What mineral supplementation program is most popular among cow-calf producers? Probably, the most common approach is to buy a bagged product from a local supplier. Some producers put out mineral whenever they happen to think about it. Others are diligent, providing free-choice mineral throughout the year. However, not all producers put adequate thought into their choice of product. In some cases, the chosen mineral formulation may be inappropriate. And, in some situations, mineral supplementation might even be unnecessary.
Without a doubt, minerals are essential to the bovine diet. They are components of body fluids and tissues, so a balance of mineral elements is important to normal metabolism. Minerals play roles in enzyme and hormone action, as well as immune system function. A deficiency (or an excess) of one or more minerals can have dramatic consequences, even resulting in death. Results are more often subtle, showing up as reduced reproductive performance, diminished disease resistance or lower feed efficiency and growth.
According to South Dakota State University Professor Cody Wright, mineral nutrition is complicated. Some minerals are well researched and requirements are well understood. Others have received less attention. Questions remain relative to requirements at different growth rates and stages of production. The presence of antagonists, particularly in the case of copper, can also create challenges when formulating mineral supplements. Wright says producers can consult nutritionists or the Nutrient Requirements of Beef Cattle publication for information about mineral requirements.
However, producers shouldn’t forget the purpose of mineral supplementation is to make up for elements lacking in their animals’ base diet. The diet may supply levels of certain minerals that meet or exceed animal requirements. In such cases, supplementing those same minerals is unproductive and a waste of money. The challenge is knowing when requirements are met by diets consisting of forages and supplemental feeds. Mineral concentrations within these feedstuffs can and do vary considerably.
“An option that may help reduce costs is strategic supplementation – providing appropriate mineral supplements only during periods when nutritional needs are greatest,” says Wright. “But there is no one-size-fits-all strategy. The key is understanding what cattle are getting from the environment. That requires testing pasture, harvested forages, and protein supplements, plus the water.”
In some circumstances, explains Wright, the need for supplemental minerals may be minimal while cattle are grazing pastures during the growing season. Even during drought, the mineral content of grazed grasses and forbs may meet cattle requirements, provided sufficient forage is available. In fact, drought conditions may result in forages with higher concentrations of nutrients, including minerals. That is not always the case, warns Wright, and producers can’t know what nutrient levels actually are, without testing forage samples.
Producers should not assume that winter pastures or harvested forages are low in minerals. Testing may show forages contain adequate or nearly adequate levels of calcium, potassium, sulfur, and iron. Phosphorous is a high-cost ingredient in any mineral supplement, but levels present in early-season forages may meet requirements for lactating cows. When cut for hay, summer annuals like Sudan grass or millets, and cereal crops like oats, triticale and barley, often satisfy dry cow requirements for phosphorous.
Forages alone could fall short of satisfying requirements, but protein supplements also contribute minerals to the diet. Again, phosphorous makes a good example. Corn co-products and commercial supplements containing co-products, such as dried distillers’ grains, typically contain relatively high levels of phosphorous.
“Even a diet of low-quality forage plus protein supplement could meet requirements for several minerals, but especially phosphorous. In many cases, there may be no need for the 12:12 mineral (12% phosphorous and 12% calcium) product many producers commonly use,” says Wright, noting how many suppliers offer less costly low-phosphorous formulations.
“I know quite a few producers that get by with only white salt for three to four months of the year, and sometimes up to six months, by strategically supplementing mineral only when it’s really needed,” Wright adds. “Some producers save money by using customized mineral mixes to provide certain minerals deficient in the base diet, but avoid over-supplying others.”
Wright cautions producers to remember that forages are most apt to be deficient in trace minerals, such as copper, zinc, manganese and selenium. However, mineral concentrations are highly variable. Soils in certain areas can have deficiencies in specific trace minerals. Assuming dietary levels of other minerals are adequate, such deficiencies might be met by feeding trace mineralized salt. Some situations may call for a more focused mineral supplementation program.
“Use of an injectable trace mineral source also can have merit in some situations,” adds Wright. “Particularly if cattle have gone through a period of low mineral consumption, an injectable product may be of value.”
For most operations, mineral deficiencies can be addressed by feeding an appropriate mineral supplement. Wright warns that cattle do not exhibit “nutritional wisdom” with regard to minerals. They may over-consume or shun mineral supplements. Cattle do have an appetite for salt, however, and will regulate intake according to need. Consequently, mixing mineral with plain salt is a way to maintain intake at a desired level.
In many cases, mineral supplementation may only be required from 45 days prior to the start of calving until the end of the breeding season. That, says Wright, is the period of time when a breeding female experiences her greatest demand for nutrients, combined with the stress of calving. Whether mineral supplementation beyond that period is warranted depends on the levels of various minerals available in her diet.
“You don’t really know unless you sample everything and have it tested, including the water,” says Wright. “That requires spending some money up front, but it may save money in the long run.”