Allow grazing in the very early morning for horses prone to laminitis

Non-structural carbohydrates are the carbohydrates the plant produces during the process of photosynthesis. During photosynthesis, a plant takes sunlight for energy and uses water and carbon dioxide to create carbohydrates like starch, sugars and fructan.

NSC production starts when the sun comes up and finishes for the day when the sun goes down again. So during sunlight hours, a plant will produce NSC. Then overnight, the plant burns some of this accumulated NSC to survive and grow. They essentially make their own food during the day, and then ‘eat’ some of this food overnight to stay alive and grow.

Which means, NSC content will be lowest in the very early morning, just before the sun comes up. And they will be highest late in the afternoon, just as the sun goes down and into the early evening.

If you have a horse that is prone to laminitis, you should allow grazing only in the VERY early hours of the morning. And if the pasture may become unsafe, you should have them off pasture within 2 hours of sunrise.

BE WARNED however, that even in the very early morning, some pastures will still be too high in NSC to be safe. Spring is a particularly risky time for this to occur as the days are long enough for high NSC accumulation, but the nights are cold enough to slow plant metabolism and growth down so much that they don’t burn up much NSC overnight.


So early morning grazing is sometimes, but not always safe!

For more information on this, as well as a crisis diet for laminitics, click here to download our FREE E-Book ‘Your Guide to Feeding the Laminitic’.


Do you have a question or comment? Do you need help with feeding?

We would love to welcome you to our FeedXL Horse Nutrition Facebook Group. Ask questions and have them answered by PhD and Masters qualified equine nutritionists and spend time with like-minded horse owners. It’s free!

Click here to join the FeedXL Horse Nutrition Facebook Group


Horse feeding on the meadow

PSSM – how do the different forms affect how you should feed?

… and how can FeedXL help?

Polysaccharide Storage Myopathy (PSSM) is an area of growing information. Dr Stephanie Valberg and colleagues at Michigan State University lead this movement and most information and nutritional guidelines we use today can be attributed to research performed by Dr Valberg and colleagues.

The purpose of this article is to summarise the most current dietary recommendations and explain how FeedXL can help manage the nutrition of horses diagnosed with the various forms of PSSM, including Type 1 PSSM, Type 2 PSSM and MFM, based on findings from research in this area.

More information about the various forms of PSSM, diagnosis and management of PSSM can be found here.

Identifying your horse has PSSM in FeedXL

With limited testing for specific types of PSSM in some countries, horses with PSSM symptoms are more broadly diagnosed under the one umbrella of PSSM. Without a specific diagnosis via genetic testing (currently only validated for Type 1 PSSM) or muscle biopsy, caution should be used for all PSSM horses and low NSC diet implemented to see if improvements occur.

When using FeedXL, the first step is to tick ‘Tying Up (PSSM)’ when entering your horse’s details. Based on this, FeedXL will help you choose safe forages, feeds and supplements based on non-structural carbohydrate (NSC) content of each individual ingredient or whether the ingredient contains grain, grain by-products or high sugar ingredients eg. molasses.

Ingredients are colour coded as:

BLACK = Probably Suitable – Known NSC less than 12%.

PURPLE = Possibly Suitable – Does not contain grain or grain by-products but NSC content is unknown and may contain other high sugar ingredients.

ORANGE – Maybe Suitable – Known NSC content between 12% and 15%.

RED – Probably Unsuitable – Known NSC content >15% or unknown NSC content but contains grain or grain by-products.

Designing a suitable diet in FeedXL


Forage is an essential part of any horse’s diet but for those with PSSM, it is an important area to focus on as part of your horse’s diet. A minimum forage intake at 1.5-2% body weight per day (7.5-10kg for a 500kg horse) is advised.

Forage analysis is highly recommended to ensure selection of appropriate forage based on digestible energy, crude protein, starch and sugar (WSC) levels. By adding your forage analysis into FeedXL, you can confidently assess the need for additional energy and protein sources and ensure mineral and vitamin requirements are being met.

Specific dietary recommendations

Type 1 PSSM

For horses diagnosed with Type 1 PSSM, research has shown that providing a low NSC diet (with each individual ingredient less than 12% NSC) is essential. Fat inclusion at 15-20% of total digestible energy is recommended (excluding overweight horses).

For easy keepers, focusing on use of lower energy forages in the diet will allow for weight loss if necessary. Inclusion of a good quality protein source may be required to meet protein requirements and in this case a grain free low NSC balancer pellet can be used to achieve a balanced diet. If adequate amounts of forage are in the diet and room permits for additional calories, oil may be added.

For horses with higher energy requirements, commercially available low starch high fat feeds are available. Alternatively, using a combination of highly digestible fibre and high fat ingredients can be used to meet energy and protein requirements. Examples are beet pulp, soybean hulls, lupins (unique to Australia), copra meal, full fat soybean and oils.

Type 2 PPSM

With the exact cause of Type 2 PSSM currently unknown, for the most part dietary recommendations remain the same as for Type 1 PSSM horses.

For easy keepers, focus on supplying good quality protein sources eg. full fat soybean or whey protein concentrate are recommended. This contrasts with supplying excessive amounts of crude protein ie. provide quality not quantity.

If more energy is required, fat/oil supplementation should be used to meet energy requirements with less emphasis on supplying a certain percentage of DE from fat sources.

MFM (Myofibrillar Myopathy)

MFM is technically a condition in its own right rather than a form of PSSM. However, some horses previously diagnosed with Type 2 PSSM, may in fact have MFM.

The latest recommendations for MFM focus on use of a high-quality protein, moderate starch diet (ingredients with up to 20-30% starch) where additional energy is required and dietary fat of 4-8%.

