Hindgut Ulcers – Your Ultimate Guide
Preventing and managing hindgut ulcers is becoming an all-too-common scenario. What was once thought to be fiction has rapidly become more of a fact. Particularly as research into this area of digestion has evolved. With a positive diagnosis, it’s easy to feel as if your world has come crashing down. However, with the help of this ultimate guide, find out how to manage this problem and get your horse back to feeling healthy and happy.
When we talk about the horse’s hindgut, we’re referring to the digestive area from the cecum to the rectum. The primary function of the hindgut is to digest fibre and convert it into useable energy from volatile fatty acids. High levels of this fermentative microbial digestion take place in the caecum by microorganisms, yeast, and friendly bacteria.
The normal acidity (PH) level in the hindgut is around 6.2. When the acidity in the hindgut is raised it lowers the pH. Lactate-producing and lactate-utilizing bacteria (bugs that cause issues) get strong in an environment with a low pH. They then start producing lactic acid rather than volatile fatty acids. This change in the microbial populations and acid proﬁles is what creates hindgut acidosis.
What causes this change to occur?
It’s caused by large quantities of undigested simple carbohydrates reaching the hindgut and producing lactic acid. These are usually starches and sugars found in processed grain feeds or rich pasture. This drop-in pH may reduce mucous production, leaving the mucous membranes of the hindgut vulnerable.
Furthermore, when fiber-digesting bacteria die off because of hindgut acidosis, endotoxins are released into the bloodstream. The result of this can cause issues such as laminitis.
What are Hindgut Ulcers?
- Hindgut ulcers are also known as colonic ulcers and are often referred to by vets as Right Dorsal Colitis (RDC). This is because most hindgut ulcers occur in this part of the large intestine on the right side of the horse.
- All ages and breeds of horses are susceptible. Hindgut ulcers have been reported to affect 44 – 63% of horses and are estimated to occur in 65% of sport horses. These types of ulcers can go undiagnosed for months because horses are usually normal between acute episodes.
- When hindgut health is compromised, a horse may also have trouble absorbing important nutrients. This can result in poor coat and hoof condition, reduced immune function, and behavioural changes.
- Whilst hindgut ulcers are less common than gastric ulcers, a horse can have both at the same time.
A definitive diagnosis is difficult because a gastroscope (used to diagnose gastric ulcers) won’t reach the colon.
However, one definitive method of diagnosis is a Transabdominal ultrasound. This type of ultrasound takes specialized equipment and skill on the part of the vet. If the ultrasound shows a thickened colonic wall, hindgut ulcers are likely to be diagnosed. If you’re concerned about hindgut acidity, ask your vet to test faecal pH first.
Horses affected by hindgut ulcers may experience a progression of signs such as
- decreased performance, lethargy
- weight/topline loss
- reduced appetite
- diarrhea, intermittent soft manure, or “squirty” bum where some horses have a liquid component that follows passing otherwise normal manure
- mild intermittent or recurring colic
- a rough coat
- a change in attitude, sudden girthiness
- sensitivity in the flank area
- difficulty bending, collecting and extending
- blood in the manure
- chewing wood (cribbing)
- swelling (oedema) along the central midline of the belly
Why do Horses get Hindgut Ulcers?
- Stress for horses can be either physical (i.e. training and performance) and/or emotional stress (i.e. separation anxiety, floating). This leaves them at a higher risk for developing both gastric and hindgut ulcers. Additionally, stress, whether physical or mental, affects the horseʼs immune system.
- Hindgut acidosis. Usually, but not always, caused by starch overload or massive doses of pure fructan and insufficient forage. Horses with hindgut acidosis often have frequent low-grade colic, loose manure, and are off their feed.
- Overuse of non-steroidal anti-inflammatory drugs (NSAIDs). These should be used for no longer than 5-7 consecutive days. Overuse can lead to damage to mucosal membranes of the gut lining and interfere with blood clotting.
- Parasites including tapeworm, small strongyles, and others. These may also cause ulcers at the site where they attach to the intestinal wall.
