Tag Archive for: oil

What is the Safest Form of Flaxseed – Whole, Ground, Heat Treated or Oil?

Confusion around what form of flaxseed (linseed) is best/safest to feed our horses is nothing new. While many of us thought the concerns around cyanide poisoning for horses were laid to rest, recent safety issues around flaxseed supplementation in human diets, more specifically for toddlers and children, has warranted us to look at this again (EFSA CONTAM Panel, 2019).

There are very few published research studies available in horses around the safety of feeding flaxseed. And there are no published reports of cyanide poisoning that we are aware of. Most safety information is extrapolated from other species including humans, rats, dogs, cattle and pigs. Although information is limited, we aim to answer three questions for you:

  1. Should we be concerned about the potential of cyanide poisoning in horses?
  2. What is the safest form of flaxseed to feed our horses?
  3. Does form then affect the fatty acid composition of flaxseed?

How is Flaxseed commonly fed?

Currently, whole and freshly ground flaxseed are the most common ways of feeding flaxseeds to our horses.

Whole flaxseeds are deemed relatively safe from the point of view of cyanide poisoning as the two things (more scientifically, the precursors for cyanide production; cynanogenic glycosides and the glycosidase enzyme) that combine to produce cyanide are contained separately within the intact whole seed. Once eaten, the chewing action grinding the seeds can allow for cyanide production, but it is thought that this is quickly halted once the flaxseed reaches the stomach and the enzyme becomes deactivated by the gastric acid.

Anecdotally horses owners have found that whole flaxseeds can pass undigested through the gastrointestinal tract presenting in manure, with some finding flaxseed plants growing in their paddocks (great for biodiversity in the pasture, but not so much benefit to our horse in getting those added fatty acids in the diet as we had hoped).

Freshly ground flaxseed has become popular for this reason – with limited time for cyanide to form, preservation of fatty acids and to ensure our horses could access all the goodness within the seed coat freshly ground flaxseed is an excellent option.

Realistically, what is the likelihood of cyanide poisoning in horses?

It appears not likely.

Extrapolated from other species, a horse’s maximum ‘safe’ intake of cyanogenic precursors is 0.4mg/ kg body weight… or 200mg for a 500kg (1100lb) horse (Dusica, I. et al., 2012).

So, even if a flaxseed product contained the highest concentration of cyanogenic precursors reported in the European Food Safety Authority database (407mg/kg) (EFSA CONTAM Panel, 2019), it can be still be safely fed at up to 500g (~1 lb) per day for a 500kg horse.

How much flaxseed can I feed safely?

There is no established recommendation, but we can be guided by amounts that have been safely fed in a few horse specific studies.

In a Canadian study, horses were fed 100g (3.5 oz) per 100kg (220 lb) body weight per day (500 grams for a 500 kg horse). This study looked at the supplementation of flaxseed for reducing skin reactions like ‘sweet itch’ (O’Neill, W. et al., 2002). The authors reported no negative effects of feeding milled flaxseed at this level and reported reduced skin reactions in response to the induced skin irritation in the flaxseed supplemented horses.

Other studies in 2009 & 2012, fed a much lower amount of milled flaxseed, estimated to be 150-165g (5.5-5.8 oz) per day. Between these two studies, positive changes in blood and muscle omega 3 content and improved immune function were reported in those supplemented with flaxseed compared with control groups (Vineyard, K. et al., 2009; Hess, T. et al., 2012).

Based on these few studies and figures extrapolated from other species, up to 100g (3.5 oz) per 100kg (220 lb) or 500 grams for a 500 kg horse per day can be fed safely.

Most horses (65% according to Facebook Poll conducted on the 15 October 2020 by FeedXL Horse Nutrition Calculator) receive 100-250g (3.5-8.8 oz) flaxseed per day.

If you are concerned about cyanide toxicity, what can you do?

Research has shown that heating flaxseed can reduce the amount of cyanogenic precursor present.

One study showed microwaving flaxseed for just over 4.5 minutes on microwave power of 400W reduced precursor by 25% (Dusica, I. et al., 2012). Beware though, you can burn flaxseed in the microwave! Microwave power > 560W for 6 minutes caused samples to burn.

