How to Test Hay and Pasture for Horses With Insulin Dysregulation or Laminitis Risk

How to Test Hay and Pasture for Horses With Insulin Dysregulation or Laminitis Risk

By Dr Duncan Houston

Hay may look soft, green and perfectly suitable while containing more sugar than an insulin-dysregulated horse can safely tolerate. The opposite is also true: coarse-looking or mature hay may provide an appropriate low-sugar forage once it has been properly analysed.

Winter can make the situation more confusing. Stored hay becomes the main part of the ration, while frost, cold nights and sunny days can allow sugars to remain high in pasture that appears brown, dormant or nutritionally poor.

The mistake is trying to assess metabolic safety by appearance, forage species or season alone. You need a representative laboratory sample and a feeding plan based on the individual horse.

Quick Answer

Test every distinct hay lot using a hay corer and a composite sample of at least 20 properly collected cores. Request an equine forage analysis that includes dry matter, water-soluble carbohydrates, ethanol-soluble carbohydrates, starch, protein, energy, fibre and minerals.

For horses with confirmed insulin dysregulation, equine metabolic syndrome or a high risk of hyperinsulinaemia-associated laminitis, forage containing less than approximately 10 percent non-structural carbohydrate on a dry-matter basis is a commonly used conservative target. However, this is a management guideline rather than a guarantee that the forage will produce a safe insulin response in every horse. (Wiley Online Library)

Which Horses Need Low-Sugar Forage?

Closer forage control is particularly important for horses and ponies with:

• Confirmed insulin dysregulation

• Equine metabolic syndrome

• Previous hyperinsulinaemia-associated laminitis

• Active or recently stabilised laminitis

• Marked obesity or regional fat deposits

• A large, firm or cresty neck

• A strong breed or family predisposition to metabolic disease

• PPID combined with insulin dysregulation

• An exaggerated insulin response after eating hay or grazing

Not every overweight horse has insulin dysregulation, and insulin dysregulation can also occur in horses that are not visibly overweight. Diagnostic testing is therefore more reliable than deciding purely from body shape.

Does every horse with PPID need low-sugar hay?

No.

Current Equine Endocrinology Group guidance states that diet selection in PPID should be based on body condition and whether insulin dysregulation is also present. Horses with PPID and normal insulin regulation do not automatically need carbohydrate restriction. Many older PPID horses are lean, have muscle loss and need more calories, quality protein and digestible fibre rather than a stricter weight-loss diet. (Equine Endocrinology Group)

This is an important distinction:

• PPID with insulin dysregulation: lower-NSC forage and controlled pasture access are usually appropriate.

• PPID with normal insulin regulation: feed according to body condition, dental function and calorie requirements.

• Lean PPID horse with muscle loss: excessive forage restriction may make the horse weaker rather than safer.

All horses diagnosed with PPID should have their insulin status assessed because the two disorders commonly occur together. (Equine Endocrinology Group)

Why Does Forage Testing Matter More in Winter?

As pasture growth declines, hay often becomes the horse’s main calorie, protein and fibre source. Any nutritional imbalance in that hay is therefore repeated through nearly every meal.

Visual inspection cannot reliably tell you:

• Sugar or starch content

• Digestible energy

• Protein concentration

• Mineral balance

• Whether the hay meets the needs of a senior or working horse

• Whether it is suitable for an insulin-dysregulated horse

Hay from the same supplier can vary between fields, cuttings, harvest dates, plant maturity and weather conditions. Each distinct lot should be treated as a separate feed until it has been analysed. (njaes.rutgers.edu)

Does stored hay become sugary because the weather turns cold?

No. Once hay has been harvested and stored, winter weather does not suddenly increase its sugar content.

The cold-weather concern applies mainly to living pasture plants. During sunny daylight hours, grass produces carbohydrates through photosynthesis. Plants normally use some of those carbohydrates for growth and respiration overnight. When nights become very cold, respiration slows, so more sugar may remain stored in the plant.

Frosted, dormant or stressed pasture can therefore be nutritionally poor in some respects while still containing enough soluble carbohydrate to create a problem for a susceptible horse. (University of Minnesota Extension)

What Is NSC in Horse Hay?