For easy keepers, focus should be on supplying adequate forage and inclusion of high-quality protein. Due to the role cysteine may play in this condition, use of whey protein concentrate which is rich in cysteine as a dietary protein source is recommended.


Dietary Consideration Diagnosed Condition
Type 1 PSSM Type 2 PSSM MFM
Low NSC Always Sometimes Not Essential
Addition/use of good quality protein sources Not essential Yes Essential
Inclusion of starch or sugar Never Sometimes Yes – if necessary
Fat supplementation Beneficial – 15-20% Not essential Limited – dietary fat of 4-8%
Elevated vitamin E & selenium Beneficial* Beneficial* Beneficial*
Other minerals & vitamins Meet requirements Meet requirements Meet requirements

*FeedXL RDI for vitamin E and selenium is elevated when ‘Tying Up (PSSM)’ is ticked on your horse’s details page.

Additional resources

Selecting the best quality protein

Choosing a suitable oil


While diet only forms part of the management for PSSM horses, exercise being the other major component, getting it right can greatly minimise the symptoms PSSM horses experience. Dietary focus should centre around providing a high forage diet with suitable levels of energy, protein, starch and sugar for your horse.

FeedXL helps to take the guess work out of supplying adequate good quality protein in the diet, can assist in calculating the amount of fat in diets and gives peace of mind knowing the diet is meeting mineral and vitamin requirements.



Do you have a question or comment? Do you need help with feeding?

We would love to welcome you to our FeedXL Horse Nutrition Facebook Group. Ask questions and have them answered by PhD and Masters qualified equine nutritionists and spend time with like-minded horse owners. It’s free!

Click here to join the FeedXL Horse Nutrition Facebook Group


What’s new with PPID (formerly Cushing’s)

Our wonderful nutritionist Sam has put together some recent findings in the PPID area:

Clear breed differences in ACTH levels in normal animals

A normal autumn seasonal rise in ACTH was observed in ponies, Andalusian horses and Standardbreds however the greatest increases were seen in ponies (range 45.5-146pg/ml) and Andalusian horses (range 38.7-84.8pg/ml) [1]. Interestingly, one pony had an ACTH of 146pg/ml in mid-Autumn but had returned to 17.9pg/ml by late autumn.

Diet can impact the result of ACTH values

In aged horses (18-24 years old) not displaying clinical sign of PPID, researchers found that on a starch-rich diet, horses had elevated ACTH levels (60.0 ± 10.7 pg/mL) compared with adult horses (5-13 years old) on the same diet (15.7 ± 12.0 pg/mL) [2]. The same aged horses on the control diet, fiber-rich diet and sugar-rich diet did not show significantly higher ACTH levels as compared to the horses in the 5-13 years of age group.

Stress may influence ACTH results

Travel for 40 minutes caused ACTH levels to increase and remain higher up to 30 minutes post-unloading [3].


Read more from the 4th Global Equine Endocrine Symposium 2020

[1] Bamford, N.J., Harris, P.A., Bailey, S.R. (2020) Seasonal variation in adrenocorticotropic hormone (ACTH) concentrations and dexamethasone suppression tests in ponies and Andalusian horses compared with Standardbreds. In: 4th Global Equine Endocrine Symposium 2020, Gut Ising, Bavaria, Germany p12.

[2] Jacob, S.I., Geor, R., Weber, P.S.D., Harris, P.A. and McCue, M.E. (2017) Effect of dietary carbohydrates and time of year on adrenocorticotropic hormone (ACTH) and cortisol concentrations in adult and aged horses. Domestic Animal Endocrinology 63.

[3] Haffner, J.C., Hoffman, R.,. and Grubbs, S.T. (2020) The Effect of Trailering and Dentistry on Resting Adrenocorticotropic Hormone Concentrations in Horses. In: 4th Global Equine Endocrine Symposium, Gut Ising, Bavaria, Germany.


Meet The Author: Samantha Potter, MSc

In 2009, Sam completed a Bachelor of Equine Studies and it was during this time she developed an interest in equine nutrition. Pursuing this passion, Sam went on to complete her Honours followed by her Masters degree in equine nutrition at The University of Melbourne. Since 2015, Sam has worked as an independent nutritionist and enjoys supporting horse owners manage their horse’s nutrition in her role with FeedXL. To learn more about Sam and to ‘meet’ the rest of the FeedXL team, check out our About Us page here.



Do you have a question or comment? Do you need help with feeding?

We would love to welcome you to our FeedXL Horse Nutrition Facebook Group. Ask questions and have them answered by PhD and Masters qualified equine nutritionists and spend time with like-minded horse owners. It’s free!

Click here to join the FeedXL Horse Nutrition Facebook Group


Horse eating from hand

Teff Hay for Laminitic Horses

Over the last few years questions about teff (Eragrostis tef) hay and its suitability for laminitic horses have started to come up and it appears production of teff hay and therefore availability is on the rise. Here is a very mini review of the published research on teff hay in horses that we can find:

Recent Research on Teff Hay for Horses

Staniar et al 2010

These authors report non-structural carbohydrate (NSC) contents for teff of 5.4% in the ‘boot’ stage and 8.4% in the ‘late heading stage’ of plant maturity. Both really low NSC levels and well below the 10 – 12% threshold considered safe for laminitic horses. Variation between samples was also minimal which is also our experience with other C4 Type grasses like Rhodes for example.

Horses in this study ate 1.5% to 1.8% of their bodyweight in teff hay, with the lower intakes being on the more mature hay. Again, this is a good thing as horses on restricted diets are unlikely to eat this hay as fast as more palatable hays like alfalfa, so they should eat for longer periods of time for lower calorie intake.