- Disturbances to the gut microbiome. Eg excess levels of lactic acid are caused by a decrease in the pH level of the colon. This acidic environment may result in:
- Damage to the mucosal lining, resulting in compromised intestinal barrier function.
- Changes in the equine microbiome eg a proliferation of pathogenic bacteria and a decrease in the population of beneficial bacteria.
- Reduced defences against toxins in the gastrointestinal tract.
BE AWARE OF OTHER CONDITIONS that could look like RDC. These include
- Gastric ulcers
- Other causes of colic (large colon displacement and/or impaction)
- Infectious causes of diarrhea (Salmonellosis, Clostridium)
- Inflammatory bowel disease
Three Steps in the Prevention and Treatment of Hindgut Ulcers
Dietary management that prevents hindgut ulcers from recurring and to support the healing of the intestinal lining.
- Your vet may prescribe medications such as sucralfate or misoprostol.
- Reduce the amount of work the colon must do by limiting long fibre (hay) consumption. Replace it with short fibre eg hay cubes, pellets, or chopped hay.
- Offer small, frequent meals whenever possible to support gut health and improve nutrient absorption.
- Try feeding Psyllium. It can help lubricate and shorten the transit time for feed and roughage. It also increases water content in the intestines and fatty acid concentration in the colon and reduces inflammation.
- Feed to provide buffering to the hindgut i.e. beet pulp, soyhull husks
Minimizing stress is an important part of recovery from Right Dorsal Colitis. This can be done by:
- Reducing strenuous exercise or training
- Providing more turnout time
- Minimalising transport
By following as many of the above strategies, you can usually see a reduction in symptoms after 1-2 weeks. However, be aware that it can take two to three months for ulcers to fully heal.
Improve digestive health. Probiotics and prebiotics can be helpful.
Can Fibregenix Platinum Pro performance balancer help with hindgut ulcers?
Yes! Platinum Pro is invaluable in the management of hindgut ulcers. It includes 4 specific digestive aids. Actisaf Live yeast probiotic, purified nucleotides, MOS, and FOS prebiotics will tackle each of the points listed below. Each of these digestive aids has proven performance when it comes to gut health.
- For increasing the number of “good” bacteria and restoring gut health in horses with hindgut ulcers.
- To improve feed efficiency and support nutrient assimilation
- Supporting hindgut function and fibre fermentation
- Assisting in the combat of toxins by inhibiting their absorption from the gut
- Supporting the immune system by increasing immunoglobulin activity
Dietary Nucleotides are of particular interest. Here are 2 reasons why we’ve included them in our balancers for preventing and managing hindgut ulcers.
Dietary Nucleotides Improve Efficiency of Cell Growth and Repair
In general, DNA is synthesized through complicated de novo pathways. These pathways create fresh nucleotides from scratch rather than using existing material. However, in the presence of dietary nucleotides, the body can down-regulate DNA synthesis. And instead, it uses an enzyme named HGPRT to scavenge the intact nucleotides improving the efficiency of cell repair and conserving energy.
In addition to ongoing maintenance, cell division is critical for repairing damaged tissue, including ulcers. This is why in times of stress, dietary nucleotides have proven to be beneficial.
Dietary Nucleotides Increase Mucosal Thickness
Nucleotides optimize the natural protective mechanisms of the mucosal lining. This helps to maintain a healthy GI tract. Supplementing a horse’s diet with nucleotides increases mucosal thickness and protein levels through increased availability of genetic precursors. It also speeds up intestinal recovery after chronic diarrhea and intestinal damage.
Nucleotides play a critical role in the body in that they accelerate the cell regeneration process. Cell regeneration allows an animal to recover much quicker from the type of stress it is under (performance, illness, disease, injury, etc.).
TAKE HOME MESSAGE
Hindgut acidosis is a nutritional problem. You feed your horse – that makes it your problem!
Consider where your horse came from that would affect his digestion. Off-track racehorses, rescued horses, performance horses, or simply grain fed at any time in his/her life. All these will have a higher risk. In fact, any horse is at risk of hindgut acidosis from conditions that don’t support microbial digestion.
