Depending on where you’re located, Spring is either just around the corner or already beginning to make its presence known. While some areas are still experiencing frosty mornings, many of those chilly starts are giving way to beautiful, warm Spring days.
Spring brings fresh, vibrant growth, greener pastures, and rising temperatures. However, it can also be a particularly stressful time for horse owners. Contributing factors may include:
- Frosty or very cold mornings (below 5°C / 41°F)
- Warm, sunny days that trigger rapid pasture growth
Limited rainfall
When these conditions combine, they often result in stressed plants with elevated sugar levels.
This can create a perfect storm for horses and ponies that are overweight or already metabolically vulnerable to laminitis. Laminitis remains one of the leading causes of death in horses, so it’s an issue every owner should take seriously.
It’s also essential to transition your horse’s diet gradually during this seasonal change. Careful feed management is particularly important for horses prone to laminitis, those with Insulin Resistance (IR), or those diagnosed with Cushing’s disease. While your horse may be eager to enjoy the lush new Spring grass, the increased sugar and starch content can significantly raise the risk of laminitis and digestive upset if grazing is not carefully controlled during the shift from Winter to Spring pasture.
At GutzBusta, we’re dedicated to helping you keep your horse healthy and protected. We’ve put together helpful news, practical tips, and expert advice to support you and your horse through the Spring transition.
When is your pasture safest?
Higher easily digestible carbohydrate content in your pasture is potentially dangerous to all horses while they’re transitioning from a low-grass/hay-based diet to the flush of feed in Spring. But animals that are IR, have Cushing’s disease or are overweight are even more susceptible to laminitis, so you need to work out when or even if your pasture is safe.
The general rules of assessing whether your pasture is ‘safe’ or not are determined by both temperature and sunlight on the plant:
- When the night temperatures are below 5°C / 41°F, the grass is too high in sugar and starch due to the stress on the grass.
- Once it gets above 5°C / 41°F at night, the lowest plant sugar and starch level is before sunrise.
- Anything that stresses a plant will raise the sugar levels eg: drought or frost or importantly - overgrazing!
- Sunny days: The NSC levels are highest in the afternoon/evening.
Overcast or cloudy days: Grass produces less sugar and starch due to less photosynthesis taking place, so pasture is a little safer.
Unfortunately, there are some horses and ponies that are never in a position to be put out to pasture for longer than an hour a day, if at all at certain times of the year.
It is important to seek veterinary/trimmer/farrier/equine nutritionist help when dealing with chronic and acute laminitis cases. Making an informed decision and getting the CORRECT advice can literally mean the difference of life or death to your horse or pony, or a lifetime of suffering. Sunny afternoons are NEVER safe to allow grazing for these types of horses and ponies.
Carbohydrates levels = ESC + Starch < 10%
This is particularly important when you are getting hay tested for laminitic-prone horses and ponies. It is not the NSC that is what you need to know, but the ESC + Starch level. This should be under 10% to be considered safe for at-risk equines. These figures are equally important for pasture, however, pasture carbohydrate levels change all of the time due to many factors already discussed above.
Dr Eleanore Kellon's page - Equine Cushings and Insulin Resistance has some fantastic information on managing, emergency protocol, and general education on this topic. All horses are capable of getting laminitis under the wrong conditions.
Factors to consider!
Many other factors can affect the ESC and Starch content of your grass and hay, including soil quality, nutrient levels, drought, flooding, and type of pasture (native V’s improved).
If you are uncertain and need some help working out which slow feeder will suit your needs best in this transition period or all year around, be sure to reach out to us here at GutzBusta. We’ll help put your mind at ease and help you decide which slow feed hay net will work for your horses.
In addition, this link is also a great read on how to decide on what hay net hole size will suit your horses or livestock.
When requesting actual feed advice we suggest speaking with an Equine Nutritionist or Veterinarian that may be familiar with your individual animals and locality.
Be prepared as we head into Spring and have your hay net stock levels up so if you have to lock up your equines to get them off the grass, you have an excellent management tool ready!