Other studies have also shown that microwave roasting achieved the highest level of precursor reduction (83.3%) in flaxseed (Feng et al. (2003).

Happily, this study also showed that there were no major changes in the main nutrient and fatty acid profile caused by microwave treatment.

Similarly, extrusion (140 degree Celsius) significantly reduced cyanogenic compounds (84%) but did not significantly change the fatty acid content – even after storage for 60 days (Imran, M et al., 2015). Limited information is available on micronized flaxseed specifically.

Interestingly, the perception that fatty acids in raw ground flaxseed deteriorate quickly is not supported by various studies, all showing minimal difference in fatty acid composition after 2-4 months storage (Khalesi, S., et al. 2011).

What about oil?

The good news is that oil doesn’t contain the cynangenic compounds of whole or ground flaxseed. It can be less stable in terms of fatty acid composition, therefore must be stored correctly and used in a timely manner. But if the reason you are feeding flaxseed is for the oil content, then using the oil may be an option worth considering.

With flaxseed oil products though, you do not get the benefit of other nutrients whole, ground or milled flaxseed provides to a diet including like protein, fibre, minerals & vitamins.


So, are we any closer to knowing what is the best and safest form of flaxseed to feed our horses? Honestly, we think it comes down to personal preference.

With cyanide toxicity appearing to be less of an issue for horses due to the low amounts commonly fed in comparison to body weight – whole or ground flaxseed is acceptable. Due to anecdotal evidence of whole flaxseeds passing undigested through the gut, freshly ground flaxseed is favourable to ensure fatty acids can be absorbed.

Ground flaxseed also offers the benefit of providing the wonderful fibre and other nutrients along with the omega 3 fatty acids compared with flaxseed oil.

Practically, freshly grinding flaxseed is not for everyone.  If this is the case for you, using a stabilised (pre-heat treated) flaxseed product may be a better option.

If you are still concerned about cyanide poisoning, microwaving your flaxseed  should significantly reduce the cyanogenic precursor and is unlikely to affect the fatty acid content. Be careful microwaving though to make sure you are not burning the flaxseed.

And do your own research on the safest way to microwave them based on your specific microwave. As a guide you should be able to safely microwave them at 400W for 5 minutes. But the quantity you microwave at any one time will have an effect on the appropriate time you should use.

Feeding rates will vary depending on a horse’s energy requirement and amount of omega 3 within the diet however up to 100g per 100kg body weight appears safe…the economics of feeding this much we are less sure about!


Dusica, I., Kokic, B., & Tea, B., Colovic, R., Vukmirovic, D. & Slavica, S. (2012). Effect of microwave heating on content of cyanogenic glycosides in linseed. Ratarstvo i povrtarstvo. 49. 63-68.

EFSA CONTAM Panel (EFSA Panel on Contaminants in the Food Chain), Schrenk, D., Bignami, M., Bodin, L., Chipman, J.K., del Mazo, J., Grasl‐Kraupp, B., Hogstrand, C., Hoogenboom, L.R., Leblanc, J‐C., Nebbia, C.S., Nielsen, E., Ntzani, E., Petersen, A., Sand, S., Vleminckx, C, Wallace, H., Benford, D., Brimer, L., Mancini, F.R., Metzler, M., Viviani, B., Altieri, A., Arcella, D., Steinkellner, H. & Schwerdtle, T., (2019). Scientific opinion on the evaluation of the health risks related to the presence of cyanogenic glycosides in foods other than raw apricot kernels. EFSA Journal 2019;17(4):5662, 78.

Feng, D., Shen, Y. & Chavez, E. (2003). Effectiveness of different processing methods in reducing hydrogen cyanide content of flaxseed. Journal of the Science of Food and Agriculture. 83. 836 – 841.

Hess, T., Rexford, J., Hansen, D. Harris, M., Schauermann, N., Ross-Jones, T., Engle, T., Allen, K. & Mulligan, C. (2012). Effects of two different dietary sources of long chain omega-3, highly unsaturated fatty acids on incorporation into the plasma, red blood cell, and skeletal muscle in horses. Journal of Animal Science. 90. 3023-31.

