Livestock Nutrition: Are mineral supplements in your stocker program this winter?

• F.T. McCollum III

• Beef Cattle Production Specialist
• Texas A&M AgriLife Extension Service
• 
  

Gazing across lush, green wheat or rye or triticale pasture, one might assume the nutrient needs of stocker cattle are well supplied. However, concentrations of macro- and trace minerals can range from adequate to deficient in these forages.

Deficiencies can slow growth and impair immune function. Deficiencies may also play a role in small-grain bloat.

Mineral concentrations in fresh samples of wheat and triticale forages submitted to the Dairy One Lab over a 16-year period demonstrate that relative to the daily requirements of 400- to 600-pound stocker calves:

• Calcium concentration in forages ranges from adequate to very deficient.
• Phosphorus ranges from slightly deficient to adequate.
• Magnesium ranges from marginally adequate to adequate.
• Copper and zinc also range from very deficient to adequate.
• Heavier calves are at less risk of a deficiency than are lighter calves.

Based on these comparisons, calcium is a primary concern in a mineral supplement for small grains, and calcium concentration required in the supplements (greater than 12 percent) will be greater than those normally included in range or warm-season pasture supplements.

Phosphorus may be of some concern, but the concentration required in a supplement (less than 5 percent) would be about half or less of that normally included in range or warm-season pasture supplements.

A low concentration of supplemental magnesium may be desirable but not the concentrations used in high-magnesium tetany minerals for cows. Research has shown stocker cattle grazing small-grains pastures will respond efficiently to a complete mineral supplement.

“Complete” meaning a supplement containing salt, macro-minerals and trace minerals in appropriate concentrations. These supplements are also a means of delivering ionophores (monensin, lasalocid) that enhance weight gain.

An Oklahoma State University study found stockers provided a complete mineral without an ionophore gained 0.24 pound per day more than stockers grazing with no mineral supplement.

Adding an ionophore into the mineral supplement increased gain another 0.23 pound per day. Compared to the unsupplemented cattle, the mineral+ionophore combination increased gain 0.46 pound per day.

Stocker cattle grazing small-grains forages will respond efficiently to mineral supplements and ionophores. Be sure to consider these tools for your management program.