay and haylage

Whether your customers choose hay or haylage, the golden rule is to go for the best quality they can. Poor quality forage may contribute to weight loss, respiratory problems and even colic.

The nutritional differences can vary just as much between hays as between haylage and hay. The main consideration is how much to feed; a few years ago most horse owners believed that haylage was nutritionally richer than hay and should be fed in lesser quantities. In fact haylage contains more water than hay (at least double the amount!) so it’s useful to remind your customers that they actually need to feed more haylage (approximately 20-50% more by weight) to provide the same level of fibre and nutrition.

The main advantage of haylage is that it is damp. This means any mould spores that are naturally present will swell up and be less likely to travel deep down into the sensitive areas of the lungs where they could contribute to conditions such as recurrent airway obstruction (RAO). Haylage is, however, best avoided for horses prone to laminitis or tying up.

Advising your customers on how to choose hay or haylage

For hay…..
• It should smell sweet and pleasant; any musty or mouldy smells should be treated with suspicion.
• The colour can vary from light yellowy green through to bright green. It is often perceived that the greener the hay the higher in protein it is but you can’t really tell without analysis.
• It shouldn’t be damp to the touch; if it is it may not have been dried properly and may be at more risk at going mouldy.
• Look for any visible signs of mould.

For haylage…
• Haylage should be well wrapped with at least six layers of plastic. Don’t buy it if there are holes in the plastic film as air will be allowed to enter and start the growth of yeasts and moulds.
• Again haylage should smell sweet and often slightly fermented but not too acidic like silage.
• Make sure there is no obvious soil contamination, as this can increase the risk of botulism.

Looking out for seniors

Seniors often need some extra special care and should all be treated as individuals. It’s helpful for your customers if you can signpost your senior-suitable feeds, especially those that have been veterinary approved, to give added reassurance.

A mash may be more appropriate for those with dental issues, for fussy types a mix may be more suitable or for good doers a balancer and a short chopped low calorie fibre may be the best option. The overriding priority should be to tailor the diet to individual needs.

Alternative forage options

As yet, the extent of any potential shortage of winter forage is unclear, although it’s likely that quantity and quality may be reduced and prices may go up accordingly. But your customers don’t need to worry because you can supply them with numerous hay and haylage alternatives that can replace or extend their winter forage supply.

Straw: Good quality straw is particularly useful for good doers and overweight horses to decrease the energy density of hay. The type of straw is less important than the hygienic quality, although oat and barley straw are used more commonly than wheat. Straw shouldn’t be used as the sole forage source though as the protein content is very low and the fibre can be particularly indigestible, which can contribute to impaction colic in susceptible horses. Up to 30% replacement is acceptable.

Chopped dried grass: Dried grass differs from hay because it is harvested earlier and is dried artificially rather than in the field. It is much greener in colour than hay and is often higher in protein and energy. It’s ideal for poor doers and veterans but shouldn’t be used to completely replace forage and should be avoided for laminitics and good doers.

Grass nuts: Harvested and dried in a similar way to chopped dried grass, nuts are pelleted rather than chopped. The protein content is higher than hay and the fibre content is lower so they provide more energy per kilo. They not suitable as a complete hay replacement but can be useful for poor doers and veterans. The high water soluble carbohydrate (WSC) levels make them largely unsuitable for those prone to laminitis.

Sugar beet: Soaked sugar beet is a palatable way to add fibre into your horse’s diet. It can’t be used to completely replace hay because it’s 80% water once soaked and doesn’t require much chewing – which is physically and psychologically important for horses. But, there is some evidence that feeding sugar beet can increase the digestibility of hay.

Short chopped fibres: These can be a useful option. Some contain vitamins and minerals in addition to chopped straw, grass and alfalfa. Likely to be particularly useful this winter are products that can completely replace hay due to their similar levels of protein, fibre and energy. Often these products are also suitable for laminitics and good doers.

Soakable fibre products: Often these can partially replace hay due to their high fibre and low sugar and starch content. Advise your customers to choose products that have protein levels of 8-10%, which is similar to hay.

High fibre cubes: These are a versatile and palatable way of providing additional fibre to the daily ration as a complete compound feed, as a partial forage replacer or as healthy fibrous treats in a snack ball.

Forage alone is not enough

Research has shown that horses on a hay-only diet may not digest some nutrients as effectively as those fed diets that include fortified feeds and could benefit from dietary supplementation.

A pertinent study published last year by Waltham, which provides the science underpinning the Spillers brand, in collaboration with Michigan State University, discovered that feeding a hay-only diet resulted in reduced digestibility of many micro and macro minerals (such as calcium, magnesium, copper and zinc).

An ideal way to balance a forage-based diet, especially for good doers that don’t require extra calories, is to add a balancer to the diet. This will provide the horse with all the additional nutrients he needs to stay healthy.

July 2018

Feeding veteran horses

By Anna Welch BVSc, BSc, MRCVS. Veterinary Nutrition Director, TopSpec

There are many factors to consider when offering advice on feeding an older horse. Dietary requirements will vary e.g. according to the horse’s activity level, environmental conditions and any health concerns, so it is always helpful to obtain thorough information from the owner about their horse and his regime.

When is a horse a veteran?

A customer is likely to ask you the age at which their horse is classed as a ‘veteran’ and therefore, when you might recommend one of the senior or veteran products available.

The answer to this question will usually depend on individual circumstances. Whilst it may be reasonable to consider a horse as a veteran from eighteen years of age, it is often more appropriate to act upon the signs associated with aging, or whichever comes first.

Age-related health issues to consider

There are a number of factors that can affect the health of older horses and impact on feed intake, digestion, condition and ability to exercise. The following problems should be considered when reviewing the diet of a veteran horse:

(1) Reduced dental function:

From a feeding point of view this is the most significant and inevitable problem to affect older horses. Over time the grinding surface of the teeth will wear down and horses may suffer from fractured or missing teeth, diastema (gaps between the teeth) and periodontal disease. A six-monthly visit from a qualified Equine Dental Technician or vet is essential to correct uneven wear, misalignment and food packing between teeth. However, there is only so much that can be done to delay the effects of wear before hay replacers will become necessary.

(2) Musculoskeletal problems:

Mobility issues are frequently reported in veteran horses, usually from a culmination of wear and tear over the years, which can result in problems such as osteoarthritis. Reduced activity is often seen as a result and can lead to muscle wastage, poor circulation, weakening of bone and stiffness. Regular, gentle exercise and plenty of turnout can help to reduce stiffness. Dietary supplementation with the scientifically recommended level of glucosamine (10g per 500kg horse per day), as well as MSM, can also be beneficial.

(3) Hormonal disease:

Pituitary Pars Intermedia Dysfunction (Cushing’s disease) is the most common hormonal disorder of veteran horses and ponies. Whilst PPID can affect younger horses, it is progressive and more frequently diagnosed in older horses. Insulin dysregulation is often associated with PPID and increases the risk of laminitis. Therefore, total diets should be low (<10 - 12%) in Non-Structural Carbohydrates (NSC) i.e. sugar and starch. Muscle breakdown (catabolism) can also develop as PPID progresses, so high quality protein is essential.

(4) Respiratory disease:

From a lifetime of exposure to dust and spores, veteran horses can become prone to developing respiratory issues such as Recurrent Airway Obstruction (RAO). The key to management is reducing exposure to dust. This means that turnout should be maintained as much as possible and steamed or soaked hay, or haylage, used when necessary.

(5) Immune system compromise:

As horses get older the strength of their immune system tends to decline. PPID can also affect immune function. To provide nutritional support for the immune system, diets should contain optimum levels of certain micronutrients particularly antioxidants such as vitamin A, E and selenium. Mannan Oligosaccharides (MOS) have also been found to be beneficial, whilst vitamin C has a role to play in lung health.

Diet recommendations:

Forage

Forage is the foundation of any horse’s diet and veteran horses are no exception.

Fibre passes, undigested by the horse, onto the large intestine where it is fermented by the cellulolytic (fibre-digesting) bacteria. This microbial fermentation produces volatile fatty acids, which supply energy (calories) to the horse. This process also produces heat, which is an important consideration during winter, as older horses will find it harder to maintain their body temperature.

A constant supply of fibre is essential to maintain a healthy digestive system, with optimal gut motility and balanced hindgut microflora. As a horse’s dental function declines, it becomes increasingly important to provide fibre sources that are easily chewed.

During the spring and summer when grass is plentiful, a veteran horse living out can often manage well. Although, when incisor function is compromised grass will need to be sufficiently long for him to harvest it.

Winter is a time of year that can highlight compromised dental function. Loose droppings, fluid passed after formed droppings or small, firm droppings can reflect insufficient fibre supply to the normal bacteria in the hindgut. Long, unchewed fibres are often seen in the droppings, even before quidding (dropping semi-chewed food) is observed.

Haylage can be easier for a veteran to manage, because of its generally lower fibre content, particularly when compared to a mature, coarse hay. Straw-based chops should be avoided but soft, short chopped grass can be used as a hay/haylage replacer for a period of time.

However, fibre in a pre-ground form rapidly becomes essential. A mash that is high in fibre, soaked fibre cubes and alfalfa/grass cubes, plus, to a lesser extent, unmolassed sugar beet pulp are all suitable alternatives to long fibre. Although, providing a horse doesn’t suffer from choke or impaction colic, it can be a good idea to continue to allow access to some hay or haylage as chewing on longer fibres can be mentally satisfying.

Hard feeds

• For the healthy veteran in good condition:

Horses that are able to maintain their level of work, without any significant health concerns, may be able to continue on their previous diet providing it is fully-balanced. The addition of a supplement including glucosamine and MSM may be sensible at this stage. Alternatively, there are top specification feed balancers available that include the recommended level of glucosamine and provide a very economical solution.

• For the overweight veteran:

It is inevitable that workload will reduce for veteran horses, eventually leading to retirement. Energy expenditure will decrease, which can lead to unwanted weight gain for a healthy older horse.

