The Benefits and Differences of Adding Oil to Horse Diets

horse topline representing the importance of oil in a horse's dietAdding oil or fat to horse diets was a common practice long before research determined the many benefits of added oil diets.  Horse traders hundreds of years ago knew that if they wanted a horse to gain weight and develop a slick hair coat, adding oil to the diet was one way to do it.

Different Types of Oils

Like many questions in the equine world, the answer is yes and no. The common vegetable oils used in horse feeds are corn oil, soy oil and flax oil (linseed oil).  Canola oil, sunflower oil, coconut oil and palm oil are also used, but less frequently.  Animal fats, excluding fish oil, are not currently used very commonly in horse feeds in the United States due to customer concern, and potential palatability concerns.

Differentiating Oil and Fat:

There are multiple chapters in nutrition books written about fats and oils.  Animal Feeding & Nutrition, Tenth Addition, by Jurgens and Bregendahl is a standard text.  For simple practical purposes, a fat is solid at room temperature and oil is liquid due to the differences in composition.  For those of you who like the full science, fats and oils are:

  • Also referred to as lipids or ether extracts
  • Insoluble in water and soluble in organic solvents
  • Contain about 77% carbon, 12% hydrogen and 11% oxygen.
  • They all contain about the same energy, 9.45 Mcal/kg or 4,290 Kcal/lb.
    • This is about 2.25 times the energy content of carbohydrates.

The Significance of Omega Fatty Acids:

There may be substantial differences in the Omega 3 and Omega 6 fatty acid profiles of different oils, particularly in the content of the essential fatty acids (EFAs) linoleic acid (C18:2 n-6),  linolenic acid (C18:3 n-3) and arachidonic acid(C20:4 n-6)  Arachidonic acid can be synthesized from linoleic acid and is essential if linoleic acid is not present.

  • Corn oil will be higher in linoleic acid, an n-6 or Omega 6 fatty acid.
  • Soy oil, particularly mechanically extracted, will contain more linolenic acid, an n-3 or Omega 3 fatty acid, than corn oil.
  • Linseed oil, from flax, contains the highest % of linolenic fatty acid.
  • Fish oil from certain cold water sources is the highest in Omega 3 fatty acids, although it may present some palatability issues.

Oil Production Methods:

Vegetable oils come from the seed of the plant with most being in the germ.  They are produced by either solvent extraction or mechanical (squeezing or crushing the seeds) extraction.  They can either be refined or in crude form, depending on the processing. All of the vegetable oils contain essentially the same amount of energy and are generally palatable if processed and stored properly.

35 Replies to “The Benefits and Differences of Adding Oil to Horse Diets”

  1. So what is the best oil to add to a horses feed? I have an older horse that I like to add a bit to her feed and a young horse that came from an unknown situation (slaughter bound, with poor hair coat, and dry, brittle hooves). She has been wormed and getting good feed now though.

    Would love to know what you recommend:)

    1. Hello Jennifer,

      The common vegetable oils, corn, soy, canola, are all similar energy and palatability. If some Omega 3 is desired, flax oil is the best source, but is more expensive. Corn or soy oil would both be appropriate for this use.

      Thanks ~ Roy J.

  2. Should also add that in HYPP horses, vegetable oil or corn oil are safer choices, as they have very low potassium contents. Whereas canola oil has a considerably higher potassium content. I use canola oil (much cheaper where I live) on my N/N horses and vegetable oil on my N/H horses and have never had an issue.

  3. I would never feed fishoil protine baced oil as in non veg. oil I dont recall any horse in my care want fish.

  4. My horse is currently eating 1/2 cup veg. (Soy) oil to a scoop of grain. I’d like to add 1 cup of flax seed meal and alfalfa cubes to help balance the calcium phoshorus ratios. How much of the alfalfa cubes should I feed when the calcium to phosphorus ratio is 2:1? Or should I consider rice bran instead of flax? Her grain is Ca 1.9 percent as max and P 0.4 percent as max.