McCown et al 2012

Report that when fed to horses unaccustomed to teff and given a choice of either teff and alfalfa or teff and timothy, their intake of teff is lower than their intake of alfalfa (no surprises there) and timothy. BUT, when given access to only teff, intake was about the same as timothy hay. So they don’t relish teff hay, but truly, this is a good thing as they are less likely to overeat it!

Askins et al 2017

These authors report that horses given free access to teff hay consumed 1.5% of their bodyweight per day which equated to 86% of maintenance calorie requirements. So the finding of lower intake on teff continues … hooray for teff!
This study also reports that resting glucose and insulin levels did not change over 10 days while the horses were fed teff. To keep this in context however, ryegrass hay (which can be very high in NSC) was fed as the control hay in this study and glucose and insulin levels also remained the same on this hay. Unfortunately the NSC content of the hays was not reported (yet!).

DeBoer et al 2017

In another recent study, these authors report that cool season (C3) perennial grasses (in this case orchardgrass, also known as cocksfoot and Kentucky bluegrass) had a significantly higher NSC content than teff pasture in summer and fall/autumn, however actual NSC content was not reported (this is just an abstract, hopefully the data will be fully published in future).

This research also looked at differences in plasma glucose levels in horses grazing either alfalfa, cool season (C3) grasses or teff and found that differences were minimal. However, we know that insulin resistant horses can maintain normal glucose levels, they just need a lot more insulin to achieve this. So just because differences in glucose levels were not apparent doesn’t mean there would not have been differences in insulin levels. These authors report that insulin levels will be reported in future research, so hopefully it is just a case of ‘watch this space’.


All in all, from the research available, teff appears to be suitable for laminitic horses and any other horses who need either a calorie restricted and/or NSC restricted diet. If you are going to feed teff hay though be sure to use FeedXL to balance the diet.

Teff, being a subtropical/warm season/C4 type grass does contain oxalate which will reduce calcium absorption by your horse and may lead to calcium deficiency if you don’t correctly balance the diets calcium to oxalate ratio (FeedXL will make sure you do this!). Teff, like almost all forages will also be low in trace-minerals and doesn’t contain great quality protein… so you will have a few gaps to fill. Of course testing your specific hay and uploading this to FeedXL will give you the best results in balancing your horse’s diet!

Finally, alfalfa/lucerne hay makes a great forage to feed alongside teff. Alfalfa is similarly low in NSC, but unlike teff is rich in quality protein and high in calcium to help offset the calcium binding tendency of the teff. They complement each other nicely.

If you need a low NSC forage, teff gets the thumbs up from us!


Askins M.J., Palkovic A.G., Leppo K.A., Jones G.C. & Gill J.C. Effect of feeding teff hay on dry matter intake, digestible energy intake and resting insulin/glucose concentration in horses. Journal of Equine Veterinary Science 52, 45.

DeBoer M.L., Hathaway M.R., Kuhle K.J., Weber P.S.D., Sheaffer C.C., Wells M.S., Mottet R.S. & Martinson K.L. Glucose response of horses grazing alfalfa, cool-season perennial grasses and teff across seasons. Journal of Equine Veterinary Science 52, 79.

McCown S., Brummer M., Hayes S., Olson G., Smith S.R., Jr. & Lawrence L. Acceptability of Teff Hay by Horses. Journal of Equine Veterinary Science 32, 327-31.

Staniar W.B., Bussard J.R., Repard N.M., Hall M.H. & Burk A.O. (2010) Voluntary intake and digestibility of teff hay fed to horses1. J Anim Sci 88, 3296-303.



Do you have a question or comment? Do you need help with feeding?

We would love to welcome you to our FeedXL Horse Nutrition Facebook Group. Ask questions and have them answered by PhD and Masters qualified equine nutritionists and spend time with like-minded horse owners. It’s free!

Click here to join the FeedXL Horse Nutrition Facebook Group


Feeding Sick or Injured Horses

Sick or injured horses, including horses suffering from burns, have different requirements to normal healthy horses, both in the types of nutrients they need and the sorts of feeds they can be fed. To determine the best thing to feed sick horse (or an injured horse) the following guidelines should be followed:

1. Don’t make any drastic changes to the diet

Sudden changes to any horse’s diet should be avoided and this is never more the case than when you have a sick or injured horse on hand. If your horse was on a primarily forage diet (mainly pasture, hay or chaff) prior to the sickness or injury, you should attempt to maintain the horse on a largely forage diet. Likewise if your horse was being hard fed, you can continue to hard feed the horse, but don’t suddenly introduce hard feeds to a horse that wasn’t on them previously, and unless there is a good medical reason (for example in the case of laminitis) you should not just suddenly stop feeding hard feeds or quickly switch to a new feed.

Keeping their feed consistent will keep them happier (they are creatures of habit and don’t like sudden changes) and also make sure you avoid problems like colic that can be associated with sudden changes in feed.

It is quite likely that you are going to need to make some changes to a horse’s diet. If this is the case, do it as slowly as possible or practical.


If your horse has to go to a veterinary hospital take along your horse’s feed he or she is used to having and leave clear directions on what and how much your horse is normally fed. If your horse was not hard fed before going to the clinic leave a note with the staff and if you have to, stick a note on your horses stable door requesting your horse is not fed any hard feed, as most horses in vet clinics will get some sort of hard feed unless otherwise directed.

