Most idle horses and pleasure horses will easily meet their needs with block salt. It is recommended when feeding salt to always use trace mineralized salt. An exception to this may be the horse that is eating large amounts of salt as it might produce a trace mineral toxicity. Trace Minerals Ohio is deficient in the trace minerals iodine and selenium, and sometimes deficient in copper and zinc. See Table 6 for a list of the common trace minerals needed by the horse, their required level, and the amount usually present in feedstuffs.
Most trace minerals are in adequate supply in the normal ration of the horse.
The horse needs selenium for normal muscle function and normal function of the immune system. This mineral is a problem because of its narrow range between the requirement and toxic levels. Toxicity is characterized by loss of appetite, loss of mane and tail hair, and in the severe form, blindness, loss of the hoof wall, paralysis, and death. Iodine Iodine deficiency or excess may result in goiter. Copper Copper is a marginally deficient mineral in Ohio.