Flaxseed (also known as linseed) is a valued feed ingredient amongst horse people. How it should be used has long been the subject of considerable debate. Its safety for horses has always been under question and methods of preparation are many and varied.
What does flax add to a diet?
Flaxseed's best known attribute is its high Omega 3 essential fatty acid content. Flaxseeds are over 40% oil and more than 50% of this oil is the omega 3 fatty acid α‐linolenic acid. A horse's natural grazing diet is high in omega 3 fatty acids. However as we add grains like corn and barley to a horses diet their diet can become skewed towards having high levels of omega 6 fatty acids. Flaxseed provides a 'natural' way to keep the levels of omega 3 in a horse's diet balanced without using expensive omega 3 fatty acid supplements. Adding 100 grams of flaxseed to your horse's diet will add over 20 ml of omega 3 fatty acids.
While omega 3 fatty acids are generally the primary reason flaxseeds are fed to a horse, flaxseeds are a decent source of protein with around 24% protein and 0.9% lysine and also contain around 25% fibre.
When can flaxseed be used?
Flaxseed is useful for horses on a high grain (and therefore high omega 6 fatty acid) diet or when they are eating hay that has been in storage for some time or grazing low quality pasture. Flaxseed may also be used when horses have a dry coat and skin, if they have problems with inflammation including arthritis and sweet itch, or when high omega 6 oils like corn oil or sunflower oil are being fed as an energy source in the diet. Flaxseed itself can be used as a source of energy in the diet and because of its high fat attribute is often found in supplements intended to promote weight gain in horses.
How should flaxseed be prepared for feeding?
Because flaxseed is such a small seed it is best to grind flaxseeds immediately prior to feeding to break the seed coat, otherwise the seeds will pass undigested all the way through the gastrointestinal tract. It is important to grind the seeds fresh just prior to feeding as the oils in flaxseed are prone to rancidity and will go off very quickly if ground and left exposed to air. A small coffee grinder is commonly used for the purpose of grinding fresh flax straight into a horses feed (very gourmet!). It is possible to purchase pre‐ground and stabilised flaxseeds if grinding your own is not an option.
Does flaxseed have to be boiled before feeding?
Tradition says that flaxseed must be boiled before feeding it to a horse because of the risk of Prussic Acid (or hydrogen cyanide) poisoning. Anyone who has boiled flaxseed knows how messy it gets and for most the effort and mess are too much to continue persisting. Well good news ... flaxseed it seems can be fed safely without being boiled.