Phosphorus (P) is required for skeletal development and maintenance, normal milk secretion, muscle tissue building, cell growth and differentiation, energy use and transfer, efficient food use, membrane formation and function of many enzyme systems.
Toxicity – causes urinary calculi.
Deficiency – reduces growth and feed efficiency, decreases dry matter intake, lowers reproductive performance depresses milk production and causes weak and fragile bones.

Magnesium (Mg) is important for enzyme activation, glucose breakdown, genetic code transmission, membrane transport, nerve impulse transmission, and skeletal development.
Toxicity – Generally, magnesium toxicity is not a problem.
Deficiency – causes excitability, anorexia, increased blood flow, convulsions, frothing at the mouth, prolific salivation, and soft tissue calcification. Young animals can mobilize magnesium from bone, but adult animals can’t so require regular and adequate supplies in the diet. Grass tetany is characterized by low magnesium levels.

Potassium (K) is the third most abundant mineral in the body, Potassium is involved in acid-base balance, osmotic pressure regulation, water balance, muscle contractions, nerve impulse transmission, oxygen and carbon dioxide transport in the blood, and enzyme reactions.
Toxicity – Potassium can be very high in lush grass contributing to grass tetany onset.
Deficiency – reduced feed intake, lowered weight gains, rough hair coat, and muscle weakness. Body stores of potassium are low, but forages are good sources.

Sodium (Na) and Chlorine (Cl) are the components of common white salt and are important for maintaining osmotic pressure, controlling water balance and acid-base balance and carrying glucose and amino acids. Animals crave salt and will consume more than needed when supplied.

Sulfur (S) is a building block in several amino acids and B vitamins along with other organic compounds. Sulfur functions in detoxification reactions and is required for growth and normal cell function.

Toxicity – causes restlessness, diarrhea, muscle twitching, and labored breathing.

Deficiency – reduces feed intake, depress growth, decreases copper levels and results in weight loss, weakness, salivation, and death. Sulfur in feedstuffs is found largely as a component of protein.

Cobalt (Co) functions as a component of vitamin B12. Ruminants are able to synthesize vitamin B12 if cobalt is present.
Toxicity – Generally not an issue as animals are very tolerant to cobalt.
Deficiency – Depressed appetite and reduced growth performance or weight loss. As cobalt is not stored, regular supplementation is required particularly if soil levels are low and manganese level are high. Cobalt supplementation is especially important in young lambs.

Copper (Cu) is an essential component of enzyme function.
Toxicity – Supplementing with too much copper or contaminating feeds with copper could result in copper toxicity especially in sheep. The liver can store copper but Molybdenum, sulfur, and iron levels in the diet affect copper levels.
Deficiency – can be a problem resulting in anemia, reduced growth, loss of hair pigmentation, changes in hair growth and appearance.

Iodine (I) is a key component of thyroid hormones involved in energy metabolism.
Toxicity – reduces weight gain, lowering feed intake, and causing coughing and nasal discharge.
Deficiency – enlargement of the thyroid (goiter). Goitrogenic substances in feeds suppress thyroid function and can affect iodine requirements.

Iron (Fe) is a critical component of haemoglobin and myoglobin, two proteins involved in oxygen transport and use. More than half of the iron in the body is in haemoglobin. In addition, some enzymes either contain or are activated by iron.

Toxicity – diarrohea, acidosis (digestive tract disturbance), hypothermia, reduced weight gain, and reduced feed intake. Iron depletes copper and can contribute to copper deficiency.
Deficiency – causes anemia, lethargy, lowered feed intake, reduced weight gain and pale mucous membranes. Severe parasite infestations which cause blood loss can lead to iron deficiency. Iron requirements are higher in younger animals.

Manganese (Mn) is important for normal skeletal development, growth, and reproductive function.
Toxicity – growth performance and feed intake are reduced.
Deficiency – skeletal abnormalities, irregular estrus, low conception rate, abortion, stillbirths and reduced birth weights.

Molybdenum (Mo) supplementation is not a practical concern.
Toxicity – results in diarrhea, anorexia, weight loss, stiffness, hair color distortion reduced weight and lower conception rates. Copper and sulfur work against molybdenum in the body. Molybdenum contributes to copper deficiency, and copper can reduce molybdenum toxicity.
Deficiency – Rare, not an issue.

Zinc (Zn) plays an important role in immune system development and is a crucial component of many important enzymes that function in nucleic acid, protein, and carbohydrate metabolism.
Toxicity – not of concern.
Deficiency – can cause listlessness, excessive salivation, swollen feet, scaly lesions on feet, tissue lesions, hair loss and slow healing.

Vitamin D forms include ergocalciferol (vitamin D2) found in plants and cholecalciferol (vitamin D3) found in animals. Vitamin D is necessary for calcium and phosphorus absorption, normal bone mineralization, and calcium mobilization from bone.

Toxicity – signs include calcification of soft tissues, bone demineralization, decreased appetite, and weight loss.
Deficiency – causes rickets where bones do not use calcium and phosphorus normally. Animals do not store vitamin D but supplementation is not absolutely necessary as it is made by the animals exposed to sunlight.

Vitamin E (alpha-tocophorol) serves as an antioxidant in the body and is important in membrane formation, muscle structure, muscle function and plays a role in disease resistance. Selenium is closely linked with vitamin E and animals with white muscle disease often respond to either vitamin E or selenium supplementation.