2. Introduce new feeds as gradually as possible

There are going to be cases when your horse:

  • No longer has access to the feed he or she was used to (as in the case of fires burning out pastures);
  • Needs new feeds or supplements to make sure requirements for the healing process are met; or
  • Cannot physically eat their normal diet due to injuries to the muzzle or mouth

When a horse no longer has access to their normal feed, you should find something as similar as possible to replace it with. For example, if a horse’s normal grass pasture is burnt out by fire, you should initially put the horse on a diet of free choice grass hay. Don’t change them to something like lucerne/alfalfa hay or a hard feed-based diet straight away as it is just too different from what they were used to and may cause problems like diarrhoea and colic.

When additional feeds or supplements need to be added you should do so as slowly as possible.
If the horse can’t eat its normal diet due to an injured mouth or muzzle, you should find ‘easy to eat’ versions of feeds similar to the feeds your horse was used to. So for example, if your horse was on grass pasture or grass hay, use oaten or wheaten chaff as an easy-to-eat alternative. If your horse was eating lucerne hay, use lucerne chaff. And if your horse is finding its hard feed difficult to chew and swallow, soak it in warm water to make it soft before feeding.


If your horse changes from moist pasture to hay suddenly keep a very close eye on water intake and use water sweetened with molasses or apple juice to encourage drinking if water intake is low. Not drinking enough when eating dry hay puts horses at real risk of impaction colic.

3. Feed enough feed, but not too much

A sick or injured horse needs to have its calorie intake carefully managed. There are two main situations you need to be aware of:

  1. A horse with an injury that is confined to box rest – in these situations you need to ensure the horse does not become overweight through inactivity and overfeeding. Being overweight will put more stress on an injury, particularly if it is some sort of leg or skeletal injury or surgery. In addition, overfeeding will make the horse more agitated or hyperactive while confined and may lead to the horse injuring itself again while locked up.The best diet for these horses is free choice moderate to good quality grass hay, a low dose rate vitamin and mineral supplement, salt lick and water. Providing access to free choice hay will also help relieve boredom. It is a good idea to feed the hay through a slow-feeding hay net or put it in two or three normal hay nets to slow intake and prolong the amount of time the horse is eating in a 24 hour period. A horse that eats for a large part of its day will be much happier and settled than a horse that finishes its feed within a couple of hours.For more help with this, click here to read our blog post ‘How to feed a horse confined to a stable’.
  2. A horse with a sickness or severe injury (including burns) – in these situations the most important considerations are to get the horse to eat (as going off feed can be a major problem) and stop them from losing weight. A sick or severely injured horse that is losing weight will be not be able to properly start the healing process because its body is in a state of breakdown and not rebuild. If a horse doesn’t eat, it is also likely that its immune system will be compromised, again slowing the healing process and exposing your horse to the risk of secondary disease and infection.First and foremost with these horses you must get them to eat (see below for tips on getting a horse to eat).Once they are eating, they need to be fed a diet with adequate calories and protein to allow them to maintain their bodyweight or gain bodyweight where required. Feeds such as lucerne hay, grass hay and good quality sweetfeeds or pellets/cubes may be needed for the horse to maintain weight. These horses need to be condition scored regularly and their rations adjusted according to whether they are losing, maintaining or gaining weight.

Tips for getting a horse to eat

  • Make sure you are managing pain as pain is one of the first things that will put them off their feed. Work with your vet to develop a good pain management strategy.
  • Don’t put medications in your horse’s feed – most medications are not particularly tasty so instead of putting them in the feed wait until after your horse has eaten and give it to them via a paste made with apple sauce.
  • Beware of ulcers. Horses that are stressed and off their feed are at real risk and this will further reduce their appetite.
  • If your horse won’t eat its normal feed you can try adding some things including:
    1. Bran
    2. Honey
    3. Molasses
    4. Applesauce
    5. Grated carrot or apple
    6. Brewers yeast; or
    7. Lucerne chaff
  • Be careful adding salt. If you make a feed too salty your horse won’t eat it, so add it sparingly if at all and try feeds without any salt to see if it helps with their appetite.
  • Make sure the feed bin is in a comfortable position for the horse to reach. For example if it has a painful foreleg injury, elevate the feed bin slightly to reduce the amount of pressure a horse has to put on its legs to eat.
  • Allow your horse to graze when possible – horses that won’t eat will generally still graze, and periods of time grazing may be enough to stimulate their appetite so they will eat what you are trying to feed them.
  • Feed in frequent small meals and remove uneaten feed every 2 hours to keep it fresh and palatable.

If none of these strategies work and the horse still will not eat, contact your veterinarian that is caring for the horse and discuss the options available for tube feeding if required.

4. Make sure the diet contains everything your horse needs

Never is feeding a balanced diet more important than when feeding a horse recovering from sickness or injury. Protein and certain vitamins and minerals are critically important for promoting the healing process as is ensuring the horse is receiving the correct amount of calories.

If your horse is only eating a small amount of feed each day, the diet should be balanced so that its nutrient needs are largely met within that small meal size. This may involve feeding high protein supplements, concentrated vitamin mineral supplements and using high energy oils and grains to help meet calorie requirements.

FeedXL allows you to balance diets accurately for horses recovering from illness or injury. Simply choose ‘Horse Recovering from Illness or Injury’ or ‘Growing Horse Recovering from Illness or Injury’ when entering your horse’s details.

Special Note for Burns Victims

Severe burns cause:

  • Increased fat metabolism
  • Protein breakdown in the body; and
  • Increased use and excretion of vitamin C and B-vitamins

Thus a severely burnt horse’s requirements for these nutrients as well as fluid and calories can be increased up to 100% above maintenance needs.

The diet for these horses should be:

  • High in protein (14 – 16% of the total diet) – this makes alfalfa/lucerne a useful forage for these horses.
  • High in fat (7 – 10% of total energy intake); and
  • Fortified with vitamins and minerals including higher than normal levels of vitamin E and the B-group vitamins as well as vitamin C.