NSC means non-structural carbohydrate.

For forage testing, it is commonly estimated as:

NSC = water-soluble carbohydrates + starch

Water-soluble carbohydrates, or WSC, include:

• Glucose

• Fructose

• Sucrose

• Fructans

Starch is generally present in relatively low amounts in most grass hay but should still be measured.

Ethanol-soluble carbohydrates, or ESC, primarily represent simple sugars such as glucose, fructose and sucrose. WSC is normally higher than ESC because WSC also includes much of the forage’s fructan content. (University of Minnesota Extension)

Why do some reports use ESC plus starch?

Different laboratories, nutritionists and published guidelines do not always use the term NSC in exactly the same way.

Some concentrate on ESC plus starch because those fractions are more directly associated with glucose absorption and the insulin response. Others use WSC plus starch, which also includes fructans and remains the conventional NSC calculation used in many equine forage reports and metabolic guidelines.

The practical lesson is:

Check which calculation your laboratory uses before comparing results.

A hay reported as 9 percent ESC plus starch is not necessarily the same as hay reported as 9 percent WSC plus starch.

Do not use non-fibre carbohydrate, or NFC, as a substitute for measured WSC, ESC and starch. NFC is calculated differently and includes additional carbohydrate fractions.

What NSC Level Is Safe for a Metabolic Horse?

There is no single percentage that is guaranteed to be safe for every horse.

A practical interpretation is:

Forage result on a dry-matter basis	General interpretation
Below 10% NSC	Preferred starting target for many horses with confirmed insulin dysregulation or previous laminitis
10% to 12% NSC	May be tolerated by some mildly affected horses but deserves individual assessment
Above 12% NSC	Often unsuitable for a high-risk or severely insulin-dysregulated horse without further management
Unknown NSC	Should not be assumed safe merely because the hay looks mature or coarse

Consensus guidance commonly recommends hay below approximately 10 percent NSC for horses with equine metabolic syndrome and insulin dysregulation. Some broader extension recommendations describe 10 to 12 percent or less as potentially suitable for carbohydrate-sensitive horses. (Wiley Online Library)

Why is 10 percent not a guarantee?

The laboratory measures the forage, not the horse.

The insulin response also depends on:

• Severity of the horse’s insulin dysregulation

• Amount eaten in one meal

• Speed of consumption

• Total daily calorie intake

• Concurrent concentrate, treats or pasture

• Body condition

• Exercise

• PPID status

• Individual digestive and endocrine response

A severely insulin-dysregulated pony may still produce a concerning insulin response to hay that technically falls below 10 percent NSC.

In difficult cases, your veterinarian may recommend measuring insulin approximately two hours after the horse eats its normal hay ration. This evaluates the horse’s response to the actual diet rather than relying on the forage number alone. (Merck Veterinary Manual)

How to Sample Hay Correctly

The laboratory can only analyse what you send. A beautifully precise result from a poor sample is still a poor answer.

Pulling one attractive handful from the top bale does not represent an entire hay lot.

1. Define the Hay Lot

A hay lot should contain hay that is reasonably uniform in:

• Field of origin

• Plant species

• Cutting

• Harvest date

• Stage of maturity

• Storage conditions

Do not combine samples from:

• First and second cutting

• Different suppliers

• Different fields

• Grass hay and alfalfa

• Old and newly delivered hay

• Bales that have been stored differently

Each distinct lot needs its own sample.

2. Use a Hay Corer

A sharp hay probe is considerably more representative than pulling flakes apart by hand.

A suitable corer should:

• Cut across leaves and stems cleanly

• Reach approximately 30 to 45 centimetres into the bale

• Maintain the correct leaf-to-stem ratio

• Produce a manageable composite sample

• Be clean and free from rust, soil and feed from previous samples

The National Forage Testing Association recommends a probe approximately 3/8 to 3/4 inch in diameter, inserted at a right angle into the bale. (Forage Testing)

3. Take at Least 20 Cores

For small rectangular bales:

• Randomly select at least 20 bales

• Take one core from each selected bale

• Sample throughout the stack rather than only the easiest bales to reach

For large bales:

• Sample at least 10 to 12 bales

• Take two or three cores from each bale

Larger or visibly variable lots may need more than 20 cores. (Forage Testing)

4. Sample the Correct Part of the Bale

For small and large square bales, insert the probe into the butt end, between the strings, and direct it towards the centre.