Despite the fact than an elderly horse may be doing little or no work, it is important that he still receives essential vitamins, minerals and trace elements to balance his diet and support his general health. An ideal way to meet these requirements is by using a top specification ‘lite’ feed balancer or multi-supplement.

The best contain both general purpose and specialised supplements, which can include those for hooves, bone, muscle, blood, joints, the immune-system and the digestive tract. The use of one fully-balanced product, rather than multiple separate supplements, avoids unbalanced or over-supplementation.

• For the underweight veteran:

As health issues start to develop, many veteran horses are likely to experience weight loss.

Hard feeds should be nutrient-dense and not exceed the horse’s maximum meal size e.g. 2kg (dry weight) for a horse with an ideal bodyweight of 500kg. A top specification, conditioning feed balancer will supply amino acids, vitamins, minerals and yeast products, which improve the utilisation of the rest of the diet. This reduces the need for additional hard feed, helping to keep feed sizes small.

Most top specification, conditioning feed balancers contain very high quality protein sources, which are rich in essential amino acids. Protein promotes muscle development and topline, which frequently wastes away in older horses.

To provide further calories, highly digestible fibre sources, or ‘super-fibres’ should be used. Ingredients like unmolassed sugar beet pulp and oatfeed are examples of these. To increase the calories further, oil can also be added.

In view of the fact that older horses are gradually able to eat less fibre, and therefore may suffer from disturbances in the hindgut microbial balance, cereal-based products that are high in sugar and starch should be avoided. Digestible Energy (DE) values, similar to those of conditioning mixes, can be achieved without the use of cereals.

Adding a low starch, conditioning blend to a top specification feed balancer, will provide a very successful solution for a veteran horse.

Summary

• The condition of a veteran horse should be monitored carefully.

• Hay replacers, which provide pre-ground fibre, will become necessary as dental function declines.

• Hard feeds should be kept low in sugar and starch and cereal-grain-free but provide high quality protein.

• A fully-balanced diet is essential, with supplementation for the immune system, respiratory tract, joints and digestive system.

TopSpec can be contacted, free of charge, on their BETA multiple award-winning-helpline tel 01845 565030

May 2018

Controlling weeds in horse paddocks

While horses relish grazing pastures filled with a mixture of plants, weeds such as ragwort, docks, nettles, buttercups and thistles are not to be encouraged, says Andy Bailey.

Weeds need managing for many reasons. Some, like ragwort, are very poisonous to horses; other such as nettles will take over a paddock so there is no grass left to eat.

The Weeds Act 1959 requires that if an order is served on them, landowners have to control common ragwort, broad-leaved and curled docks and spear and creeping thistles.

The Ragwort Control Act 2003 strengthens this by placing onus on the occupier to take action where ragwort poisoning poses a serious risk to grazing animals.

Ragwort

Common ragwort should not be tolerated in horse pastures. The plant contains an alkaloid – a cumulative poison which, when grazed over a long period of time, affects an animal’s liver. As little as 20kg taken over the lifetime of a 500kg horse can be fatal.

Horses will not usually eat ragwort while it is growing – but when it has been cut and has wilted it becomes much more attractive and palatable. Grass fields with growing ragwort should never be cut for hay.

Cutting ragwort just encourages new and vigorous regrowth and the dying plants pose a great danger to horses.

Digging out whole plants by hand - wearing gloves, when the soil is moist in spring, can get rid of an infestation. All pulled plants must be removed from the field.

Where there is too much ragwort to pull by hand, high levels of control can be gained by spraying with a modern, translocated herbicide. This must be done when the plants are still at their vegetative stage and actively growing. Do not wait until the plants are flowering, as this is too late to spray to achieve good control.

It is essential to ensure all the remains of all ragwort plants have completely decayed before reintroducing horses.

Docks

Docks like to grow in nutrient-rich soils and are often found in latrines – the areas where horses regularly urinate and defecate. They are deep rooted and spread easily as every mature plant can release up to 60,000 viable seeds each year.

Once established, docks can withstand a high amount of trampling, which is another reason why they are so commonly seen in horse fields. They are not poisonous to horses but are less digestible and palatable than grasses.

Never top docks as a means of control, as this does not affect the large taproot and the plant will regrow energetically after cutting.

The best way to get rid of docks is by spraying with a selective herbicide that will kill perennial broad-leaved weeds without harming any grass species present. These should be applied when the plants are dinner-plate sized and actively growing but not flowering.

Nettles

Nettles also like to grow in horse latrines, as they are phosphorous-loving. They can form large ‘nettle-beds’, which block out light to the ground and stop any other beneficial plants from growing.

Nettles can also be sprayed with a herbicide though a knapsack sprayer or weed wiper, as they often grow above the level of the surrounding vegetation, or boom sprayer off an All-Terrain Vehicle (ATV) or tractor.

It is important to reseed any bare areas of ground left after the weeds have died and been removed, so that new weed seeds do not come in and germinate in their place.

Buttercups

Buttercups are poisonous but taste very bitter, so horses will not eat them unless there is nothing else growing. Unlike ragwort, they lose their toxicity as they wilt and dry, so they are not a problem in fields cut for hay.

Having buttercups growing is often a sign of wet soils and improving drainage can reduce their growth. Small patches can be dug out by hand. Larger areas can be sprayed using a herbicide early in the season. Once the buttercups have flowered it is too late to spray for optimum control.

Thistles

There are many different species of thistle, but the most common are creeping and spear thistles. Having thistles growing in a field is unsightly and when they are releasing seed, this can spread the problem to neighbouring fields.

They also reduce the amount of feed growing in the field because where thistles grow, grass cannot grow.

Topping thistles has minimal effect and they tend to regrow. Spot-treating small areas with a herbicide through a knapsack sprayer or spraying larger areas using a tractor mounted/self-propelled sprayer, are the best options. These must be applied early in the season, when the plants are in their vegetative stage with no flowering stems present.

Herbicides

There is a range of selective herbicides that will kill perennial broadleaved plants in a field, but not the grass species. If the sward includes desirable broad-leaved species, use an alternative method of control to spraying.

Modern, translocated products provide the longest lasting control, as they enter the plant and circulate around it – from the top of the leaves to the bottom of the roots, which kills the plant from within.

Some are formulated to tackle particular weeds like docks, while other broad-spectrum products work well on several different weeds.

Before a field is sprayed, the animals must be removed and kept out for however long the stock withdrawal period says on the product label.

This grazing interval, which can be as short as seven days for some products, is a legal requirement and anyone putting horses back into the field before the stated time is breaking the law.

To allow the products to work to their best potential, users should respect the advice given on the label, which may allow for a longer period without animals in the field so the herbicide can do a good job. These statements are advisory, but the stock exclusion is mandatory.

Where treated fields contained ragwort, make sure every last bit of wilted or dying material has completely decayed before the animals return.

The law now states that anyone who applies professional use pesticides must possess a valid pesticide certificate in order to comply with regulations.

Many paddock owners contract out their spraying to local certified farmers or contractors. For those who wish to carry on spraying themselves, for instance with a knapsack, they also need to complete a City and Guilds/National Proficiency Test Council (NPTC) course, such as PA1 (theory module) and PA6 (handheld lance or knapsack). The City and Guilds Level 2 Award for the Safe Use of Pesticides Replacing Grandfather Rights is another option for those born before 1964. It is a quicker and easier path, but is only available until the end of 2018.

There are more details at www.nptc.org.uk.

Andy Bailey is the principal biologist for Dow AgroSciences.

April 2018

Supplementing the performance equine diet

By Kate Hore RNutr(Animal), senior nutritionist at NAF.

Competing to a high standard takes a lot out of equine athletes, so we must provide them with the nutritional tools for recovery.

As the competition season really gets underway, it’s important we can advise our customers on how to get the best from their horses, and ensure they recover quickly and efficiently ready for the next competition.

Supplementing for performance

The performance diet should stick as closely to the natural equine diet as possible. We increasingly understand the potentially detrimental effects of small, starchy bucket feeds, particularly with respect to issues such as Equine Gastric Ulcer Syndrome and excitability, both of which are very relevant to the performance horse.

Therefore we should be advising our customers to keep their horses on a high fibre, low concentrate diet. The challenges of the high forage diet for performance are firstly to ensure that all micronutrient requirements are met, and secondly that sufficient energy for performance is provided.

Grazing and forage alone may be micronutrient deficient, particularly when that forage is preserved, for example in hay or haylage. In the UK common grazing deficiencies include copper, zinc and selenium. Alternatively it may be that natural levels are lost during forage preservation. Vitamin E is a classic example of an essential nutrient for performance present in fresh pasture, but lost by processing.

We should also consider annual fluctuations, ie. nutrients such as magnesium may be low in the spring, while vitamin levels drop later in the season.

When we also consider the increased requirement for performance, we can see that supplementing is advised in order to ensure that all the elements required for fine tuning the equine diet are present. For example, if we consider vitamin E, the requirement doubles from 500 I.U. [international units] per day at rest, to 1000 I.U. per day for elite performance (500kg horse).

Supplementary multi-vitamins are available as powders, liquids or concentrated pellets, each of which have their benefits for horse owners. For busy competition yards, we often find a liquid product with a measured pump dispenser, is a quick and easy way to make sure everyone gets their quota accurately when feeding a yard of horses.

The forage diet alone may fail to provide sufficient energy for the demands of performance. However, we don’t need to go back to feeding starchy cereals.

Oil provides a concentrated source of energy which is readily metabolised by the horse. The energy from oil is free of starch, slow release, ideal for maintaining stamina right through a competition, and less likely to cause those explosive releases of energy sometimes associated with other sources.

The energy from oil is more concentrated than that from cereals, which is very useful for elite horses where poor appetite can be an issue. The high oil diet also provides significantly lower levels of waste heat, which is particularly important if competing in warm or humid conditions to avoid heat stress. For example, if you needed to supply an additional 10MJ of useable energy to your horse, the following shows how that would be metabolised dependent on source.

