How To Prevent Tying Up in Horses Through Nutrition

By Dr Duncan Houston

Tying up is one of those horse problems that can look dramatic, painful, and frightening very quickly.

A horse may start stiffening during work, refuse to move forward, sweat heavily, tremble through the hindquarters, or stand locked in place like every muscle has suddenly gone wrong. In severe cases, muscle cells break down and release myoglobin, which can darken the urine and place stress on the kidneys.

Nutrition matters, but tying up is not one disease with one diet.

Some horses tie up after overexertion, dehydration, heat stress, or an abrupt change in workload. Some have recurrent exertional rhabdomyolysis, or RER, where stress, excitement, high-grain feeding, and exercise routine can trigger repeated episodes. Others have polysaccharide storage myopathy, or PSSM, where muscle fuel storage is abnormal and diet plus daily movement are central to control.

The best feeding plan depends on which type of tying up your horse has.

Quick Answer

Tying up, or exertional rhabdomyolysis, is painful muscle damage that occurs during or after exercise. Nutrition can help prevent episodes by matching calories to workload, avoiding large high-starch grain meals, feeding adequate forage, maintaining hydration and electrolytes, and using low-starch, higher-fat diets in horses with PSSM or some recurrent forms of tying up. Horses with active tying up signs, severe stiffness, sweating, dark urine, weakness, or reluctance to move need veterinary care immediately, because severe muscle damage can affect the kidneys. Merck Veterinary Manual notes that PSSM management requires both diet change and gradual increases in daily exercise and turnout. (MSD Veterinary Manual)

What Is Tying Up in Horses?

Tying up is the common name for exertional rhabdomyolysis.

It means muscle fibres are damaged during or after exercise. The damaged muscle cells leak enzymes and muscle pigments into the bloodstream, including CK, AST, and sometimes myoglobin.

Common signs include:

• Stiffness during or after exercise

• Painful, firm muscles over the back, loin, croup, or hindquarters

• Sweating

• Trembling

• Reluctance to move

• Short, stiff steps

• Anxiety or distress

• Increased heart rate

• Dark red, brown, or coffee-coloured urine in severe cases

• Collapse or recumbency in extreme cases

Merck describes exertional rhabdomyolysis as muscle pain, stiffness, sweating, reluctance to move, and increased muscle enzymes, with severe cases potentially causing myoglobinuria and kidney compromise. (Merck Veterinary Manual)

The key owner rule is simple:

If your horse is actively tying up, stop exercise immediately and call your vet.

Do not walk them around aggressively to “loosen them up.” That can worsen muscle damage.

Is Tying Up Always a Nutrition Problem?

No.

Nutrition is important, but tying up can be triggered by several overlapping factors.

Common contributors include:

• Sudden intense exercise

• Exercise after rest while still receiving high-energy feed

• Poor conditioning

• Heat and humidity

• Dehydration

• Electrolyte loss

• Stress or excitement

• High-starch grain meals

• Irregular exercise schedule

• PSSM

• RER

• Muscle disease

• Metabolic disease

• Pain or lameness changing muscle use

• Viral illness or systemic disease in some cases

Rutgers lists treatment priorities for tying up as maintaining hydration, replenishing electrolytes, pain management, muscle relaxation, monitoring blood and urine markers, and preventing further muscle damage while promoting blood flow and recovery. (esc.rutgers.edu)

So nutrition is one part of prevention. It is not the whole answer.

The best plan combines diet, exercise routine, hydration, electrolyte support, turnout, stress reduction, and veterinary diagnosis.

Sporadic vs Recurrent Tying Up

Tying up is usually divided into two broad categories.

Type	What it means	Typical trigger
Sporadic tying up	One-off or occasional episode in a horse without a chronic muscle disorder	Overexertion, heat, dehydration, electrolyte loss, sudden workload increase, feed and exercise mismatch
Recurrent tying up	Repeated episodes, often due to an underlying muscle disorder or inherited tendency	PSSM, RER, stress, high starch feeding, irregular exercise, genetic predisposition

This distinction matters because the feeding plan is different.