Imran, M., Anjum, F., Ahmad, N., Khan, M., Mushtaq, Z., Nadeem, M. & Hussain, S. (2015). Impact of extrusion processing conditions on lipid peroxidation and storage stability of full-fat flaxseed meal. Lipids in health and disease. 14. 92.

Khalesi, S., Jamaluddin, R. & Ismail, A. (2011). Effect of raw and heated flaxseed (Linum usitatissimum L.) on blood lipid profiles in rats. International Journal of Applied Science and Technology. 1(4). 84-9.

O’Neill, W., McKee, S. & Clarke, A. (2002). Flaxseed (Linum usitatissimum) supplementation associated with reduced skin test lesional area in horses with Culicoides hypersensitivity. Canadian journal of veterinary research = Revue canadienne de recherche vétérinaire. 66. 272-7.

Ratnayake, W., Behrens, W., Fischer, P., Labbe, M., Mongeau, R. & Bearerogers, J. (1992). Chemical and nutritional studies of flax-seed (Variety Linott) in rats. Journal of Nutritional Biochemistry. 3. 232-240.

Vineyard, K., Warren, L. & Kivipelto, J. (2009). Effect of dietary omega-3 fatty acid source on plasma and red blood cell membrane composition and immune function in yearling horses. Journal of Animal Science. 88. 248-57.


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!

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5 Ways One Balanced Diet Can Be Better Than Another

We recently had a member of our nutrition forum ask ‘Can one balanced diet be better than another, or is the key point that it is balanced?’

This is probably the best question I have ever been asked! And the answer is absolutely YES! One balanced diet can be better than another!

BUT, before I explain why, I just want to say that diets balanced using FeedXL will be 1000 (or more) times better than a diet that is unbalanced and not meeting a horse’s basic nutrient requirements. So take heart that if your diet is balanced on FeedXL, you are way ahead in keeping your horse healthy.

So balanced diets that meet all of your horse’s known nutrient requirements are better than unbalanced diets that do not meet requirements.

But, one balanced diet can certainly be better than another.

Here are 5 examples of what makes one diet better than another:


Factor OK Option Better Option Why is this better?
Forage Amount Diet just meets the FeedXL minimum forage requirement. Forage is a major component of the diet and is used to meet as much of a horse’s daily digestible energy requirement as possible. The more forage in a diet the better your horse’s gut health will be. If you feed a balanced diet but your horse’s gut is unhealthy, your horse’s overall health will be limited.
Forage Variety You feed only one or two different types of forage. For example Teff hay and alfalfa/lucerne chaff or pellets. Your forage (pasture, hay, chaff, forage pellets or cubes) is made up of several different plant species. For example, your pasture has 3 different grass species plus clover, and you feed a mixed meadow hay plus alfalfa/lucerne chaff. Lots of forage variety gives good fibre variety and this supports a diverse and robust hindgut microbiome that is less prone to disturbance and more able to provide the nutrients, immune function and hormone support a horse needs. PLUS…while we know a lot about many nutrients a horse needs (like copper, vitamin E etc) there are MANY nutrients (like the omega fatty acids and most of the essential amino acids) that we know your horse needs. We just don’t know how much he needs. Feeding a large variety of forages improves the chances you will meet requirements for all of these nutrients we don’t understand very well yet.
Uncooked Grains The ONLY OK option for uncooked grain is oats. ALL other grains must be cooked. They are definitely not OK to feed uncooked. All grains are easier to digest when they are cooked (boiled, extruded, steam flaked, micronized). In fact you must only feed barley, corn and rice if it has been cooked. Feeding any of these grains uncooked is going to make your horse sick. The starch from cooked grains can be almost fully digested in your horse’s small intestine. Meaning less starch is allowed to get into your horse’s hindgut to feed the ‘bad’ bacteria. If you do feed raw grains, your horse’s hindgut will become acidic, bad bacteria will flourish and your horse’s gut and overall health will suffer.
Using Oil All oils are ‘safe’ and all provide the same amount of digestible energy in a diet. But, some oils like sunflower and corn oil are extremely high in omega 6 and can unbalance your horse’s omega 3 to 6 ratio. Canola oil provides a good blend of omega 3 and 6 fatty acids and is particularly useful in diets that contain no grain to provide the omega 6 your horse will need. Flax/Linseed oil is very high in omega 3 and is super useful in high grain diets to balance the omega 3 to 6 ratio. If you feed too much omega 6 in a diet it can result in excessive inflammation. Choosing your oils to match your diet (a little like choosing your wine to match your meal) means you will meet omega 3 and 6 requirements and keep the ratio between the two balanced.
Protein Quality As long as you meet your horse’s protein AND lysine requirement in FeedXL you will be doing a good job of providing enough protein and essential amino acids. BUT, not all proteins are created equally. Cottonseed meal, for example, contains lysine, but 60% of it is unavailable for absorption. Or flax/linseed meal is high in protein but it is low in essential amino acids. Choose premium quality proteins for your horse’s diet so that when FeedXL shows you that crude protein and lysine requirements are met, you also have an excellent chance of meeting all requirements for the essential amino acids. This includes choosing things like a component of soybean in preference to an unnamed ‘vegetable protein meal’ and/or using some alfalfa/lucerne together with your grassy forages. When you feed better quality protein you will get more muscle! When you are able to use high-quality sources of protein that meet your horse’s essential amino acid requirements you will have a better chance of 1. Providing enough of the amino acid ‘Leucine’ to switch muscle building on; and 2. Providing the building blocks needed to actually build muscle.