    1. Hello Samantha, Thanks for the question. The main thing you need to consider, before adding more items to the diet, is the calcium & phosphorus levels in the WHOLE diet, not just th oils or grain. So, first, you will need to have your hay tested, to know the calcium & phosphorus levels there – because that is the main contributor to the diet due to the volume a horse eats. Once you know the values for your hay, you should be able to total up ALL of the calcium and phosphorus your hay is consuming, and then look at the intake ratio to determine if you need to add anything further or not.

      As for things to add, yes, the alfalfa cubes will help with that ratio. Flax seed is higher in phosphorus than calcium, as is rice bran – unless you buy products that have added calcium to balance the ratio, such as Empower Boost

      Generally speaking, if you stick with commercial horse feeds and a quality hay source, you should not have to worry about ratios and adding more things to “fix” them.

      Thank you ~ Gayle R.

  5. does any one know about coconut oil for horses? is it the same as other oils you would add to horse feed? also sunflower oil any feedback is appreciated.

    1. Hello Mattie, Thank you for your question. All the common vegetable oils (corn oil, soy oil, safflower oil, flax oil, canola oil, coconut oil etc.) have similar DE values of 8.1-8.2 Mcal/kg (3682-3727 Kcal/lb) and are all quite palatable as long as they have been handled properly.

      Corn oil has long been considered the most palatable, but is also the highest in Omega 6 fatty acid compared to Omega 3 fatty acids. Safflower oil is also high in Omega 6. Soy oil is lower Omega 6 and higher Omega 3. Flax (linseed) oil is the highest Omega 3 of the vegetable oil sources. Fish oil is one of the best Omega 3 sources, but there are aroma and palatability issues.

      Coconut oil is a little different in that it is lower in both Omega 6 and Omega 3, but has more mid-chain fatty acids. There is some mixed research on the benefits of these for performance animals. Also a little easier for coconut oil to have some aroma issues.

      We hope you find this information useful. Thank you ~ Roy J.

  6. Hi,

    We have a 14.2 pony that got kicked and ended up at the vet school getting his hock joint flushed twice as he had a really bad infection. He is now back in work and seems to be coping well (touch wood) we feed him Veg oil from supermarket in his feed is there any other oil that would be more beneficial to him for his general condition and perhaps joints?

    Look forward to your reply, Jane

    1. Hello Jane, We are glad to see that your 14.2 hand pony is doing well after his hock injury and treatment.

      In view of his history, you may wish to consider incorporating some properly heat treated flax (linseed) oil as a part of his diet in case he still gets some inflammation as a result of his injury. Flax oil is one of the best vegetable oil sources of Omega 3 fatty acids, which have some anti-inflammatory benefits. You do not want to use raw linseed oil as this may have some anti-nutritional properties that are eliminated by heat treatment. Vegetable oils are very similar in terms of digestible energy content and flax oil has the highest Omega 3 content.

      Best wishes, Roy J.

  7. I have a Thoroughbred and I’m going to start giving him feed as I only got him. Is it ok to out in normal vegetable oil? Thank you:)

    1. Hello Brid, Thank you for the question. Yes, you may use vegetable oil on your horse – although we might suggest seeing what plain feed and hay/pasture will do for his condition before delving in to using supplements or oils – you may find you don’t need to mess with them!
      Thank you,
      Roy J.

  8. Is Caster oil safe to add to a horses hard feed and in what amount and how often.

    1. Hello Judith, Castor oil is produced from the seed of the castor bean plant Ricinus communis L. It has been widely used in many cultures as a laxative and for medicinal purposes as it has some anti-microbial and anti-viral properties as well as other reported uses.

      Castor oil is approved for feed usage at up to 250 ppm (0.0250 %) for specific purposes as anti-caking agent, a releasing agent and as a diluent in animal feeds. (AAFCO Manual 2014, page 444.)

      I would not recommend using castor oil in horse feeds as an oil source for energy as it contains a high % of ricinoleic fatty acid has very laxative effects and may cause irritation of the small intestine. The same properties that make castor oil anti-microbial may also have an adverse impact on the microflora of the gut which could contribute to digestive disturbances. Various digestive system upsets have been reported with intakes of castor oil and may be dose related.

