Minerals are an essential nutrient for beef cattle. If minerals are not consumed in the diet, deficiencies can occur. At the same time, overconsumption of certain minerals can result in toxicity. Providing the proper balance of each mineral without overconsumption is necessary for optimal performance, as minerals are essential for supporting growth, reproduction, lactation, and health.
The eighth revised edition of Nutrient Requirements for Beef Cattle, published in 2016 by the National Academies of Sciences, Engineering, and Medicine, identified 17 minerals as essential for beef cattle. Minerals are further classified into two categories based on how much is needed by the animal. Macrominerals are needed in a higher quantity (parts per hundred or percent) compared to microminerals or trace minerals (parts per million [ppm] or milligrams per kilogram [mg/kg];
Mineral Function
Minerals have a variety of functions in the body, but in general, they help support all tissues and major metabolic processes
required to maintain beef cattle performance. Minerals play essential roles in the immune system, connective tissue and
muscle, digestion, metabolism of feed, and both male and female reproduction. Further details regarding the functions of specific minerals are shown in Table 2.
As with other nutrients, such as protein and energy, performance can decrease when mineral intake is low. However, certain processes are affected more quickly than others. For example, immunity is affected before growth or fertility. As mineral intake decreases, initial losses in performance are difficult to measure and can often go unnoticed. In cases of severe mineral deficiency, symptoms develop quickly, and decreases in immunity, fertility, and growth may be noticed throughout the herd in a relatively short period of time. Grass tetany, a disorder caused by hypomagnesemia (abnormally low magnesium concentration in the blood), is an example of how quickly a deficiency can lead to a noticeable impact.
Cattle Mineral Requirements
The latest beef cattle mineral requirements are published by NASEM in the 2016 edition of Nutrient Requirements for Beef
Cattle. Mineral requirements are based on peer-reviewed scientific literature and updated periodically. They are defined as the
minimum concentrations of each mineral that must be consumed to prevent deficiencies. Current mineral requirements for selected classes of cattle are shown in Table 3.
Most mineral requirements are similar across classes of cattle. For example, a growing steer, mature bull, and lactating cow all have a zinc requirement of 30 ppm. Exceptions to this include calcium, phosphorus, and manganese, which have varying requirements across classes of cattle. Stressed cattle have increased mineral requirements compared to other classes, partly due to their lower feed intake and circulating corticosteroids, or stress hormones, which can impact mineral usage and recycling in the body. Thus, feeding a more concentrated mineral product during stressful periods can compensate for decreased intake from the feed. Elevated diet concentrations are not needed for long periods of time (five to seven days). Research indicates that once intake returns to pre-stress levels, no benefit is noted for higher diet concentrations.
Although research has shown some differences in mineral utilization across different breeds or breed types (for example, Bos taurus versus Bos indicus), these differences have not been shown to change the minimum requirement to prevent deficiencies. Thus, minerals currently are not formulated to be breed or breed-type specific.
The Mineral Content of Feedstuffs
All feedstuffs contain minerals; however, most feedstuffs are not balanced and are deficient in one or more essential minerals (Table 4). Mineral content can also vary significantly within a given feedstuff. Additionally, little is known about the potential availability of minerals contained in feedstuffs to the animal. Therefore, it is often recommended to feed beef cattle a complete mineral supplement that contains 100 percent of the animal's requirement of certain minerals to overcome any potential deficiencies in concentration or availability. Exceptions to this practice include minerals such as potassium or iron that are routinely supplied at two to three times the animal’s requirement in forages.
Forms of Mineral Supplementation
Several options exist for supplying supplemental minerals to cattle, including blocks, tubs, free-choice loose supplements, injectable products, and complete feeds. While multiple forms of supplementation are available, it is crucial to recognize that not all forms are equal in terms of the concentration and source of minerals supplied.
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