So if you want the best possible diet, here are my top 5 tips:

  1. Feed as much forage as possible to meet digestible energy requirements.
  2. Use as many different types of forage as possible.
  3. Never feed uncooked grains!
  4. Use oils that have an omega 3 to 6 profile that will complement your horse’s diet; and
  5. Use high quality proteins.

If you can do all of that AND have a balanced diet, your horse will be ready to take on the world!



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


Oil for Horses: Good or Bad?

Hard working horses have enormous requirements for energy that are traditionally filled using high grain rations fed together with chaff and hay. However, feeding large amounts of grain does come with its own set of issues which can include colic, hindgut acidosis, nervous or fiery behaviour, tying up and loss of appetite. Oil has gained popularity in recent years as a substitute source of energy for working horses, but is it effective, how much can be fed, are all oils equal in the benefits they can provide and do they cause any health issues of their own?

A little bit goes a long way

The biggest benefit oils provide working horses is their very high energy content relative to grains. Oils contain nearly 3 times more energy than oats, with 400 mls of vegetable oil providing as much energy as 1 kg of oats. The real benefit in this is you can reduce the size and sheer bulk of feed a horse has to consume without reducing calorie intake, allowing you to get enough ‘feed’ into horses with poor appetites. The end result being these horses can hold their weight and continue to train and compete for longer than they otherwise would on a more traditional diet.

Reducing heat load

Oils generate less heat during the digestive and metabolic processes than an equivalent amount of grain or forage. Feeding oil also means that you can feed less grain and still meet energy requirements. Combined, this means that high oil diets place less of a heat load on working horses, reducing electrolyte losses and the amount they need to sweat to stay cool, a big bonus for hard working horses, especially those training and racing in hot environments or working over very long distances.

Saving glycogen

Fatty acids from oils are the preferred fuel for muscles during slow and medium pace work while glycogen is the only source of energy a muscle can use during sprints and strenuous exercise. Once a horse runs out of glycogen its muscles fatigue and the horse will slow down and lose the ability to perform at the level it is capable of. Feeding oil in diets provides a source of fatty acids for muscles to burn during the warm up and slower phases of a competition, meaning muscles are able to conserve valuable glycogen and avoid fatigue.

Problem solving

‘Problem horses’ and particularly those that tie up or get excited and nervous on high grain diets will often benefit from rations that provide a portion of the dietary energy from oils. It is thought that the positive effects seen in these horses on high oil diets is due more to the reduction in grain intake as opposed to the addition of oil, but using oil in the diet allows you to reduce grain intake without compromising energy intake and performance.