If you are not sure where to start with feeding a sick or injured horse seek professional help. We can certainly help on the FeedXL Members Facebook Group. Feeding a horse the wrong thing when sick or failing to recognise that your horse has special requirements can slow the healing process, suppress your horse’s immune system and expose your horse to secondary disease and infections. It is important to get it right.

Meet The Author: Dr Nerida McGilchrist

Dr Nerida McGilchrist is FeedXL’s co-founder and equine nutrition specialist. She holds a degree in Rural Science, a doctorate degree in equine nutrition and nearly 20 years of full time, on the ground experience in feeding all types of horses. To learn more about Nerida and to ‘meet’ the rest of the FeedXL team, check out our About Us page here.



Do you have a question or comment? Do you need help with feeding?

We would love to welcome you to our FeedXL Horse Nutrition Facebook Group. Ask questions and have them answered by PhD and Masters qualified equine nutritionists and spend time with like-minded horse owners. It’s free!

Click here to join the FeedXL Horse Nutrition Facebook Group


featured image alt


Bighead is a disease resulting from long term calcium deficiency in the diet. Bighead has severe effects on your horse, making movement painful and lameness a constant issue. Luckily though, it is a condition that is easily avoided by carefully balancing your horse’s diet.

What is Bighead?

Bighead, correctly known as nutritional secondary hyperparathyroidism is a severe calcium deficiency resulting from a horse not absorbing enough calcium from its diet. During these periods of calcium shortage, horses will mobilise calcium (and phosphorus) from their bones to keep blood calcium levels ‘normal’.

When this state of calcium deficiency occurs for prolonged periods of time horses mobilise so much calcium and phosphorus from their bones that their bones become fibrous and weak.

What are the symptoms?

As its name suggests, Bighead results in the horse’s facial bones becoming fibrous and swelling to give the horse a ‘bighead’ appearance as shown in this photo. This facial swelling appears most commonly in young horses whose facial bones haven’t fully formed and hardened, though it is possible for it to occur in mature horses as well.

Because nutritional secondary hyperparathyroidism affects a horse’s entire skeleton it will also result in shifting lameness and generally sore bones and joints. In severe cases horses will be reluctant to move or may move with a ‘hopping rabbit’ gait.

Affected horses also tend to lose weight even though they have access to ample feed. Because of the swelling that occurs in the bones, the upper airways can become obstructed resulting in noisy breathing during exercise and it is also possible for teeth to fall out.

What causes Bighead?

Bighead is literally a severe and long term calcium deficiency. There are two major causes of bighead in horses. These are:

  1. An incorrect dietary calcium to phosphorus ratio with more phosphorus in the diet than calcium. Phosphorus is able to block the absorption of calcium if there is more phosphorus than calcium in the diet eventually leading to a severe calcium deficiency. Diets that contain large amounts of high phosphorus ingredients like wheat bran and pollard (also called wheat middlings, millmix, millrun or broll), rice bran, copra and cereal grains have high levels of phosphorus and have the potential to cause an incorrect calcium to phosphorus ratio.
  2. Grazing high oxalate pasture. Sub‐tropical or C4‐Type pastures like kikuyu, buffel grass, setaria, green panic, pangola grass, guinea grass, purple pigeon grass, para grass and signal grass contain a compound known as oxalate. The oxalate in the grass binds most of the calcium available in the grass making it unavailable for absorption when the horse eats it. So even though these grasses may contain plenty of calcium, horses cannot access it, so over time they will develop a severe calcium deficiency. The more oxalate the pasture contains, the more rapidly a horse will develop bighead. Setaria, and specifically Kuzungula Setaria is the most dangerous high oxalate grass for horses, with severe bighead appearing in horses grazed on this grass species within one to 3 months.

Avoiding bighead

Fortunately, bighead is a disease that is easily avoided given the correct nutrition. The strategy to avoid bighead depends on its cause.

If the disease is occurring because of an incorrect calcium to phosphorus ratio, adding additional calcium to the diet to balance the calcium to phosphorus ratio will make sure you avoid this problem. Calcium can be added by feeding calcium supplements like limestone or a branded calcium supplement or calcium intake can be increased by adding high calcium forages like alfalfa/lucerne and clover to the diet. Dolomite is best avoided as a calcium supplement as its calcium bioavailability (the amount of calcium the horse can actually absorb) is low.

The calcium to phosphorus ratio must be kept above 1 part calcium to 1 part phosphorus for all horses. For young horses, the ideal calcium to phosphorus ratio range is 1:1 to 3:1. For mature horses the ideal range is 1:1 to 6:1.

If high oxalate grasses pose a threat to your horse, you must feed enough calcium in the diet to keep the calcium to oxalate ratio above 0.5 parts calcium to 1 part oxalate. The biggest difference between bighead caused by high oxalate pastures and bighead caused by an incorrect calcium to phosphorus ratio is that when adding calcium to the diet of horses on high oxalate pastures, phosphorus must also be added.

To correct the calcium to oxalate ratio of a horse’s diet, you should use a 2 parts dicalcium phosphate to 1 part limestone (calcium carbonate) mixture, adding enough of this to the diet to keep the calcium to oxalate ratio at or above 0.5 parts calcium to 1 part oxalate. Of course you must also make sure the calcium to phosphorus ratio remains balanced.

Are you groaning by now? So much math…

FeedXL to the rescue

Doing all the maths to work out correct calcium to phosphorus ratios and calcium to oxalate ratios can be tricky, but luckily FeedXL makes it very easy for you. The last section at the bottom of the Nutrient Table in the results section of the FeedXL report shows a number of ratios. The first two are the calcium to phosphorus ratio (shown for all diets) and the calcium to oxalate ratio which is shown only when a horse is grazing a high oxalate pasture or eating high oxalate hay.

