Dennis Bauer: Testing forage for minerals can keep dollars in your pocket

Gayle Smith

As cattle move to grass in the region, beef producers have an opportunity to save money on their mineral program.

“Many mineral requirements can be met through what cattle are already being fed,” said Dennis Bauer, a University of Nebraska extension educator.

“The bottom line is to test your feed supply for mineral content, including protein and energy supplements,” he explained. “Then consider a custom mix mineral to meet your cowherd’s requirements.”

Bauer said that phosphorus is the most expensive part of most mineral programs. Data from several states over the last 20 years is conclusive that phosphorus levels in most forages are adequate for a dry cow, and usually for a lactating cow – especially if the cow is supplemented with something like distillers’ grain, according to Bauer.

On the other hand, copper and zinc are usually deficient in most forages. “Only about 50 percent of the cow’s requirements for copper is supplied by the forage, and 50-65 percent for zinc.”

When forage is tested, the analysis takes into account that 100 percent of the mineral in a forage will not be utilized by the cow, Bauer said.

“Mineral requirements for calcium, potassium, sulfur, iron and manganese are met 90-100 percent of the time, based on the forages that have been tested,” Bauer said. “The requirement for selenium supplementation is dependent on the region of the country. In some cases, there is a problem with selenium toxicity. In north central Nebraska, selenium levels were found to be adequate in the forages tested.”

Testing for cobalt and selenium can be expensive, Bauer said, therefore not much research is available. “I would encourage producers to test their feed if they are concerned about it, or if they think they have a production problem,” he said.

Bauer said there are producers who spend over $1,250 a ton on mineral supplementation, which amounts to $42.70 per day if the animal consumes 3 ounces each day. Bauer said ranchers should do what they can to keep mineral costs around $250 to $450 a ton, which can still meet the animal’s requirements without hurting their reproductive performance.

“It is hard to find concrete evidence from research … that would support that supplemental mineral programs have increased productivity or reproductive performance in cows,” he said. “The majority of the studies that have been done are inconclusive.

“It is possible to keep mineral costs as low as $5 per head, per year,” Bauer said. “If you are spending over $15 to $20 per head, per year on mineral, you might want to get a second opinion.”

Once producers determine which minerals their feed is deficient in, the extension educator encouraged them to take bids from feed producers to custom mix a mineral. “Don’t be afraid to ask more than one feed salesman for a bid,” he said.

Bauer also said ranchers need to eliminate over consumption of mineral, and feed mineral only when the animals need it, which is generally late summer through winter months. “Cows don’t need to eat mineral every day,” he said. “Research has shown that only 85 percent of the cows will eat mineral. Of the ones that do eat mineral, don’t let them over consume it,” he said.

“When pastures are lush and green in early spring and summer, grass can nearly meet all the animal’s requirements without any supplementation,” Bauer said. “We have some producers who feed mineral from late August or early September through April, and then just feed salt through the summer months. They get by just fine,” he said.

Distillers’ grain and cornstalks can be an excellent source of protein and energy, in addition to being high in phosphorus. It can be a good choice through the winter months, he added. “It has proven to be an excellent feed source of growing cattle with no negative associative effects on forage digestibility.”

In an example for a 1,200-pound dry cow, Bauer showed a base forage of 6 percent crude protein (CP) and 50 percent total digestible nutrients (TDN). The requirements for the cow were 1.8 CP, 13 TDN, and 19 phosphorus. By feeding the cow 23 pounds of the base forage and two pounds of dry distillers’ grain, the cow met her requirements by consuming 2.0 CP, 13.5 TDN, and 23 phosphorus.

In another example with a 1,250-pound cow, 200 days pregnant, Bauer showed how consuming 23.8 pounds of cornstalks and two pounds of dry distillers’ grain still made the cow deficient in copper and zinc. By supplying the two minerals in a pellet or cube with dry distillers’ grain, Bauer estimated it would cost $1.70 per ton to add the two minerals to the cake, and provide free-choice salt. Another alternative is to custom mix the salt, copper and zinc into a mineral mix that he estimated would cost $155.60 a ton. “If you feed that at 2 ounces per day, it will meet the cow’s requirements for copper and zinc for less than a penny a day per head,” he said.