Flax Seed: How and why to feed it

These beautiful blue flowers are the signature of the flax plant.
These beautiful blue flowers are the signature of the flax plant.

I’ve been feeding my horses flax seed (also called linseed) for about a decade. I started with HorseTech’s fabulous products, first with Glanzen, their hoof & coat supplement, then moving onto one with glucosomine in it. I found that feeding a flax-seed based supplement improved their coats so that they glowed. I also liked the fact that flax seed adds Omega 3 fatty acids to the diet — the only other natural source of Omega 3s in a horse’s diet typically is fresh grass, something my horse doesn’t get enough of!

These days I feed flax as part of my horse’s overall diet. I feed it separately now mostly because when I had two horses, they had different needs: it was easier for me to customize their nutritional packages by buying individual components than finished products. Now I’m used to “building” my own supplements.

There are several benefits associated with Omega 3 fatty acids:

  • It can help reduce inflammation which may help horses with joint stiffness or arthritis.
  • It helps improve coat quality adding shine and softness.
  • It improves digestion.
  • It boosts the immune system and can help regulate thyroid function.
  • It can help reduce the chance of laminitis.

In humans, Omega 3 fatty acids improve heart health and can reduce the chance of blood clots forming in the veins, thereby reducing the chance of strokes. There have been no comparable equine studies, but hey, it can’t hurt!

Horses are able to extract the nutrients from whole flax seeds.
Horses are able to extract the nutrients from whole flax seeds.

How do you feed it?

If you do a Google search on feeding flax seed you’ll see that there are several recommended ways to feed it: ground, boiled, soaked — anything except whole seeds. Lots of sites tell you that whole seeds can’t be digested. However, that appears to be a myth. Current research shows that horses can masticate flax seeds just fine and that the nutrients were extracted from the seed hulls even if you see a few whole seeds in your manure pile.

I’ve been feeding whole flax now for about a year. Previously, I fed ground flax seed. I haven’t seen any changes in my horses so far and it’s far easier to feed it and store it. I’ve also read that there’s another benefit to feeding whole seeds: when they are eaten they form a coating in the digestive tract that helps keep the gut moving effectively.

Probably the most popular way to feed flax is ground. When you buy commercially ground flax seed it is stabilized. That’s an important point: if you grind it yourself, you need to grind it fresh for each meal. The nutrients in flax seed start to degrade very quickly if they are not stabilized and when they are exposed to heat, light or oxygen. Ground flax also goes rancid quickly so you should be very careful about cleaning the grinder very well as the remnants can contaminate new batches. Refrigeration can help extend its shelf life a few days, but you’ll still see a loss in nutrients.

People who boil or soak their flax seed often do so because they believe that otherwise the flax might contain harmful levels of cyanide, which is toxic. In truth, while the seeds do contain the two components necessary to create cyanide, they are in different parts of the seed. Ironically, it’s the contact with water that brings the two components together and causes the formation of cyanide. Soaking is actually the most dangerous way to feed flax.

Boiling isn’t a good idea because while it changes the cyanide to a gas form, removing it from the flax, it also destroys the fatty acids which is why you feed flax!

Another consideration

While cyanide shouldn’t be a concern, if you feed flax seed keep in mind that it’s calcium/phosphorous ratio is not balanced appropriately for horses. Since it is high in phosphorous you should feed either a calcium supplement or a feed high in calcium (such as alfalfa) to balance your ration.

Generally nutritionists recommend feeding 4-8 oz of flax seed per day which makes it a very low cost supplement with many nutritional benefits.

59 thoughts on “Flax Seed: How and why to feed it

  1. Thanks for your article.

    My wife and I are avid believers in the benefit of feeding horses raw flax seed. We have several aging, rescued horses that were getting to that joint “creaking” and “snapping” stage in life. Our vet recommended freshly ground flax seed and exactly the amount you suggested.

    It’s been 18 months since the introduction of this supplement and I can honestly say that there has been an almost total elimination of the “snap, crackle, pop” from the pasture and the horses and their coats simply glow.

    I was not aware that you could add it straight, without grinding, but plan to forward this information off to my wife, the Equine Chef, as it sure would save some time and effort over grinding before every meal.

    Thanks again for your very informative article. I will point the readers of my blog in your direction.

    May the Force of the Horse be with you.