It’s recommended that plant based oils can be fed for performance up to a level of 1ml/kg BW [bodyweight]. It’s important to introduce the high oil diet gradually, building up over several weeks, to allow the horse’s metabolism to gradually adjust.

If feeding a high oil diet, the requirement for vitamin E, as an antioxidant, also increases, and it’s recommended to supplement at 1-1.5 I.U. of vitamin E per 1ml of additional oil fed.

Supplementing for recovery

Competing to a high standard takes a lot out of our equine athletes, and if we want to keep them sound and strong, and get them back to work quickly, it’s essential that we provide our horses with the nutritional tools for recovery.

Perhaps the most well-known of nutrients lost during exercise is the electrolyte group. These essential body ions are involved in many metabolic pathways including muscle and nerve function, maintaining the acid-base balance of all cell functions and are vital for healthy hydration in hard working horses.

The principle electrolytes for horses are sodium, potassium and chloride and, to a lesser extent, magnesium and calcium. The most important is sodium, as this is commonly deficient in the forage based diet, so it’s important that we allow free access to a salt lick (sodium chloride) on a daily basis.

Large amounts of electrolytes are lost through sweating. For example, a horse working hard may lose up to 25% of his total body chloride alone in just a couple of hours, so it’s essential that electrolytes are replaced in order to avoid both short and long term problems. Upgrading that salt lick to a broad spectrum electrolyte supplement for hard work and competition will ensure that these essential nutrients have been replaced.

Of course sweat doesn’t just lose electrolytes. We must ensure that the water which has also been lost is replenished concurrently, or you risk further dehydrating the horse rather than rehydrating. The best way to ensure adequate water is taken, is to either feed the electrolytes in a nice wet, sloppy feed, or train the horse to take them dissolved in water. For those travelling regularly, training the horse to take their electrolytes in water can help overcome any differences in water taste around the country – something horses can be surprisingly sensitive to.

One of the other effects of hard work on the system is that of oxidative stress. Oxidative stress occurs when the antioxidant defences within the system are overcome by a build-up of Reactive Oxygen Species (ROS) or free radicals.

There may be a number of reasons for the escalation but, specific to performance horses, ROS will build as a by-product of oxygen metabolism during exercise. The harder the athlete works, the more oxidative stress will build. In human athletes, the condition of ‘over-training’ is increasingly associated with oxidative stress. Over-training is also recognised by trainers, as a horse going ‘sour’ or ‘off-form’.

When considering antioxidants it’s advised to look beyond a straight vitamin E product, or similar. It’s understood that feeding a combination of antioxidants will be more effective than any one on its own as they often have slightly differing, and complementary, roles during the ROS scavenging process.

Look for natural antioxidants such as turmeric, rosehip and omicha berries, as they retain their complex of phytochemicals rather than being over-purified. For owners and managers of hard working horses, it’s recommended to feed a short course of concentrated antioxidants following intense exercise to facilitate a return to full training as soon as possible.

In conclusion, by ensuring that we’re advising our customers both how to prepare equine athletes for the season ahead, and how to counteract the stresses of competition, we can keep our horses sound and strong throughout the coming season.

About the author: Kate Hore is a Registered Animal Nutritionist and has been with NAF for more than 20 years, where she specialises in fine tuning equine diets through supplementary nutrition.

Large amounts of electrolytes are lost through sweating.

November 2017

Nutritional management of forage intake to maintain health and performance in horses and ponies

By Lizzie Drury MSc Registered Nutritionist of Saracen Horse Feeds

It is well established that forage remains one of the most important components in the diets of all horses and ponies irrespective of their life stage or level of exercise.

Forage not only contributes to the overall supply of energy and nutrient content of a horse’s ration but a supply of forage is essential to the healthy function of the equine digestive tract, through the physical movement of food through the gut, retention of fluid within the digestive tract and the protective effect of the microbial balance within the hindgut.

Ad-lib basis

Forage should ideally be fed on an ad-lib basis, which means that it should be available at all times. Where this is not possible, long forage should be fed at least NO less than 1.0 % of bodyweight e.g. 4.5kg of long forage daily for a 450kg pony. For haylage, where the dry matter may range from 60-75%, a higher intake of 1.5% ‘as fed’ is recommended as being the absolute minimum.

Many causes of weight loss and behavioural issues can be related to below optimum forage intake. It is a good idea to find out how much forage an individual horse is eating to ensure optimum intakes.

For a few days, weigh the daily forage allocation and any that is left over. If there is none left over, then you may not be feeding enough, especially if the horse is losing weight. If there is still plenty left over and your horse is losing weight, then you need to find alternative methods of increasing fibre intake. Do not simply make up the deficit by feeding more concentrate feed!

Energy demands

Recent work has sought to dispel the view that forage is just gut fill and something to keep the horse occupied. Research has shown that good quality forage is able to maintain the bodyweight and meet the energy demands of Standardbred horses in heavy training with the energy demands of two times maintenance, over a 2.5-year period (Ringmark et al. 2012).

The protein content of many UK forages is low in low biological value and much of the protein present is locked up within lignified cell walls, rendering it unavailable to small intestine digestion and thus unavailable for anabolic purposes.

However, gut partitioning studies have revealed that some forages e.g. red clover silage and alfalfa are 50% digested within the small intestine making them good sources of protein (Moore-Colyer et al. 2005). When preparing rations for horses it is recommended that the amino acid profile is established rather than protein content per se.

The physiological age of a forage will also influence its mineral profiles, so it is best to analyse forage for mineral content to determine if and what supplementation is required.

Respiratory challenges

One of the major challenges when feeding stabled horses forage is the level of airborne respirable dust (ARD) that it produces. Both hay and haylage can present respiratory challenges.

The traditional method for reducing ARD is soaking for between ten and 30 minutes but this leaches valuable nutrients and increases the bacterial concentration by two to five times that are found in dry hay. These figures further increase over time.

A better way to reduce ARD and improve the hygienic quality of the forage is to high temperature steam. Research studies have shown that specifically designed steamers consistently improve the hygienic quality of a forage while maintaining the nutrient value (Moore-Colyer and Fillery 2012).

Soaking hay

The practice of soaking hay to leach out water soluble carbohydrates (WSC) and produce a forage of less than 100g WSC/Kg DM [dry matter], as recommended by Harris and Geor 2010, for obese and laminitic horses is widespread.

Soaking hay, aside from the increased bacterial burden, also gives very variable results. Thus it is recommended that testing of the forage is done post soaking, which presents practical issues for the average horse owner.

A recent study by Moore-Colyer et al. 2014 has shown that maximum WSC loss can be achieved by soaking for nine hours, then steaming the post soaked hay in a high temperature steamer.

Fibre products

The traditional fibre sources - grass, hay and haylage - have been joined in recent years by alternative products that offer fibre in a chopped, cubed or shredded form.

These alternative fibre sources are considered ‘super fibres’ because they have energy levels much higher than typical forages. The energy levels in super fibres are slightly less than those found in cereals, such as oats and barley, but they are safer to feed to horses than lots of cereals because their fibrous nature reduces the likelihood of starch overload.

Two popular super fibre sources include sugar beet and soya hulls. These feeds are more digestible than traditional fibre sources. For instance, hay is 40 to 60% digestible, depending on its quality, and beet pulp and soya hulls are 80% and 75% digestible respectively.

Super fibres

Some performance horses also benefit from super fibres, especially those asked to perform at moderate speeds for long distances such as endurance horses.

In addition to being a steady energy source for horses, super fibres maintain intestinal health. Consumption of fibre can increase water intake, creating a holding tank of water and electrolytes in the hindgut (Meyer and Coenen 1989). This reservoir may prevent dehydration and electrolyte depletion during an exercise bout.

Forage and super fibres significantly help with the nutritional management of gastric ulcers.

Ulcers and colic

Allowing horses free access to pasture and feeding alfalfa or other high calcium or high protein forages may help to reduce the risk of gastric ulceration. When adding alfalfa chaff to the ration to increase its buffering potential prior to exercise, 100 to 200 grams per 100kg bodyweight is suitable. This also helps to increase saliva production and does not add to significant ‘gut fill’.

Optimum levels of forage and fibre in the ration help to reduce the incidence of colic by maintaining optimum digestive tract contractions and general digestive health.

Increasing the proportion of long stem forage and super fibres within a ration helps to reduce the reliance on cereals and starch and can significantly reduce the incidence of colic.

Supplementing the ration with live yeasts such as Saccharomyces-containing probiotics and ScFOS prebiotics helps to optimize forage digestion and utilization by the microorganisms in the hindgut.

Evidence to date shows that high forage diets support a more stable hindgut microbiome and thus promote digestive health in horses.

“Long forage should be fed at least no less than 1% of bodyweight.”

September 2017

Understanding carbohydrates

By Anna Welch BVSc, BSc, MRCVS. Veterinary Nutrition Director, TopSpec

Carbohydrates play an essential role in a horse’s diet. When providing horse owners with nutritional advice, it’s essential to have an understanding of the different types of carbohydrate and how they are utilised. Getting the balance right will promote good health and performance, as well as relaxed behaviour.

What are carbohydrates?

Carbohydrates are the main source of energy for a horse. Glucose is the simplest form of carbohydrate and is a building block for many others.

Glucose is a monosaccharide which consists of just one sugar unit (fig. 1). Two units linked together are called a disaccharide. Sucrose (glucose + fructose) is an example of a disaccharide and is the most common sugar found in plants. Another disaccharide is lactose (glucose + galactose) which is important for nursing foals but cannot be digested in mature horses.

Oligosaccharides are made up of short chains of monosaccharide units. Mannan Oligosaccharides (MOS) are used in the diet of horses as an immune system stimulant and a prebiotic, promoting the normal cellulolytic (fibre-digesting) bacteria in the hindgut.

Polysaccharides are long chains of sugar units which can be found in the cell wall of plants as fibre (e.g. hemi-cellulose and cellulose), or as a form of stored energy called starch. The horse itself can also store energy as a polysaccharide known as glycogen.

