Missing link: Protein for horses prone to laminitis

Have you considered the crucial role of protein in the diet of horses prone to laminitis? If you are soaking and restricting hay for a good doer horse, prone to laminitis, how can you be sure there is enough protein in the daily diet?

Protein is key to every part of a horse’s body system. Find out in this article how we know, from analysis of thousands of samples of hay and haylage, that a missing link is the level of protein for horses prone to laminitis.

Forage analysis and protein for horses prone to laminitis

In a typical year, Forageplus analyses thousands of samples of hay and haylage for horse customers. We are experts in forage analysis, looking at the greatest proportion of the diet and formulating horse diets based on what is missing in the forage horses eat. We are experts with unique analytical data where protein for horses prone to laminitis is concerned.

We use science to be smart about determining deficiencies and nutrients which are not sufficient in horse diets.

Many clients have good doer horses, which are also laminitis-prone. They often come to us to check the simple sugars (ESC) and starch in the hay or haylage their horses are eating by using a nutritional analysis.

It is the simple sugars and starch that will affect laminitis-prone horses. But what many people don’t realise is that protein for horses prone to laminitis is crucial for the support of all-around health and strong hooves.

The benefit of conducting a nutritional analysis on hay or haylage for a horse that is a good-doer and prone to laminitis is that it not only helps ensure that the ESC and starch levels are below 10% in the forage, but it also provides important information on the protein content.

Are protein levels in hay and haylage enough for horses?

The purpose of this article is to demonstrate to horse owners like yourself that inadequate protein levels, a common occurrence in the UK and Europe, can be detrimental, especially for horses prone to laminitis, as they often do not meet the minimum maintenance requirements.

What are the average protein levels in hay for good-doer horses?

In recent years, protein levels in UK hay and haylage have typically ranged between 6% and 7.5% (as sampled). During certain seasons, especially when a dry spring is followed by a hot summer, protein levels can fall even lower, reducing the overall nutritional quality of the forage.

These averages are based on Forageplus multivariate analysis of thousands of annual forage samples. This scientific approach enables us to provide accurate, data-driven feeding guidance tailored to the specific hay, grass, and haylage your horse consumes.

At Forageplus, we rely on smart science, not guesswork – gathering and analysing real-world data to help horse owners make informed nutritional decisions that directly support long-term health, recovery, and performance.

Year	DE (MCal/Kg)	Protein % in Hay
2017	2.11	7.45
2018	2.13	6.86
2019	1.90	7.30
2022	2.12	6.94
2023	2.18	6.30
2024	2.19	6.10
2025 (so far)	2.15	6.00

The data above illustrates a steady decline in crude protein levels in UK forage since 2019, while digestible energy (DE) has remained relatively consistent. This means that, although modern hays and haylages continue to supply comparable energy values, their protein density has fallen.

Average DE values have stabilised between 2.10 and 2.19 Mcal/kg, indicating that energy yield per kilogram of forage has not changed significantly. However, crude protein levels have declined from around 7.3% in 2019 to approximately 6.0% by 2025, reflecting a notable reduction in the nutritional quality of forage protein.

This downward trend is likely influenced by factors such as later harvests, reduced nitrogen fertiliser use, and seasonal weather variation, all of which affect grass growth, leaf-to-stem ratio, and overall protein content.

Is high protein in horse diets a problem?

Based on our extensive analysis of UK hay and haylage samples from 2017–2025, the average crude protein content typically ranges between 6% and 7.5% (as sampled).

With forage protein levels continuing to decline in recent years, it is highly unlikely that any horse fed a primarily forage-based diet will consume excessive protein. In fact, most horses are far more at risk of not getting enough quality protein, rather than too much.

There are many myths in equine nutrition, and one of the most persistent is that high protein intake is harmful.
Some claim that excessive protein can damage the kidneys, yet there is no scientific evidence to support this in healthy horses.

When dietary protein exceeds requirements, the surplus is processed in the liver into urea and then safely excreted in urine. The kidneys are well equipped to handle this process, provided the horse has constant access to clean, fresh water.

The only noticeable effect of higher protein intake is often increased drinking and urination, which is perfectly normal and not a sign of harm.

Other claims are:

• High protein is a risk factor in developmental orthopaedic disease (DOD)
• High protein makes horses hot and hard to handle
• High protein causes laminitis

Does high protein cause developmental orthopaedic disease (DOD) in young horses?

There is no evidence or biological basis to support the idea that high protein intake causes developmental orthopaedic disease (DOD) in young horses. In fact, there is no plausible mechanism by which protein could even contribute to this condition.

The true dietary culprits are unbalanced or deficient mineral levels, particularly calcium, phosphorus, copper, and zinc, combined with excess calorie intake that drives overly rapid growth.