    R.T. Fitch
    Author – “Straight from the Horse’s Heart”
    The Force of the Horse®, LLC

    1. i feed horse shine ground flax seed and my farrier told me that my mares feet looked the best they have seen since he has been doing her. She has tiny tea cup feet, she showed in Western Pleasure and did excellent until her feet couldn’t handle the work , so she is retired and enjoying it. Even though it’s so soggy hear in Connecticut my paddock is sloppy mud. Her coat is nice and shinny and very soft and she seems to be more comfortable in her hocks too. will I get better result for feed her flax seed?

      1. As long as you are feeding stabilized flax seed, you will be fine. Flax seed degrades very quickly once it is ground unless it is stabilized. Personally, I feed whole flax because it’s easier & less expensive but i think that it’s mostly a matter of preference.

  2. This is why I have to read your blog every single day. 😉 Thank you, once again, for bringing us important information. I’m a believer in flax seed also. I’m thrilled to find out grinding it is not a must!

  3. Thanks for the information. Omega 3 fatty acids are definitely very important to horse nutrition. Without a supplement there is not way for a horse to get enough of these fatty acids.

  4. Hello,
    Could you tell me your source for the ‘current research’ on feeding flax seed whole. I would like to read how this research was done and by whom.
    Thank you,

  5. Hi Anne, thanks for your question. I based my article on information I found published on horseadvice.com, a discussion with a vet and an equine nutritionist, and also found it published here: http://www.understanding-horse-nutrition.com/flax-seed.html. I will keep looking for the published research. I have been feeding flax seed for about 7 years. For the first 4-5 I fed stabilized ground flax; I switched to whole seeds after discussing it with a nutritionist. I have not noticed any change in my horses coats, hooves etc. However, there are plenty of stabilized ground flax seed options out there for people who are more comfortable feeding it ground. You just need to be aware that unless it’s stabilized it’s nutritional value decreases quickly once it’s ground.

  6. OK, I’ve done my online homework and one question.
    Can it be slow-cooked on LOW for 6-8 hours and still retain its health benefits and eliminate the toxic properties

    1. I never saw an answer to my query in 2009.
      OK, I’ve done my online homework and one question.
      Can it be slow-cooked on LOW for 6-8 hours and still retain its health benefits and eliminate the toxic properties

      1. I know that lots of people believe in boiling flax seed before feeding. I do not. I spoke to an equine nutritionist and recently found the same information attributed to her on another forum. Here’s what she said:

        “Older cultivers of flax contained much more of the cyanogenic glycosides. Today’s have very little, and boiling does absolutely nothing, so far as de-toxifying anything, lol, especially when as mentioned, feeding 8 ounces or less (all that is recommended) to a 1000 lb animal.

        The only thing boiling does now is to destroy all the beneficial essential fatty acids.

        There is no problem with feeding modern cultivars of flax whole and unboiled. Concerns about needing to boil it are generally from people who do not understand the modern changes in the development and the agriculture surrounding flax.”

        I personally do not boil or grind the flax seed that I feed to my horse. He gets one cup am/pm and I add it to his soaked beet pulp. I’m sure that in large quantities the cyanogenic glycosides could be harmful but from my research I’ve concluded that in this quantity, fed to a 1200 lb horse, they are not harmful. I have fed whole, soaked flax seed now for the past 5 years without a problem.

        However, I think you should do what makes you comfortable.

  7. Great article! Saves me a lot of time not grinding it. I’m using it on an Insulin Resistent pony . . . “flax oil makes the cell walls more permeable to insulin, and kicks in the fat-burning metabolic pathways in the liver.” (Dr. Joyce Harman) Wish me luck!

  8. That is great that horses can benefit from flax just like we can. Thanks for the article!

  9. What about older horses that probably need soaked food. Would you grind it and add it on top, leave it whole and put it on top or soak it with the grain, (which is said to be toxic) . I’m wondering because I have a 35 year old pony who needs more weight. He is getting 15 lb.s of soaked grain -old timer and alfalfa based grain WITH VITAMINS, VITAMIN E, MSM, HEIRO (FOR SORE FEET), AND i WOULD LIKE TO ADD SUNFLOWER SEEDS AND GROUND (or whole) Flax

    1. I feed my horse soaked beet pulp and I always add the flax seed and let it soak. From what I’ve read there’s not really a toxicity issue — the amount of cyanide produced is very low.

      1. I am curious about the cyanide content-

        I have 3 cases(horses) that I am doing research on for adding whole flax seed to their diet.
        Horse #1 receives 1 lb of high fat/high fiber twice a day with 1/4 cup of corn oil. She is turned out from 7 am to 7pm daily on 200 acres of pasture with access to hay and grass. She is 12 years old, and receives lightly soaked grain. (In hot water until fully saturated)

        Horse #2 receives 1 lb of high fat/high fiber saturated in hot water daily. He is turned out 24/7 in the 200 acre pasture with access to hay and grass. He is 4 years old.