A horse that tied up once after a hard ride in hot weather may need better conditioning, hydration, and electrolyte management.

A horse with PSSM needs long-term low-starch feeding and daily exercise.

A fit Thoroughbred with RER may need a lower-starch, higher-fat performance diet, consistent training, and stress management.

One label. Several very different horses.

When Is Tying Up an Emergency?

Tying up becomes urgent when the horse is painful, stiff, weak, or showing signs of significant muscle damage.

Call your vet immediately if your horse has:

• Sudden severe stiffness

• Refusal to move

• Heavy sweating

• Trembling or muscle fasciculations

• Painful hard hindquarter or back muscles

• Dark brown, red, or coffee-coloured urine

• Depression or weakness

• Collapse or recumbency

• Rapid breathing

• Very high heart rate

• Signs after intense exercise, heat stress, or dehydration

• Repeated tying-up episodes

• Any episode in a horse with known PSSM, RER, HYPP, or previous severe muscle disease

Dark urine is especially concerning because it may indicate myoglobin release from damaged muscle. Severe rhabdomyolysis can contribute to kidney injury, especially if the horse is dehydrated. (Merck Veterinary Manual)

What Should You Do During an Episode?

If your horse starts tying up:

1. Stop exercise immediately
   Do not keep riding, lunging, or forcing the horse forward.

2. Keep the horse calm
   Stress can worsen struggling and muscle tension.

3. Call your vet
   Your vet may need to check CK, AST, kidney values, electrolytes, hydration, and urine colour.

4. Do not force walking
   Gentle movement may be appropriate only if your vet advises it. A painful horse should not be marched around.

5. Offer water
   Do not force water or feed if the horse is distressed or at risk of choking.

6. Keep the horse comfortable
   Shade, shelter, and a quiet area matter. Avoid chilling a sweaty horse in cold weather.

7. Do not give random medication
   NSAIDs may be used by your vet, but kidney risk, dehydration, and severity matter.

8. Monitor urine
   Tell your vet if urine is dark, red, or brown.

Tying up is not a “feed a supplement and wait” situation when signs are active.

How Vets Diagnose the Type of Tying Up

Your vet may use:

• History of exercise, rest days, feed changes, and stress

• Physical exam

• Muscle palpation

• Bloodwork for CK and AST

• Kidney values

• Electrolytes

• Urinalysis for myoglobin

• Genetic test for PSSM1

• Muscle biopsy in selected cases

• Testing for other disorders such as HYPP where relevant

• Review of diet and forage analysis

• Assessment of exercise routine

UC Davis notes that PSSM1 is caused by a known genetic mutation and DNA testing is available, while PSSM2 is less clearly defined and currently lacks scientifically verified DNA tests, with muscle biopsy used for diagnosis in some cases. (ceh.vetmed.ucdavis.edu)

That distinction is important. Do not rely on unvalidated genetic panels to make major diet or breeding decisions without veterinary guidance.

Nutrition Goal 1: Feed Forage First

Forage should be the foundation of the diet.

Most horses should receive about 1.5% to 2% of body weight per day in forage, adjusted for body condition, workload, metabolic status, and veterinary advice.

For a 500 kg horse, that is roughly 7.5 to 10 kg of forage per day.

Forage helps:

• Maintain gut health

• Reduce large starch meals

• Support hydration through normal chewing and gut fill

• Provide steady energy

• Reduce stress from long fasting periods

• Support more stable behaviour in some horses

Merck’s PSSM feeding guidance includes forage at 1.5% to 2% of body weight as the basis of the diet. (MSD Veterinary Manual)

The important part is not just “feed hay.”

It is feeding the right forage, in the right amount, for the right horse.

Should You Avoid Alfalfa?

Not always.

The draft says straight alfalfa is discouraged because of high calcium and protein. That needs nuance.

