Horse owners are often reading feed tags and looking for feed and supplements to ensure that horses will receive all the nutrients they need for good health. Flax has been used for centuries as a nutritional supplement for horses.
Flax is high in omega-3 fatty acids, which are essential to the horse and responsible for improving cellular integrity and balancing inflammatory response in the body. Flax has soluble fiber that not only supplies energy to the horse but also has mucins that have a beneficial effect on gastrointestinal function.
Flax seeds can be fed whole and mixed into horse feed but are best if ground immediately before feeding. Previously, the traditional way to feed flax has been to boil it. When cooked, it makes a thick, gelatinous soup that horses eat readily. Boiling or grinding breaks open the hard shell to expose the most nutritious parts of the seed to digestive processes.
The concern with grinding in advance of feeding or soaking in unheated water stems from the fact that there are neurotoxic cyanogenic glycosides in the flaxseed that produce cyanide when exposed to air or water. Ideally, flax should be added only to water that is boiling, not water that is on the verge of boiling.
Grinding well in advance is also not recommended but grinding just before feeding is acceptable. Commercial products that are milled or ground can be safely fed because they have use a stabilization process that stops the enzymes that produce the cyanide.
Typically horses are given between 25 and 75 g per day. If the horse has access to fresh grass, it is getting plenty of omega-3 fatty acids, so horses on pasture do not usually have a deficiency of omega-3 fatty acids. Horses fed hay and grain or concentrates will benefit from additional omega-3 fatty acids.
In humans, flax can interfere with absorption of certain medications, so timing of flax consumption is important. This may be similar if the horse is on thyroid medication; flax should not be fed within two hours of receiving the medication.
There is another product on the market by the name of linseed meal or flax meal. This is not the same as ground flax. The meal is a by-product of oil production.
The residual fat content of the meal by-product, averages around 12%. The meal can be fed to horses and has some of the same benefits as the regular flax seed although it is not as high in the omega-3 fatty acids. Flax meal is more commonly used as a protein supplement because it has about 36% protein.