As the genetic progress of the herd improves, mineral supplementation strategies become more complex and are influenced by a variety of factors, including forage mineral bioavailability, trace mineral interactions, stage of production and even breed.
Adequate mineral intake and balance are required for proper functioning of metabolic processes, including immune response and reproduction. The trace elements most commonly identified as having an impact on cattle productivity include copper and zinc.
Copper is an essential trace element required for enzyme systems, iron metabolism, connective tissue metabolism and mobilization, plus integrity of the central nervous and immune systems.
Copper functions in the immune system through energy production, neutrophil activity and antioxidant enzyme production. In addition, it aids in the development of antibodies and lymphocyte replication. Reproductive efficiency may be reduced when a copper deficiency occurs because of metabolic alterations of enzyme systems.
Zinc is actively involved in enzyme systems through metabolism of protein and carbohydrates. Zinc is also required for maintaining responsiveness of the immune system through energy production, protein synthesis, stabilization of membranes against bacterial endotoxins, antioxidant enzyme production and maintenance of lymphocyte replication and antibody production.
Virtually every phase of cell growth involves zinc, and a deficiency can negatively impact productivity.
Mineral supplementation may also be required for forages, which provide the nutritional base of beef and dairy operations. Supplementation decisions pivot around both the quantity and quality of the forage base. In addition to the protein and energy content of the feed resource, mineral concentrations must also be considered.
Minerals and reproduction
Intake of bioavailable minerals is necessary in postpartum cows for proper involution of the uterus, display of estrus, ovulation, conception and maintenance of a new fetus.
Research has reported a decrease in length of time from the beginning of the breeding season to conception for cows supplemented with trace minerals compared to cows fed supplement without trace minerals or those receiving no supplement. In a copper-deficient status, productivity may be reduced due to metabolic alterations of enzyme systems.
Delayed or suppressed estrus and embryo death have been identified as common symptoms of copper deficiency in beef cattle. Infertility associated with a copper deficiency may also be a result of excessive dietary molybdenum intake. In a recent study, authors reported that heifers receiving a diet with marginal copper and high molybdenum levels exhibited delayed puberty, lower ovulation and conception rates compared to heifers consuming a diet containing high levels of iron.
Zinc deficiency can adversely affect reproductive processes in females from estrus to parturition. Inadequate zinc levels in gestating cows may result in abortion, fetal mummification, lower birthweight or altered uterine contractions with prolonged labor.
Research has reported impaired growth, delayed puberty and decreased appetite in zinc-deficient bull calves. In addition, a loss of appetite results in lowered mineral ingestion, which further decreases feed utilization due to hindered nutrient metabolism.
Economic impact of mineral deficiency
Subclinical or marginal mineral deficiencies may have an economic impact on beef producers and can be the result of dietary levels, water source, production demands, breed differences and mineral antagonisms. Subclinical trace mineral deficiencies in cattle may be a larger problem than an acute deficiency because they do not produce obvious symptoms that can be recognized.
Cattle with a subclinical status continue to reproduce or grow but may have decreased feed efficiency and a depressed immune function.
Given the complexity of determining mineral status in cattle due to interactions among minerals, variability of trace mineral levels in forage and bioavailability to the animal, dependence on a single variable of mineral status may result in an incorrect diagnosis.
To determine mineral status of your beef herd, consider the following checklists for forage, water, serum and liver tests:
Forage analysis
- Copper
- Zinc
- Manganese
- Iron
- Sulfur
- Molybdenum
- Selenium
Water analysis
- Iron
- Sulfur
Serum sampling
- Selenium
Liver biopsy
- Copper
- Zinc
- Molybdenum
Cattle producers face numerous management challenges and many of them compound the trace mineral requirements of the beef cow. Mineral supplementation strategies also become more complex because of forage maturity, mineral absorption antagonists and stage of production.
Therefore, adequate supplementation of a bioavailable trace mineral is required for proper function of the immune system and reproduction. 
Troy Wistuba, Ph.D., PAS, is a dairy technology manager for Phibro Animal Health Corporation. He’s a former animal science professor and specializes in working with producers, nutritionists and veterinarians to meet the nutritional needs of cattle.
References omitted due to space but are available upon request. Click here to email an editor.
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Troy Wistuba
- Phibro Animal Health Corporation
- Email Troy Wistuba