The signs of hindgut ulcers should always be taken seriously. If you suspect your horse might be affected by hindgut ulcers, get him examined by your vet as soon as possible.
In some cases, hindgut ulcers might be unavoidable. However, you can greatly reduce his chances of developing this debilitating condition. The bottom line is to limit NSAID use, minimize stress whenever possible and manage/feed your horse appropriately.
What are Feed Balancers? Feed balancers, or ration balancers as they are sometimes referred to, are a versatile approach to feeding horses. Yet despite their usefulness, there is still so much misunderstanding of this type of horse feed. Whilst they might look like just another pelleted feed, they will provide that extra ‘punch’ to any feeding programme. We all want our horses to look and feel their very best with a happy outlook on life. Keeping their diets as close to nature as possible ie mostly forage, is the best way to achieve this.
So What Are Fibregenix Feed Balancers?
A Fibregenix balancer may seem like any other vitamin/mineral supplement for your horse. However, it provides every daily essential nutrient in a low-intake, low energy, highly concentrated source. And not just vitamins and minerals. Added extras such as specific digestive aids to promote a healthy gut and improve feed utilisation are also included. This makes a Fibregenix Feed Balancer the ultimate ‘all in one’ feed product.
These balancers are designed for when additional calories are not required. And they’re fed in much smaller amounts than standard hard feeds. Usually 100g per 100kg bodyweight (500 grams for a 500kg horse). Your standard 50-100g of a vitamin and mineral supplement just won’t match the functionality provided by a proper balancer.
So when, why and how would I feed a Feed Balancer?
Fibregenix Feed Balancers can be used in the following ways:
Fed alone as a low-calorie source of protein, vitamins, and minerals to balance forage.
Depending on forage quality, your horse should be able to get all his daily essential nutrients from pasture or hay. However, it’s widely recognised that modern forage and pasture is frequently deficient in minerals and other nutrients. Forage analysis can help you pinpoint exactly what is lacking. This is when a balancer is a great way to counteract these deficiencies. Furthermore, feeding the recommended daily amount of a balancer means no additional vitamin or mineral supplement should be required.
Fed alongside ‘Straights’.
Some owners prefer to incorporate ‘straights’ such as lupins, oats, barley etc with beet pulp, chaff, oil etc. Whilst great ingredients, they can leave a diet unbalanced in some specific areas such as macro minerals. So, a balancer is ideal for this type of feeding programme. The main components of the feed provide the calories. And the balancer is added to ‘fill in the nutritional gaps’ of these ingredients, supplying amino acids, vitamins and minerals.
Feeding less than recommended?
Concentrated balancers really come into their own if you need to feed less than the recommended quantities of a hard feed. For example, a performance muesli or pellet. Maybe you’re cutting back your horse’s feed to keep weight down or to avoid hot behaviour. In this way, balancers are ideal, providing essential nutrients for health and performance without additional energy (calories) or starch. They also give you the option of feeding smaller amounts of a lower energy hard feed. Then you can top up the nutrient, (but not energy) levels, to meet the increased demands of work or competition.
Many modern horse breeds maintain weight on limited calories, even when asked to perform hard work. Because of the concentrated nature and low feeding rate, a feed balancer can meet all the protein, vitamin, and mineral needs. And it does this without adding excessive calories or starch to the diet. Even those on stable rest/convalescing benefit from a source of essential nutrients without the calories, provided by a balancer.
Added Extras in Balancers:
Whilst feed balancers are a modern and cost-effective approach to feeding horses, you need to do your research. Not all balancers are created equal, and the best balancers should be:
- Ideally free from whole cereal and molasses.
- A specialist tailored range catering for different types of horses and ponies rather than a ‘one balancer suits all’ approach.
- High in functionality with specific digestive enhancers eg nucleotides and approved probiotics and prebiotics. These are key to ensuring digestive health and maximising nutrient yield from forage.