Carbohydrates can be divided into two groups, simple and complex. These two groups are distinguished by a simple difference in structure which dictates whether or not they can be broken down by enzymes in the horse’s small intestine.

Simple carbohydrates

Simple carbohydrates, or Non-Structural Carbohydrates (NSC), include sugar and starch.

The monosaccharide units in NSCs are bound by ß-linkages (fig. 2a). These can be broken down by enzymes, such as amylase, in the small intestine of the horse to produce glucose. However amylase is only produced in small quantities by the horse and therefore can only hydrolyse [break down by chemical reaction with water] a limited amount of starch at a time.

Glucose is then absorbed into the bloodstream and transported to various tissues in the body, where it can either be used to provide energy immediately, or stored as glycogen or fat. Glycogen is stored in the muscles or liver, where it can be utilised as fuel at a later time as required.

If large quantities of starch are fed, excess undigested starch passes into the hindgut where it is digested by acid producing bacteria, including amylolytic [starch-digesting] bacteria. Consequently, numbers of amylolytic bacteria increase and the hindgut becomes more acidic, which can result in a number of problems for the horse.

Complex carbohydrates

Complex carbohydrates, or structural carbohydrates, occur in the cell wall portion of the plant and are referred to as fibre. In contrast to simple carbohydrates, the sugar units are bound by ß-linkages (fig. 2b) which cannot be broken down by the enzymes in the horse’s small intestine.

Therefore, fibre passes to the large intestine where it is fermented by the cellulolytic (fibre-digesting) bacteria which can break the bond. This microbial fermentation produces volatile fatty acids, mainly acetate, propionate and butyrate, which can be used as energy sources.

Not all fibres passing into the hindgut are fermented equally (fig. 3). Of the fibre reaching the hindgut, pectin is believed to have the highest digestibility, followed by hemi-cellulose and then cellulose.

Lignin is not at all digestible and, although technically not a carbohydrate, it is closely related and an important promoter of gut motility. Lignin rich forage, such as straw, can be useful in limited quantities to prolong fibre consumption in good-doers on restricted forage intake.

Misconceptions associated with the use of carbohydrates

Low NSC diets are recommended for horses in many situations, such as those prone to gastric ulcers, diarrhoea, colic, laminitis, Insulin Dysregulation (ID), PPID (Cushing’s), tying-up, fizzy behaviour, Developmental Orthopaedic Disease (DOD) and stereotypical behaviour. However, it is a misconception by some that this means their diet should be ‘low-carbohydrate.’ Fibre is a carbohydrate and should form the basis of all horses’ diets, especially those with any of the issues above.

Sugar and starch is present, although the levels vary, in grass and hay/haylage, as well as in the raw materials used in hard feeds. Glucose is the primary energy source used by tissues in the body, especially within the central nervous system, including the brain. Blood glucose levels of the horse are maintained within tight parameters.

Therefore, NSCs should not, and cannot, be eliminated from the diet completely. If the diet provides insufficient amounts, other nutrients may be converted to glucose inefficiently to meet essential demand.

What does this mean for your customers’ horses?

A constant supply of fibre (complex carbohydrate) is essential to maintain a healthy digestive system, with optimal gut motility and balanced hindgut microflora. Most horses should be offered forage ad-lib and it is beneficial for as much of their calorie needs as possible to be met by their forage.

Grass early in its growth cycle (i.e. spring), tends to be lower in fibre (structural carbohydrates) and higher in sugar/starch (NSCs). Haylage cut at this time will also reflect these nutritional values. This type of forage is more appropriate for competition horses, poor-doers, and pregnant or lactating mares.

Conversely, as grass matures through the growing season, fibre (including cellulose and lignin) content rises and NSCs reduce. This makes the grass, and hay cut at this time, better suited to those needing a high fibre and low sugar and starch diet, such as over-excitable horses, good-doers or those with PPID (Cushing’s) or laminitis.

For a horse with low-energy requirements, ad-lib high-fibre forage, balanced using a top specification low-calorie feed balancer or multi-supplement, may be all that they require providing a salt lick is available 24/7.

A horse with higher calorie requirements may not be able to meet their needs with good-quality forage alone. A top specification conditioning feed balancer will enable the horse to utilise maximum nutrients from his forage whilst the addition of an appropriate blend, straights or compound feed can provide more concentrated energy sources.

Feeding a diet that is low in sugar and starch is beneficial to most horses. Therefore, before reaching for cereal-grains or cereal containing compounds, products containing highly digestible fibre sources (‘super-fibres’) should be used to supply additional calories. Examples of ‘super-fibres’ include sugar beet pulp and soya hulls. The addition of oil can also be useful to increase the Digestible Energy (DE) of the feed, without the need for high starch ingredients.

When higher starch diets are necessary, it is important to feed cereal-grains which are digested well in the horse’s small intestine. This means that provided excessive quantities are not fed, overflow of starch into the hindgut is less likely.

Pre-caecal digestibility as it is termed, is not only influenced by the cereal grain used but also whether they are fed raw, or have been processed or cooked.

Raw oats have the highest pre-caecal digestion rate (95%); all other cereal grains such as wheat, barley or maize need cooking before they are fed to a horse.

Summary

• Carbohydrates are the main source of energy for a horse.
• Complex, or structural, carbohydrates (fibre) should form the bulk of a horse’s diet whenever possible.
• The digestion of simple, or non-structural, carbohydrates (sugar and starch) in the horse’s small intestine is limited. Therefore intake should be controlled.
• The appropriate level of sugar and starch will vary according to individual requirements.

By Anna Welch BVSc, BSc, MRCVS. Veterinary Nutrition Director, TopSpec

July 2017

Feeding the senior horse or pony

By Clare Barfoot RNutr

The senior horse population across the developed world is increasing. This is primarily because of improved healthcare and nutrition but also because the reason we keep horses has changed, with the majority of horses and ponies now being pets rather than working animals.

This means that owners are much more committed to providing the best care they can in order to keep their older horses as fit and active as possible.

Age is not just a number

Age can be measured in three ways: Chronological age which is simply the horse’s age in years can give you some information but it can be misleading as some horses, just like people, age more or less successfully.

Physiological age uses markers of ageing and perhaps is the most accurate way to measure ageing, but this whole area is still being researched.

Another way to look at age is demographically; the age at which there is 25% survivorship within the overall population. For horses in the UK in 1999, this was 15 years old. However the cut-offs vary per country with a survey in Australia in 2010 finding 38% of the population was over 15 years old.

However you look at age, one thing is for sure, it’s highly individual with most owners using a combination of chronological age and physiological age to ‘judge’ if their individual horse is old and needs a change in feed and/or management.

The science of ageing – what we know about the horse

Digestion and gut function

Other species including rats and humans show gut and gut based immunity problems as a consequence of ageing. Although little work has been carried in horses, and there have been some conflicting findings, it’s generally thought that, under most practical feeding situations, healthy older horses that have good teeth and appropriate worm control don’t have any reduction in digestive efficiency compared with their younger counterparts.

However, work undertaken by Dougal et al in 2014 did show reduced diversity in bacterial species in the hindgut of aged horses. From a practical perspective, this could mean that older horses may be potentially more sensitive to dietary changes. Therefore it is very important that all grazing, forage and feed changes are carried out slowly to avoid digestive upset.

Body condition and muscle tone

Many horse owners will tell you that their older horse loses weight more easily and has lost muscle tone. However these observations may not be a direct effect of ageing.

A reduction in exercise has a larger effect on muscle tone than ageing per se. With regard to bodyweight changes, equine obesity unfortunately brings just the same challenges to the senior horse population as it does to the general horse population. Two recent surveys, one in the UK and one in the US, found that 10.5% and 28% respectively of the older horse population were found to be overweight, potentially increasing their risk of age-related disease.

Temperature control

Older horses do not cope as well in extremes of temperature compared with younger horses, in the same way that humans often become more sensitive to heat and cold as they age.

So, in colder months, consider rugs, shelters, stabling and during hotter months concentrate on keeping older horses cooler with clipping, hosing down and making sure they have appropriate shade.

Immune defence

Just like humans, horses do show signs of age-related declines in immune function which leaves them more susceptible to infections. This effect is exacerbated in overweight and obese horses and is another reason to keep them lean!

What to consider when feeding an older horse

Fundamentally, feeding a healthy older horse is like feeding any other; only when your customers start to notice age-related health issues should they consider adapting their management and feeding regime.

Below are some of the considerations they may have to take into account:

Dental issues

There is a saying that horses survive as long as their teeth and this is certainly true in the wild. In a domestic situation, dental issues are one of the main reasons for weight loss in older horses. It can be recognised through a lack in condition, digestive issues such as colic, choke, quidding, bad breath, lack of appetite, long fibres in the droppings or obvious pain and discomfort when eating and chewing.

If these signs are not picked up, some owners will increase the compound feed. But the fundamental issue that needs to be addressed is how to replace the long fibre forage portion of the diet appropriately.

Insulin dysregulation

Insulin dysregulation, which often encompasses insulin resistance, is associated with ageing and is often a core component of Cushing’s disease/ Pituitary pars intermedia dysfunction (PPID). It is also thought to be involved in laminitis and Equine Metabolic Syndrome (EMS), which are more prevalent in middle aged and senior horses.

On this basis, an appropriate low non-structural carbohydrate diet is beneficial in the management of all senior horses and ponies.

Joint disease

Pain from general joint disease can affect appetite as well as the horse’s desire to graze and eat from a haynet if there is any pain in his neck and/or fore limbs. Therefore pain management should be discussed with a vet to maintain good welfare.

Herd dynamics

As horses age, herd dynamics become increasingly important. Horses benefit in many ways by living in a herd environment, but as they get older they may be pushed down the pecking order by younger animals which means they may lose out when it comes to feed and water.

Look out for signs of bullying and feed horses separately if needed. Ideally provide a large water trough or more than one water supply in the field too.

Practical feeding advice

Older horses can be perhaps divided into four categories which are described below along with some practical feeding recommendations:

• Young at heart

These are horses or ponies that are in good body condition and are often still ‘in use’. They will not have any apparent age-related conditions and are maintaining bodyweight and health status on their ‘normal’ adult ration.