Do not routinely sample the flat side of a square bale. A side core may pass through only one flake and fail to represent the full leaf and stem distribution.

For round bales, sample multiple bales through the curved surface towards the centre, following the corer and laboratory instructions. (Forage Testing)

5. Sample Randomly

Do not deliberately choose:

• The greenest bale

• The leafiest bale

• The mouldiest bale

• The bale nearest the door

• Only bales from one level of the stack

The sample should represent what the horse will actually be eating.

If part of the lot is clearly different, separate it into another lot and test it independently.

6. Combine the Cores

Place every core into one clean container or sealed bag.

Mix the entire composite without picking out:

• Coarse stems

• Seed heads

• Weeds

• Brown pieces

• Fine leaves

Removing unattractive material makes the sample look nicer but the analysis less honest.

7. Send the Correct Amount

Follow the laboratory’s submission instructions. A composite sample of approximately 200 to 500 grams is commonly sufficient.

The objective is not to fill a feed sack. An excessively large sample may be subsampled by the laboratory, potentially losing some of the advantage of careful collection. (Forage Testing)

8. Label the Sample Properly

Include:

• Horse or property name

• Hay lot identifier

• Supplier

• Field or cutting if known

• Harvest date

• Forage type

• Date sampled

• Intended horse or group

• Requested analysis

Photograph the label and the relevant hay stack so the result cannot later be matched to the wrong batch.

Can You Take a Grab Sample Without a Hay Probe?

You can, but it is less reliable.

When a corer is genuinely unavailable:

1. Collect material from deep inside at least 20 different bales.

2. Wear clean gloves.

3. Include leaves and stems in their natural proportions.

4. Chop the material using clean stainless-steel equipment.

5. Mix thoroughly before taking the final laboratory sample.

A hand sample is better than no analysis, but a properly collected core sample is preferable when the result will determine whether a high-risk horse can safely eat the hay. (njaes.rutgers.edu)

What Should You Request From the Laboratory?

Ask for an equine forage analysis, not simply a generic protein test.

For an insulin-dysregulated or laminitis-prone horse, useful measurements include:

Laboratory measurement	Why it matters
Dry matter	Allows meaningful comparison between feeds
WSC	Includes simple sugars and fructans
ESC	Primarily measures simple sugars
Starch	Contributes to glucose and insulin responses
Calculated NSC	Screening measurement for metabolic suitability
Digestible energy	Helps determine calorie intake and weight-loss suitability
Crude protein	Helps assess whether the ration supports muscle and tissue maintenance
NDF	Indicates total cell-wall fibre and can influence voluntary intake
ADF	Helps estimate forage digestibility
Calcium and phosphorus	Essential for ration balance
Magnesium	Relevant to the total mineral programme
Potassium	Important in selected medical conditions
Copper, zinc and other trace minerals	Needed when balancing the complete ration

A sugar-and-starch panel may answer one question, but it cannot tell you whether the winter ration is deficient in protein, energy or minerals.

Forage-only or restricted diets often require a low-sugar ration balancer or mineral supplement. That supplement should be selected using the full forage analysis rather than chosen by whichever tub has the most enthusiastic horse on the label.

Should You Request Wet Chemistry or NIR?

Near-infrared reflectance spectroscopy, or NIR, is quick and comparatively inexpensive. It predicts nutrient values by comparing the sample with a database of previously analysed forages.

Wet chemistry directly measures the selected nutrients and is generally more accurate, particularly when:

• The hay is unusual

• The forage comes from a different region from the laboratory’s calibration set

• The horse has severe insulin dysregulation

• Precise sugar, starch or mineral information will influence treatment

For routine ration assessment, a well-calibrated NIR analysis may be useful. For a high-risk metabolic horse, ask the laboratory or nutritionist whether WSC, ESC and starch should be measured by wet chemistry. (njaes.rutgers.edu)

How Do You Read the Hay Report?

Use the Dry-Matter Column

Laboratory reports commonly show:

• As sampled or as fed

• Dry matter

The as-fed value includes the sample’s water. The dry-matter value shows nutrient concentration after moisture has been mathematically removed.