      As an aside, the castor seed mash, what is left over after the seed is processed for oil, is the source of the very potent toxin ricin, one of the deadliest toxins that occur in nature. The ricin does NOT transfer to the oil.

      Regards, Roy J.

  9. I just purchased a draft horse with EPSM. He currently gets 3 cups canola oil a day. It worries me that he is getting such a large amount of canola oil. Would he be better off with 3 cups of flax seed oil instead? Thank you!!

    1. Hello Laura, Thank you for your question about feeding 3 cups of canola oil to your draft horse with EPSM. 3 cups of oil, which will be about a pound and half or so, will seem like a lot in human terms, but if you look at the intake of your horse, it is not a high% of the diet. An 1800 pound horse consuming 1.5-2.0 % of bodyweight in hay and feed would be eating about 27-36 pounds per day. 1.5 lbs of added oil would be increasing the fat content of the diet about 4 or 5%, which is a good approach for an EPSM horse when accompanied by a reduction in the amount of starch and sugar in the diet and along with regular work.

      If the horse has any inflammation issues, switching to flax oil would provide a higher level of Omega 3 fatty acids in the diet. It would need to be heat treated/stabilized oil as raw flax oil can contain some anti-nutritional compounds. Same reason why whole flax needs to be heat treated when we use it in feed. In terms of providing energy, both oils will be similar digestible energy.

      Thank you ~ Roy J.

  10. I have a 14 yo thoroughbred that gets a high fat feed, about 6% I think, whatever the highest I can find. Now that winter is approaching should I add oil to his grain to help him put on some weight. He doesn’t keep weight on well and is not currently being ridden a lot. Which oil is preferably, coconut or corn?

    1. Hello Dawn, Thank you for contacting us. Corn oil has long been considered the most palatable, but is also the highest in Omega 6 fatty acid compared to Omega 3 fatty acids. Coconut oil is a little different in that it is lower in both Omega 6 and Omega 3, but has more mid-chain fatty acids. There is some mixed research on the benefits of these for performance animals. Also a little easier for coconut oil to have some aroma issues.

      That said, one simple solution many horse owners overlook is to simply increase the amount of feed being given in small amounts – this will provide an easy boost to calories, along with added and balanced nutrients, as well as being a lot less messy!

      Thank you ~ Gayle R.

  11. Hi
    We have been given a 3 year old tb who is really under weight. She was no good for racing and as she wasnt any good she was to much to keep for nothing, since she has stopped she has been out to graze and has put on some weight however is very skinny.
    Can you recommend a good feed that would help her start to build weight without giving to much energy also what oil would be best to add if this is a good thing to do?
    Ive got alot of experience in horses however I havent had one in this condition before! Apparently they used to feed her four scoops of some feed and no matter what they gave her she wouldnt keep the wait and never looked as good as she could. I believe maybe it was the stress of work and training that perhaps her body couldn’t deal with hence why she couldnt maintain it!? and has put on slightly since being grazed in the field.
    Anyway I hope this all make sense and any advice would be appreciated.

    Oh and she has been in a good worming program plus the 5 day worming program.

    1. Hello Rachel, Thank you for contacting us in regards to your new filly. TB’s are somewhat notorious for needing a lot of feed, so it’s best to prepare yourself for that!

      First, make sure she has all the pasture and/or hay access she will eat, which it sounds like you are doing. As for a feed product to use, SafeChoice Senior is often our go-to feed for rehabilitating horses who are severely underweight. If she’s not to the point of being emaciated, then you can either still go with the SafeChoice Senior, or try SafeChoice Original.

      You can figure out how much she should be fed per day by using the feeding rate calculator found on the “Feeding Directions” tab of the product pages on our website – just put in her weight, select her current activity level, and click “Calculate”. One thing to keep in mind is that to help her gain weight, you will want to feed for one activity level higher than she is actually doing – because then the calories going in will be more than she needs to maintain, and thus she will gain. Once she is up to the proper body condition, you can back down the feeding until you find the rate that she maintains at.