Feeding recommendations for your customers

Maintain them on their current ration assuming it is balanced for their needs. Continue to monitor condition using a body condition scoring system, maintain a good worming and vaccination programme and have their teeth checked regularly.

But more importantly look out for any gradual changes that may suggest age related conditions are developing. Many horses and ponies that are retired or in light work will maintain their bodyweight on good quality pasture and forage alone so won’t need any supplementary feed. If this is the case, a feed balancer is ideal to provide a balanced diet. Senior balancers often contain higher levels of protein, antioxidants and joint support so are ideal in this situation.

• Old and overweight

This is the ‘middle-aged spread’ character; he will be clinically normal but overweight or obese due to reduced physical activity, his type or because of over feeding.

Feeding recommendations for your customers

Weight loss is the priority here and a calorie restricted diet needs to be put in place asap! Depending on the horse or pony’s current management and diet, the key things to consider are a restriction in grazing, removing all supplementary energy giving feeds, switching to a lower calorie hay (although do not restrict intake to less than 15g per 1kg bodyweight (dry weight) without veterinary advice), and soaking it for at least three to six hours in tepid water.

A feed balancer designed to complement a calorie restricted diet is ideal in this situation as it will balance the diet without providing unwanted calories.

• Aged but with a tendency to lose weight

These are horses and ponies that are again clinically normal but struggle to maintain weight on their ‘normal’ adult ration particularly during the winter months.

Feeding recommendations for your customers

Firstly, a general health check to rule out anything underlying would be a good idea. After that, increase the calories in the diet; which feed you choose will depend on the horse’s current diet. Appropriate options may include a senior feed which is likely to provide more calories, protein, oil and phosphorus than their current ration.

Keeping the sugar and starch restricted will be of benefit, as it will help maintain insulin sensitivity and optimum gut health. Look for feeds that provide energy through highly digestible fibre sources (sugar beet, alfalfa and soya hulls) and oil.

• The golden oldie - the true geriatric

This is the old horse that does have some age-related conditions that require careful management.

Feeding recommendations for your customers

Firstly it’s important to make sure underlying health conditions are checked and monitored by your vet and then welfare can usually be greatly increased with appropriate dietary management.

Below are some tips to help manage two of the most common conditions we see in older horses:

Cushing’s disease (PPID)

This condition needs to be managed in a similar way to laminitis, namely restricting the level of non-structural carbohydrate (water soluble carbohydrate plus starch) in the overall diet to less than 12% in the dry matter. This will often mean a restriction in grazing and choosing an appropriate low NSC forage. Depending on the horse’s condition, choose a feed suitable for a laminitic and if weight gain is required, contact a nutritionist for advice.

Dental issues

Choose softer, easier to chew hays or consider using a chopped hay replacer. However if no long fibre can be managed, a complete soakable diet will have to be provided. There are a few on the market that can be soaked into a mash, or you can soak high fibre cubes alongside sugar beet, hay or alfalfa cubes. The most important consideration is that you will need to replace at least 15g per 1kg of your horse or pony’s bodyweight per day; this is 7.5kg (dry matter) per day for a 500kg horse. Ideally this needs to be fed in five meals per day, fed four hours apart.

Summary

Healthy, older horses with no age-related issues can be fed just the same as their younger counterparts as long as their diet is balanced for their needs and maintains them in an ideal body condition.

However, once you start to notice failing dentition, joint disease or age-related conditions such as PPID, the diet should be adapted to maintain wellbeing, body condition and to prolong quality of life.

Luckily, with so many different feeds on the market, there is an appropriate diet for every senior horse no matter what their individual needs. After all, they deserve it for all the years of fun they have given us!

“Older horses may be potentially more sensitive to dietary changes.”

About the author: Clare Barfoot RNutr is a Spillers nutritionist.

April 2017

Feeding performance veterans

By Kate Hore RNutr (Animal), senior nutritionist at NAF

If horses are kept fit and active, there’s no reason why their competitive life shouldn’t extend well into their 20s.

Older horses in the UK

Without doubt, the equine population in the Western world, including within the UK, is ageing.

One study in the US found that while horses over 20 years of age represented just 2% of admissions to a referral veterinary hospital in 1989, by 1999 this had risen to 12.5% and around 20% by 2003.

Similarly, surveys within the UK find about 30% of horses to be over 15 years old, with 11% being between 20 and 30 years, and 2% over 30 years of age.

The reason for this change is likely to be twofold. In part, more people keep horses purely as pets, and are happy to commit to keeping that horse or pony well into old age. And partly the improvement over the years in nutrition knowledge, routine use of efficient anthelmintics and improvements in equine dentistry have all contributed to horses living happily and healthily into their twenties and beyond.

However, that doesn’t mean we’re growing a population of equine retirees – far from it! As improvements in equine health continue, so we find that horses maintain fitness through their teens and well into their twenties.

A study in 2001 found that while 61% of owners of veteran horses did report that the intensity of the work might decrease, the majority of older horses were still in regular ridden work, and 21% were still actively competing at a median age of 18.

Advances in human health tell us that keeping fit and active throughout your life, and maintaining that activity into older age, helps us keep healthy into older age, and the same is likely to be true of horses. So what can we do from a feed and dietary point of view to help maintain our OAPs? That’s Old Age Performers, of course!

Feeding the veteran

It’s traditionally thought that older horses will suffer with reduced absorption and digestibility of the diet, and so struggle to maintain condition. Therefore their diet needs to be changed accordingly.

It’s now considered that thinking is somewhat out of date, dating back to horses born in the 1960s and 70s who had not had the advantage of modern diets and wormers throughout their lives. Now we find that ageing itself does not significantly affect digestive efficiency in horses until horses become decidedly geriatric, and not just older.

A recent study at CAFRE, Co. Antrim found that maintaining bodyweight (BW) and Body Condition Score (BCS) does not become an issue until an equine is in their late twenties (27 +). In fact, just as with younger horses, a high BCS should be avoided as it may exacerbate health concerns (see Keeping Sound, below).

The advice to owners of older horses, therefore, should be to certainly regularly review BCS and diet as the horse ages, but so long as the horse is maintaining condition and working well, then no radical changes are required. For those horses who do need a little help, ensure the diet stays fibre based but consider short chop fibres or cubed hays which are more easily digested, especially when soaked.

For performance veterans the addition of oil to a fibre diet provides an ideal form of energy. Easily metabolised by the horse and non-heating, oils - such as linseed or soya - are a useful energy source. Just remember if feeding at significant levels for energy, the high oil diet should be balanced with supplementary vitamin E.

Gut health

One area where it is worth considering supplementary support is in gut health. Gastrointestinal conditions, such as colic, are a major concern in older equines. A 2009 study in the UK found colic second only to musculoskeletal issues for reasons for mortality in older horses.

It is recommended to balance the diet with a concentrated balancer, providing live probiotic yeasts and prebiotics, to support a healthy microbiota (microbes including yeasts, fungi, bacteria) of the hind gut.

Concentrated balancers are formulated to include the essential micronutrients, such as vitamins, minerals and trace elements, to balance the fibre based diet.

Keeping sound

Musculoskeletal conditions, particularly lameness and osteoarthritis, are consistently found to be the biggest concern in older horses. In one study at a UK equine charity, the average age of euthanasia was 20, with 66% of those being due to osteoarthritis. So it represents a challenge for owners who wish to keep their older horses performing.

Of course, the joints of performance horses undergo stress as part of normal work, but that is not the whole issue. It is thought that horses, like humans, show evidence of ‘inflamm-ageing’, that is, a raised pro-inflammatory state within the system which comes from higher levels of those cytokines (cells of the immune system) involved in inflammation, including interleukins, interferons and TNF-α (Tumur Necrosis Factor).

As obesity also increases circulating pro-inflammatory cytokines, this is a principle reason why all horses - including older horses - should be kept ‘fit not fat.’

To maintain joint health in older horses, it is recommended to feed a good quality joint supplement. With the huge choice available it can be difficult to know which to advise. Ensure any joint supplement provides a significant level of glucosamine sulphate, which research shows is the most efficient form of glucosamine.

However, thanks to the research advancements in molecular biology, we know that joint stress is a very complex multifactorial condition. Multifactorial problems require multifactorial approaches – one size (glucosamine) cannot possibly fit all. Look for a supplement where glucosamine is combined with other key nutrients including MSM, chondroitin sulphate, HA and specific antioxidant groups, all of which have been shown to work synergistically with glucosamine when in the right combination.

For older horses, or simply older joints in particularly hard working horses, look for a supplement designed for that specific life stage. Supplements for older joints are likely to include the key joint support nutrients, but also omega 3 fatty acid which not only has a role in inflammation but also in heart and brain health.

To summarise

In conclusion, by keeping horses fit and active, monitoring any BCS changes and ensuring gut and joint health are supported, there is no reason why the competing life of performance horses can’t extend well into their twenties and beyond.

Adding oil to a fibre diet provides an ideal form of energy for performance veterans.

November 2016

Fibre for veterans

By Joanna Palmer BSc (Hons) equine nutritionist at Allen & Page

Horses need to ‘trickle feed‘ and should ideally have fibre in the form of grass, hay or haylage available at all times.
Aside from water, fibre is the most important component of every horse’s diet. And for the majority, their fibre needs are easily met through grazing and supplementary forages such as hay and haylage.

There is, however, a growing need for alternative sources of fibre, most notably for the increasing population of veteran horses and ponies who can have difficulty chewing long stem fibre, due to poor teeth.

Why is fibre important?

Horses have evolved to eat a diet that is predominately fibrous forage and in the wild they would graze for up to 18 hours a day. To mimic their need to ‘trickle feed‘, our domesticated horses should ideally have fibre in the form of grass, hay or haylage available at all times.

Fibre is not only essential for good digestive health, its digestion also provides a good source of calories and body heat as it is fermented in the gut. This means that the horse has to use fewer calories to keep warm and is more likely to maintain condition.