If protein plays any role at all, it is typically in the opposite direction: low protein intake can increase the risk of developmental issues, as young horses require higher levels of quality protein to support correct growth, tissue development, and bone formation

Does high protein cause horse behaviour problems?

No, this is an old wives’ tale. High-energy feeds without adequate exercise where calories are too high will cause behavioural problems in horses.

Behavioural changes are far more likely to occur when horses are fed high-calorie or high-energy feeds without sufficient exercise or turnout. In these cases, excess energy, not protein, leads to restlessness, excitability, or unpredictable behaviour.

When a horse receives more calories than it can burn, especially if stabled or restricted in movement, energy builds up and may appear as “fizzy” behaviour.

Some horses do seem to become more reactive when fed alfalfa, but this is not due to its protein content. The exact cause is unclear and may relate to other nutritional or individual sensitivity factors, not protein itself.

Does high protein cause laminitis?

No, high protein does not cause laminitis. While there are several recognised causes of laminitis, dietary protein is not one of them.

The vast majority of laminitis cases are linked to endocrine disorders, most commonly Insulin Resistance (IR) or Pituitary Pars Intermedia Dysfunction (PPID, also known as Cushing’s Disease).

Current research indicates that 80–90% of laminitis cases are the result of endocrine-related dysfunction, where abnormal insulin regulation leads to inflammation and damage within the hoof.

Protein plays no role in this process. In fact, maintaining adequate protein intake is important to support hoof growth, repair, and overall metabolic health in laminitic horses.

Is low protein in horse diets a problem?

Insufficient protein levels in hay may not be an issue for horses that are not overweight or prone to weight gain and have unlimited access to hay. However, for horses with a tendency to gain weight and a higher risk of laminitis, the protein levels in hay may not be enough.

Where a horse needs both forage and bucket feed limiting to control weight gain, you might find that these horses don’t even have the minimum levels of protein suggested by the Nutrient Requirements for Horses 2007 NRC tables. Without the correct levels of protein, it will be difficult for that horse to maintain a good level of health.

Why do horses need protein in their diet?

Protein is crucial for all life, and without good levels of protein in the diet, horses may struggle to maintain muscle mass and support and maintain health in many different ways.

Good quality refers to the availability of the essential amino acids which have been identified, through research, as being necessary for good horse health. You can find out more about protein and how it is important to health, vitality and resilience by reading this Forageplus article here.

What does a Forageplus analysis show about horse protein?

A customer who has a good-doer and laminitis-prone horse contacted us to check that the simple sugar (ESC) and starch levels in the hay fed to her horse were low enough to be suitable without soaking.

Ideally, hay or haylage should not be soaked when feeding laminitis-prone horses so that valuable water-soluble nutrients are not lost. A better approach is to check that the ESC and starch levels are below 10% and feed a measured amount of hay for calorie control. Where levels are a little high, a short soak of one hour will be sufficient.

The hay was tested using a nutritional analysis hay test for horses. The sugar levels (ESC and starch combined) were borderline at just under 10%, so we advised her to soak for one hour if her horse was not a well-controlled laminitic horse in some work.

But something else caught our eye: the protein for horses prone to laminitis. The levels were low, and when the horse was fed restricted hay for weight maintenance, the protein levels would be insufficient.

What about calories for horses prone to laminitis?

This particular hay nutritional analysis was carried out for a good-doer horse, but the customer was managing the weight well. The horse weighed 450 kg, and the following table is a guide to how much this horse, fed this hay, had to eat to provide enough calories for the different work levels. This is based on the hay tested having a DE level of 8.58 MJ/kg, which is a good calorific value.

Horse Work Level (450kg Bodyweight)	DE (MJ/Kg) needed to maintain bodyweight	Amount of forage to be fed (Kg)
Maintenance Level	62.9	8.1
Light Level	75.4	9.7
Moderate Level	87.8	11.3
Heavy Level	100.2	12.9

Maintaining body weight with this hay was relatively easy, but the protein was a different matter.

If you look at the Forageplus Nutritional Report below (click on the picture to enlarge), protein in the hay was reported at 5.1%. This amount is well below the ideal of 8% for forage-fed to all horses.  This means that a 450kg horse will be short of protein when fed the amount needed to maintain weight.

A horse eating this hay will need feeding an additional protein form, other than forage, to boost protein levels when calorie levels are correct.

The following information shows you just how much protein a 450 kg horse needs and how much it receives when fed the weight of this hay for each work level. The red text is the protein level provided by the hay. The green text is the NRC (Nutrient Requirements for Horses 2007) minimum daily protein levels for a horse weighing 450kg:

Maintenance
Feeding 8.1kg: 372 grams 486 grams
The horse will be 113 grams short of the minimum levels.

Light Work

Feeding 9.7kg: 446.2 grams 567 grams
The horse will be 120.8 grams short of the minimum levels.

Moderate Work
Feeding 11.3kg: 519.8 grams 648 grams
The horse will be 128.2 grams short of the minimum levels.

