Reduced performance, lethargic calves, retained placentas, skin and hoof ailments, and other health complications can many times be linked to mineral interactions. Interactions can result in one mineral restricting the bioavailability of another mineral. Subsequently, this can lead to deficiency. Another way to put this is: An excess can cause a deficiency.

Meteer travis
Beef Extension Educator / University of Illinois

One of the most common mineral interactions in beef cattle is the interaction between calcium and phosphorus. Generally, calcium and phosphorus levels are recommended in a ratio (Ca to P). Ideally, a ratio of 2-to-1 is targeted. Cattle can handle slightly lower Ca-to-P ratios; however, when the ratio becomes inverted, or more phosphorus is provided than calcium, steer cattle can be at risk of urinary calculi (also known as water belly). A prolonged period with a Ca-to-P imbalance in young cattle can interfere with bone growth and decrease overall performance.

Many corn co-product feeds, such as distillers grains, are high in phosphorus. In cases of high levels of calcium and phosphorus in the diet, other mineral requirements for magnesium, manganese, iodine, sulfur, iron and zinc will all increase.

The relationship among copper, iron, molybdenum, sulfur and zinc is another crucial mineral interaction. These minerals can all influence the bioavailability of each other. High levels of zinc, iron, molybdenum or sulfur can all interfere with copper availability. Copper deficiency is one of the most common mineral problems across the country.

Do you have hard water? Are your cornstalk bales dirty? Did your hayfield get flooded before you cut and baled it? These are all likely suspects for more iron in your cattle rations. Iron is really good at reducing the availability of crucial trace minerals.


Are you feeding distillers grains or ethanol co-products? These feedstuffs are higher in sulfur. High sulfur levels in the ration will bind trace minerals, especially copper. Cows that suddenly have red-tinged hair coats are likely experiencing copper deficiency.

Selenium deficiency is a problem in the Midwest. Selenium and vitamin E are generally used in conjunction to supplement against selenium deficiency. This is because both selenium and vitamin E work along the same lines in the body to prevent hydroperoxides. Administering selenium and vitamin E together is a good supplementation strategy to combat selenium deficiency.

It is important to not overlook the obvious: mineral consumption. Even the correct mineral formulation doesn’t solve the problem if the animal doesn’t consume it – make sure you are monitoring consumption. Most mineral supplements are formulated to deliver appropriate nutrition at 4 ounces per head per day. A 50-pound bag of mineral should last 20 cows about 10 days. Moving the mineral feeder closer to the water source, the animals' path or shade can increase mineral consumption.