If a horse is not getting enough fibre in his diet, he will lose weight, almost in spite of how much high calorie 'bucket' feed he may also be given.

Fibre is made up of lignin, cellulose and hemicellulose. Lignin is indigestible but cellulose and hemicellulose are readily digested in the hind gut by microbial fermentation. The hind gut makes up 62% of the horse’s entire digestive system and is populated by billions of bacteria which break down fibre into volatile fatty acids (VFAs). These VFAs are an important source of slow release energy which are absorbed from the hind gut into the horse’s bloodstream and transported around the body.

Horses that do not eat enough fibre are more likely to develop serious problems, including colic and gastric ulcers. Horse’s saliva contains bicarbonate which is important for neutralising stomach acid; but saliva is only produced when the horse is actively chewing.

If a horse spends a reduced amount of time chewing he will produce less saliva and the acidity of his stomach contents will rise. This more acidic environment can result in damage to the stomach lining and increases the risk of gastric ulcers occurring.

A diet that is low in fibre can also cause horses to develop behavioural issues such as aggression, grumpiness and crib biting due to their inability to fulfil their natural feeding and chewing behaviours.

Hay replacers for veteran horses

Continued advances in veterinary medicine, together with an increase in our own understanding and management of our horses and ponies, have led to a significant increase in their lifespans, with many horses now healthy and active well into their twenties and thirties.

Unfortunately, even with the best possible care and regular attention from a qualified equine dental technician, there is little we can do to prevent the deterioration in dental condition that occurs naturally with age. Loose, worn or missing teeth and pain from sore gums will all affect a horse’s ability to chew efficiently.

Balls of partially chewed food form in the horse’s mouth and are then dropped on the floor. This is known as quidding and is a tell-tale sign that a horse is suffering from problems with their teeth and would benefit from a hay replacer.

The choice and availability of these hay replacers has grown significantly over the last few years and includes short-chopped chaffs, sugar beet, grass nuts, alfalfa pellets and specially prepared, soaking feeds which combine all the necessary ingredients and vitamins and minerals to provide a balanced diet.

It is important to be aware that products such as sugar beet and some of the grass and alfalfa chaffs are high in calories and so not suitable to be fed in large quantities to good doers already at ideal bodyweight. A hay replacer should provide similar nutrition to that of good quality hay. If necessary, additional higher energy fibre sources or a conditioning feed can then be added to the horse’s diet, to provide a calorie boost.

A hay replacer can be fed to replace all or part of the horse’s normal daily fibre intake, depending on their individual needs. As well as veteran horses and ponies, other equines that may benefit from a hay replacer include:

• Fussy feeders who simply do not eat sufficient fibre to meet their nutritional needs.
• A horse or pony that has sustained an injury or undergone an operation that affects their ability to chew - a soaked fibre feed that is easy to eat can be particularly beneficial during recovery.
• Horses and ponies who are prone to colic or recovering from abdominal surgery - again the provision of a soaked fibre feed ensures the horse receives the fibre they need for digestive health and the additional water content helps to keep the gut hydrated and able to function efficiently.
• Those with access to only poor quality grass, hay and haylage.

Feeding a soaked hay replacer

Many people enjoy the convenience and peace of mind of feeding a specially made fibre feed that is balanced with all the essential nutrition a horse requires. One of the most important qualities of a hay replacer is that it is easy to eat, particularly as the main reason for a horse needing an alternative fibre source is poor dental condition. An affected horse is more at risk of choke, simply because he is not able to chew properly.

For this reason a soaked fibre feed is popular with horses and their owners alike, not only for ease of eating and preparation, but with the added benefit of increasing water consumption. Veteran horses can be reluctant to drink enough water, particularly in the winter and by feeding a soaked hay replacer their water intake can be significantly increased.

As a soaked fibre feed takes considerably less effort and time to eat than the equivalent amount of hay, it is important to try to maximise the amount of time a horse spends eating to avoid long periods when no fibre is passing through the gut. A horse’s feeding time can be extended by:

• Dividing the horse’s daily feed into as many meals as possible.
• Feeding from a long trough or straight on the floor to spread the feed out and prevent the horse from taking large mouthfuls.
• Placing obstacles such as large, flat stones in the trough so the horse has to eat around them.
• Splitting each meal into several containers around the stable or field to encourage foraging behaviour.
• Mixing in a chaff if the horse is capable of chewing one.

Horse’s saliva contains bicarbonate which is important for neutralising stomach acid, but saliva is only produced when the horse is actively chewing.

A soaked fibre feed is popular with horses and their owners alike, not only for ease of eating and preparation, but with the added benefit of increasing water consumption.

October 2016

Supplementing the equine diet

By Kate Hore RNutr(Animal), senior nutritionist with NAF

Any bucket feeds should also be based on short chop fibre and split between multiple feed times to mimic grazing.
Horses and ponies evolved as trickle grazers which means, as most of us know, they love to eat all the time!

Around 16 to 18 hours grazing per day is normal for horses allowed free access to pasture. This habit of eating for hours isn’t greediness, but a natural adaptation which allows horses to effectively digest tough, fibrous plants, and extract their required energy, fibre and nutrients from that.

As horse owners, and advisors, this means that if we want to keep our horses and ponies happy and healthy we should be basing their diet predominantly on forage, ie. grazing, hay or haylage.

Natural diets, high in fibre and low in starch, have been shown to improve behaviour and reduce the risk of a number of common health issues such as Equine Gastric Ulcer Syndrome (EGUS) and laminitis. Ideally, any bucket feeds should also be based on short chop fibre and split between multiple feed times to mimic grazing.

Balancing the diet

The only real issue with this natural diet is that it can be lacking in nutrients required for health and vitality, particularly the micronutrients – vitamins, minerals and trace elements. It’s a fair question to ask - why, if it’s so natural, is the forage diet not meeting our horses’ dietary requirements?

There are a number of reasons as to why this might be. Firstly, grazing for the modern horse lacks the variety of the shrubs, herbs, legumes and trees available to natural horses. Studies have shown wild horses graze a huge number of species, and will even select different herbs and grazing dependent on the time of year.

Conversely, modern grazing usually only contains one or two species of grass and, perhaps, a legume. So it’s important to put back some of the variety in the diet. Secondly, areas of soil deficiency for certain nutrients are common in the UK. This deficiency will be passed to the grazing and also to the forage harvested in that area. Therefore, again, it’s important to balance up those deficiencies. This is where supplements are advised.

Broad spectrum supplements contain the required vitamins, minerals and trace elements, and are available as powders, liquids or pellets; the choice of which is usually personal preference.

A good quality product will be designed to balance what is naturally provided in a high fibre diet, rather than, for example, providing 100% of RDI (Recommended Daily Intake) for all nutrients - which rather implies the horse shouldn’t eat anything else at all!

Remember, over-supplying just means the horse works harder to excrete excesses, or runs the risk of stores building within the system. So look for a balancing product to suit that horse, their age, work load and body condition score. For working equines, and where maintaining condition is important, supplements will usually include gut support. The harder the horse works, the harder the gut works – and keeping the gut happy and healthy is the secret to keeping the horse happy and healthy.

That gut support may be live probiotic yeast, such as Saccharomyces cerevisiae for the hind-gut microflora; prebiotic sugars, which support the role of the probiotics; natural antacids, such as calcium carbonate, or herbal gut support from plants including mint, ginger and psyllium.

Brewer’s Yeast is also commonly included and is an inactive form of Saccharomyces cerevisiae, meaning the yeast is killed off so doesn’t have a probiotic action, but it’s a useful source of B vitamins, and is considered to support gut health as a prebiotic.

Both probiotic yeast and brewer’s yeast commonly appear together in products, and can cause confusion when reading the label, so it’s worth understanding the difference.

The live probiotic will be listed as Saccharomyces cerevisiae in the Additives section of the label, and will have a ‘cfu’ (colony forming unit) figure telling you the inclusion rate of the yeast. Brewer’s yeast may be listed as ‘Saccharomyces cerevisiae (inactive)’ and will be under Composition, as it’s classed as a feed material rather than additive. This explains how ‘Saccharomyces cerevisiae’ may appear twice on a label from very different ingredients.

The final combination of gut support used in a product will depend both on the manufacturer, and the type of horse the product is designed for.

Feed balancers, which are concentrated, nutrient rich feeds typically fed at between 100g – 500g per day, are really just an extension of this. Balancers usually include gut support alongside vitamins and minerals for health and vitality, so are a form of broad spectrum supplement, generally fed as pellets.

Nutraceuticals

Once the diet is balanced, supplements can then be considered which go beyond simply diet balancing to target various areas of health specifically. The term ‘nutraceutical’ is a fairly new one, but simply means using nutrition as a therapy tool.

This is nothing new, herbal veterinary formulae can be found recorded in the pyramids of ancient Egypt. And increasingly, ‘old wives tales’ are being validated through scientific research.

We all know the power of plants, whether we think we do or not. For example, would you casually chew on some deadly nightshade, or let your horse graze ragwort? So if we know certain plants can be powerfully harmful, it’s not a big leap to understand that others can be powerfully beneficial.

The science of supplements is putting the right combination of those plants and natural ingredients together to support health. Nutraceutical supplements can cover all areas from a simple biotin and zinc blend for hooves, through technical combinations of glycosaminoglycans (GAGs) for joint health, to innovative herbal antioxidant complexes to flush out oxidative stress.

Legal classification

All supplements are legally classed as complementary feed and, as such, come under EU feed law, which prevents any medical claims being made.

While this is a good thing in preventing unsubstantiated claims, it does mean manufacturers are restricted in how they market their supplements, particularly for the targeted nutraceuticals. So if you’re unclear as to whether a supplement is appropriate for a particular horse or not, discuss it with the manufacturer who should be happy to advise.

In conclusion, supplements can basically be split into two groups – those designed to balance the diet, whether covering deficiencies or replacing what has been lost through work, and those designed to be used in a targeted way for specific health support.