Oils aint oils

All oils contain virtually the same amount of digestible energy, but there are other differences you may want to consider when looking to purchase an oil, including:

Essential Fatty Acid Content: Horses need omega 3 and omega 6 fatty acids in their diet. Grains are naturally high in Omega 6, so for horses on a high grain diet, it is preferable to choose an oil with some omega 3 content. The table below shows the amount of omega 3 and omega 6 in some commonly used oils. Linseed and canola oil contains the highest omega 3 fatty acid content of the natural vegetable oils.

Ingredient Name Omega 3 (%) Omega 6 (%)
Linseed (Flax) Oil 57 13.9
Cod Liver Oil 25 2
Canola Oil 10 20
Soybean Oil 7 52
 Corn Oil  1  55
 Olive Oil  1  11
 Rice Bran Oil  1  39
 Sunflower Oil  0.3  60
 Coconut Oil  0.1  2

Some linseed oils and fish oil including cod liver oil are notoriously unpalatable for horses, so while these oils are useful for providing omega 3 fatty acids, they can’t be fed in large amounts as most horses simply won’t eat them.

Processing Method: Oil is extracted from oilseeds in two main ways; cold pressing where oil is squeezed out of seeds, often in a water cooled environment to keep the oil at less than 60C; and solvent extraction where a solvent like hexane is added to extract oil from seeds. The oil is then heated to remove the hexane. Cold pressed oils tend to be higher in quality as more of their essential fatty acids and natural antioxidants are left intact in comparison to solvent extracted oils.

It takes time

Horses need time to adapt to digesting and metabolising oils. Oils should always be introduced into a diet slowly, starting with ¼ cup of oil per day and increasing this by ¼ cup every 5 days until you reach the full amount you want to feed. Introducing oil into a diet too quickly can result in soft manure and reduced fibre fermentation in the hindgut.

It will take a minimum of 3 weeks before a horse starts to really benefit from the oil in its diet and it could take up to 3 months before the full benefits of oil are realised.

How much can you feed?

Horses can be fed up to 20% of their total energy intake as oil, which in real terms means just over 3 cups of oil per day for a 500 kg horse in full work. While this level of oil is useful for horses that tie up, very few horses are fed this much oil per day. Feeding between 1 and 2 cups of oil per day is enough to give horses the benefits discussed above without making diets messy, unpalatable or unnecessarily expensive.

Good Stuff

Oils are ‘good stuff’ for working horses. They reduce reliance on grains, make the amount of feed a horse needs to eat smaller, keep horses cooler, allow horses to conserve muscle fuel for sprinting, give horses that tie up a safer and more effective source of energy and provide essential fatty acids in the diet.

For the best results, introduce oils slowly into the diet and select oils based on the following: their omega fatty acid content with oils containing some omega 3 fatty acids preferred; palatability, be aware that some oils including linseed and fish oils can be unpalatable; and method of processing, with cold pressed oils preferred over solvent extracted oils.

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


Omega 3 for Horses: What, Why, How?

What is Omega 3?

‘Omega 3’ is a term used to describe a group of fatty acids that cannot be made by an animal. They are therefore classified as essential fatty acids because they must be consumed in the diet. There are three ‘Omega 3’ fatty acids; the ‘short chain’ alpha-linolenic acid (derived from plants) and the ‘long chain’ eicosapentaenoic acid (EPA) and docohexaenoic acid (DHA) (available almost exclusively from oily fish). Alpha-linolenic acid is the only form of Omega 3 present in a horse’s natural diet. This form of Omega 3 can be transformed (elongated) into EPA and DHA via a metabolic pathway in the horse’s body. EPA and DHA are the two biologically active forms of Omega 3.

What does Omega 3 do?

Omega 3 fatty acids are important constituents of all cell membranes. They are primarily needed for the production of eicosanoids, including leukotrienes (involved in inflammatory responses), prostaglandins (involved in smooth muscle contraction and inflammation), and thromboxanes (involved in blood clot formation). All cells in a horse’s body except the blood cells produce eicosanoids and the eicosanoids have their effect directly on the cell that produced them. They are highly potent chemicals and absolutely essential for the normal functioning of a cell.