Alfalfa can be useful in some horse diets. It can provide quality protein, calcium, and calories. The problem is when the total ration is too energy-dense, mineral balance is inappropriate, or the horse is gaining too much weight.

For tying-up-prone horses, the bigger concerns are usually:

• Excess starch and sugar

• Feed and exercise mismatch

• Excess calories causing obesity

• Poor electrolyte intake

• Low vitamin E in horses with little pasture

• Selenium deficiency or excess depending on region

• Sudden feed changes

• Long fasting followed by large meals

Alfalfa is not automatically dangerous. It should be evaluated as part of the whole ration.

If the horse has PSSM and is overweight, rich forage may need to be limited. If the horse is a hard-working athlete with high calorie needs, some alfalfa may be appropriate.

Test the forage. Do not guess.

Nutrition Goal 2: Reduce Starch and Sugar Where Needed

High-starch feeds can be a major trigger in some tying-up horses, especially horses with PSSM or RER.

Feeds to limit or avoid in susceptible horses often include:

• Sweet feed

• Large oat meals

• Corn-heavy feeds

• Molasses-heavy feeds

• High-starch performance mixes

• Large concentrate meals

• Sugary treats in excess

For PSSM horses, Merck recommends limiting starch to less than 10% of daily digestible energy and replacing grain calories with fat where needed. (MSD Veterinary Manual)

University of Minnesota explains that PSSM horses tend to be more insulin sensitive, and sugar from the diet can stimulate an insulin response that worsens excessive glycogen storage in PSSM1. (University of Minnesota Extension)

The practical message:

For horses with PSSM, low-starch feeding is not optional. It is central management.

Nutrition Goal 3: Add Fat Carefully

Fat can provide calories without the same insulin and starch load as grain.

Useful fat sources may include:

• Stabilised rice bran

• Vegetable oil

• Flaxseed

• Commercial high-fat, low-starch feeds

• Fat-supplemented ration balancers or performance feeds

Fat is especially useful when a horse needs more calories but should not receive high-starch grain.

Merck notes that the ideal PSSM diet provides more than 15% of digestible energy as fat while limiting starch, but also warns that caloric needs must be assessed first to avoid obesity on a high-fat diet. (MSD Veterinary Manual)

That warning matters.

Fat is not magic. It is still calories.

A fat pony with PSSM does not need to be drowned in oil. They need a low-starch, calorie-controlled diet plus regular movement.

Nutrition Goal 4: Match Feed to Workload

A common tying-up trigger is continuing to feed a high-energy ration when exercise suddenly drops.

This happens when:

• Weather interrupts training

• The horse gets a day off but receives full grain

• Travel disrupts routine

• A competition horse rests after a hard event

• Injury causes sudden stall rest but feed is not adjusted

• The owner keeps feeding for a workload the horse is no longer doing

In practice, this is one of the simplest prevention wins.

If work decreases, high-energy concentrate usually needs to decrease too.

Do not suddenly starve the horse. Maintain forage. Adjust grain, starch, and calories to match actual work.

Nutrition Goal 5: Hydration and Electrolytes

Dehydration and electrolyte loss can contribute to sporadic tying up, especially in hot, humid weather or after heavy sweating.

Key electrolytes include:

• Sodium

• Chloride

• Potassium

• Calcium

• Magnesium

For most horses, plain salt is the foundation. Many horses need loose salt added to feed because salt blocks alone may not provide enough intake.

Electrolyte supplementation may be useful when horses:

• Sweat heavily

• Travel

• Compete

• Work in hot or humid conditions

• Are in endurance or high-intensity training

• Have recurrent mild muscle cramping associated with sweating

Rutgers includes maintaining hydration and replenishing electrolytes among the key treatment principles for tying up. (esc.rutgers.edu)

Do not give electrolyte paste to a dehydrated horse that is not drinking. Electrolytes need water intake to be safe and useful.

Nutrition Goal 6: Vitamin E and Selenium

Vitamin E and selenium support muscle health, antioxidant function, and cell membrane stability.

Deficiency can contribute to muscle problems, but excess selenium can be toxic.