Around 16 to 18 hours grazing per day is normal for horses allowed free access to pasture.

The harder the horse works, the harder the gut works.

Kate Hore is a Registered Animal Nutritionist. She has been with NAF for almost 20 years, where she specialises in fine-tuning equine diets through supplementary nutrition.

May 2016

Keep calm and feed a calmer?

What do calmer supplements contain? And what research there is that they actually work? Vet Becky Lees has the answers.

Horses evolved as flight animals to stay safe by running away from predators. However, since modern horses are usually unable to run away from what scares them, considerable stress and anxiety can be suffered.

Some horses find particular events stressful, such as vet and farrier visits, travelling or clipping. Others can be stressed by their management; for example a horse who dislikes being without company being stabled out of sight of other horses.

Stress manifests in many different ways which are perceived as undesirable behaviour. It may become dangerous as the horse adopts more desperate behaviour to avoid what he is scared of. Stressed horses represent poor welfare, underperform and may develop vices.

Calmers are presented as powders, liquids and syringe pastes.

Training and environment

Training works best for horses that react to particular stressful events, such as loading onto a trailer. Environment modification is most successful for horses with longstanding stress.

A holistic attitude is needed to look at the horse’s management, feeding and routine and to establish the likely cause of stress. Then appropriate steps can be taken. Retailers may wish to suggest seeking professional help.

Pain or stress?

Some behaviours can be due to pain rather than stress. For example, a horse may not want to hold up his feet because he has joint pain. In these cases, veterinary attention is required. Some horses find certain events, such as clipping, so stressful that prescription drugs are needed to sedate them.

How can calmers help?

Calmer supplements are incredibly popular with horse owners. They are most effective when used alongside training and environment modification. But how do you recommend a product when there are so many on the market, all claiming to have excellent results?

Here are the key questions to ask when choosing which calmer supplement to recommend:
• What does the supplement contain?
• Will the horse be safe to handle and ride when it is on the supplement?
• Could it cause any adverse effects or affect performance?
• Is there any evidence that it will actually work?
• Is it legal for competition?

Most horse owners are aware of what causes their horse to be stressed and calmer supplements are ideal for use in these situations. However, they shouldn’t be given as an excuse for poor management and are best used alongside training and environmental management. There are always going to be certain times when we can’t completely prevent stress and calmer supplements have a definite place for use during these times.

Powder, liquid or syringe?

Powders and liquids are designed for daily maintenance use or for use over several days during a potentially stressful time, such as moving yard or around bonfire night. Syringe pastes are designed as a ‘top-up’ for specific stressful events, such as clipping.

Supplements containing magnesium

Magnesium is important for brain function as it’s involved in neurotransmitter synthesis and receptor binding. Magnesium depletion in horses has been associated with brain malfunction and a heightened stress response.7

Unfortunately, blood magnesium concentration is an insensitive indicator of magnesium intake.8 There is some evidence to show beneficial calming effect, one study found that magnesium supplemented horses had lower heart rates in stressful situations², however further research is needed to prove the benefit of magnesium in a calmer supplement.

Magnesium is safe, with no adverse effects as the levels in horse feed when combined with calmer supplements will not cause an imbalance. However horses are not able to absorb some magnesium compounds, so magnesium calmers need to be chosen carefully.

To have any effect, the magnesium calmer supplement must be bioavailable. This simply means it can be absorbed by the horse into the blood.

Magnesium oxide is extremely poorly absorbed¹ and should be avoided. Magnesium sulphate and magnesium chloride have low bioavailability. Chelated magnesium and magnesium aspartate hydrochloride have the highest bioavailability, so these are what you should look for in a calmer supplement.

There is no benefit to having more than one magnesium compound in a supplement.

Magnesium topical sprays should be avoided as magnesium compounds are not absorbed through the skin. This also means that they are not absorbed into the blood and therefore won’t work. Any effect will be due to the placebo effect only (see box).

The placebo effect

A placebo is an ineffective treatment for a medical condition intended to deceive the patient. When patients given a placebo have a perceived or actual improvement in a medical condition this is known as the placebo effect. The placebo effect can work on animals too.5

For example: A horse is being difficult when ridden, shying and napping. The owner puts the horse onto a calming supplement and the horse’s behaviour dramatically improves. Is this due to the supplement, or the owner’s belief in the supplement which means that she is more confident when riding the horse with the result that the horse does not misbehave?

This is why proof that a supplement works from published peer-reviewed research is so important! Unfortunately there is little published research about calmer supplements in horses due to the high costs of running studies. It’s also extremely difficult to design a study that will give statistically significant results.

So, we are left with the following conundrum:
If a calmer appears to work – by real or a placebo effect - and has no adverse effects on the horse, then using it will actually give a real and beneficial effect to both horse and owner. So does it matter whether the effect is real or due to the placebo effect?

Supplements containing herbal extracts and/or tinctures

Many supplements contain a variety of compounds. These may be dried herbs, a purified extract or as a tincture (alcoholic extract). Unfortunately research in horses is very limited.

These are some common herbal compounds:

• Valerian: This is a plant remedy used for insomnia in humans. It has been shown to have a sedative activity in mice and is assumed to have a sedative action in horses, although no research has been carried out. Anecdotal reports of its use in horses suggest a sedative effect, however it may affect coordination and horses given valerian may not be safe to ride. The amount of active ingredient (valerenic acid) can vary in supplements and it can enhance the effect of tranquilisers and anaesthetics. Valerian can cause diarrhoea and colic. Overdose can cause excitement or overstimulation. Valerian is a prohibited substance under FEI rules and should not be used in competing horses.

• St John’s wort: The active ingredients in St John’s wort are hypericin and hyperforin. Research has demonstrated a positive response for mild to moderate depression in humans. There is no research in any species that demonstrates any effectiveness for stress or anxiety, so it’s unlikely to be of benefit in a calmer supplement. St John’s wort can interact with a number of prescribed medications. Higher doses can cause severe photosensitisation (sunburn) in all species.

• Hops: There is a small amount of contradictory research in humans that suggests a sedative effect at higher doses; however no equine research exists. Hops have no adverse effects.

• L-tryptophan: This comes from plant or synthetic sources and is an amino acid precursor of serotonin (a neurotransmitter). The response to L-tryptophan depends on species. In humans, dogs, pigs, poultry and fish, it has been shown to decrease aggression. In calves, vixens and poultry research shows it may reduce fearfulness. However, behaviours linked to excitability are not modified in any species³. Recent research shows that it is absorbed by horses and that there are no beneficial behavioural effects. In horses, low doses were shown to actually cause mild excitement while high doses can reduce endurance capacity and cause acute haemolytic anaemia³. L-tryptophan is included in many calmer supplements, however this research suggests that products containing it should be avoided.

• L-Theanine: This is an amino acid derived from green tea. In humans it is thought to have an anti-stress effect without causing drowsiness or affecting coordination by increasing GABA and dopamine levels in the brain – the ‘happy chemicals’. There has been no research looking at whether it has the same affect in horses. It has no adverse effects.

Supplements containing calcium compounds

There is no evidence linking calcium deficiency with anxiety or behavior problems. Grass and hay are high in calcium so deficiency is incredibly rare. There is absolutely no evidence that calcium compounds have any effectiveness as a calmer supplement, so any effect will be due to the placebo effect only.

Supplements containing milk

These are derived from a milk protein called casein, a molecule known to promote relaxation of newborns after breastfeeding. There is some research in horses showing that it can be beneficial in combination with behaviour modification and training programs.4 It has no adverse effects.

Supplements containing B vitamins

Many calmer supplements contain B vitamins; however no research exists to see if they are beneficial. B vitamins assist the maintenance of nervous system functions and deficiencies create nervous system effects. Without any research it’s impossible to tell whether they are beneficial; however they have no adverse effects.

Helping customers decide

With so many calmer supplements on the market, it can be incredibly difficult for SQPs to know which one to recommend.

Read the ingredients section on the label so that you can help the horse owner understand what each ingredient does. The customer should be happy that the supplement chosen will have no adverse effects, be bioavailable to the horse, have as much evidence for effectiveness as possible and be legal for competition.

References:
1. Coenen M. Macro and trace elements in equine nutrition. In: Equine Applied and Clinical Nutrition. Saunders. 2013. 191-228.
2. Dodd JA, Doran G, Harris P, Noble GK. Magnesium aspartate supplementation and reaction speed in horses. 2015. 35(5): 401-402.
3. Grimmett A, Sillence MN. Calmatives for the excitable horse: a review of L-tryptophan. Vet J. 2005. 170(1):24-32.
4. McDonnell SM, Miller J, Vaala W. Calming Beneﬁt of Short-term Alpha-Casozepine Supplementation during Acclimation to Domestic Environment and Basic Ground Training of Adult Semi-Feral Ponies. Journal of Equine Vet Science. 2012. 33(2): 101-106.
5. McMillan FD. The placebo effect in animals. JAVMA. 1999. 215(7): 992-999.
6. Noble GK, Brockwell YM, Munn KJ, Harris PA, Davidson HP, Li X, Zhang D, Sillence MN. Effects of a commercial dose of L-tryptophan on plasma tryptophan concentrations and behaviour in horses. Equine Vet J. 2008. 40(1): 51-56.
7. Stewart AJ. Magnesium disorders in horses. Vet Clin North Am Equine Pract. 2011. 27: 149-163.
8. Stewart AJ, Hardy J, Kohn CW, Toribio RE, Hinchcliff KW, Silver B. Validation of diagnostic tests for determination of magnesium status in horses with reduced magnesium intake. American journal of veterinary research. 2004. 65, 422-430.

Some horses find travelling stressful. Using a calmer may help, but will work best combined with training and managing the horse’s environment.

About the author: Dr Becky Lees BVSc Cert AVP (EM) MRCVS is an experienced equine vet who works as veterinary technical manager for Nettex. Before joining Nettex, Becky spent ten years working in specialist equine practices and has a post graduate qualification in equine medicine. She enjoys dressage and has two horses and two Shetland ponies of her own.