      I hope you find this helpful! If you have any other questions, please let us know! Thank you ~ Gina T.

  12. Hi,
    I have a warmblood suspected of having EPSM. We added 2 cups of oil to his diet daily and he is doing well. He has arthritis and a few bone spurs, so inflammation is an issue. I am searching for the best fat option for him.
    I started with corn oil, then canola, then cocosoya oil, then EFA-X (a dry powdered vegetable fat), then cool calories (another dry powdered fat), now I am considering sobean oil. I am trying to get high omega 3s, reasonable price, and a long shelf life so that I can buy in bulk.
    Questions: Are the dry fat products the same as oils? Better/worse?
    What oil do you think is best for inflammation and my pocket book?
    Thank you, Nancy

  13. Hi,
    I forgot to ask, have you heard of “coolstance” it is a product made from coconut oil and coconut meal. I just saw an advert online, any thoughts as a viable fat source?
    Thanks again,

    1. Hi Nancy,

      Thank you for your questions regarding you Warmblood suspected of having EPSM and also having some arthritis with some bone spurs. All of the vegetable oils (corn oil, soy oil, linseed oil (flax), sunflower oil etc.) have similar energy content. Corn oil has been used for decades as an oil source as it is very palatable energy source. It does have a lower Omega 3 content that some of the other oils. Linseed oil (flax) has the highest Omega 3 content of the vegetable oils. Soy oil is also higher in Omega 3’s than corn oil. The coconut oil sources are higher in what we call medium chain fatty acids and are a good energy source, but not high in Omega 3’s unless a source is added.

      As you have are feeding the oil both as an energy source and perhaps to provide some anti-inflammatory benefits, soy oil or a product combining soy oil and linseed (flax) oil would be a better recommendation than the corn oil. The dry fats would all depend on what oils they use as a base.

      You should be able to buy soy oil in bulk and it has good shelf life stability. Linseed oil should be heat treated, not raw, as raw flax or flax products contain some anti-nutritional compounds that are eliminated by heat treatment.

      Best wishes,

  14. I have an older Arab that is a hard keeper. I have tried Rice Bran but she was allergic to it. I have also tried Vegetable, Canola & Corn oil which she was allergic to all of them. She colicked on Alfalfa so she can only have grass hay. She does eat Beet Pulp which helps but I’m wondering if anyone has had success with other oils that might help put weight on her and if anyone else has had trouble with their horse getting hives from the above mentioned oils? Her teeth have been floated and she is dewormed on a regular basis. Any advice is greatly appreciated. Thanks!

    1. Hi Michelle,

      It sounds like you have a bit of a challenge on your hands with your older Arabian that is a hard keeper. I am a little surprised with the allergic response to some of the oils. Most allergic responses are triggered by a specific protein in an ingredient or a fairly specific allergen. You might want to try linseed oil (flax oil) as this will have comparable energy content to other vegetable oils and contains a higher level of Omega 3 fatty acids which may help reduce allergic response to other nutrient sources. Coconut oil sources might also be useful.

      If you want to stay with grass hay, you will want to make sure it is early cut and fairly fine textured. You may also want to use a ration balancer type product to provide minerals, vitamins and some additional amino acids.

      If you have not done so, you should also make certain that dental care and deworming program are up to date.

      Best wishes,

  15. Hello,

    I have a blm Mustang a little over 15hh, narrow built & has always had the ugliest back & always seems to get ribby close to winter. I always feed a whole 55-60 pound bale between him & my mare daily in a show feeder & there is always a little left by morning. He was a good weight this past summer, but he got caught in a fenceline between a gate & fence post (I was right there, he decided the grass looked greener on the other side) when he realized he was stuck he pulled back so hard the fence post (which was sturdy) moved 3 feet & he flipped over backward. To make a story short, my vet says he has facial paralysis & the right side of his face no longer works. His ear, & mouth are droopy. Because of this, he drops 70-80% of any grain I’m feeding. I got a nosebag & that works well- he is able to finish all the grain. Last winter his teeth were floated, & when he was a bit underweight then my vet said to use corn oil. I started out slow, & after 2 weeks I was giving him 1 cup per day between 2 feedings. He became a different horse on the corn oil. He was disrespectful, pinned his ears, etc. I just started giving him coconut oil over his grain in hopes he wont become like that again. But I’ve been racking my brain as to why he keeps loosing weight & currently cant seem to get any over the rib area. Any advice would be appreciated! Thank you!