        Horse #3 receives 1lb of high fat/high fiber soaked and saturated thoroughly as she coughs excessively otherwise. She is turned out in the 200 acres with access to hay and grass. She is 30 months old.

        Will the moisture in their grain create a high cyanide content? The top mare would receive the flax daily in her pm feed, and approximately 1 cup of if. The other two would receive it in their pm feed and then turned back out, they would get approximately 3/4 cup of flax seed.

        I was also told that black uncracked sunflower seeds do the same as the flax seed- is there a difference in quality or concerns? I’ve tried researching it but have come up with nothing!

    2. I have a old chinco stallion that has lost most of his teeth. I feed equine senior and beet pulp soak for at least 2 hours plus “Missing Link”. It has a lot of flax seed already ground and other essential vits and mins. plus Glucosamine that helps him. The beet pulp really helps with keeping the weight on since he doesn’t really digest any grass.

  10. I used to feed my horse whole flax seed and then a (former) know it all friend told me that I shouldn’t. The thing is, I didn’t notice a difference in my horse from the ground and stabilized flax than the whole seed.
    I’m so glad I came across this article. I think I’d like to add it back to his diet. Thanks for sharing!

  11. I have been researching adding flax to my Arabian’s diet and like others have read tons of information. I am leaning towards whole flax seed but the only thing I have come across is that some people claim to have sprouts as a result of the seeds passing through? Has anyone had these problems? I recently came across another mention of Horsetech and was looking to order their milled nutraflex, but still cannot decide whether whole seeds would be better. Any tips? Thanks, love this article!!

    1. Hi – glad the article was helpful! I’ve been feeding whole flax seed for many years and have never had “sprouts.” Before I made the decision I consulted with two equine nutritionists who assured me that my horse had the necessary equipment (teeth) to grind their own. I have been advised that you might want to feed slightly more whole flax than ground but that in general it’s better to feed whole because so much of flax’s nutritional value is lost after it’s ground.

      Some people I know grind their own right before use with a coffee grinder but if you do that you need to be careful to clean the grinder thoroughly as the ground flax goes rancid quickly. You also need to grind for each feeding as if the flax is not stabilized it looses its nutritional benefits very quickly.

  12. Hi. Loved the article but I do have a question that I cannot seem to find enough research on! About supplementing the calcium. I feed 1/2 cup of whole flax a day but how can I find out how much calcium to put with it?

    1. It depends on what else you are feeding. Half a cup of whole flax a day isn’t going to really cause an imbalance in your feed as long as everything else is balanced . . . however if you want to add more calcium you can feed some alfalfa (pellets, cubes or hay) or some beet pulp.

  13. I came upon this article while researching flax seed for horses which I was ready to add to their diet already. I do have a question- My horses are very easy keepers, and they receive about a double handful of dry beet pulp (which is then soaked) and about the same in alfalfa cubes, which is then soaked. So each feeding, in wet food, they get about a 1/4 bucket. Is there really enough calcium in this small amount of food to balance the flax once added?

    1. Hi Dachia, that’s an interesting question. I’ve always fed flax seed as part of a diet that includes both Alfalfa and Beet pulp so have never worried too much about Calcium/phosphorous balance. I guess part of the question would be how much flax seed are you feeding and how much grass/grass hay does your horse eat? I don’t think that a cup of flax per day will through the balance off. Grass hay typically has a calcium content of 0.6% as compared to beet pulp, which has a calcium content of 0.91%. If it worries you, there are flax supplements that are already “balanced” so that the nutritional profile is complete.

      1. Thanks for the info. I’ve been feeding Omega Shine for about 18 months now and am hooked on flaxseed. Was looking for a way to cut costs and curious about buying whole and grinding myself, but what great news, I can just feed it whole. My Girls both get beet pulp and are field boarded so I don’t have any calcium/phosphorous issues. Also, since I’ve been feeding my arthitic mare flax, I no longer need to supplement with B-L, another money-saver. The benefits are awesome, wish I’d started feeding it sooner.

  14. Liz, I am glad you have researched the info you have written about. It helps when making decisions about what to add to the horse diet. My question is how do you calculate the fat percentage of the diet when you add x amount of flax with x fat perceentage to a concentrate with a known fat content?

  15. I’m wanting to make horse treats using flax seed. Do you know whats the safest way to use it. Will cooking it and or mixing it with oats, molasses, soy, wheat germ and water change it to toxic?

