For example, copper is often deficient in Florida beef cows, which may result in failure to respond to vaccinations and rough, dull hair coats. “Dietary sulfur is an important component in the copper/molybdenum interaction,” he says. “Researchers suspect that dietary sulfur levels greater than 0.35% are highly likely to interfere with both copper and selenium utilization in cattle.”

He adds that blood copper concentrations may be elevated in stressed cattle, suggesting a higher copper requirement. “Consider using copper sulfate, tri-basic copper chloride or an organic source when supplementing copper,” he says. “Copper oxide is poorly utilized in cattle and should not be used in the formulation of their supplements.”

Arthington says signs of zinc deficiency may include compromised hoof integrity, bull reproductive failure and anorexia and weight loss, notably in calves.

Signs of iron deficiency may include anemia, immune suppression and decreased calf weight gain. An iodine deficiency may produce reduced fertility, enlarged thyroid or stillborn, weak and/or hairless calves. Signs of cobalt deficiency include loss of appetite leading to weight loss, listlessness, diarrhea and anemia.

Arthington notes that selenium can be difficult to supplement because it has a narrow range between deficiency and toxicity. “Many regions are concerned with selenium toxicity in pasture forages,” he says. “Selenium is essential for the maintenance of tissue integrity. One widely recognized deficiency symptom is the degeneration of tissue, resulting in a condition referred to as ‘white-muscle disease.’”

Sodium selenite is a commonly used source of supplemental selenium. Because of the selenium-rich pasture forage problem in other regions, selenium inclusion in supplemental feeds is federally regulated at a maximum inclusion level not to exceed 3 mg/d.

Larry Stalcup is a freelance writer based in Amarillo, TX.