Heavy Work
Feeding 12.9kg: 593.4 grams 900 grams
The horse will be 306.6 grams short of the minimum levels.

Remember that this article is only about protein for laminitis horses and good-doers, however, you can see that all horses would be affected by the low protein in this hay.

A young horse would be affected, as would a breeding mare. If a horse was in light work and not fed adlib hay, then protein would be a problem. For a horse in moderate or heavy work, protein would be a problem unless a bucket feed was fed to top up protein requirements.

If you want to learn more about how protein levels affect young horses, then click here.

If you are interested in feeding breeding mares, then click here.

What is the best way to feed extra protein to horses?

We suggest that some of the hay is substituted for a higher protein bucket feed. The amount you need to substitute can be as great as you like if you use fibre-based feeds, with some grass nuts being able to be used as total hay replacers as long as the ESC sugar and starch total is below 10%. Protein for horses prone to laminitis is best substituted with low-sugar feeds such as Speedi-Beet or Hay Pellets.

You could choose a higher protein hay nut, beet pulp or a small amount of micronised linseed, which will be safe for a pony prone to laminitis. You need obviously to be very careful about the feed you choose that it is suitable for protein for a horse prone to laminitis. Make sure the sugar and starch combined are below 10%.

You could also use protein supplements such as whey, pea or essential amino acids to top up levels without adding significantly to the calories in the horse’s diet. Often, an approach that combines both the use of a bucket feed to replace hay and a protein supplement is the best approach.

Find protein and amino acids for horses

We will assume vitamins and minerals are being fed matched to that needed to balance the hay or grass eaten.  This could be matched to the forage fed through a full mineral analysis or levels established by statistical analysis, such as the ones contained within the Forageplus forage-focused balancers. 

A forage-focused balancer allows you to add minerals and vitamins at the correct levels needed for horse health without adding further calories to your horse’s daily diet. Protein for horses prone to laminitis can be substituted according to average levels.

With the vitamins and minerals covered, you would need the following to maintain calorie (DE) levels to maintain weight but also boost protein. 

Understand that some of the hay must be substituted with a bucket feed to boost protein levels, but keep calories at the right level.

Below are examples of what would be needed for a horse in maintenance or light work using the hay tested by the customer.

Maintenance
7 kg hay
600 grams unmollased beet pulp or Speedi-beet (dry weight, rinse through before soaking and then again after soaking using a large sieve across a bucket.
250 grams of micronised linseed

If you want to add a handful of chop or high-fibre cubes for palatability at a small amount, this is fine.

This will give you a protein level of 463.5 grams against a needed protein level of 486 grams.  The level is nearly there, but adding 50 grams of whey protein into the bucket feed as well will top it up to adequate levels.

Light Work
8 kg hay
700 grams unmollased beet pulp or Speedi-beet (dry weight, rinse through before soaking and then again after soaking using a large sieve across a bucket).
350 grams of micronised linseed

If you want to add a handful of chop or high-fibre cubes for palatability at a small amount, this is fine.

This will give you a protein level of 552.1 grams against a needed protein level of 567 grams.  The level is nearly there, but adding 50 grams of whey protein into the bucket feed as well will top it up to adequate levels.

What if you can’t analyse hay or haylage?

You can still assume a shortage of protein for horses prone to laminitis by substituting a higher protein bucket feed in place of the hay; feeding 1 kg of beet pulp in place of 1.5 kg of hay; 1 kg of grass/hay nuts for 1 kg of your hay; and weighing your horse each week to check that weight is being maintained at the correct level.

Another option is to add 100 grams of a protein supplement such as Pea Protein, Whey Protein or Essential Amino Acids into a daily bucket feed that contains a forage-focused horse feed balancer. Topline Plus is an affordable blend which will help with protein for laminitis-prone horses.

Always feed micronised linseed at 42 grams per 220 kg of body weight if your horse is not eating on green and growing spring or summer grass, so you provide vital essential omega-3 fat in the diet.

How much hay to feed a laminitic horse

If you don’t know the calorie/energy (DE) level of your forage, then you can calculate the amount to be fed to maintain weight at 2% of body weight to maintain weight or 1.5% of the body weight if the horse needs to lose weight.

Another approach to weight loss is to decide how much weight you want your horse to lose and calculate 2% of that number.  You can then choose either 1.5% of present body weight or 2% of the future body weight you want the horse to be and feed whichever gives you the greatest feed amount. 

What you should never do is feed a horse or pony prone to laminitis less than 1.5% of body weight as this could lead to weight loss, which fuels further laminitis.

We hope this helps horse owners understand the implications of understanding just how forage protein levels can affect all horses, especially horses prone to laminitis.

A simple nutritional analysis of forage can help you manage your horse’s diet so that it is healthy and at the right weight and those prone to laminitis are managed correctly.