  16. Liz, Thanks for all the great information! I have been feeding whole flaxseed, about your 4 to 6 oz. reccomendation, to our two boys for about 5 yrs. now along with hay cubes (65% alfalfa 35% grass) I put about a gallon of water each feeding mixed into their feeders with their cubes, this helps with adding more water into thier system and keeping down any dust that may be there. It’s wonderful to know that I have been doing the right thing for these two loves of my life.

  17. Does anyone on this forum feed liquid flax seed oil? I recently purchased a gallon for our aged horse (rather than soaking flaxseed) He is a 33 year old Arabian that has recently been diagnosed with leukemia. It is suggested on the jug 25 to 50 ml. per day but I have read on different sites that you can feed up to a cup per day safely. Also would like to know if anyone has fed Ginseng? If so how much for a l,000 pound horse and how often? Both liquid flax seed and ginseng have been suggested to slow this form of cancer down. Aside from the findings on his blood work he is a happy, active, very content horse.

  18. Bom Dia, gostei muito do seu artigo, ha 1 ano forneço a 2 eguas de 15 e 3 anos linhaça misturada com agua , ficando de molho de 6 a 12 hs, resulta em uma gelatina, mas estou preocupada com a questão da liberação do cianeto, como posso fornecer este grao de uma forma segura para os animais! obrigada e parabéns!!!

    1. Thanks for your question. I have run it through Google translation and hope that it is close to what you meant:
      Good day, I enjoyed your article, I provide the ha 1 year 2 mares three years of 15 and flaxseed mixed with water, getting soaked 6-12 hours, resulting in a jelly, but I am concerned with the issue of the release of cyanide how can I provide this in a safe grain for the animals! Thank you and congratulations!

      From what I have read the amount of cyanide released from soaking flax seed is very, very small and should not be a problem. I soak my own horses’ grain with the flax seed mixed in (1 cup a.m. and p.m.) and have had no issues with it.

  19. I am going to be mixing up my own feed for horses that are on mostly hay. Could you tell me what you think of this:
    200 lb of corn
    300 lb of oats
    25 lb linseed meal
    35 lb molasses
    Thanks for your help

    1. Hi Deanna,

      It kind of depends on how much you will be feeding of that mixture. It’s very high in NSC (non structural carbohydrates) and sugar. Corn and oats are both high in NSCs. However, if you are feeding mostly hay and it’s a small portion of their diet, it might not be an issue. For my TB? That would be rocket fuel! You might consider adding a multi-vitamin to the mix just to make sure all of their nutritional bases are covered.

      1. I would be feeding around 4lb a day. I have a 16 year old quarter horse that needs extra during the cold winter in MN.
        What mix would you think would work for me ? Thank you for your time.

    2. Update on our 33 year old Arabian which was posted on March 21st. and had been diagnosed with leukemia. I have spoken to the owner of Herbs for Horses, Ralph and also our vet has spoken to him to determine what would be most beneficial of the natural products. Our horse is now on Herring Oil rather than Flaxseed Oil. It is more beneficial.

      His morning diet consists of Senior feed, soaked beet pulp, alfalfa cubes soaked, glucosamine,
      equi sol, along with a good hay.

      His evening diet consists of Senior feed, soaked beet pulp, alfalfa cubes soaked, glucosamine, herring oil, ginseng, multi-vitamin. osteoaid (formerly Nasprin)

      He is very content. Every day is a bonus.

  20. I have a question that maybe/ hopefully someone can give me some info -I picked up this little filly in Jan- she was about 6mo old, malnourished, stunted, and full of rain rot, I slowly got her on Equine Jr- that’s what I had my own 6mo old colt on- well she eventually started to blossom out , some growth change( assumed she would just be a small horse because of the other issues she came to me with) well about 2 months ago she hit that growth spurt and shot up!!! Now I’m having leg issues- she is knuckling over on the front end – my vet changed her feed to Statagy special care only a dbl hand full – is there anything else that could be worth trying ?? She walks pitiful

    1. Hi Laurie
      I would suggest to contact:
      Herbs for Horses ask for Ralph and tell him Fran from Almonte, ON. suggested you contact him. I would be very surprised if he is not able to make a sound, helpful suggestion. There is a 1-888 number listed below. I have had amazing help from him and so has our horse Moses. It’s worth a phone call. Even if you copy and paste the above post and send it to both places. But I believe a phone call is the best way.