FeedXL will warn you when your horse’s diet has an incorrect calcium to phosphorus ratio or if your horse’s diet has a calcium to oxalate ratio that is too low so that your horse is kept out of bighead harm’s way.

Meet The Author: Dr Nerida McGilchrist

Dr Nerida McGilchrist is FeedXL’s co-founder and equine nutrition specialist. She holds a degree in Rural Science, a doctorate degree in equine nutrition and nearly 20 years of full time, on the ground experience in feeding all types of horses. To learn more about Nerida and to ‘meet’ the rest of the FeedXL team, check out our About Us page here.



Do you have a question or comment? Do you need help with feeding?

We would love to welcome you to our FeedXL Horse Nutrition Facebook Group. Ask questions and have them answered by PhD and Masters qualified equine nutritionists and spend time with like-minded horse owners. It’s free!

Click here to join the FeedXL Horse Nutrition Facebook Group


Feeding Horses That Tie Up

Tying up is a painful condition for a horse and a frustrating one for you as an owner. Symptoms can range from severe muscle pain and distress, apparent colic, excessive sweating, elevated heart and respiration rates, a stiff gait, muscle tremors and a reluctance to move to more mild and elusive symptoms that just involve the horse feeling stiff, lazy or slightly lame.

Whether your horse suffers with severe tying up or a mild form, it will limit your horse’s performance and sense of well being, so the more you do to reduce the frequency and severity of bouts of tying up, the better your horse’s performance and health will be.

What is tying up?

Tying up, also called exertional rhabdomyolysis is a group of diseases that cause muscle damage and pain during and immediately following exercise. There are two main forms of tying up; polysaccharide storage myopathy (PSSM) which most commonly affects quarter horses, draft breeds and warmbloods; and recurrent exertional rhabdomyolysis (RER) which most commonly affects thoroughbreds as well as standardbreds and possibly arabians.

Horses affected by PSSM store abnormally high levels of glycogen in their muscles. These horses also accumulate abnormal amylase‐resistant polysaccharide in their fast twitch muscle fibres. Horses with PSSM appear to have no problem utilising the glycogen they have stored in their muscles when exercising. Why the storage of abnormally high levels of muscle glycogen causes muscle damage is still unknown. Recently a mutation in the gene for the skeletal muscle glycogen synthase enzyme (GYS1) has been identified as the primary cause of PSSM in quarter horses, draft horses and their crosses.

Horses affected by RER do not accumulate high concentrations of muscle glycogen, however they tend to exhibit abnormal and excessive muscle contractions, likely due to a heritable defect in calcium regulation within their cells. RER is often triggered by exercise and excitement and it is well recognised that young fillies and horses with a nervous temperament are most affected.

Dietary management of horses with tying up

Both forms of tying up benefit from close dietary management. Following are 5 tips for formulating diets for horses with tying up:

Tip 1—Minimise starch and sugar intake. Diets high in starch and sugars (for example those that contain large amounts of grain based feeds) are well known to make tying up occur more frequently and severely. For horses with the PSSM form of tying up, we recommend that all feeds containing grains be removed from the diet completely. By ticking that your horse is affect by PSSM when you are filling in your horse’s details in FeedXL, all feeds that contain grain or grain by‐products are red listed to make it easy to avoid them.

For horses affected by the RER form of tying up, you should try to keep the amount of energy supplied by grain based feeds to 20% or less of the total digestible energy intake. To monitor this in FeedXL, simply hover your mouse over the Digestible Energy bar in the graph for a full breakdown of where the energy is coming from in the diet (see the screen shot below). If your grain based feeds are supplying more than 20% of the digestible energy and your horse continues to be affected by tying up, reduce the amount of these feeds in the diet.

Tip 2—Use high energy fibres and oils to supply energy.

Current recommendations suggest that horses with PSSM should receive 13% or more of their daily digestible energy intake as oil, while horses with RER on high energy diets (for example thoroughbreds in race training) should be receiving 20 to 25% of their daily digestible energy intake as oil or high fat feeds like rice bran. With these very high levels of oil, care must be taken to introduce it to the diet gradually to allow time for the horse and its gut to adapt to that level of oil feeding.

You should also keep in mind the omega 3 and omega 6 levels in the diet. If you use oils like corn or sunflower oil as the main oil in the diet, consider adding some flax/linseed (see Newsletter #22: Feeding Flaxseed) or a specialised omega 3 oil to balance omega 3 and omega 6 intakes.

Below are some examples of diets for horses with PSSM and RER that follow the first two tips given here.


This diet is for a 500 kg (1100 lb) Quarter horse in moderate work. Note that there is no grain or grain by products used in the diet below and that vegetable oil is providing 13 percent of the horse’s daily digestible energy requirement.

Example PSSM diet in printable (PDF) FeedXL results format

Digestible energy component of example PSSM diet in FeedXL

RER Diet

This diet is for a 500 kg (1100 lb) thoroughbred in hard work. Note that cereal grains are providing less than 20 percent of this horse’s daily digestible energy requirement and that vegetable oils and high fat feeds like rice bran are supplying 24% of the horse’s daily digestible energy requirement.

Example RER diet in printable (PDF) FeedXL results format

Digestible energy component of example RER diet in FeedXL

Tip 3—Use FeedXL to make sure the horse’s diet is balanced, and importantly that its requirements for the electrolyte minerals sodium, chloride, potassium and magnesium and requirements for the antioxidants selenium and vitamin E are met. Avoiding very high levels of protein is also a good idea.