Vitamin E may be especially important for horses with:

• No pasture access

• Poor-quality hay

• Neuromuscular disease

• High workload

• Muscle soreness

• Confirmed deficiency

Selenium depends heavily on region. Some areas are deficient. Some are high. Supplementing selenium without knowing the diet and local risk is not smart.

The safest approach is:

• Test forage where possible

• Review total selenium intake from all feeds and supplements

• Consider blood vitamin E or selenium testing in recurrent muscle cases

• Supplement based on veterinary advice

Do not stack multiple supplements that all contain selenium. That is how “helping” turns into poisoning.

PSSM: The Nutrition Plan

Polysaccharide storage myopathy is a muscle glycogen storage disorder. PSSM1 is associated with the GYS1 mutation, and affected horses store abnormal amounts of glycogen in muscle.

Commonly affected breeds include:

• Quarter Horses

• Paints

• Appaloosas

• Draft breeds

• Warmbloods

• Some stock horse lines

• Crossbreds

UC Davis states there is no cure for PSSM, but most affected horses can be managed successfully with diet and exercise. (ceh.vetmed.ucdavis.edu)

The core PSSM plan is:

• Forage-first diet

• Low starch and sugar

• Calories controlled to avoid obesity

• Fat used only where extra energy is needed

• Vitamin and mineral balance

• Regular daily exercise

• As much turnout as practical

• Avoid long periods of stall rest

• Avoid sudden diet changes

• Avoid irregular exercise schedules

Merck states that improvement in PSSM requires both dietary change and gradual increases in daily exercise and turnout. (MSD Veterinary Manual)

This is the phrase owners need to remember:

PSSM is managed in the feed bin and in the exercise schedule.

Not one or the other.

RER: The Nutrition Plan

Recurrent exertional rhabdomyolysis, or RER, is different from PSSM.

It is often seen in fit, excitable, high-strung horses, especially Thoroughbreds, Standardbreds, and Arabians. University of Minnesota notes that Thoroughbreds are particularly susceptible to recurrent exertional rhabdomyolysis, with 5% to 10% of Thoroughbreds developing ER during a racing season. (College of Veterinary Medicine)

Common triggers include:

• Excitement

• Stress

• High grain intake

• Stall confinement

• Irregular exercise

• Nervous temperament

• Sudden changes in routine

• Fitness and workload mismatch

The RER diet often aims to:

• Reduce starch

• Replace some grain calories with fat

• Maintain enough calories for athletic work

• Keep meals consistent

• Avoid large grain feeds

• Maintain electrolytes

• Reduce stress around feeding and exercise

Merck notes that horses with recurrent exertional rhabdomyolysis often need higher caloric intakes than PSSM horses, and at high workloads specialised feeds designed for exertional rhabdomyolysis may be needed because oil or rice bran alone may not supply enough calories. (Merck Veterinary Manual)

This is where RER differs from an overweight PSSM horse.

A race-fit RER horse may still need substantial calories. The goal is not low-energy feeding. The goal is lower starch with enough safe energy for work.

PSSM vs RER: Why the Diet Is Not the Same

Feature	PSSM	RER
Common issue	Abnormal glycogen storage	Abnormal muscle contraction regulation and stress-related episodes
Common horse type	Stock horses, drafts, Warmbloods, easy keepers	Thoroughbreds, Standardbreds, Arabians, fit excitable horses
Diet goal	Low starch, calorie control, fat if needed	Lower starch, higher fat performance calories if workload requires
Exercise goal	Daily steady exercise and turnout	Consistent routine, avoid stress, avoid irregular work
Key mistake	Feeding too much energy to an easy keeper	Cutting calories too much in a high-performance horse

This is why “low starch and high fat” is not a complete answer.

You still need to know which horse you are feeding.

How Worried Should You Be?