      558 Massey Road
      Unit 6
      Guelph, ON N1K 1B4

      1 – (888) 423-7777

      Superior Supplements…Naturally., Hours: Mon-Fri 9 am

      You can also contact Equine Research in Guelph, ON. and speak to their specialist or email them for suggestions. Hope this helps.

  21. Hello Liz,

    I’ve seen that article before that you referenced as your information. However, I was unable to see this woman’s qualifications? Also, I sent her a message asking her for her references in regards to amount of flaxseed that should be fed, and flaxseed’s reaction with water. I have been unable to find any credible references (scientific journal published and peer reviewed) that point to either of those things. I can provide the articles that i have been looking at for anyone interested…Just trying to get to the truth.

  22. I agree that there is a lot of debate about Flaxseed and very few definitive answers.

    Here are a few articles/discussions that might be interesting to you:

    I have also spoken to a nutritionist who works for Foxden Equine (they manufacture horse supplements). She feeds whole flax seed to her own horses.

    I feed 1 cup/whole flax seed per day. I don’t grind it because the EFAs are so easily damaged and even the leftover ground seeds can cause issues with rancidity.

    I have read that a tiny amount of cyanide is emitted if the seed is soaked before feeding but that it so negligible that it is not a problem — I suppose if you were feeding pounds of it there could be an issue.

    I have been feeding flax seed for at least 10 years and haven’t had any issues with it!


    1. I don’t believe there’s a nutritional difference. Lots of people don’t like to feed oil because it’s messy or their horse finds it unpalatable.

  23. This week, I just started feeding 1/4 cup whole flax seed (am & pm) to my 20 year old MFT. I’m a tad bit concerned that I have been placing it, with his other supplements, in his beet pulp THEN soaking with water. He gets twice a day: 2 cups beet pulp, 1/4 cup flax seed and other supplements soaked. Then I add that with his dry grain of 2 cups alfalfa and 1 cup rice bran pellets. He grazes about 5 1/2 hours a day, 7 days a week usually. He also gets 2 flakes am and pm of grass hay in his stall. Are you concerned that I’m SOAKING the flax seed? THX

    1. I wouldn’t worry about it. I’ve been throwing half a cup of flax in my gelding’s soaked feed for years now — 2x/day. Never had a problem. I know people worry that soaking flax causes it to release cyanide but it’s a very, very tiny amount.

    2. You could always just throw it in the soaked beet pulp just before you feed. I picked up a 50lb bag of flax from the feed mill and will start feeding whole flax after years of feed ground stabilized flax. I have been debating on feeding whole, ground, soaked etc. I have read that the soaked seeds stick to anything and everything, so I’m hoping if I throw it in the beep just before I feed will help with that. Just a thought 🙂

  24. Cool. Glad that Equine Ink gave you some information that you could use. My horses have been eating flax seed for years now and in addition to the health benefits, it makes them very shiny!

  25. Hello Liz,
    Should I be feeding 1 cup per day (as you have stated above) or 1 cup of whole flax seed in the am/pm as you stated in a post from 2011? In addition, would I be able to add the whole flax seed in with the pellet feed (without soaking prior)?


    1. Hi Yvonne –

      There really is no “set” amount for flax seed so it depends on what your horse’s needs are. For example, when Freedom was recovering from Lyme, I fed him more because the Omega 3s are supportive. In general I feed 1 cup/day (I’ll have to go back and look at the 2011 post to see why I fed more then). I do not soak the flax seed. I simply add whole seed to their grain. Certainly feeding more doesn’t hurt.

      1. Hi Liz- I have been researching the debate of soaking or not soaking whole flax seed(one of my horses does not have much tooth contact so she would not be able to grind them on her own) and I just read through your excellent article and all the resulting discussions and many times you said that you have for years soaked the whole flax seed in beet pulp, which I have also been doing for about 2 months, 1/3 cup twice a day(it soaks for 12-24 hours) and now in your final reply above you say you do not soak flax seed. So I had been intending to continue my soaking method but now I am confused- could you clarify please? Thanks much!

      2. Hi Maria — Sorry to confuse you. Yes, I fed it soaked in beet pulp for many years. However, I currently don’t feed beet pulp any more so I simply add it to their dry grain. Sometimes I’ll add a little water to make sure they stick, and in the winter I sometimes give them soaked alfafla/timothy cubes so add it to that. Basically, I think you can feed it either way. Does that help?

      3. Hi Liz- thank you, yes it does- I am planning a near future switch from beet pulp and senior feed to soaked timothy pellets, stabilized rice bran, flax(of course!) and a few other ingredients for a less processed feed. Thanks for replying!

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