How an organic proteinate mineral behaves in your horses body is vastly different to a common inorganic or synthetic mineral. High quality organic minerals are selectively taken up by the body, are completely bio-available, stable in the gastric system and the tub, and are almost completely non toxic. Any excesses are easily excreted. They are body friendly.
Synthetic minerals are absorbed by osmosis, meaning the principal of equalization. They are taken in by the body indiscriminately, are far less stable under changes of pH, therefore are far less bio-available, and have a much higher toxicity level. In some cases even being highly toxic. For example, Selinium selinate was the synthetic form of selenium responsible for the deaths of 21 polo ponies in Florida in April 2009. This is why blood tests are only part of the picture.
Different mineral forms have different absorption levels. So, if you feed a supplement with different forms of minerals, the horse absorbs different amounts of each one causing imbalances. These imbalances my not be noticeable when the horse is young or not in extremely hard work, but in time they can result in unsoundness, the breaking down of body systems and loss of performance, whether your horse is a performance horse, breeding mare/stallion or pony club pony. More immediate signs that the body is not optimum may be not getting in foal, lack of muscle, staying focused, succumbing to opportunistic infections like mud fever, or fighting off a virus. In fact research has indicated that conditions like Cushings Disease are triggered by long term mineral deficiencies.
Feeding top quality organic minerals is like an insurance policy on your horses future health and wellbeing. No its not a magic bullet, but it considerably improves the chances of your horse having a long and productive life with less vet bills! That's important when you have spend many years training.