Low Risk

This is more likely when:

• The horse had one mild episode after unusual exertion

• Signs resolved quickly with rest and veterinary guidance

• CK elevation was mild

• No dark urine was seen

• The horse has no history of repeated episodes

• The diet and workload mismatch is obvious and correctable

Action: review conditioning, hydration, electrolytes, feed on rest days, and return to work gradually.

Moderate Risk

This is more likely when:

• The horse has had more than one episode

• Stiffness appears after normal work

• The horse is on high-starch grain

• The horse is overweight or an easy keeper

• The horse is excitable or stressed

• Episodes occur after rest days

• Muscle enzymes are clearly elevated

Action: get a veterinary workup. Review PSSM, RER, electrolyte status, forage, workload, and exercise routine.

High Risk

This is more likely when:

• The horse ties up repeatedly

• Episodes occur with light exercise

• The horse has dark urine

• The horse is very painful or reluctant to move

• CK is markedly elevated

• Kidney values are abnormal

• PSSM or RER is suspected

• The horse is in heavy work and cannot maintain training safely

Action: stop training until your vet has a diagnosis and prevention plan. Diet change alone may not be enough.

Critical

Treat this as an emergency if:

• The horse cannot move

• The horse is recumbent

• Dark urine is present

• Severe sweating or distress occurs

• The horse is weak or collapsing

• Breathing is abnormal

• The horse is dehydrated or heat stressed

• Severe pain persists

• Kidney compromise is suspected

Action: call your vet immediately. This horse may need fluids, pain control, bloodwork, electrolyte correction, and kidney monitoring.

What Else Can Look Like Tying Up?

Not every stiff or painful horse is tying up.

Important rule-outs include:

Colic

Some horses with colic sweat, resist moving, paw, or appear stiff. A colic horse may lie down, look at the flank, roll, or stop passing manure.

Laminitis

Laminitis can cause reluctance to move, stiffness, and a rocked-back stance. It is a hoof emergency, not a muscle cramp.

HYPP

HYPP can cause trembling, weakness, muscle fasciculations, collapse, and breathing noise in Quarter Horse-related breeds. It is a potassium-related genetic disorder and needs different management.

Shivers

Shivers causes abnormal hindlimb movement, especially when backing or lifting the hind feet. It is neurological, not the same as tying up.

Exertional Heat Illness

Heat stress can cause weakness, sweating, collapse, high temperature, and muscle damage.

Back or Sacroiliac Pain

Back pain can make a horse stiff, reluctant, and short behind.

Tendon or Ligament Injury

A horse may suddenly stop or refuse to move because of a limb injury rather than muscle disease.

Seasonal Pasture Myopathy

This toxin-related muscle disease can cause severe weakness, stiffness, dark urine, and high mortality. It is not ordinary exertional tying up.

The diagnosis matters because the treatment is different.

What Should You Do Right Now if Your Horse Is Tying Up?

1. Stop exercise immediately.

2. Call your vet.

3. Keep the horse calm.

4. Do not force movement.

5. Offer water if the horse is calm and able to drink.

6. Keep the horse warm if sweating in cold weather.

7. Provide shade and cooling if heat stress is possible.

8. Do not give extra grain.

9. Do not give random supplements.

10. Monitor urine colour.

11. Wait for veterinary advice before giving medication.

Once your vet has assessed the horse, the plan may include bloodwork, fluids, NSAIDs, muscle relaxants, electrolytes, and repeat CK monitoring.

Rutgers specifically lists blood and urine monitoring as part of tying-up treatment. (esc.rutgers.edu)

What To Feed After a Tying-Up Episode

This depends on severity and diagnosis.

In the short term, many horses need:

• Forage

• Water

• Salt

• No high-starch grain

• Electrolyte correction if deficient

• A calm environment

• Veterinary-guided return to feeding and exercise

Do not immediately add lots of fat, magnesium, selenium, vitamin E, and multiple “muscle support” products all at once. That makes it impossible to know what is helping and increases the risk of over-supplementation.

The first step is stabilisation.

The second step is diagnosis.

The third step is a targeted diet plan.

