CALCIUM (Ca)	Deficiency: Rickets and enlarged joints in young animals; generally, enlarged joints, soft and deformed (crooked) bones. Osteoporosis and spontaneous pelvic fracture in older horses. Toxicity: Osteochondrosis and hypercalcition.
CHROMIMUM (Cr)	Deficiency: Inability to regulate blood glucose, insulin shock based laminitis, hyper-active behavior, lack of mental focus, tendency to fatty deposits and a cresty neck. Toxicity: Source Dependent.
PHOSPHOROUS (P)	Deficiency: Rickets in young animals; osteo malacia and osteoporosis in older animals. Poor appetite, slow weight gains, low mild production in brood mares, low blood phosphorous, unthriftiness, may eat soil and chew non-feed objects. Toxicity: Reduced rate of calcium absorbtion (nutritional secondary hyperparathyroidism, osteofibrosis, fibrous osteodystrophy) this is characterized by shifting lameness and, in advanced cases, by enlargement of he upper and lower jaws and facial crest.
MAGNESIUM (Mg)	Deficiency: Nervousness; muscle tremors; ataxia; collapse, hypernea, sweating, padding, and untimately death. Toxicity: Had not been studied.
POTASIUM (K)	Deficiency: Poor appetite, wight loss, unthrifty appearance; lowered serum potassium concentrations. Toxicity: Has not been studied.
SODIUM (Na)	Deficiency: Decreased skin turgor, a tendency to lick tool handles, slow rate of eating, decreased water intake, cessation of eating, muscle contractions, uncoordinated chewing, unsteady gait, decreased in serum sodium and chloride concentrations. Toxicity: Sodium Chloride (salt) if offered free choice in block form, this is the only mineral intake a horse will self regulate.
CHLORIDE (CI)	Deficiency: not described in horses. Inferred from other species - decreased food intake, weight loss, muscle weakness, decreased milk production in broodmares, dehydration, constipation, depraved appeite. Toxicity: See Sodium
COBALT (Co)	Deficiency: Generally malnutrition, unthriftiness, weakness, anemia, decreased fertility, slow growth, decreased milk production in broodmares. Toxicity: Toxic in large amounts in other species, not studies in horses.
COPPER (Cu)	Deficiency: Low blood and liver copper, sun bleaching of har, abnormal bone matabolism, muscular uncoordination, weakness at girth, anemia, a significant decline in serum copper with aged mares - related to incidence of usually fatal rupture of the uterine artery. Toxicity: Toxic in large amounts in other species; not studied in horses.
IODINE (I)	Deficiency: Stillbirths, weak foals -difficulty in standing, thyroid hyperplasia, abmormal estrus cycles, infected navels in foals. Toxicity: Toxic dietary iodine concentrations may result from feeding excessive supplemental iodine, such as etheylenediamenehydriodide, or from using feedstuffs high in iodine. A common feedstuff containing excess iodine is kelp. It may contain as much as 1,750 mg. of iodine/kg. Liotronic iodinism and as associated aolpecia may result; iodine toxin goiter in foals born to mares received excess iodine.
IRON (Fe)	Deficiency: Microcytic and hypochromic anemia, low blod hemoglobin, listlessness Toxicity: Causes depression of serum and liver zinc and copper. Especially toxic to foals, causing diarrhea, ictewrus, dehydration, coma and death.
MANGANESE (Mn)	Deficiency: Abnormal cartilage development, bone malformation, crooked limbs of newborns, congenital contractions, and hyperextensions. Toxicity: High manganese levels are causes of any otherwise unexplained problems.
SELENIUM (Se)	Deficiency: (Nutritional myopathy - involves skeletal and cardiac muscles) Weakness, impaired locomotion, difficulty suckling and swallowing in foals, respiratory distress, impaired cardiac function, low fertility, (Tyingp-up syndrome does not correlate with Selenium or Vitamin E.) Toxicity: Blind staggers, Head pressing, perspiration, abdominal pain, colic, diarrhea, increased heart and respiration rates, and lethargy. Alopecia about the mane and tail. Cracking of the hoof around the coronary band.
ZINC (Zn)	Deficiency: Poor appetite, reduced growth rate, Keratosis (especially on lower limbs), alopecia, reduced serum and tissue zinc concentration, and decreased alkaline phosphatase. Toxicity: Enlarged epiphyses, stiffness of gait, lameness, increased tissue zinc. Causation of secondary copper deficiency.

Virginia Equine Research