It’s important to understand how pasture sugars change throughout the day. On bright, sunny days, grass produces and stores sugars (ESC) and starch as it photosynthesises. These levels tend to build during the day and are often highest in the late afternoon and evening.
Overnight, the plant normally uses some of these stored sugars for growth and maintenance, which usually means sugar levels are lower by the early morning. As the sun rises the next day, the plant begins producing and storing sugars again.
However, there is an important exception. When overnight temperatures drop below around 41°F (5°C), the plant becomes stressed and cannot use those sugars effectively. Instead of being used up overnight, the sugars remain stored in the grass, meaning levels can still be elevated the following morning.
For horses that are prone to laminitis or metabolic issues, it’s wise to avoid grazing during these conditions, as pasture sugar levels may still be higher than expected.
Why starvation is NOT the answer
When a horse experiences stress, the body releases cortisol. Unfortunately, long periods without feed create exactly that kind of stress. Horses are designed to graze and consume small amounts of forage for around 18 - 20 hours a day, so extended fasting goes directly against their natural biology.
For this reason, starving a laminitic horse is not the solution. Elevated cortisol levels can interfere with the delicate connection between the hoof wall and the coffin bone, potentially slowing recovery and delaying the rebuilding of a stronger, healthier hoof attachment once proper management is in place.
What is Low Grade / Subclinical Laminitis?
Most horse owners recognise the classic laminitis stance, the horse leaning back to take weight off its toes. But low-grade or subclinical laminitis is much sneakier. It often develops gradually, showing few obvious signs until the condition progresses.
Over time, the connection between the hoof wall and the coffin bone slowly weakens and separates. Without careful management, a horse can continue down the laminitis cascade, which is a serious condition and the second leading cause of death in horses. Some horses may cope under sub-optimal management for months or even years… until suddenly they crash.
Seeing a beloved horse or pony struggle with laminitis is truly heartbreaking. As we head into Spring, it’s a good idea to check your hay net supplies and be prepared. Having these tools on hand allows you to safely bring your equine off the grass when needed, helping you manage their intake and protect their hooves.
Signs of Sub-Clinical Laminitis?
Sub-clinical laminitis can show up in many subtle ways, and the signs are often easy to overlook at first. Some common indicators include:
- Becoming uncomfortable on hard ground when they were previously fine.
- Shortened stride, particularly on firm surfaces.
- Horizontal ridges or “rings” appearing on the hoof wall.
- Reluctance to pick up feet for cleaning.
- Increased soreness after a trim when they would normally be comfortable
- A noticeable digital pulse
- Frequently shifting weight from foot to foot.
- A stretched laminae line or signs of blood within the white line.
- A flatter-than-normal sole.
One of the most telling signs is the presence of rings in the hoof wall. These are often dismissed as normal growth changes, but they can be a very important indicator that something isn’t quite right.
Good management is the key to turning things around. With consistent trimming and appropriate management practices, significant improvement can occur over time. The hoof photos above show the progress made over a six-month period, highlighting the difference that regular trimming and correct management can make, however these feet were still a working progress and further improvement, is expected.
Every horse is capable of becoming Laminitic
While some horses and ponies are certainly more prone than others, the reality is that any horse can develop laminitis under the right (or wrong) conditions.
Many horses live for long periods in a low-grade, sub-clinical state without obvious signs. Seasonal changes in pasture, weather patterns, and management can allow them to cope for quite some time… until eventually too many risk factors stack up and they tip over into a painful laminitic episode.
And it’s important to remember, laminitis isn’t just a “pony problem.” Horses and ponies of all breeds and sizes can be affected.
Management Plans:
Good management is the foundation of laminitis prevention and recovery. Some important things to consider include:
- Do you have a safe area where you can confine your horse or pony during higher-risk periods, or if they begin showing signs of soreness or sub-clinical laminitis?
- Have you checked your GutzBusta hay net supply so you’re prepared if you need to bring horses off grass and manage their intake?
- Are your horse’s hooves being attended to regularly? Hoof growth can increase significantly in Spring and Summer, and waiting six weeks between trims is often too long for many horses, whether they are shod or barefoot.