Use the dry-matter column when:

• Comparing different hays

• Comparing results with an NSC target

• Formulating a complete ration

• Comparing hay with published recommendations

Use as-fed weight when calculating how many kilograms or pounds you physically place in the feeder.

Do not compare one hay’s dry-matter NSC with another hay’s as-fed NSC. That is a splendid way to become confidently wrong. (University of Minnesota Extension)

Look Beyond the NSC Number

A low-sugar hay may still be unsuitable if it is:

• Too calorie-dense for an obese horse

• Too low in protein for a horse with muscle loss

• Too indigestible for a senior with poor teeth

• Unbalanced in minerals

• Dusty or mouldy

• So coarse that the horse will not eat enough

• Contaminated with toxic plants

The ideal forage should be:

1. Low enough in sugar and starch for the horse’s insulin status

2. Appropriate in calories for the body-condition goal

3. Palatable enough to maintain adequate fibre intake

4. Safe from mould, toxic plants and physical contamination

5. Balanced with the rest of the ration

Is Alfalfa Safe for a Metabolic Horse?

Sometimes.

Alfalfa often contains less WSC than cool-season grass hay, but it is usually:

• More calorie-dense

• Higher in protein

• Higher in calcium

• More palatable

That can be helpful for a lean horse with insulin dysregulation or PPID-associated muscle loss. It may be less appropriate as the main forage for an obese easy keeper unless the total ration is carefully controlled.

There is no forage species that is guaranteed to be low in carbohydrate. Test the actual batch rather than choosing from the name alone. (University of Minnesota Extension)

How to Sample Pasture

Pasture testing is more difficult than hay testing because its carbohydrate content changes continuously.

A result reflects:

• The plants sampled

• The grazing height

• Time of day

• Recent sunlight

• Night temperature

• Frost

• Drought

• Plant maturity

• Regrowth

• Fertilisation

• Rainfall

A single result does not permanently certify a pasture as safe.

Step-by-Step Pasture Sampling

1. Identify the grazing area. Sample where the horse actually eats, not the lush strip behind the fence.

2. Walk a zigzag route. Collect material from approximately 20 or more representative locations.

3. Clip at grazing height. Take the part of the plant the horse is consuming.

4. Include relevant weeds. If the horse eats them, they are part of the diet.

5. Record the conditions. Include time, temperature, sunlight, frost and recent rainfall.

6. Cut long material into short lengths. This allows thorough mixing.

7. Mix the entire collection.

8. Freeze the sample promptly. Follow the laboratory’s storage and shipping instructions to limit carbohydrate changes after collection.

9. Repeat when conditions change. A spring morning result does not describe the same pasture on a sunny autumn afternoon. (njaes.rutgers.edu)

Can pasture testing prove grazing is safe?

No.

Pasture analysis can help quantify risk, but the horse’s insulin response is what ultimately determines whether the exposure is acceptable.

Research has shown that grazing can produce substantially higher insulin concentrations in insulin-dysregulated ponies than in normally regulated ponies, with peak responses often occurring within two to four hours. (Wiley Online Library)

A horse with severe insulin dysregulation, active laminitis or repeated pasture-associated laminitis may require complete grass exclusion even when a single pasture sample appears reassuring.

When Is Winter Pasture Most Concerning?

Pasture sugar tends to be lower in the early morning under warm, normal growing conditions because the plant uses stored carbohydrate overnight.

That rule becomes unreliable when nights are cold.

Risk can increase during:

• Sunny days followed by cold nights

• Early spring or late autumn

• Frost

• Drought

• Rapid regrowth

• Overgrazing

• Pasture containing abundant seed heads

• Warm-season growth interrupted by sudden cold

After a hard frost, respiration can slow or stop while stored carbohydrates remain in the plant. For a susceptible horse, frosted grass should not be assumed safe simply because it looks dead. (University of Minnesota Extension)

Is early-morning grazing always safer?

No.

Early morning is often lower risk after a warm night, but it may remain high risk after:

• A near-freezing night

• A hard frost

• A sunny cold spell

• Drought stress

• Repeated plant stress

For a horse with severe insulin dysregulation, there may be no reliably safe grazing time.