Omega 3 fatty acids are also important in maintaining cell membrane structure and function as well as central nervous system development and immune function, plus they have a role in male fertility, affecting the shape, motility and concentration of sperm in seminal fluid.

Why is the Omega 6 to Omega 3 ratio important?

Omega 6 is another essential fatty acid. Omega 6 is present in equine diets as the ‘short chain’ linoleic acid (the plant form of Omega 6) which is then transformed (elongated) to the biologically active ‘long chain’ forms of Omega 6 known as dihomo-gamma-linolenic acid (DGLA) and arachidonic acid (AA). Both Omega 3 and Omega 6 are required in the equine diet. Omega 6, like Omega 3 is an important constituent of cell membranes and plays a critical role as a precursor for the eicosanoids (leukotrenes, prostaglandins and thromboxanes) that control swelling, inflammation, clotting and dilation.

The reason the Omega 6 to Omega 3 ratio is important is the plant derived Omega 3 fatty acids and Omega 6 fatty acids share a common enzyme in the first step of the metabolic pathway they need to travel to be ‘elongated’ into the long chain forms of Omega 3 and 6 fatty acids (which are then used to produce physiologically active prostaglandins).

Omega 3 fatty acids are first elongated to EPA and then EPA is turned into what are termed ‘series 3 prostaglandins’. Omega 6 fatty acids are elongated to DGLA which is then turned into ‘series 1 prostaglandins’ or AA which leads to the production of ‘series 2 prostaglandins’.

The first step in the elongation of Omega 3 and 6 fatty acids requires an enzyme called Delta-6 Desaturase (D6D). If there is too much Omega 6 present in the cells where prostaglandin production is occurring, the Omega 6 will ‘outcompete’ the Omega 3 fatty acids for this enzyme. The result being overproduction of the Omega 6 derived prostaglandins and not enough of the Omega 3 derived prostaglandins. The Omega 3 prostaglandins tend to have an opposing or modulating effect on the Omega 6 derived prostaglandins (Omega 3 derived prostaglandins aren’t necessarily anti-inflammatory, but they are less inflammatory than their Omega 6 relatives). The ultimate effect of too much Omega 6 in a diet is increased inflammation, increased risk of blood clotting and constriction of blood vessels.

Interestingly, phenylbutazone’s (Bute) mode of action is to block these same pathways, preventing Omega 6 fatty acids from being transformed into pro-inflammatory prostaglandins.

With the competitive nature between Omega 3 and Omega 6 and the consequences of a diet too high in Omega 6, the ratio of Omega 3 to Omega 6 in any animal’s diet (including our own) is extremely important.

Other nutrients including biotin, vitamin E, zinc, vitamin B12 and vitamin B6 are also reportedly required to allow the efficient transformation of alpha-linolenic acid to EPA and DHA.

What is the recommended Omega 6: 3 ratio in a horse’s diet?

To date there is no established ratio of Omega 6: Omega 3 in a horse’s diet. However, if we look at the diet horses evolved to eat, being primarily grasses and herbs, we can start to hypothesise that horses should have a diet that contains more Omega 3 than Omega 6. I would suggest at the very most a horse’s diet should contain 1 part Omega 6 to 1 part Omega 3.

How much Omega 3 and Omega 6 are in common horse feeds?

Forages contain more Omega 3 than Omega 6 while grains contain more Omega 6 than Omega 3. Some oilseeds like sunflowers contain more than 200 times as much Omega 6 as Omega 3 while other oilseeds like linseed (flax) contain close to 3.5 times more Omega 3 than 6. A detailed breakdown of the amount of Omega 3 and 6 in common horse feeds is shown in the table below (data from Premier Nutrition).