Building a Prevention Diet

A practical tying-up prevention diet should answer these questions:

• Is the horse overweight, underweight, or ideal?

• How much work is the horse actually doing?

• Is the horse an easy keeper or hard keeper?

• Has PSSM1 been ruled in or out?

• Is RER suspected?

• What is the forage NSC?

• How much starch is in the concentrate?

• How much fat is already in the ration?

• Is salt intake adequate?

• Are electrolytes needed for workload and sweating?

• Is vitamin E intake adequate?

• Is selenium deficient, adequate, or excessive in the region?

• Are rest-day feeds adjusted?

• Is turnout consistent?

• Is exercise routine consistent?

A good diet is not a product. It is a calculation.

What Should a PSSM-Friendly Diet Look Like?

For a horse with confirmed or strongly suspected PSSM, discuss a plan with your vet or nutritionist based on:

• Forage at about 1.5% to 2% body weight

• Low starch and sugar intake

• Limiting starch to less than 10% of daily digestible energy

• Using fat as an energy source only when needed

• Avoiding obesity

• Balanced minerals

• Vitamin E support where appropriate

• Regular daily exercise

• Turnout rather than prolonged stalling

These points align with Merck’s PSSM diet guidance. (MSD Veterinary Manual)

If the horse is overweight, the focus should be low-starch and calorie-controlled.

If the horse is thin and working, fat may be useful to maintain condition.

What Should an RER-Friendly Diet Look Like?

For a horse with suspected RER:

• Reduce high-starch grain load

• Use a specialised low-starch, higher-fat performance feed when calories are needed

• Feed smaller meals

• Keep feeding times consistent

• Maintain adequate forage

• Maintain salt and electrolytes

• Avoid sudden feed changes

• Reduce stress around feeding and training

• Avoid long stall confinement where practical

• Keep exercise routine consistent

For high-calorie performance horses with RER, Merck notes that specialised feeds may be needed because rice bran or oil alone may not supply enough energy. (Merck Veterinary Manual)

Supplements: Useful or Overrated?

Supplements can help when they correct a real deficiency or support a clear diagnosis.

Potentially useful:

• Salt

• Electrolytes for heavy sweating

• Vitamin E when intake or blood levels are low

• Selenium only when appropriate

• Magnesium only if deficient or indicated

• Balanced ration balancer if forage is not complete

Often overused:

• Random muscle powders

• Multiple selenium products

• High-dose magnesium without a reason

• Large amounts of oil in overweight horses

• “Tying-up cures” with no diagnosis

A supplement should fill a gap.

It should not hide a broken feeding and exercise plan.

Common Mistakes Owners Make

Feeding Full Grain on Rest Days

This is a classic trigger. If exercise drops, high-energy concentrate often needs to drop too.

Assuming All Tying Up Is PSSM

PSSM is common in some breeds, but RER, sporadic ER, heat stress, electrolyte loss, and other diseases can all cause muscle damage.

Adding Fat Without Checking Calories

Fat helps some horses but makes others obese. Obesity can worsen metabolic strain and lameness.

Cutting Forage Too Much

Forage supports gut health and reduces stress. Restricting calories should be done carefully, not by leaving the horse hungry for long periods.

Ignoring Electrolytes

Heavy sweating horses may need electrolyte support, especially sodium and chloride.

Giving Selenium Blindly

Selenium has a narrow safety margin. Test or calculate first.

Resting Too Long Without a Plan

PSSM horses often worsen with long periods of inactivity. Exercise should resume gradually once pain subsides and your vet approves. UC Davis and Merck both emphasise diet plus regular exercise for PSSM management. (ceh.vetmed.ucdavis.edu)

Returning to Full Work Too Fast

Muscle enzymes may still be elevated after signs improve. Follow your vet’s guidance.