Take Home Message: Ultimately, the beauty of a feed balancer is the flexibility provided in customizing the nutritional management of individual horses. Keep your horse’s diet as simple as possible. This means more emphasis on fibre feeding as the healthiest approach for your horse. Keeping it simple with a Fibregenix feed balancer is an ideal means to satisfying nutritional demands even for working horses.
Tango Charlie fed on Fibregenix Platinum Pro
Bucks tucking into his Fibregenix
Here’s our ultimate guide to effective, simple feeding with balancers. So, you’ve taken the plunge and got your first bag of Fibregenix. A good decision made! Fibregenix feed balancers will be you and your horse’s best friends. Bucks certainly thinks so!
The 3 big questions we are most often asked.
1. How do I keep an effective, simple feeding regime with Fibregenix feed balancers?
Well, as you know, we are big promoters of fibre feeding in the first instance. It’s what is naturally best for your horse or pony, and what he/she has evolved to eat. So, it’s a no-brainer to keep your horse or pony’s diet mostly forage based. However, we do appreciate that there are times when your horse may require more calories (energy). Furthermore, not all horses are good doers. More on that later…
2. What other feeds do I feed with it?
Here are some suggestions to accompany your balancer (which is fed at 100g per 100kg of bodyweight). (Remember, to avoid dietary imbalances and potential nutrient conflicts, you generally shouldn’t need to feed additional supplements).
Fibregenix Prime Original for horses up to novice level, show horses & ponies, broodmares & foals:
Suggested Fibre feeds: Hay (cereal, meadow, legume), haylage, hay cubes, Lucerne chaff/pellets, cereal chaffs, shandy chaffs, beet pulp products. There are plenty to choose from but avoid heavily molassed products.
Fibregenix Platinum Pro for performance horses in hard work, veterans or those with compromised digestive systems.
Feed any of the fibre feeds as above and if feeding for slow-release energy eg endurance – oils/fats NB: Cold pressed linseed oil has the best balance of OM3:OM6)
Feeding for fast-release energy eg, eventing, racing, polo etc
Straight Grains: oats, (whole, crushed or naked); barley, (boiled or micronized); maize – (flaked/ micronized). Legumes eg lupins. Oil can also replace part of your grain ration. We suggest linseed oil or simple veggie oil. Standard hard feeds can also be partially replaced with any of the balancers. Be aware of the starch content of grains or standard hard feeds. Always feed in several small meals to avoid compromising the digestive system.
Healthy Horse Tip: A horse’s stomach can only hold approx. 0.5% of its bodyweight in feed at one time. Eg a 500kg horse’s stomach can only hold 2.5kg of feed. This includes not just hard feed, but chaff and any other additional feedstuffs eg beet pulp. So always keep within this parameter and split feeds into smaller meals. Yes, tedious I know but it’s all for the greater good! …
Fibregenix Lami Low-Cal – for laminitis prone horses and ponies and other metabolic issues, good doers, stable confinement.
Soaked hay, low NSC hay (preferably below 10%), low sugar chaff, unmolassed beet pulp. Restrict grazing or yard with appropriate amounts of soaked hay fed in a slow feeder net. (Never starve an overweight or laminitic horse or pony)
3. Do I still need to feed hard feed?
This totally depends on the type of work your horse/pony is doing. You also need to consider his breed type/temperament, or if he has any health issues. Always feed for the work being done, not what you think your horse is going to do. This means if you aren’t working your horse, back off the hard feeds! Generally, horses and ponies can be split into 3 types – good doers, normal doers and poor doers.
Good doers eg native ponies, cobs or horses with a naturally laid-back temperament. Fibre feeds alongside Lami Low-Cal balancer will suit these types best. Even in light to moderate work. And if in hard work, low energy feeds such as beet pulp or small amounts of legumes such as lupins or good quality forage will provide extra energy.
Normal doers are just that. They are easy to keep weight on but don’t get overly heavy or drop weight when the wind changes direction. Keep the diet high in fibre and monitor weight as you go along. Add legumes such as lupins and oil for grain free energy sources.