Tip 4—Avoid oats. Oats seem to trigger the RER form of tying up in horses and particularly fillies more frequently than other grains (and we don’t know why). So for horses with RER that are still receiving some grain in their diet, use cooked corn, barley, rice or other grains you might have access to in place of oats.

Tip 5—Reduce or remove the grains and high energy fibre components from the diet on days off. Horses fed their full ration on rest days seem more likely to be affected by tying up once they resume work. You should increase the horse’s allocation of hay or amount of turn‐out time to compensate for the feed you have taken out of their diet on rest days. If your horse is prone to gaining too much weight, you should also reduce the amount of oil fed on days off.

Combine good feeding with good management

A well balanced diet containing the right amount of energy from fibre, starch and oil with all requirements for vitamins and minerals being met is only part of the puzzle for effectively managing both PSSM and RER forms of tying up.

Horses that suffer with tying up need to undergo a regular exercise program. Care must be taken to ensure horses are allowed to gradually build up fitness and horses should never be exerted beyond their level of fitness. Prolonged periods of stall confinement should be avoided, with horses that tie‐up being better off housed in larger pastures or yards so they can move around freely.

Rest days need to be managed carefully. While these horses certainly do need some time off to be horses, they should never be fully box rested, but instead should be walked or turned out to pasture for voluntary exercise on these days.

Nervous horses that are prone to RER should be managed to keep their stress levels down. Always housing them with a buddy, allowing them plenty of turn‐out time, feeding them first and maintaining as regular a daily routine as possible are a few things that might help.

Avoiding the knots

Following good dietary management by minimising or completely removing starch intake, providing 13 to 25% of daily energy intakes as oil or high fat feeds, meeting all essential vitamin and mineral requirements including those for electrolytes and antioxidants and providing a regular exercise routine that remains within the horse’s level of fitness will all help to keep your tying up prone horses’ muscles … untied.

Meet The Author: Dr Nerida McGilchrist

Dr Nerida McGilchrist is FeedXL’s co-founder and equine nutrition specialist. She holds a degree in Rural Science, a doctorate degree in equine nutrition and nearly 20 years of full time, on the ground experience in feeding all types of horses. To learn more about Nerida and to ‘meet’ the rest of the FeedXL team, check out our About Us page here.



Do you have a question or comment? Do you need help with feeding?

We would love to welcome you to our FeedXL Horse Nutrition Facebook Group. Ask questions and have them answered by PhD and Masters qualified equine nutritionists and spend time with like-minded horse owners. It’s free!

Click here to join the FeedXL Horse Nutrition Facebook Group


Feeding the Laminitic Horse

Laminitis can be time consuming, painful for your horse and heartbreaking for you. A proper diet can make it a whole lot easier.

A majority of laminitis cases are due to insulin dysregulation. For this reason a diet based on low non-structural carbohydrate (NSC; starch + sugars) forage is vital. Good quality protein is important for aiding in recovery, especially of the hoof. And meeting requirements for vitamins and minerals is also a must for general health and immune function.

The good news is, feeding a laminitic horse doesn’t have to be difficult. The following are some guidelines for making it easier; first is getting the basics right. Then we fine‐tune for weight changes. And finally there are some tips on dealing with boredom and associated problems like hoof repair.

Getting the basics right

  1. A low NSC forage should make up most of the diet
  2. Never feed grain, grain by‐products or molasses
  3. Make sure the diet is balanced for vitamins and minerals

Base the diet on low NSC pasture or hay

All horse diets should be based on forage and the laminitic horse is no different. However they need low NSC forages. There are a few ways you can give your horse access to low NSC forages. These are:

  • Graze in the VERY early hours of the morning from 2 hours before until 2 hours after sunrise. This is when pasture NSC levels are lowest.
    If you are unable to control the hours of the day your horse is allowed to graze, use a grazing muzzle to reduce your horse’s intake of pasture.
  • Feed hays that are typically low in NSC. These include mature or stemmy subtropical grass hays like Rhodes grass has and mature, stemmy or weather damaged lucerne hay.
  • If you can’t access these kinds of hays, soak the hay you do have available in warm water for 30 minutes 2 hours or in cold water for 2 to 10 hours*, draining and feeding. Do not give your horse access to the soaking water.
    *In warm climates, avoid soaking for longer than 2 hours.
  • Avoid any hays that are known to have high levels of NSC, including ryegrass hay, oaten, wheaten or barley hay.
  • Lucerne haylage or silage that has been produced specifically for horses is also a low NSC forage option (check there is no molasses added).

Never feed a grain or grain by‐product based feed

If your horse needs extra feed in addition to the low NSC forage you are feeding you must be very careful when selecting a suitable feed. You should never feed a laminitic horse with a feed that has any of the following ingredients:

  • Oats, corn, wheat, rice, triticale, rye, barley or other cereal grains.
  • Wheatfeed, millrun, millmix, broll, bran (rice or wheat), pollard, middlings or any other variation of these ingredients.
  • Any form of steam flaked, micronised or extruded grain.

Read all labels and lists of ingredients carefully before buying a feed. And it is buyer beware. Many feeds that contain grain ‘by‐products’ like wheatfeed/millrun, bran or pollard advertise themselves as being ‘grain‐free’. This is grossly misleading and these feeds present as much danger to your laminitic horse as a feed that contains grain.

Other feeds claim to be ‘Low GI’, but again, if they contain any of the ingredients listed above, they should be avoided for laminitic horses. And finally, watch out for molasses added to feeds as this can make a feed high in sugar.

FeedXL will help you select suitable feeds that do not contain these ingredients by highlighting all unsuitable feeds for laminitic horses. Very few feeds are truly suitable for a laminitic horse.