- Diet - Have you sourced “safe” hay that tests below 10% combined ESC and starch?
- Are you paying attention to weather patterns, pasture growth and time of day when managing grazing? (See our previous email and post for more information on this topic.)
- Exercise - Even 20 minutes of hand walking three to four times a week can be beneficial.
- Movement - Horses are designed to move. Having a companion often encourages natural movement and helps keep them mentally settled.
- Reduce stress wherever possible, as stress can negatively impact overall health and recovery.
What is the difference between laminitis and founder?
These 2 terms are often used interchangeably, however, the following gives a little more insight into their definitions.
Laminitis:
- Laminitis is the weakening of the laminae, the tissue that connects the coffin bone to the hoof wall inside the hoof.
- Horses and ponies are experiencing increasing metabolic issues, often linked to too much feed, inappropriate feed, and not enough exercise.
- Laminitis can be an early warning sign of PPID (Cushing’s disease) or Insulin Resistance (IR).
- Laminitis can occur as sub-clinical or low-grade laminitis, meaning the signs may be subtle and easy to miss.
- If left unresolved, laminitis can progress to what many people call 'founder'.
- This progression is more common in cresty-necked or overweight horses, which is why horses should ideally come out of winter on the lean side.
- Laminitis occurs on a spectrum, ranging from mild or low-grade cases to severe cases (founder).
Founder:
- The term founder is often used interchangeably with laminitis but generally refers to advanced disease progression.
- Founder typically describes a case where the coffin bone has separated from the hoof wall attachment and becomes displaced.
Not just limited to grass, Carbohydrate/Grain overload can also be a major cause of laminitis. Nutritionally induced laminitis through carbohydrate overload (grain, fruit, snacks, molasses) is another common cause. An excess of starch and sugars overflowing into the hindgut upsets the microflora (bacteria), which in turn, produces lactic acid, increasing the acidity of the hindgut. A toxic environment is created and toxins are released into the bloodstream via leaky hindgut epithelium.
Although laminitis is commonly caused by feed, grass, or grain overload, it is also important to realize that not EVERY case of laminitis is feed or metabolically related. There are other causes such as:
- Snakebite.
- Retained fetal membranes (placenta) after the birth of a foal.
- Toxaemia- Many different causes, but horses that have high levels of toxins in the bloodstream are at high risk of laminitis. Bacterial, viral, plant, chemical and fungal toxins have all been implicated in causing laminitis. Keep an eye on horses that are suffering from fever, diarrhoea, colic (particularly after surgery), pneumonia, and pleurisy. Treatment of the initiating cause must be accomplished before improvement in laminitis can be expected.
- Medications and Steroids- Although controversial, prolonged use or high doses of corticosteroids may contribute to the development of laminitis in some horses. Routine vaccinations have also been known to cause laminitis for some horses, therefore careful consideration needs to be given of the time of year they are given for metabolic-type horses and ponies.
- Trauma- If a horse is injured and therefore is excessively weight-bearing on one leg. Fast or prolonged work on hard surfaces is another cause that has been associated with mechanical laminitis.
WSC, NSC, and ESC - what are these?
What are WSC, NSC, and ESC? These are terms for various carbohydrate fractions in forage or feeds.
- Water Soluble Carbohydrates (WSC) are carbohydrates solubilized and extracted in water. Includes monosaccharides, disaccharides and some polysaccharides, mainly fructan.
- Fructan is a major storage carbohydrate in grasses.
- Non-Structural Carbohydrate (NSC) is calculated by adding Water Soluble Carbohydrate (WSC) and Starch.
- Ethanol Soluble Carbohydrates (ESC) are simple sugars. Only ESC and Starch will cause glucose spikes and insulin spikes.
It is the ESC and Starch levels added together that give the percentage of carbohydrates in the hay. For laminitic, IR/Cushings, or any obese or metabolically challenged horse or pony, this should be under 10%, with the starch portion being 4% or lower.
How much should a horse be fed?