Poor Doers. This category of horse or pony often has a history of digestive issue – predominantly ulcers. (Stomach or Hindgut). They could also have a history of a heavy worm burden which can affect gut motility and create a horse which will be a poor doer all its life. They may be super sensitive types and have a hot temperament which can be genetic or due to the aforementioned gut issues eg TBs or Warmbloods. So, what do you feed a poor doer when high energy feeds are needed for work but must be limited or are totally off limits? Grain free energy sources eg lupins, beet pulp and oil/fat. We have customers with starred TB event horses that cannot tolerate grains. These horses do very well on a basic diet fed in appropriate amounts of course.
Meeting his daily feed requirements.
Bear in mind that your horse needs at least 2% of his bodyweight in total dry matter feed intake every day. If he drops off, firstly check the quality of your forage and how much you’re actually feeding.
Secondly, remember the Horse Health Tip of small regular feeds, rather than overburdening the digestive system. If you’re feeding heaps of feed and he isn’t gaining or is still dropping weight, consult with your vet. He may need scoping for ulcers, and they must be treated to heal and clear. Alternatively, there could be other digestive or health issues, so get him checked out.
Take Home message: Maintain a simple feed regime to keep your horse’s digestive system happy. Contact us if you need help with your horse’s diet. We’re always happy to advise and have a wealth of experience of feeding all types of horses and ponies whatever their workload/circumstances.
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RER, PSSM, Azoturia, Monday Morning disease, Set-fast…
So what exactly is tying up in horses? These muscle problems have previously had a variety of different names which have described the symptoms rather than the disease. However, advances in research have resulted in a better understanding of the disorders and more appropriate names have been introduced. Two distinct disease processes have been identified. Each one seeming to be prevalent in certain breeds, suggesting that a genetic factor is likely to be involved. Furthermore, it might be worth checking what you’re feeding…
Trigger Factors for Tying Up in Horses
One of the questions that frustrates owners of horses that suffer with tying up is why does it happen one day and not the next? Often, there’s no obvious reason why the problem occurred on any given day. However in some cases it can be that a number of trigger factors all coincided sufficiently to tip the balance. Possible trigger factors include
- not reducing the feed prior to a day off,
- not warming-up or cooling down properly,
- high starch diets,
- viral infections.
On their own, the horse can often tolerate one or other of these factors but when several combine, problems can occur.
Symptoms of Tying Up in Horses
The degree of severity of the symptoms of tying up in horses can vary enormously. A horse may appear slightly stiff but is still able to work to some degree. Alternatively, it could be a complete seizing of the muscles so that the horse can’t move. If the symptoms are only very slight then it’s very difficult to diagnose the problem as there could be several other causes. When seeking advice from a vet or nutritionist it’s very important you give details of when the problem occurred. For example, was it before, during or after the horse had worked? You will also need to provide details about the horse’s regime that day to enable them to advise you on a suitable diet.
DIET SUGGESTIONS FOR TYING UP IN HORSES
POLYSACCHARIDE STORAGE MYOPATHY (PSSM)
- Quarter horses, Warmbloods and draught horses are most commonly affected
- Typically, quiet laid back animals but with no gender bias
- Prevents normal metabolism of glycogen which is how the horse stores starch and sugars in his muscles
- Eliminate cereal grains and molasses from the diet
- Use oil and fibre as energy sources according to the horse’s bodyweight and workload
- Provide a balance of vitamins, minerals and protein
How to achieve this:
Step 1 – Feed plenty of forage – Forage should form the basis of all horse’s diets but is particularly important in horses that can’t tolerate large amounts of grain. Select as good a forage as possible as this will provide more energy and nutrients which will help to meet the horses overall requirements.
Step 2 – Select a balancer – Fibregenix Lami Low-Cal for horses in light to moderate work or Fibregenix Platinum Pro for horses and ponies in moderate to hard work. These will provide the nutrients required to maintain health and condition and for work.
Step 3 – Add oil or highly digestible fibre – A high oil supplement can be fed alongside a balancer and provides a concentrated source of slow-release calories. Sources of highly digestible fibre, eg beet pulp, are also useful.