Ingredient Name Omega 3 (%) Omega 6 (%) O6: O3 Ratio
Pasture (3.5% Crude Fat)* 1.8 0.6 0.3: 1
Grass Hay 1.0 0.3 0.3: 1
Alfalfa/Lucerne Hay 0.5 0.4 0.7: 1
Oats 0.1 2.4 19.5: 1
 Corn/Maize  0.03  1.9  55: 1
 Barley  0.1  1.1  9.1: 1
 Rice Bran  0.2  6.6  37: 1
 Wheat Bran  0.2  2.1  11.6: 1
 Sunflower Seeds  0.13  27.1  206: 1
 Full Fat Soybean  1.4  9.8  7.2: 1
 Soybean Meal  0.1  1.0  7.2: 1
 Lupins  0.7  1.5  2: 1
 Faba Beans  0.1  0.9  12.8: 1
 Copra Meal  0  0.2  N/A
 Canola Meal  1.1  2.2  2.0: 1
 Sugarbeet Pulp  0.04  0.2  5.8: 1
 Soybean Hulls  0.2  1.1  7.2: 1
 Brewers Grains  0.2  2.2  9.3: 1
 Dried Distillers Grains (maize)  0.1  3.8  55.4: 1
 Linseed (Flax) Whole  19.1  5.6  0.3: 1
 Linseed Meal  4.5  1.3  0.3: 1
 Coconut Oil  0.1  2.0  20: 1
 Cod Liver Oil  24.5  2.0  0.1: 1
 Canola Oil  9.8  19.5  2: 1
 Soybean Oil  7.2  51.7  7.2: 1
 Sunflower Oil  0.3  60.5  206: 1
 Corn Oil  0.9  55  55: 1
 Olive Oil  0.7  10.8  15.7: 1
 Linseed (Flax) Oil  57.4  13.9  0.24: 1

* Data from Mel’uchova et al (2008)

Diets primarily based on forages that don’t use large amounts of oils like corn or sunflower oil should contain more Omega 3 than Omega 6. Diets that contain a moderate to large amount of grain and small amounts of forage (like the typical racehorse diet) will almost certainly contain far more Omega 6 than Omega 3.

Is there research to support the use of Omega 3 fatty acids in horses?

Most of what we know about omega fatty acids is derived from research in other animal species including humans. There is however some equine research that does lend support to supplementing diets with Omega 3 fatty acids. In a study that used 16 horses with arthritis, Manhart et al (2009) reported that horses supplemented with DHA and EPA experienced a greater decrease in joint fluid white blood cell counts and lower plasma prostaglandin E2 levels (an Omega 6 derived prostaglandin which is a pro-inflammatory pain producer and plays a major role in osteo-arthritis. It is this prostaglandin that many non-steroidal anti-inflammatory drugs block the production of to reduce pain and inflammation).

A study published in the Canadian Journal of Veterinary Research in 2002 (O’Neill et al) looked at the ability of flaxseed to reduce the inflammation associated with culicoides (midge) hypersensitivity (sweet itch or Queensland itch). These researchers reported that feeding 1 lb of flaxseed per 1000 lb of bodyweight to horses (or 0.5 kg per 500 kg bodyweight, equivalent to 3.5 oz or 100 ml of flaxseed oil) over a period of 42 days reduced inflammation and the size of the area that reacted to culicoides extract which was injected into the skin. In contrast to this study however, Friberg et al (2002) reported that horses supplemented with either 200 ml/day of flaxseed oil or 200 ml/day of corn oil showed no difference in the lesional surface area associated with culicoides allergy or the number of times horses itched. O’Neill et al believe the difference between the results reported by these two studies may lie somewhere in the fact they used whole flaxseed and not just the extracted oil. Unfortunately the omega 6 to omega 3 ratio was not reported in these studies. Horses in the Friberg et al study were maintained on ‘pellets’ so it is possible that their dietary Omega 6 ratio was too high for 200 ml of flax oil to have a noticeable benefit. It was noted in this study that a miniature horse receiving the full 200 ml dose responded particularly well to the supplement which may indicate that the dose for the larger horses needed to be much higher to have a significant benefit.

Brinsko et al (2009) studied the sperm quality in 8 stallions when they were fed their normal diets with or without a DHA-enriched supplement. This study found no difference in fresh sperm quality, however, as the semen was cooled and stored, sperm quality tended to be better when the stallions were supplemented with DHA. Most of the improvements observed however were not statistically significant (which means they may have just happened by chance and may not actually be due to the supplement).

