Mineral nutrition is complex, with different macro minerals (required as percentage of diet) and micro minerals (required in ppm of diet) that are of concern. Our forages also do not stay the same in mineral composition throughout the year, and differ by region of the state. In addition, cattle in different stages of production have different minerals that we need to keep in mind.
Minerals that we most often have issues with include sodium (provided by salt), calcium, phosphorus, magnesium, cobalt, copper, and zinc. Minerals are involved in all aspects of the animal’s life. Calcium, phosphorus, and copper are important for bone strength and development. Calcium and magnesium are essential in nerve and muscle function. Phosphorus has roles in energy metabolism, cell membrane structure, and rumen microbe growth and function. Cobalt, copper, and zinc have roles in immune function. Deficiencies of phosphorus, copper, and zinc result in reduced fertility.
- Salt is always deficient in forage based diets.
- Calcium should be at a 1:1 to 3:1 ratio with phosphorus, but 7:1 can be tolerated.
- Phosphorus is one of the more expensive ingredients in mineral mixtures. It is important not to short on this mineral when it is needed even when the mineral costs more!
- One of the first visible symptoms of a copper deficiency is a dulling of the hair coat, but deficiencies have probably already affected immune function and growth before this sign shows up.
- Research shows zinc supplementation improves hoof and eye health.
Native range pastures are often deficient in sodium, calcium, phosphorus, magnesium, cobalt, copper, and zinc for both growing stockers and cows. A 12% calcium 6% phosphorus mineral mixtures providing highly available micro minerals works well for growing stocker calves. Cows need a 12% calcium, 12% phosphorus mineral to meet requirements.
In well-managed bermudagrass pastures, phosphorus is often only marginally deficient or adequate, but calcium can be variable, ranging from deficient to adequate. Zinc is often sufficient in bermudagrass. In Eastern Oklahoma, highly weathered soils with low pH and mineral antagonists (molybdenum is a primary culprit) often results in copper deficiency. For growing stocker calves and lactating cows, minerals should provide salt (18 to 20%), calcium (12%), and trace minerals from highly available sources such as copper sulfate (copper oxide is not digestible). Phosphorus can be included at lower levels.
- Red salt blocks (or Trace mineralized salt) are not good sources of micro minerals and usually do not provide sufficient mineral concentrations or quality to meet cattle’s needs.
- Watch the suggested consumption of minerals fed. Mineral mixtures are available that recommend 2 ounce per day consumption, but many require 4 ounce consumption. Monitor mineral consumption to ensure adequate intake.