By ANN HINCH
Assistant Editor

ST. LOUIS, Mo. — In addition to vitamins, minerals are important to livestock, as well as human bodies. Each mineral serves a vital function; in some cases, one is designed to work with one or more vitamins, such as vitamin D helping a body absorb calcium properly.

Both types of nutrients were addressed in sessions at the four-day Feed Industry Institute in St. Louis in June. Besides being in rocks and metals, minerals are needed by human and animal bodies for basic functions. Minerals come in two categories: macro, which are needed in a higher percentage, and trace – which, as the name suggests, are needed in far smaller quantities.

Buying minerals to add to livestock feed differs from buying any other kind of nutrient because of how they’re produced, according to Tim Costigan, vice president of Quality Affairs for Prince Agri Products.

For one thing, ore might be the purest source of minerals, but not all intended for eating can safely come straight from ore. It’s a case where “all-natural is not always all good,” Costigan said.
Copper is a prime example of the importance of paying attention to suppliers. The U.S. animal feed industry uses far less than 1 percent of the nation’s copper, and most of it comes from scrap metal, Costigan said. Copper is important for the production of hemoglobin in blood, and for use with enzymes dealing with heart function.

The problem with this is the condition of the scrap and how the copper is removed, since copper often shows up on components with insulation and lead. Burning away these undesirables can create dioxin; stripping copper is better. Also, scrap brass is a good source of both copper and zinc. Electronic waste components are a source of trace metals, as are scrapped jet engines (for cobalt).
Costigan estimated 80 percent of trace minerals used in U.S. animal feed comes from outside the country. The better a manufacturer understands how these metals are mined and obtained, the safer suppliers they can pick.

“The problem is, the majority of these are not driven by the feed industry,” he said. “(Does a supplier) understand about dioxin” and the effect it has on livestock?

Suppliers need to be educated how their minerals are used in feed. To an extent, so should farmers. For example, feeding the wrong food to the wrong livestock could result in rejection. Sheep hate zinc, a mineral that’s in other kinds of feed.

Unlike vitamins, mineral prices can slide up and down widely, since some are traded commodities. Feed supplement buyers have to be aware of the market and understand why prices are going up or down.

Macro minerals include calcium, phosphorous, potassium, sulfur, sodium, chlorine and magnesium. Richard Bristol, director of Nutrition and Technical Services for ILC Resources in Des Moines, Iowa, said these are in body tissue and bone. They regulate how well materials can pass through cells walls and help organs maintain homeostasis, or equilibrium.

“No minerals can stand alone,” he said. “There are many interactions among those minerals – some are synergistic; some are antagonistic,” or undesirable.

Calcium is the most abundant mineral in the body. Bristol said all diets require a supplement to meet minimum requirements. Like some vitamins, calcium might be in livestock feed but the body unable to “access” it – for example, the phytate of corn contains the mineral, but an animal body cannot break it down.

Absorption is affected by the size and solubility of calcium particles. A laying hen needs low-solubility coarse bits in her gizzard to grind food, whereas a pig needs a finer supplement (but, not too fine, since it would dissolve too quickly and go right into manure, bypassing vital organs). Also, younger animals can absorb the mineral faster than adults can.

Other well-known minerals are sodium and chlorine; together, they make salt, which helps regulate bodily fluids and blood pressure. Many understand the harm too much can do, but there is an amount every body must have. (This is true with any mineral, though some are difficult to become toxic because they can be quickly excreted – such as phosphorous and potassium.)