(RECURRENT) EXERTIONAL RHABDOMYOLYSIS (RER/ERS)
- Thoroughbreds and Standardbreds most commonly affected
- Excitable, highly-strung increases risk, with fillies more prone
- A stress-related disorder involving disruption of normal muscle calcium regulation
- Reduce the starch content of the diet
- Ensure that any cereals in the diet have been cooked
- Ensure the diet is balanced
How to achieve this:
Step 1 – Choose a feed with as low a starch content as possible – Feeds which contain high levels of digestible fibre and oil, as energy sources. These will be lower in starch than those which are primarily cereal-based. Generally, pellets/cubes will also have a lower starch content than a mix with an equivalent Digestible Energy content.
Step 2 – Check that the feed used is appropriate for the type and level of work the horse is doing and fed at recommended levels to ensure a fully balanced diet – Feeds are formulated to be fed at certain levels. However, using the wrong one or feeding less than recommended can mean that the horse isn’t receiving sufficient nutrients. Unfortunately, increasing the feed can result in over-exuberant behaviour or weight gain. Therefore a good alternative is to add a Fibregenix balancer to provide nutrients without energy.
Step 3 – Add an electrolyte supplement – ERS is most common in horses in hard, fast work and so an electrolyte supplement is vital to replace salts lost in sweat.
Management Tips for Tying Up in Horses
- Warm up and cool down the horse thoroughly
- Do not confine the horse to the stable for long periods
- An episode of ERS often seems to occur after the horse has suffered with a virus. If you suspect your horse has a virus then reduce the workload, particularly if the horse has had RER/ERS before.
Electrolytes are minerals that, when in solution, dissociate and have electrical charges. The concentrations of electrolytes affect the movement of body fluids between cells. Most of the sodium, chloride and much of the water, lost in sweat comes from the extracellular fluid. This fluid consists of the plasma portion of blood and the interstitial fluid which surrounds the cells in the body. Most of the potassium and some of the water comes from the intracellular fluid (water inside the cells).
The most effective way to re-hydrate a horse is to supply water and electrolytes. This is more effective than either on their own. Ideally, electrolytes should therefore be added to the water. However, if this puts the horse off drinking, add them to the feed but make it wet and slushy.
Take home message:
Follow appropriate management procedures and nutrition for tying up in horses. This will help reduce the likelihood or frequency of episodes even for those with an underlying genetic susceptibility.
Reviewed and republished April 2021
If you’ve ever wondered what is a low-starch diet for horses, and more importantly, should my horse be on one, then you’re not alone. However, it isn’t ideal for all horses. Ultimately, it will depend on their caloric requirements, the work they’re in and existing health conditions..
Forages should of course be the basis of any diet and are 75-90% carbohydrates. Carbohydrates include sugars, starches, and some fibre. These carbohydrates found in pasture and hay fall into two broad categories: nonstructural and structural. So horses actually rely on carbohydrates as the largest portion of their diet. Especially soluble and insoluble fibres that make up forage.
Carbs, sugars and starches in forage.
Non-structural carbohydrates (NSCs) in forages are simple sugars and fructans and can be readily digested or fermented by horses. They are produced in plants during warmer weather, and are higher in more immature forages. Pasture is usually lowest in NSCs in the early morning unless overnight temperatures are cold. However, these carbohydrates can affect some disease processes, so you need to monitor how much your horse eats.
Carbs, sugars, and starches in your horse’s hard feed
Grain based hard feeds contain carbohydrates, including simple sugars and starch. Grains such as barley, maize and oats are high in NSCs, mostly starches. Starches are long chains of attached sugar molecules. These sugars get broken apart during the digestive process and the simple sugars (glucose) readily absorbed. Most horses can digest and absorb sugars and starches in the small intestine through a process called hydrolysis. From there, glucose in the bloodstream triggers the pancreas to release insulin. Then the glucose molecules move into cells for storage as glycogen. This is the fuel for the working muscles.
