July 11, 2001

Choosing the right mineral supplement for a beef cattle herd requires a cattleman to do a little homework.

There are many companies and many formulations making the possibilities nearly endless, said Roy Burris, University of Kentucky Extension beef specialist. Many of these supplements can also be expensive, but good mineral supplements can be found at a reasonable price, he said.

Some producers choose to mix their own supplement but Burris said they should be cautious in doing so.

"Although many of the trace elements that we are dealing with are necessary, they must be mixed in very small amounts and can be toxic at higher levels," he said. "Most producers are not equipped for this level of accuracy."

Producers choosing a commercial product need to read and understand the feed tags on the bags, something that is not always easy, Burris said. Ingredients, especially trace elements, may be listed as percentages, parts per million or even milligrams per kilogram. Milligrams per kilogram and parts per million are the same thing and you can change percent to parts per million by moving the decimal four places to the right.

You aren't likely to find a lot of agreement from field representatives or even nutritionists on what levels of various minerals and vitamins should be in a supplement, he said. It depends in part on the cattle's diet, the type of cattle being fed and the level of intake.

For the past 10 years, researchers have been formulating a mineral mix for beef cows grazing fescue at the UK Research and Education Center in Princeton. Production, blood and liver levels of trace elements have been monitored.

This formulation is also being used by many Integrated Resource Management (IRM) beef herds in Kentucky so it is available and should be moderately priced, Burris said.

A range of minerals/vitamins that might serve as a guideline for producers is suggested by Burris. This guideline includes the following suggested ranges: salt, 20 to 28 percent; magnesium, 2 to 18 percent; calcium, 7 to 12 percent; phosphorus, 3.5 to 7 percent, copper, 1,000 to 1,500 parts per million; zinc, 2,000 to 4,000 ppm; selenium, 25 to 50 ppm; iodine, 40 to 100 ppm; cobalt, 10 to 20 ppm; manganese, 2,000 to 5,000 ppm; vitamin A, 200,000 to 300,000 international units per pound; and vitamin E, 100 to 500 units per pound.

For grass tetany control, Burris said levels of salt and magnesium should be changed to approximately 15 percent each prior to and during the tetany season.

Other ingredients such as yeasts, thiamine, antibiotics, insecticides, and growth promotants can be included such as chlortetracycline for anaplasmosis control and ionophores for increased growth/efficiency. The extra cost of additional ingredients should be weighed against the benefits.

Some products imply by their name they are beneficial for high endophyte fescue but claims for controlling fescue toxicosis are largely unsubstantiated, Burris said.

Whenever, a producer is considering a particular mineral feed, they should check the feed tag for all ingredients and ask the store representative to obtain the level of any ingredients that are not listed.

Also, Burris said, producers should avoid high levels of iron as it may interfere with the utilization of other minerals, and avoid products using copper oxide because the availability is very low.

Finally, producers need to resist the temptation to "cut" the cattle's mineral mixture with plain salt to decrease consumption - they are supposed to eat it.


Roy Burris, (270) 365-7541