    1. Hello Jesse, Thanks for contacting us. This sounds distinctly like a lack of quality protein in his diet. Adding a ration balancer such as our Empower Balance should help quite a bit – you should see an improvement in his topline and over his ribs with the addition of a good dose of protein. You might also try something like rice bran for weight gain.
      Thanks ~ Gina T.

    1. Hello Virginia, Thanks for the question! We have an excellent comprehensive article on managing a Cushing’s horse here.

      From there, it depends on what you do with your mare and how her condition is. If she is not used much, or is an easy keeper, we would suggest use of a ration balancer such as our Empower Balance product – this will provide the nutrients she needs to stay healthy, without the calories of a traditional feed. In this case, we wouldn’t suggest adding any oil.

      If she is in work, or is a harder keeper, you can try either our SafeChoice Senior (especially if she gets to the point of being unable to chew hay/pasture), or SafeChoice Special Care. These will offer the nutrients plus some of the extra calories she may need. These should both cover her calorie needs, in which case oil would not likely be needed either.
      Thanks ~ Gina T.

  16. Just wondering, is plain old store bought vegetable oil okay to use for wright gain for my older TB mare? She has a tough time keeping weight on, unfortunately our turnout doesn’t offer grass for free grazing…she is on grain and timothy/alfalfa cubes wet down twice a day as well. Just curious if vegetable oil would be okay to use or should I stick to cocasoya or corn??

    1. Hi Jennifer,
      Thank you for your question regarding the use of plain old store bought vegetable oil for weight gain for your older TB mare. Vegetable oils (corn oil, soy oil, sunflower oil, canola oil, flax oil etc.) have about the same Calorie content, digestibility and similar palatability, so you can use any of them or a blend off the shelf of your local grocery store as suitable energy source for weight gain. There are some differences in profile for Omega 6 and Omega 3 levels, but not for Calories, which is what you are after to help her gain weight. You can start gradually and build up to a cup of oil per day split in at least 2 feeds. Works well to add to the cubes. If she starts to get loose stool or shiny appearance to droppings, may have to back off on intake. Added oil up to 10% of concentrate portion of diet is readily accepted.

      Best wishes,

  17. I have a register quarter horse mare and I was wounding how much vegetable oil should I start her out on? She is a little under weight and I am giving her oats and hay, but she isn’t gaining any weight, and I don’t want to ride her till she gets more weight on her.

    1. Hello Angelicia,

      Thanks for the question. First, we would suggest a more balanced diet than plain oats. This diet is lacking in protein, amino acids, as well as many vitamins and minerals. The lack of protein may be contributing to a lack of muscling, especially over her topline, that would give her an appearance of being underweight. We would recommend either adding a ration balancer, such as Empower Balance, at a rate of 1.5-2 lbs per day, to her oats, or switching entirely to a higher fat, nutritionally balanced feed. SafeChoice Original, or a similar product that you can find in your area, is a great starting option.

      If you would like to add oil to her diet, start out slowly – adding it too quickly to a diet can cause loose stools, which aren’t much fun in the barn! Try adding 1/4 cup at each feeding to start with, and after 5-6 days increase that to 1/2 cup per feeding. Hold her there for a while and see how she responds. If after a month she isn’t gaining weight from the oil, increase it by another 1/4 cup per feeding. Continue this until you find the rate at which she increases, then once she reaches a desired condition, slowly decrease the amount being fed until you find the rate at which she maintains the desired body condition.

      Thank you ~ Gina T.

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