Can Soaking Hay Make It Safe?

Soaking can reduce water-soluble carbohydrate, but the result is variable.

The amount removed depends on:

• Original hay composition

• Water temperature

• Amount of water used

• Soaking time

• Hay maturity

• Leaf-to-stem ratio

• How tightly the hay is packed

Cold-water soaking for approximately 60 minutes is commonly recommended when low-NSC hay cannot be obtained or the hay has not been tested. Shorter periods of 15 to 60 minutes have also reduced WSC in experimental hay samples. (Wiley Online Library)

Soaking is not a guarantee

A high-sugar hay may remain too high after soaking.

For a severely insulin-dysregulated horse:

• Test the hay before soaking.

• Follow a consistent soaking method.

• Consider analysing a soaked sample.

• Ask whether post-meal insulin testing is appropriate.

Do not assume that an hour in a bucket automatically transforms every hay into metabolic hay.

How to Soak Hay More Safely

1. Weigh the dry hay before soaking.

2. Fully submerge it in clean cold water.

3. Soak for the period recommended by your veterinarian or nutritionist, commonly up to approximately 60 minutes for sugar reduction.

4. Drain it thoroughly.

5. Discard the soak water where horses and other animals cannot drink it.

6. Feed the hay promptly.

7. Remove uneaten wet hay before it spoils.

8. Clean the soaking container regularly.

Soaking also removes some dry matter, potassium, phosphorus, magnesium and other soluble nutrients. Longer soaking generally causes greater losses. The complete ration may therefore require rebalancing. (University of Minnesota Extension)

Important winter considerations

In freezing weather:

• Do not feed hay encased in ice.

• Prevent soak water from freezing where horses or people walk.

• Do not leave soaked hay sitting overnight.

• Make sure the horse continues drinking adequately.

• Use a practical system that can be repeated consistently.

Can soaking fix mouldy hay?

No.

Soaking may reduce airborne dust but does not reliably make visibly mouldy, musty or spoiled hay safe. Begin with hygienic forage.

How Much Hay Should a Metabolic Horse Receive?

Hay composition and hay quantity are separate decisions.

An obese insulin-dysregulated horse generally needs controlled calorie intake, but forage should not be reduced casually or abruptly.

Consensus guidance commonly begins weight-loss programmes around 1.25 to 1.5 percent of current body weight as dry matter per day, depending on the horse and protocol. Reductions below this level require close veterinary or nutritional supervision because of concerns about inadequate fibre, behavioural stress and hyperlipaemia, particularly in ponies and donkeys. (Wiley Online Library)

For a 500-kilogram horse:

• 1.5 percent dry matter equals 7.5 kilograms of forage dry matter.

• If the hay is 90 percent dry matter, this equals approximately 8.3 kilograms of hay as fed.

Do not estimate the ration by flakes. Flakes from different bales may vary enormously in weight.

Avoid prolonged fasting

Use:

• Several smaller meals

• Properly designed slow feeders

• Multiple feeding stations

• Timed feeders

• A carefully balanced hay-and-straw mixture where appropriate

The goal is gradual weight loss without leaving the horse standing hungry for long periods.

What Else Can Cause Winter Foot Pain or Weight Change?

Do not blame every problem on hay sugar.

Other causes of acute foot pain include:

• Hoof abscess

• Sole bruising from frozen or hard ground

• Nail pressure

• Hoof cracks

• Fracture

• Septic joint or tendon sheath

• Supporting-limb overload

• Acute laminitis from systemic illness

Other causes of winter weight loss include:

• Dental disease

• Poor chewing ability

• Inadequate total forage intake

• Low-quality or indigestible hay

• PPID

• Parasites

• Chronic pain

• Liver or kidney disease

• Intestinal disease

• Social competition at the feeder

A horse can have metabolic disease and another problem at the same time.

If the horse is losing weight, the answer is not automatically to keep restricting the diet because the horse once had laminitis.

How Worried Should You Be?

Low Risk

The horse:

• Has normal insulin regulation

• Has no history of laminitis

• Maintains a healthy body condition

• Is eating a tested and balanced forage ration

• Has normal digital pulses and comfortable movement

What to do: Continue routine body-condition monitoring and test each new hay lot.

