Seaweed has been fed to animals including horses for many years, and it is a very useful sea ‘vegetable’. It’s a rich natural source of minerals, polysaccharides (long chain carbohydrates), amino acids, vitamins and other compounds, all of which provide a useful addition to the diet of our horses. Seaweed is usually fed dry but there are still areas in Scotland and Ireland where native ponies with access to beaches will graze fresh seaweed.
Seaweed is reported to be good for horse’s hooves and coats, improving their quality. It is also a potential stomach soother for horses, but more research is necessary to confirm all of these properties. The polysaccharides that seaweed contains include algin, fucose and laminarin, none of which are found in land vegetables. These polysaccharides are believed to have a range of health benefits and might contribute towards seaweed’s historic use as an anti-obesity compound. Seaweed has traditionally been fed and eaten for its mineral content and as an anti-obesity compound, as an immune booster and an anti-viral, anti-tumour and anticancer compound. It is also reputed to be an anticoagulant and hypoglycaemic. Animals fed seaweed are reputed to be healthier, more fertile and maintain condition better than those not fed seaweed. It is generally recommended that seaweed is not fed on top of a balanced diet during pregnancy – due to its very high iodine content – but it can be fed to lactating mares with good effect.
Seaweed is probably the best natural source of minerals for horses, and it is particularly high in iodine. The amount of iodine many seaweeds contain mean that it should be fed in limited quantities to horses, since it could oversupply this mineral if given in ample quantities. Restricting the amount fed to ensure you avoid iodine toxicity means that seaweed will not supply enough of the other essential minerals that are short in forage for horses (zinc, copper and selenium) to balance a forage-only diet. Therefore ideally you do need to feed a multi-vitamin and mineral supplement as well as seaweed, if your horse receives no other vitamin and mineral fortified feed or supplements.
There is no doubt that seaweed is a healthy dietary addition and the richest natural source of essential minerals, but for at least part of the year, another source of vitamins and minerals more specifically formulated to balance horse forage should be fed.