November 2015

What do horses eat?

Nutrition plays a significant role in equine health and welfare, so it’s difficult not to discuss feeding within any healthcare conversation. For SQPs, therefore, a working knowledge of nutrition means a better service to clients, says Ruth Bishop.

The dietary options on offer in any store are many and varied. No wonder the choice of product can sometimes be quite overwhelming for consumers.

The spectrum of feedstuffs is very wide, with intake ranging from many kilos per day to a few grammes. The major categories are as follows -

Of course there’s some blurring of the edges between categories as some products sit between two, for instance mixes containing high proportions of fibre.

Horses mainly eat forage, in the form of grass, hay or haylage; forages are what horses are designed to eat, and are essential for a healthy horse. Forage is capable of supplying the energy, fibre and protein needs of a horse, especially one at maintenance or light work – although essential micronutrients will in many cases need topping up.

At least 50% of the daily diet should be forage, but in most horses it is significantly greater than this – typically over 80% of the daily diet in many horses kept for leisure purposes.

Grass

Good pasture contains an even cover of palatable grasses, free from weeds, and provides a rich source of nutrients from energy and protein to vitamins, minerals and plant phytochemicals.

Horses thrive at grass - physically and mentally – but some do too well, gaining excess weight. A recent survey of predominately outdoor living horses found that over 30% were overweight.

The amount of nutrition that grass provides varies according to the time of year, the grazing management, the number of horses (or other animals) grazing the land and how long the horse is turned out for. Good grass is generally equivalent to a medium or high energy, high protein feed. It’s at its very richest in spring (and often again in the autumn), when the protein content can be above 20% and the energy content equivalent to that of a racing feed. Actively growing grass can be rich in sugar – as much as 3% of every mouthful, and this together with fructans, a storage form of plant sugar, has been implicated in the incidence of pasture-associated laminitis.

Poor grazing isn’t as rich, but a horse turned out for several hours a day can still easily receive more from its pasture than it will from most low energy feeds.

Hay

Hay is dried mature grass, normally in the form of either:

• Seed hay - usually perennial ryegrass varieties, timothy or specialist blends of them, grown and sown specially for hay. Seed hay tends to be quite coarse in nature with a relatively low energy and protein content; or

• Meadow hay - from pasture permanently kept as grass, usually comprised of a more varied mixture of grass species, and tends to be softer and finer with a higher nutritive value than seed hay.

As a general rule of thumb, small bales weigh about 20kg, with large bales weighing 250-350kg depending on size. A slice or section from a small bale typically weighs about 2kg / 4lbs.

The main concern with hay is its hygienic quality: moulds, spores and other dust particles that develop during harvest or storage can cause respiratory irritation and lead to the development of Recurrent Airway Obstruction (RAO) in horses.

Soaking and steaming Hay

Unless it’s been expertly dried in controlled conditions (there are suppliers who do this), UK hay is likely to contain some mould and dust. Soaking or steaming hay are popular ways of removing any dust, by either removing the particles, or effectively ‘sticking’ them to the grass stalks so that they are consumed rather than inhaled.

Soaking time

Research has shown that 30 minutes’ soaking is effective. Soaking hay also causes some loss of nutritional value as some soluble sugars and proteins are leached out into the water; more soaking equals less nutritional worth. Owners of laminitis-risk horses can take advantage of this to reduce unwanted sugar contents.

Haylage

Haylage is grass that is baled moist (typically 35-40% moisture) and then bagged or wrapped to keep the air out and moulds from forming. It’s popular with growers because it’s easier to make than hay, and with horse owners because of its low dust and spore content. Plastic packaging means it can be stored outside.

Disadvantages are that quality can be variable between different suppliers. Also portioning can be a challenge, since the bales don’t often break into easy slices. Moisture content can be variable between suppliers, ranging from 20-50%.

Small haylage bales weigh about 25kg, whereas large wrapped bales can be 180-250kg or greater.

Haylage tips for SQPs

• Up to 50% of haylage can be water, compared with 15% in hay, so it cannot be fed on a weight-for-weight basis with hay; advise feeding about 1½ times the weight of haylage as hay.

• The quality of the airtight seal is essential. Air ingress will allow mould growth in the bales. Small bales may split at the seal, large bales can be punctured by haylage stalks or from bird, rodent or mole damage.

• Quality is all important, so choose a supplier with a good reputation and ask for an analysis of their product.

• A good rule of thumb is to use a bale within four days of opening (less in summer) as moulds start to grow again immediately the bale is opened.

• Avoid feeding visibly mouldy haylage and “gritty” or soil contaminated material, as there could be a risk of listeriosis.

Forage analysis

Hay and haylage are often thought of as an inert and safe nutritional bases. However because they constitute such a large part of the diet their contribution is worth monitoring especially if the horse competes, is at risk of laminitis, has Cushings disease etc. Energy, protein and sugar contents can vary depending on the grass species, date of cutting and the weather during cutting and baling. Sugar contents can exceed 10% in some forages. Nutritional value can be quantified by a simple test, a service offered by many feed manufacturers.

Ad lib forage feeding

Many owners feed on a free access or ad libitum basis to ensure the horse always has forage available. Actual individual amounts consumed should be monitored though as offering ad lib doesn’t always mean an optimum intake especially where several horses share the forage, or if the quality is variable.

Chaffs and forage replacers

A number of chopped fibre products are marketed as forage replacers. Chops and chaffs that can be added to the hard feed to bulk it up or slow down the rate of eating. There is some evidence to show that horses take longer to eat short chop forages than they do hay or haylage.

There are also complete fibre feeds available fortified with protein, vitamins and minerals etc., designed as the full compound feed. These aim to fit more closely with the digestive physiology of the horse, and are particularly good for horses or ponies prone to laminitis and digestive issues such as gastric ulcers.

Compound feeds

Compounds are balanced blends of ingredients formulated to meet the requirements of horses when fed in conjunction with forage. A recent survey found 87% of owners feed some form of compound, the majority of which was commercially prepared.

The market for compound feed is highly fragmented with different products and product forms for every kind of horse or pony (see table below). Balancers are concentrated, nutrient-rich versions of compounds, and the balancer category has itself recently become more fragmented along similar lines to compound feeds.

Feed	Description	Typical feed rate
Low energy / High fibre	Cubes and mixes with a high fibre content designed for horses at maintenance, in light work, or for horses that work well off low energy feeds.	1-4 kg per day
Senior feeds	Cubes and mixes with additional nutrients for older horses. Some come in low-and high-energy form; some contain joint support ingredients.	1-4 kg per day
Feeds for laminitics	Usually in fibre-mix or cube form, low energy, high fibre, low starch and sugar complete feeds.,Capable of replacing the total diet of at risk animals.	1-10 kg per day
Competition feeds	Medium energy cubes and mixes with higher vitamin and mineral contents designed for the working and competing horse or pony.	2-6 kg per day
Conditioning feeds	Higher energy and protein feeds designed to put on weight. Some are starch based, but more modern versions are high in fibre and oil to ensure condition is achieved without increased excitability.	1-3kg per day
Stud and breeding feeds	High energy, protein and mineral feeds designed for breeding stock.	2-6 kg per day
Racehorse feeds	High energy cubes and mixes for horses in training or intense work.,Traditional products are starch based, but modern variants use alternative energy sources such as oil and digestible fibre to support digestive health and aid performance.Some companies offer low energy lay off or rest and recuperation variants for horses on the easy list.	5-7 kg per day
Feed Balancers	Concentrated nutrient-rich pellets, supplying essential amino acids, vitamins and minerals.,Commonly marketed to complement high-forage diets, but also as top-ups to existing diets or when cereals, eg. oats, form a large part of the diet.	250g– 1kg

Supplements

Supplements augment the nutrition provided by the main part of the diet. They come in a variety of forms; powders, herb blends, liquids, pastes, pellets, licks - and in a variety of packaging.

Under regulations governing animal feed, supplements are considered “complementary compound feeds” as are cubes, mixes and balancers. However in the horse owner’s eyes, they fulfil a different role, tailoring individual diets to meet specific needs.

Supplements are used regularly, with estimates of their use in 80% of equine diets.

There are two main categories of supplements:

- Broad-spectrum: providing a broad spectrum of major and trace minerals together with vitamins, these are designed for topping up micronutrient levels where little or no hard feed is fed. There’s some blurring of the edges here between balancers and broad spectrum supplements in terms of the nutrients they supply. Balancers tend to be in pelleted form whereas supplements can be in the form of a powder or a lick.

- Specific: providing an ingredient or mixture of ingredients designed to perform a specific function. These range from daily addition of salt and/or oil to the diet to more targeted support, eg. for joints or hooves.

The top five specific nutritional concerns of horse owners are hoof quality, joint quality, colic, care of the senior horse and laminitis. Behaviour also ranks highly especially related to supplement purchases. Different companies takes different approaches to each functional area, and the following table gives some examples of these.

Medicinal claims for supplements and feeds are not permitted. There is an exception for laminitis, but only in relation to a product’s (low) starch and sugar content. Claims linking laminitis and hoof health are not permitted.

Category	Examples of typical product approaches
Behaviour	- Nutrients and herbs associated with calming or modifying behaviour eg.magnesium Probiotics – in case behaviour is caused by digestive discomfort
Joint support	- Support to the cartilage via providing building blocks for cartilage formation e.g. glucosamine, chondroitin sulphate, MSM, collagen - Increased antioxidant support to combat free radicals in the joint - Substances added to support joint comfort
Hoof	- Nutrients to support hoof growth and development - Biotin is research proven but other vitamins, amino acids and trace elements can also be added.
Skin and coat	- Oils, particularly sources of omega 3 fatty acids - Nutrients and herbs that help coat and skin quality
Digestive support

About the author

Ruth Bishop is a director Ruth Bishop Consulting Ltd. She has 25 years’ research and development experience in animal nutrition both in consultancy and commercial roles in major food businesses including Dalgety and Mars. She is a former technical director of Mars Horsecare and works with feed industry trade associations.