MINERAL DEFICIENCIES
These could be the most common cause of disease in horses because almost all pasture is mineral deficient and most general feeds are formulated to prevent serious disease and not to ensure first class all round health. The quality of grains produced today is some 50% inferior to that produced 50 years and more ago and the need for minerals differs with each individual horse.
Small levels of mineral deficiency can impair the immune system, increase the healing times of wounds and make bones, cartilage and ligaments much more prone to arthritis. More importantly it can make allergies more common. A good mineral and trace element supplement can go a long way to redressing the imbalance and improve all round health.
As a rule of thumb it is important to note that chemically produced minerals are less easily absorbed and utilised by the body than those in growing plants (feed grade) and consequently more is required. Even then the quality of the minerals in plants is far superior and have always formed part of the diet of wild horses who used to roam the plains with access to a huge variety of plants and herbs. Many of these herbs are available in dried form for easy daily use in your horse's feeds and they could be regarded as the 'salad bowl' for horses. Some chemically produced mineral supplements have been made more useable by the body and are desbribed as bio-available or chelated.
Fresh nettle tips (use gloves to pick them) are full of iron for the blood (essential for pregnant mares) and vitamin C for the immune system, and probably growing near you. Just wilt them in boiling water for a minute and use the water plus the nettles to damp the feed. (They can make an excellant alternative to spinach in your own diet!)
Rose hips full of vitamin C to aid the immune system, can be gathered in the autumn from the hedgerows round your fields.
Seaweed especially natural unfarmed Arctic seaweed contains over 47 natural vitamins and minerals for complete health, but care in feeding to pregnant mares is called for because the level of iodine is high.