Feeds labelled by NSC content in FeedXL

Make sure the diet is balanced!

It is very important to make sure the diet you are feeding your laminitic horse is balanced. Meeting the laminitic horse’s requirements for protein, amino acids, vitamins and minerals will help them recover from any previous bouts of laminitis, help them to resist other disease and infection and will keep them in good overall health with a strong immune system!

FeedXL will help you put a low NSC diet together that also meets requirements for protein, amino acids, minerals and vitamins.

Fine Tuning the diet

Feed according to your horse’s need to gain, hold or lose weight

Assess the body condition (fatness) of your horse and have a clear goal in mind as to whether you want the horse to gain, hold or lose weight. Click here to read our post ‘Why Body Condition Score’.

To gain weight

If the goal is to gain weight you should:

  1. Provide your horse with access to as much low NSC pasture or hay as he wants to eat (within reason, if he is consistently eating more than 3% of bodyweight you may need to limit the hay provided).
  2. Add some alfalfa/lucerne hay to the diet, feeding up to 4kg/day for a 500 kg horse (8.8 lb/day for an 1100 lb horse).
  3. Feed a low NSC complete feed at the recommended rates for your horse’s bodyweight and current activity (only use the complete feeds that are not highlighted red in FeedXL). Complete feeds will provide your horse with the calories, protein, vitamins and minerals he needs.


Mix your own low NCS balanced feed by using high calorie unfortified ingredients like soybean or lupin hulls, sugarbeet pulp and copra meal. Then add your own vitamins and minerals via a low dose rate vitamin and mineral supplement and add protein from soybean or lupins.

If additional weight gain is needed add some oil to the diet. Start with ¼ of a cup per day and gradually increase the amount if required. Flaxseed (linseed) oil is a good choice for laminitics due to its high omega 3 content.

To maintain weight

To maintain your horse’s weight you should:

  1. Allow the horse access to up to 2.5% of its bodyweight of low NSC forage (12.5 kg for a 500 kg horse) per day, including a small amount of alfalfa/lucerne hay.
  2. Balance the diet with a low dose rate vitamin and mineral supplement or balancer pellet and additional protein from soybean or lupins if your pasture or hay quality is poor.
  3. Monitor your horse closely. If he is not holding his bodyweight on this diet, increase the amount of alfalfa/lucerne you are feeding and reassess your horse. If he still isn’t holding condition, you can add high calorie unfortified ingredients like soybean or lupin hulls, sugarbeet pulp and copra meal to the existing diet.


Switch to using a low NSC complete feed at the recommended rate for your horse.

To lose weight

If your horse needs to lose weight you must do it carefully, as forcing the laminitic into rapid weight loss can also stop them from healing their damaged hoof tissue and may cause other problems like hyperlipaemia. To gently encourage your horse to lose weight you should:

  1. Feed up to 2% of your horse’s body weight (10 kg/day for a 500 kg horse) per day as low quality, low NSC forage, including mature or stemmy subtropical grass hays and/or weather damaged alfalfa/lucerne hay.
  2. Balance the diet with a low dose rate vitamin and mineral supplement and good quality protein from full fat soybean. FeedXL can help you find an appropriate supplement using the ‘Find a Supplement to Fix This Diet’ feature.
  3. Constantly assess your horse’s body weight and adjust the diet according to the rate of weight loss. If your horse is not losing weight, reduce the amount of low sugar forage being fed to 1.5% of the horse’s current bodyweight (7.5 kg/day for a 500 kg horse; 16.5 lb for an 1100 lb horse). If this reduction doesn’t achieve the weight loss you want, reduce the amount of forage being fed to 1.5% of the horse’s ideal bodyweight.

Preventing boredom

To prevent boredom in these horses, make their forage hard to eat so it is more time consuming for them. One way you can do this is by using slow feeder hay nets. Or you can use forage feeding systems like the Savvy Feeder.

If you do feed hay out of hay nets you may need to dampen it down slightly to reduce dust. You should also feed their daily allocation of hay in 2 or 3 meals per day. When the horse is fully sound and able to exercise, a gentle exercise routine each day will also help them to lose weight and reduce their risk of further bouts of laminitis.

Assisting hoof repair

Feeding a low NSC diet will help to prevent further damage to your horse’s hooves. Providing high quality protein that contains good levels of the essential amino acids lysine and methionine (soybean contains the highest quality protein) as well as making sure your horse is getting its essential vitamins and minerals will give your horse the building blocks it needs to repair damaged hoof tissue.

If you find your horse’s hooves are taking a long time to respond to a well balanced, low NSC diet, you may find the addition of biotin to the diet is helpful. For more information on the use of biotin to promote hoof growth, see our post Biotin: Should You Supplement?

By using FeedXL to balance your laminitic horse’s diet you will ensure you avoid unsuitable feeds and that you meet your horse’s requirements for good health and hoof repair.

For more detailed information on managing and feeding the laminitic, click here to get your copy of our FREE ebook ‘Your Guide to Feeding The Laminitic’.

Meet The Author: Dr Nerida McGilchrist

Dr Nerida McGilchrist is FeedXL’s co-founder and equine nutrition specialist. She holds a degree in Rural Science, a doctorate degree in equine nutrition and nearly 20 years of full time, on the ground experience in feeding all types of horses. To learn more about Nerida and to ‘meet’ the rest of the FeedXL team, check out our About Us page here.



Do you have a question or comment? Do you need help with feeding?

We would love to welcome you to our FeedXL Horse Nutrition Facebook Group. Ask questions and have them answered by PhD and Masters qualified equine nutritionists and spend time with like-minded horse owners. It’s free!

Click here to join the FeedXL Horse Nutrition Facebook Group


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