As a feeding guide, a horse should receive approximately 1.5 - 2.5% of its body weight in forage on a Dry Matter basis. Therefore on average, a 500kg / 1,100lbs horse in maintenance up to moderate work should be getting approximately 7.5 - 12.5kgs / 16.5 - 27.6lbs of forage (hay/grass from grazing) per day, depending on its condition score. Remember that this calculation is based on the Dry Matter content of hay, which is usually around 85%, so you have to take that into consideration when working out how much your horse or pony could or should be fed.
If your horse is overweight, then aiming for 1.5% is ideal and if underweight then heading for 2.5% would be ideal. If your horse needs to lose weight, feeding 1.5% of its current body weight in Dry Matter (DM), or 2.0% of its ideal body weight (whichever is more) is recommended.
Purchasing a hay weigher is a great way to help owners weigh their hay and feed to know exactly what weight they are feeding.
Horses should never be fed per biscuit but by weight. For example; a biscuit of Lucerne compared to a biscuit of pasture hay can be very different and the horse might be getting too much or too little.
This is where a slow feeder comes in handy as it can be loaded up with hay and the horse can get the amount of forage it requires in the speed and quantity needed for optimum health.
The right hay is so important!
No matter if there is a short period of fasting or if you have ad-lib 24/7 grazing, the MOST important factor is the sugar and starch content of the hay. If your horse has 24/7 access to high sugar hay then you will never get on top of the laminitis and your horse will head on a downhill run to more severe laminitis or 'founder'.
I personally used to get my hay tested by Equi-Analytical/Dairy One in the USA. I now use Feed Central in Toowoomba, Australia (who send the sample there on your behalf). There is no way that you can look at hay and know its sugar levels, protein levels general mineral profile, or the quality of the hay. So if you are buying quantities large enough, then testing the hay to take the guesswork out or knowing you don't have to soak to reduce sugar levels, is well worth the extra expense.
Ryegrass and Clover are among the biggest Equine no-no's of hay. There are however many hays that are really good for horses such as Cocksfoot, Teff, Native grasses, Smooth Bromegrasses etc. Phalaris can be ok, under the right circumstances.
Every species has its pluses and minuses, so it is a good idea to research what species are in your area and are likely to be the best for your individual horses. The time of day that the hay is cut holds a BIG bearing on the sugar levels, so finding a farmer that cuts in the morning is a great asset to find.
Learning about endophytes and plant toxicity levels is also an important thing to consider when choosing a suitable hay variety.
Mowing your Pasture!
Many people mow pastures to reduce available feed and make grazing “safer” for horses and ponies. However, mowing can actually increase sugar levels in the grass.
Anything that stresses a plant causes it to store more sugar, and mowing is a stress. While there may be less grass volume, the short, stressed blades that remain are often much higher in sugar. In contrast, taller, mature pastures, after seed heads have formed, are generally safer.
There can be some benefit to mowing to prevent seed head formation, as sugar content peaks while seed heads are developing. But this effect varies depending on your grass species and paddock, and must be assessed individually.
Studies suggest that sugar levels remain elevated for 2 - 4 weeks after mowing, so by the time the pasture might seem safe again, seed heads may already be growing, raising sugar levels once more.
Every grass species responds differently to mowing, and the more species in your pasture, the more variables you need to consider.
RIRDC - Managing pastures to reduce laminitis
Quite a few years ago RIRDC came out with a good article on this topic. They analysed pastures available in Australia and discussed stages of growth, different varieties of species available, the best pasture species for horses, and stress factors that affect plant sugar levels.
Although it's referencing NSC (non-structural carbohydrates), if you transpose ESC (ethanol soluble carbohydrates) where NSC is written or just remember that it is the sugar/carbohydrate that is the issue then you will still find an article that is worth reading.
Over Grazing
As I keep mentioning, anything that stresses a plant raises its sugar content levels and overgrazing will certainly do that.
This is very important to realise for at-risk horses and ponies as they are often locked up in a small yard or paddock that seemingly has little to graze on. However, that short stressed grass that they are picking that is growing at ground level can be VERY high in sugar and starch and although well-meaning, may keep these horses in a laminitic state and not aid their return to soundness.
