Micromineral Functions, Deficiency Diseases, and Interrelationships
Micromineral | Requirement (mg/kg dry matter) | Major Biological Function | Deficiency Disease or Clinical Signs | Interrelationships or Toxicity |
|---|---|---|---|---|
Cobalt (Co) | 0.1–0.2 | Component of vitamin B12 (ruminants only) | Megaloblastic anemia; enzootic marasmus (ketosis), reduced growth, body weight | Cobalt needs to be supplied to rumen microbes; toxicosis unlikely |
Copper (Cu) | 10–15 | Hemoglobin synthesis; bone formation; pigmentation; myelin formation; oxidation-reduction reactions; immune function | Achromotrichia; neonatal ataxia (swayback); infertility; hypochromic-microcytic anemia; profuse diarrhea; immune failure | High iron, zinc, and selenium reduce availability; excess molybdenum and sulfur inhibit utilization and storage in ruminants; toxicity variable in species, results in hemolytic crisis |
Iodine (I) | 0.5–1.0 | Thyroxine formation | Goiter; stillbirths, infertility; malformations, hairless neonates; immune failure | Dietary goitrogens inhibit function; high intakes reduce uptake efficiency; toxic intake results in goiter, fetal malformations |
Iron (Fe) | 50–100 | Cellular respiration, oxygen transport | Hypochromic-microcytic anemia; easily fatigued | High calcium may decrease absorption; copper status influences metabolism; excessive amounts are pro-oxidants; interferes with copper metabolism |
Manganese (Mn) | 20–40 | Bone formation; activator of enzymes with carbohydrate, lipid, and protein metabolism | Crooked calf disease; impaired fertility; poor growth; impaired immune function | Excess calcium and phosphorus decrease availability; toxicosis unlikely; may interfere with other minerals |
Selenium (Se) | 0.3 | Antioxidant—cellular iodine function, immune function | White muscle disease; acute death; retained placenta; impaired immune function | Sulfate, acid soil conditions interferes with selenium availability; maximum tolerable level 2 mg/g in nonruminants— alkali disease of horses (chronic toxicosis); acute toxicosis from parenteral products— respiratory collapse |
Zinc (Zn) | 30–60 | Component of >90 enzymes influencing all aspects of metabolism immune function | Anorexia; parakeratosis; poor skin and hair formation; male infertility; impaired immune function | High calcium, phytates or oxalates bind zinc; high zinc interferes with copper metabolism |