Moderate Risk

The horse:

• Is overweight or cresty

• Has PPID but has not had insulin status assessed

• Has an unknown hay analysis

• Is grazing during cold, sunny weather

• Has gained weight over winter

• Has a previous mild metabolic concern but no current foot pain

What to do: Arrange insulin assessment and forage testing. Restrict risky pasture while the plan is reviewed.

High Risk

The horse:

• Has confirmed insulin dysregulation

• Has previously had laminitis

• Is eating untested or high-NSC forage

• Shows stronger digital pulses

• Is becoming reluctant to turn

• Is shifting weight repeatedly

• Has new mild foot soreness

What to do: Remove pasture access, stop high-sugar feed and contact your veterinarian the same day. Do not exercise the horse until laminitis has been ruled out.

Critical

The horse:

• Is markedly lame in several feet

• Has a rocked-back stance

• Refuses to walk or turn

• Lies down repeatedly because of foot pain

• Has very strong digital pulses

• Has persistently hot feet

• Appears severely distressed

What to do: Treat this as an emergency and contact an equine veterinarian immediately.

When Is This an Emergency?

Acute laminitis is a medical emergency because structural damage and displacement of the coffin bone can develop rapidly.

Seek urgent veterinary care if your horse develops:

• Sudden foot pain

• Reluctance to walk

• Severe difficulty turning

• Constant shifting from one foot to another

• A short, pottery gait

• Strong or bounding digital pulses

• Increased hoof temperature

• A rocked-back stance

• Repeated lying down

• Refusal to rise

• Sudden severe lameness

• Rapid deterioration after pasture or feed exposure

Keep the horse calm and avoid forcing it to walk. Move it only as much as necessary to reach a safe, deeply bedded area, unless your veterinarian directs otherwise. (Center for Equine Health)

Do not wait for hoof rings, a visibly rotated coffin bone or an obviously distorted hoof. Those are later consequences, not the signs you should be waiting to see.

What Should You Do Next?

1. Confirm the Horse’s Metabolic Status

Discuss:

• Resting insulin

• Oral sugar testing

• PPID testing where appropriate

• Previous laminitis history

• Body and cresty-neck condition

• Current medications

• Whether a post-meal insulin test is needed

2. Identify Every Forage Source

List:

• Hay

• Pasture

• Haylage

• Hay cubes

• Chaff

• Straw

• Treats

• Weeds in dry lots

• Bedding the horse may eat

The horse’s insulin system does not care whether the carbohydrate came from a hay bale, a treat bag or a suspiciously delicious corner of the paddock.

3. Sample Each Hay Lot

Use a core sampler and at least 20 representative cores.

Do not wait until you have bought six months of unsuitable hay before testing it.

4. Request a Full Equine Analysis

At minimum, request:

• Dry matter

• WSC

• ESC

• Starch

• Protein

• Energy

• ADF and NDF

• Major minerals

5. Weigh the Daily Ration

Use a hanging or platform feed scale.

Weigh:

• Hay before soaking

• Concentrates

• Balancers

• Treats

• Straw when included

6. Review Pasture Exposure

Account for:

• Time of day

• Night temperatures

• Frost

• Drought

• Regrowth

• Grazing muzzle use

• Actual time spent eating

• Dry-lot weeds

7. Reassess Every 30 Days

Record:

• Body weight or weight-tape measurement

• Body condition

• Cresty-neck score

• Photographs

• Digital pulses

• Exercise

• Laminitis signs

• Insulin results when repeated

Weight loss should be gradual. Rapid restriction and prolonged fasting are not signs of a more disciplined programme.

8. Retest When the Hay Changes

Retest when you begin:

• A new delivery

• A different cutting

• Another supplier

• A new field

• A visibly different group of bales

One result cannot be applied to every bale the supplier produces for the rest of time.

Common Hay-Testing Mistakes

Sampling One or Two Bales

This measures those bales, not the entire lot.

Pulling a Handful From the Outside

Leaves, stems and fine material are not evenly distributed through a bale.

Mixing Different Hay Lots

The final average may describe none of the individual lots accurately.