Dirt is the best place for these horses and ponies in a laminitic state, with low sugar hay that has an ESC and Starch content of less than 10%. New shoots of grass are also higher in sugar and starch which will be seen in an overgrazing situation.
Another important consideration is that most of the sugar in grasses tends to be in the bottom 3 - 4 inches of the plants. While it might be tempting to think that a very short, overgrazed pasture is safe because there’s “nothing much there, such pastures present several risks, grasses are very stressed and only the lower inches of the plant are available, meaning these pastures can be very high in sugar. Add a frost to this and this short, stressed grass can be diabolically high in sugar.
Frosts and High Temperatures
One of the general rules of assessing whether your pasture is ‘safe’ or not is determined by both temperature and sunlight on the plant:
- When the night temperatures are below 5°C / 41°F, pasture grasses can accumulate higher levels of sugars and starch due to stress on the plant. At these temperatures, grass growth slows, meaning the stored sugars aren’t used up overnight and remain elevated into the early morning. They’ll still be high in the early morning and in this situation, potentially at-risk horses should not have pasture access.
- Once it gets above 5°C / 41°F at night, the lowest plant sugar and starch level is before sunrise
- However, once temperatures are heading over 32 - 40°C / 89 - 104°F (depending if the plant is a C3 or C4 species), the plant is also stressed and it's sugar levels are raised.
At this temperature and below, the plants’ growth rate is slow, which means stored sugars aren’t used up. As such, they’ll still be high in the early morning. In this situation, potentially at-risk horses should not have pasture access.
Balanced Soils
Nothing can truly replace grass when it comes to its nutritional value for horses. It contains vitamins and minerals that no supplement or commercial feed can fully replicate.
Horses have evolved to graze 16 - 20 hours a day, consuming a high-fibre diet, which is essential for a healthy, properly functioning digestive system. Horses fed high-grain, low-fibre diets are more prone to colic, stomach ulcers, and other digestive issues. Fibre is key to keeping horses and ponies happy and healthy.
For horses that cannot safely graze at certain times, or sometimes ever, high-quality hay becomes critically important. Using hay nets allows horses to have a constant supply of fibre, supporting digestion and overall well-being even when grass is limited.
When choosing hay, low-sugar, high-quality options are especially important for horses prone to laminitis. Supplementing with a good vitamin and mineral mix is also recommended, particularly for horses that rely solely on hay.
What is regenerative farming?
Regenerative farming works in harmony with nature’s cycles, fostering biodiversity and allowing the natural flow of life to thrive.
Unlike large-scale conventional farming, which often prioritises efficiency over animal welfare and the health of surrounding ecosystems, regenerative practices focus on respect for both the land and its inhabitants. This approach may include planting trees, rotating animals daily, and actively observing how the farm ecosystem responds.
By combining ancient knowledge, careful observation, and techniques that mimic natural processes, regenerative farming raises animals in a way that enhances the soil, enriches the land, and strengthens the overall ecosystem.
Grass is still the best!
Nothing can truly replace grass when it comes to its nutritional value for horses. It contains vitamins and minerals that no supplement or commercial feed can fully replicate.
Horses have evolved to graze 16 - 20 hours a day, consuming a high-fibre diet, which is essential for a healthy, properly functioning digestive system. Horses fed high-grain, low-fibre diets are more prone to colic, stomach ulcers, and other digestive issues. Fibre is key to keeping horses and ponies happy and healthy.
For horses that cannot safely graze at certain times or sometimes ever, high-quality hay becomes critically important. Using hay nets allows horses to have a constant supply of fibre, supporting digestion and overall well-being even when grass is limited. Grass is still the best!
Seek Professional Assistance
The information provided in our emails is for general educational purposes only and is not intended to diagnose or treat any medical conditions, nor to replace professional veterinary advice.
Every horse is unique, and a variety of factors can affect their health and management, including soil type, pasture nutrients, feeding routines, management practices, workload (from retired horses to performance athletes), and each horse’s individual metabolic profile.
For guidance tailored to your horse, property, and local conditions, we strongly recommend consulting your veterinarian, equine nutritionist, or another qualified equine professional, who can provide advice specific to your horse’s needs.