If there’s more starch in a single meal than the horse can digest, starch will enter the caecum, (the first part of the hindgut after the small intestine). Any undigested starch here is rapidly fermented creating lactic acid. This lowers hindgut pH, killing the good bacteria that live there. The endotoxins released from microbial death can then contribute to both colic and laminitis.
So, just how much starch is in a low-starch diet for horses?
A “low-starch” feed usually contains less than 15% starch, but some feed companies might classify low-starch as any feed below 20%. Compare this to a traditional hard feed with grains such as barley, maize and oats as its base. These types of feed might be as much as 40-60% starch. A “mid-level” starch content is usually between 20 and 25%. Whilst many horses are fed high starch feeds seemingly without problems, the key consideration that still remains for any horse is how much starch is fed in any one meal.
Ultimately, there is no single definition of a “low- starch” diet as both sugar and starch concentrations are important. Therefore, it’s better that feeds are referred to as ‘low-sugar and starch’ or ‘low nonstructural-carbohydrates (NSC). NSC is a laboratory measure containing starch plus all water-soluble carbs (sugars and fructans). The recommendation for horses with metabolic issues therefore is not actually low-starch but low-Non-Structural Carbohydrates. So, if f low starch/low NSC is a primary concern for your horse and it’s not quoted on your bag of feed, then contact the feed manufacturer directly to find out.
Starch Content of Common Feed Ingredients
|Legume hay (besides lucerne)
|Mixed, Mostly Grass, Pasture
|Beet Pulp, Dried, No Molasses
|Maize, Whole Grain
Data collected from Equi-Analytical Laboratories
When should your horse have a low-starch diet?
For some horses with certain health conditions, vets and nutritionists might recommend a low-starch diet to help maintain blood glucose at a steady level. These are conditions that cause horses to become more sensitive to sugars and starches. This then means that owners will need to reduce these levels in both forages and concentrates. Individual horses have variable responses related to a variety of factors, including age, body condition, fitness, metabolic status, and disease status.
Obesity and equine metabolic syndrome (EMS)
These metabolic conditions are of major concern and there needs to be an overall reduction in calories consumed, not just from starches. Some breeds, especially pony breeds are “metabolically thrifty”, so they’re able to readily convert glucose into fat for storage. They will benefit from a lower-quality forage and no hard feed. This is where a quality feed balancer supplement such as one from the Fibregenix range, is ideal. It will provide vitamins, minerals, protein, fatty acids and other essential nutrients to bridge nutritional gaps in forage.
Insulin dysregulation (ID)
Insulin dysregulation is considered a component of EMS. In affected horses or ponies, insulin is not effective at transporting glucose from the bloodstream into cells, so both remain elevated. This can increase susceptibility to laminitis. Horses with this condition are extremely sensitive to starches. Ideally, they should be on as low a starch and, specifically, soluble-carbohydrate diet as possible.
Pituitary pars intermedia dysfunction (PPID, formerly Equine Cushing’s)
This endocrine disease mostly affects horses or ponies over the age of 15. Some, but not all, PPID horses will require a lower-starch diet. PPID horses that are also insulin-dysregulated are the ones which will benefit. However, some PPID horses are thin, non-insulin-dysregulated, and they need calories. In such cases a more traditional NSC level is fine.
Polysaccharide storage myopathy (PSSM)
Horses with this muscle disorder often have a normal glucose/ insulin metabolic process. They’re unable to use the form of glucose stored in their cells as energy and are also susceptible to tying-up (exertional rhabdomyolysis). This is the breakdown or destruction of skeletal muscle cells associated with exercise.
Laminitis prone horses and ponies should also have diets low in soluble carbohydrates and starch. Elevated levels of starch reaching the hindgut can lead to hindgut acidosis, killing off the good microbes. This releases endotoxins, which can negatively affect enzymes involved in maintaining the integrity of the laminae in the hoof leading to laminitis. Susceptible horses should not be allowed to graze immature or lush, rapidly growing pasture routinely found in spring and early autumn.