Pagan et al (2010) reported that supplementation with 60 ml of fish oil significantly increased serum and red blood cell EPA and DHA while supplementation with 60 ml of corn oil significantly reduced red blood cell EPA levels. Pagan et al (2012) have also reported improved insulin sensitivity in horses supplemented with omega 3 fatty acids from fish oil.

When should you supplement?

If your horse’s diet contains a moderate to large amount of grain or high Omega 6 oils like corn or sunflower oil you may need to consider adding additional Omega 3 to the diet to keep the ratio of Omega 6 to Omega 3 at or preferably below 1: 1. Take the following diets as examples:

Diet 1 – High in Omega 3

10 kg/day (22 lb) Pasture
2 kg/day (4.4 lb) Alfalfa/Lucerne Hay
0.5 kg/day (1.1 lb) Oats
200 g/day (7 oz) Sunflowers
100 g/day (3.5 oz) Vitamin and Mineral Supplement

This diet will contain an Omega 6 to Omega 3 ratio of 0.4: 1 and does not need additional Omega 3 supplementation. The diet is however still higher in Omega 6 than a 100% forage based diet so some Omega 3 supplementation may be warranted in certain situations, for example if the horse is arthritic.

Diet 2 – High in Omega 6

2 kg/day (4.4 lb) Pasture
4 kg/day (8.8 lb) Alfalfa/Lucerne Hay
3 kg/day (6.6 lb) Oats
2.5 kg/day (5.5 lb) Corn/Maize
250 g/day (9 oz) (5.5 lb) Sunflowers
250 ml/day (9 floz) Corn Oil
100 g/day (3.5 oz) Vitamin and Mineral Supplement

This diet will contain an Omega 6 to Omega 3 ratio of 3.5: 1 and would benefit from additional Omega 3 supplementation. Adding 400 ml of linseed oil to this diet will lower the Omega 6 to Omega 3 ratio to 1: 1 and also allow for some of the high Omega 6 grain to be removed from the diet.

At this point in time there is no easy way to calculate your horse’s dietary Omega 6 to Omega 3 ratio. We will be incorporating this feature into FeedXL as soon as we can. The greatest challenge is going to be gathering the information needed for all of the commercially produced feeds.

How should you supplement?

There are various ways to add additional Omega 3 to diets. The best known Omega 3 supplement for horses is linseed (flax) oil. Linseed oil is 57% Omega 3, making it a useful Omega 3 supplement. Freshly ground linseed can also be used (read FeedXL Newsletter # 22 Feeding Flaxseed). Linseed meal will have very little effect on a diet’s overall Omega 6 to 3 ratio as even though linseed meal does contain more Omega 3 than 6, the amount of Omega 3 in linseed meal is so small it really won’t influence the overall diet’s Omega fatty acid ratio. Commercial Omega fatty acid supplements are also available and these now often contain fish oil to provide a direct source of DHA and EPA in the diet.

Of course the best way to maintain a balanced Omega 6 to 3 ratio in your horse’s diet is to maintain them on a largely forage based diet and only use grains and oilseeds like sunflower seeds in moderate to large amounts where absolutely necessary.

Take Home Messages

  • Diets that contain a lot of grain or high Omega 6 oils like corn or sunflower oil may cause your horse’s diet to contain more Omega 6 than Omega 3 fatty acids.
  • Too much Omega 6 in a horse’s diet interferes with the body’s use of Omega 3 fatty acids. This imbalance could lead to excess inflammation and problems like arthritis.
  • To help modify the inflammatory reaction of a horse’s body to stimuli like exercise, the Omega 3 to 6 ratio needs to be kept in balance.
  • Omega 6 is just as important in the diet as Omega 3, they just need to be kept in balance with one another.
  • There is no established ratio of Omega 6 to Omega 3 for horses, however a horse’s natural diet contains more Omega 3 than Omega 6, so keeping your horse’s diet ratio at 1: 1 or less is logically what will be best.
  • FeedXL currently doesn’t calculate your horses Omega 3 to Omega 6 ratio, however given the importance of this aspect of equine nutrition, this is a feature we are now working on implementing.

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.



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