Sampling the Side of Square Bales

This may collect only one flake rather than a proper cross-section.

Reading the As-Fed Number as Dry Matter

This can make two feeds appear more similar or different than they really are.

Treating 10 Percent as a Magical Safety Line

The horse’s individual insulin response still matters.

Assuming Old or Coarse Hay Is Low in Sugar

Appearance and age do not reliably establish carbohydrate content.

Assuming Frosted Grass Is Safe

Cold stress can leave carbohydrates stored in the plant.

Soaking Without Rebalancing the Diet

Soaking can remove dry matter and minerals as well as sugar.

Restricting Every PPID Horse

PPID horses with normal insulin regulation may need more nutrition, not less.

Buying a Sugar Panel but Ignoring Calories

An obese horse can continue gaining weight on low-sugar hay if too much energy is supplied.

Using Hay Analysis to Excuse Mould

A nutrient report does not turn unhygienic hay into safe forage.

A Practical Winter Forage Checklist

Before winter feeding begins:

• Confirm insulin and PPID status

• Assess body condition and cresty-neck score

• Test each hay lot

• Use dry-matter values

• Confirm how NSC was calculated

• Weigh the daily forage

• Provide a low-sugar vitamin and mineral balancer where required

• Avoid prolonged fasting

• Monitor pasture after cold nights and frost

• Maintain regular hoof care

• Check digital pulses routinely

• Store hay off the ground and protect it from moisture

• Reassess weight monthly

• Contact your veterinarian immediately if foot pain develops

Will My Horse Be Okay?

Most horses with insulin dysregulation can be managed successfully when the condition is recognised before repeated laminitis occurs.

The most useful steps are:

• Identifying insulin dysregulation

• Controlling total calorie intake

• Selecting appropriate forage

• Limiting unsafe pasture exposure

• Maintaining exercise when the horse is sound

• Treating concurrent PPID

• Monitoring the feet

• Acting immediately when laminitis signs appear

A forage test cannot remove every risk, but it replaces guesswork with information and gives the horse’s veterinary and nutrition team a much stronger basis for making decisions.

The outlook becomes more guarded once laminitis has caused substantial coffin-bone displacement or permanent hoof damage. Early recognition matters.

Frequently Asked Questions

How often should horse hay be tested?

Test every distinct hay lot, not according to a fixed number of months. Retest when the field, cutting, supplier, harvest or appearance changes.

Is hay under 10 percent NSC completely safe?

No. It is a useful conservative target for many insulin-dysregulated horses, but individual responses vary. Severely affected horses may need post-meal insulin testing to confirm that the forage is appropriate.

Can I soak hay instead of testing it?

Testing is preferable. Soaking reduces WSC inconsistently and may not lower a high-NSC hay enough. It also removes dry matter and minerals.

Should every horse with PPID eat low-sugar hay?

No. Restriction is primarily required when PPID occurs with insulin dysregulation or excessive body condition. Lean PPID horses with normal insulin regulation may require additional calories and protein.

Is early-morning winter grass safe for a laminitis-prone horse?

Not reliably. Sugar may be lower after a warm night, but cold nights and frost can prevent the plant from using stored carbohydrates. Severely susceptible horses may require complete grass restriction.

The Real Takeaway

Hay testing is not simply about finding one sugar number.

A good forage plan answers several questions:

• Is the hay low enough in sugar and starch for this horse?

• Does it provide the correct amount of energy?

• Is there enough protein?

• Which minerals need balancing?

• How much should be fed?

• Does the horse’s insulin remain controlled after eating it?

Collect a representative sample. Use at least 20 cores. Keep different lots separate. Read the dry-matter column. Treat the 10 percent NSC target as a useful starting point rather than an absolute guarantee.

Most importantly, feed the horse in front of you.

A cresty pony with severe insulin dysregulation and a lean senior horse with PPID may be standing beside each other, but they should not automatically be eating the same winter ration.

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Unsure whether your hay analysis is suitable for your horse’s insulin status, body condition or laminitis history? ASK A VET™ can help you organise the laboratory report, feeding amounts, pasture exposure and ongoing weight or hoof changes so you can prepare a safer plan with your veterinarian or equine nutritionist.