Prevention: The Practical Checklist

To reduce tying-up risk:

• Feed forage first

• Test hay when possible

• Avoid large high-starch meals in susceptible horses

• Match concentrate to actual workload

• Reduce grain on rest days

• Use low-starch feeds for PSSM and many RER horses

• Use fat carefully when extra calories are needed

• Maintain salt intake

• Add electrolytes for heavy sweating

• Test or calculate selenium before supplementing

• Provide vitamin E if forage and pasture intake are low

• Maintain daily turnout where possible

• Keep exercise consistent

• Warm up properly

• Avoid sudden intense work

• Avoid long stall rest in PSSM horses once pain has resolved

• Keep stress and excitement low in RER-prone horses

• Recheck CK and AST after significant episodes

• Build a return-to-work plan with your vet

The prevention plan is not glamorous. It is consistency.

Muscles love consistency. Horses, annoyingly, also love making us earn it.

Myth vs Reality

Myth	Reality
Tying up is always caused by too much protein.	Starch, calories, exercise mismatch, genetics, hydration, and muscle disorders are usually more important than protein alone.
All tying-up horses need high-fat diets.	PSSM and some RER horses may benefit, but overweight horses need calorie control.
If the horse walks it off, it is fine.	Forcing movement can worsen muscle damage. Severe cases need bloodwork and vet care.
One supplement prevents tying up.	Prevention depends on diagnosis, diet, exercise, hydration, electrolytes, and routine.
PSSM and RER use the same diet.	Both often need lower starch, but calorie needs and management differ.
Dark urine is normal after tying up.	Dark urine suggests significant muscle breakdown and possible kidney risk. Call your vet.

FAQs About Preventing Tying Up in Horses

What should I feed a horse that ties up?

Start with forage, remove large high-starch grain meals, match calories to workload, provide salt, and test the forage where possible. Horses with PSSM usually need a low-starch diet with fat used carefully if extra calories are needed. Horses with RER may need a lower-starch, higher-fat performance diet if they are in heavy work. (MSD Veterinary Manual)

Should I stop all grain?

Not always. Some horses can do well on forage plus a ration balancer. Hard-working horses may need concentrates, but the type matters. Low-starch, higher-fat feeds are often safer than large sweet feed or grain meals in tying-up-prone horses.

Does alfalfa cause tying up?

Alfalfa does not automatically cause tying up. The total ration matters more than one forage. Evaluate calories, starch, protein, calcium, phosphorus, electrolytes, vitamin E, selenium, body condition, and workload before blaming alfalfa alone.

Should a PSSM horse exercise every day?

Most PSSM horses do best with regular daily exercise and turnout once they are comfortable after an episode. Merck notes that PSSM improvement requires both diet changes and gradual increases in daily exercise and turnout. (MSD Veterinary Manual)

When should I call a vet for tying up?

Call your vet immediately if the horse is painful, stiff, sweating, reluctant to move, weak, recumbent, breathing abnormally, or passing dark urine. Recurrent episodes also need veterinary investigation, even if each episode seems mild.

The Bottom Line

Nutrition is one of the most powerful tools for preventing tying up, but only when it is matched to the type of tying up.

Sporadic tying up often comes from workload, heat, dehydration, electrolyte loss, or feed-exercise mismatch.

PSSM requires low-starch feeding, careful calorie control, and regular daily movement.

RER often needs lower-starch performance nutrition, adequate calories, consistent exercise, and stress reduction.

The best prevention plan is not “add oil” or “buy a muscle supplement.” It is:

• Diagnose the type of tying up

• Feed forage first

• Reduce starch where needed

• Match calories to actual work

• Maintain hydration and electrolytes

• Use fat thoughtfully

• Balance vitamin E, selenium, and minerals

• Keep exercise consistent

• Adjust feed on rest days

• Recheck muscle enzymes after significant episodes

A horse that ties up is not just being stiff. The muscles are telling you the system is not balanced.

Fix the system, not just the symptom.

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If your horse has tied up, has recurrent muscle stiffness, or you are unsure whether the diet fits PSSM, RER, workload, or electrolyte needs, ASK A VET™ can help you organise the signs, bloodwork, feeding plan, forage results, and questions to discuss with your treating veterinarian.