Gastric ulcers (EGUS)
Signs of this condition include poor performance, poor attitude, and mild colic. Horses prone to ulcers and hindgut acidosis benefit from a low-starch/high fibre diet. This is because chewing and consuming fibrous carbohydrates produces more saliva which in turn helps reduce acidity in the stomach.
Anxious or hyperactive horses may also benefit from less starch in their diets. Multiple studies (Bulmer et al., 2019; Destrez et al., 2015) have focussed on the diet’s effect on behaviour. But more recently, they’ve focussed on the “why” behind this. The latest studies have revealed that glucose is a sugar that easily crosses the blood-brain barrier. Elevated glucose levels are associated with increased dopamine production. And this can lead to elevated awareness or hyperexcitability.
Should you change your horse to a low-starch diet?
If your horse doesn’t have any of the aforementioned conditions, then he probably doesn’t need a low-starch diet. In fact, performance horses benefit from a diet with readily available carbohydrates needed to replace the stored glycogen in skeletal muscle. Especially those that do anaerobic exercise (short bursts of high-intensity training) during work. When muscle glycogen is low, the muscle adapts by slowing contraction rate and power to conserve fuel (glycogen). This is obviously not desirable in a competition horse. Traditional hard feeds with grains such as barley, maize and oats as its base might be as much as 40-60% starch. A “mid-level” starch content is usually between 20 and 25%. Whilst many horses are fed high starch feeds seemingly without problems, the key consideration that still remains for any horse is how much starch is fed in any one meal.
Similarly, hard keepers might not be good candidates for low-starch feeds either, unless you increase the fat content in the diet. These horses need more readily available calories than the fibrous ingredients often used in low- starch feeds.
The table below shows ideal targets to follow when considering how much starch your horse should have.
||% starch in your hard feed
|To avoid starch overload,rapid fermention in the h/gut
||50-65% for sweet feeds, 45-75% for straight grains
|To avoid risk of gastric ulcer syndrome
|For metabolic disorders such as IR, Cushings, laminitis etc
Making Changes To a Horse’s Diet Safely
Any changes MUST be slow and gradual so as not to upset the hindgut microflora. Gut microbes must have time to adjust to a new diet, so it’s generally accepted to make the complete transition over about two weeks.
For horses needing a low-starch concentrate, transition them the same way you would to any new diet. Start with a meal that is ¼ of the new feed and ¾ old feed and stay at this level for four days. Move up to ½ and ½ for another four days. Then switch to ¾ new feed and ¼ old feed for another four days. By the end of this period, you should be able to feed a full meal of the new feed. If you are concerned about NSC levels in forage, then limit pasture access when they’re elevated (e.g. during spring grass growth). Soak hay before feeding. Just remember to discard the soak water, so the horse doesn’t drink it.
What if a sudden change can’t be avoided?
Sometimes, the transition to a low-starch diet has to happen suddenly. For instance, after a metabolic event (e.g., laminitis) where the horse is moved from lush pasture to being yarded. Or begins to wear a grazing muzzle. In these cases, you don’t have days or weeks to make the change. So watch your horse carefully for signs of digestive disturbance such as diaorrhea. If signs develop (and if possible), back off the transition rate and make the conversion more slowly.
What if you have more than one horse and only one requires a low-starch diet? You might be tempted to think you could feed all the horses the same feed. However, whilst it may make feeding more convenient, you still have to consider each individual horse’s needs and feed accordingly.
Feeding for individual needs
What if you have more than one horse and only one requires a low-starch diet? Tempted to feed all the horses the same feed? Whilst it may make feeding more convenient, you still have to consider each individual horse’s needs.
5 Take-home messages
- A low-starch diet might be a suitable option for your horse, but it depends on his health status.
- Horses in good body condition, fit for their discipline, with high caloric demands can cope on a more traditional feed containing higher starch levels. Even so, care must still be taken with how much starch is fed in any one meal.
- Before making any changes, talk to your vet or an equine nutritionist.
- Find out how much starch is in your horse’s feed when the term “low starch” is used. This will ensure you are making decisions based on the best information available.
- Always make any changes to the diet gradually so as not to upset the digestive microbes.
Reviewed and amended April 2021