Managing the nutritional needs of beef cows is a complex task with nuances that producers need to learn about in order to establish optimum cow health and herd profitability.
Kansas State University Research and Extension beef specialist Chris Reinhardt says that means paying attention to the need for trace elements such as copper, zinc, selenium, manganese and cobalt as well as macro minerals such as calcium, phosphorous, sodium, chlorine, potassium and magnesium.
The entire sum of minerals are important building blocks of bodily functions and processes, Reinhardt says, and producers need to be sure their feeding and supplemental regimen supply every cow with what she may need during crucial periods throughout the year.
The need for trace minerals is measured in parts per million rather than percentages like the macro minerals, Reinhardt said. Some of these minerals are stored in the liver or other tissues during times of plenty for use during times of deficiency.
“We need to be aware of the mineral balance in the forages a cow might be consuming, and we have to be aware of the demand that cow has for those minerals,” he said.
He outlined a scenario where a cow may have different needs: “Calcium is being drawn out in milk during lactation. Copper and zinc are used heavily for reproduction, during the gestation and during immune challenges. The needs of the cow change throughout the year, and the supply of minerals available changes tremendously throughout the year as well. Our job as producers is to make sure we are matching what the cow has access to with what her needs are.”
Clinical deficiencies of minerals occur when a required mineral has been deficient in the diet for an extended period of time, Reinhardt said. Producers can see these deficiencies in obvious outward symptoms showing the animal is lacking a mineral or minerals.
He cited a classic example: “In the 1930s, we didn’t always supplement phosphorus to cows in the western range states. When cows become extremely phosphorus deficient, they will chew bones.”
One of the clinical signs that indicates a cow is extremely deficient of phosphorus is she will not breed or have a calf. A cow cannot reproduce without adequate phosphorus.
“However, in between adequate status and clinical deficiency is what we call subclinical deficiencies,” Reinhardt said. “These are where most of the deficiencies occur in the U.S. beef industry.”
For example, he said cows could be marginally copper deficient when they seem to produce well, but maybe their fertility doesn’t quite match up to the producer’s expectations. In this case, the herd overall may be calving on time, but one cow that didn’t calve as expected. The cow in question may have looked fine and had access to the same food sources as the rest of the herd. This is why subclinical deficiencies are often difficult to detect and require a close watch.
Management tips to help producers
“The first step is to assess the needs of the animal,” Reinhardt said. “For instance, a gestating cow requires different levels of calcium and phosphorus than does a lactating cow. When that cow is in the peak of lactation, we have to ensure the cow has access to adequate macro and trace minerals.”
“The second step of developing a strategy is assessing what is available to the animal,” he continued. “For example, we’ve had abundant rains throughout Kansas and much of the western United States. In the spring when we have adequate rainfall to produce abundant, lush forage, the forage alone is adequate in phosphorus to meet most of the needs of a lactating cow. However, as that forage matures into summer months, phosphorus content will decline to well below the needs of a lactating cow.”
This is where producers need to intervene and ensure adequate provisions are made not only for calcium and phosphorus, but also many of the trace minerals.
To determine the mineral content in the available forage, producers may initially want to have forages analyzed for mineral content, he said. Then, producers can work with their veterinarians or beef nutritionists to determine a supplement that fills the gap.
“One mineral concept”
According to Reinhardt, many producers use the “one mineral concept,” where they buy a mineral that meets most of the animals’ needs most of the time. When the cattle eat it adequately and predictably, the producer simply leaves the mineral out year-round. During times of the year where the cattle’s needs may be lower, such as spring when there is ample high-quality forage available, they may eat only a little or none of that one mineral.
“As the grass quality declines you will notice an increase in the consumption of that mineral,” Reinhardt said. “In the fall or winter when we are supplying supplemental feeds, such as soybean meal, distillers grain and good-quality hay, the cattle may go back to a period where they may not be eating a tremendous amount of mineral.”
Another option is using different mineral formulations during different times of the year.
“If you’re feeding wet distillers grains and high-quality hay, you may have a need for calcium and trace minerals but not a tremendous need for supplemental phosphorus,” he said.
There may be a better option when doing a mix feed with a force-feeding situation. During the summer, a producer needs a mineral that works with the forage. Also, it is highly important that the cattle will eat independently in a predictable manner.
Deciphering mineral labels
Mineral labels are subject to law that states if a mineral ingredient is included in a product, there are certain items that must be included on the tag, which is the first place producers should check, Reinhardt said. Pay close attention to levels of phosphorus, calcium, salt, potassium, copper and selenium.
Adequate selenium is important in beef cattle diets, but it is highly regulated by the federal government, as it is toxic to humans and livestock at high levels. Because soils and forages in parts of the United States have low levels of selenium, it is important that producers make sure cattle are getting adequate selenium.
If copper is included in the product, it must be at a guaranteed minimum level on the label. There are many areas of the United States during various times of year where copper is deficient in the soil and in the forages, so Reinhardt said make sure to have a formula that works well with the geography.
Don’t put off the minerals
Cattle producers are often extremely busy, but a good mineral program should remain important, the beef specialist said: “A rancher always has about a hundred different things to do daily. Occasionally, the mineral formula works its way toward the top of the list.”
Even then, determining how much cattle are consuming is often overlooked. Information on the mineral tag sometimes includes a recommended range of consumption. Depending on the animals’ needs, geography and pasture conditions, cattle may not eat the predicted amount of the mineral. In that case, it’s possible their mineral needs are not being met.
“We want to ensure that we have the right formula for the cattle,” Reinhardt said. “If they’re not eating the mineral, we have to go back to the drawing board and find a product the cattle will eat.”