Adequate trace mineral supplementation is important and essential, particularly during stress periods of a cow's production cycle such as pre-calving, pre-breeding and pre-weaning, says John Paterson, Montana State University Extension beef specialist. It's also shown positive effects on reproduction, immune status, disease resistance and feed intake of incoming feeder cattle.

Other research indicates that cows calving in a good nutritional condition produce better colostrum, and their calves suckle more quickly and have more vigor than calves from mother cows with poor body condition scores.

"Trace mineral supplement is an important ingredient of any management approach," Paterson notes. "However, it's only part of a program to provide balanced nutrition with emphasis on supplying adequate protein, energy and trace minerals to prevent loss of beef cattle productivity," Paterson says. He was one of several specialists updating producers at the recent Cow/Calf Health and Nutrition Symposium in Fayetteville, AR.

Beef cattle need macro-minerals such as calcium, phosphorus, salt and magnesium, but also copper, selenium, iron, cobalt and zinc, according to Arkansas Extension livestock specialist George Davis.

Davis says its critical that producers be aware of the specific nutrient deficiencies in their area and provide adequate levels. Arkansas, for instance, tends to be deficient in copper, zinc and seleniun, all of which are associated with immune function in cattle. But a lot of land fertilized with poultry litter actually has high levels of copper and zinc, he adds. That's why it's so important to know your ranch's nutritional profile.

How do you determine your trace mineral needs? Analyze forages first, then where your water comes from.

"Shallow wells and ponds tend to have higher levels of sulfate than deeper wells, for example," Paterson says.

If your forages and water are okay and things still don't seem right on the ranch, consider doing a liver biopsy as a last resort, Paterson suggests. This is a costly procedure - $35-40 each - but biopsies on 10% of a cow herd will give you a representative sample.

He doesn't normally recommend it as a routine practice, however. "If I've supplemented my cows correctly, and water and forages are good, and I still get scours, or reproductive or respiratory problems, I might say, 'Let's do a biopsy,' " Paterson says.

Whether to use a blend of organic or inorganic minerals depends on what the forage and water samples indicate, Paterson says.

"If you have high levels of iron, molybdenum or sulfur, then I would recommend use of a blend of inorganic and organic trace minerals," says Paterson. "I would do this rather than increase the total amount of inorganic minerals. In reviewing several studies, I really haven't seen justification for over fortification of the diet with inorganic trace minerals. In general, organics do have higher bioavailability than inorganic trace minerals."

Here's what specialists suggest for efficient use of trace minerals:

Phosphorus Phosphorus is a tough one to grasp because a cow's needs and available phosphorus in forages vary drastically depending on the time of year and location of your operation, Paterson suggests. The content is usually higher early in the spring when grass is green and lush, but drops when it gets hot in the summer.

"In poultry raising country like Arkansas, there probably is too much of this mineral," adds Jeff Hill, beef nutritionist for Farmland Industries Inc. "But in other parts of the country, additional phosphorus may be needed."

Test your well water if that's your source for cattle, Hill suggests. "Take forage samples periodically," he adds. "If you can't collect samples, consult your local or state Extension service."

Be sure to consider what the calves in your herd eat, suggests Hill. "They need minerals, too," he says. "Above all, a cow's phosphorus needs vary during her production cycle. If you're on the ball, this gives you a chance to save money."

Phosphorus is the most costly nutrient added to a mineral supplement, according to Hill. "But there are ways you can save money, yet provide adequate phosphorus."

For a long time, the industry revolved around a 12% phosphorus (P) mineral, Hill notes. But you don't always need that much, offering opportunities to save sizable dollars on mineral costs.

For example, a cow's supplemental phosphorus needs range from 6% to 16% through her production cycle. Note that recommended P levels are at 16% for high milking cows during lactation while forage P levels range from 0.05% to 0.15%, says Hill.

Yet only 6% levels are adequate during the maintenance period, especially when forage P levels are liberal. This also reduces environmental contamination, he adds, and offers sizable savings in mineral supplement costs.

"A rule of thumb is that every one percent change in P changes the cost per ton of a mineral supplement by $11," he says. "Feeding 12 percent P when you only need six percent costs you more than $60 per ton."

Magnesium Magnesium is most important for lactating animals, but can be a concern in stocker or growing animals because of the threat from grass tetany, caused by low blood magnesium. Rapid forage growth is the problem, where nitrogen, calcium or organic acids can cause antagonistic effects that reduce absorption of this mineral. Hill recommends feeding 8-10 grams/head/day from readily available magnesium sources.

Copper And Zinc Copper and zinc are deficient in many forages. Add the antagonistic effects of copper availability from excess sulfur, iron or molybdenum, and it is the most common deficiency of any mineral in breeding cows, Hill says.

"A copper deficiency can reduce growth rate, but it's hard to measure. It also decreases disease resistance because animals either don't eat enough copper or are exposed to antagonist minerals," he says.

Paterson recommends maintaining a ratio of four parts copper to one part molybdenum in the ration. "If impossible, this might be a case where a blend of inorganic and organic copper is required," he says.

Based on state and national surveys, it appears that zinc is often deficient in many forages, notes Paterson. Attention should be paid to forage analyses because supplemental zinc is often required.

"Dramatic help can come, particularly from organic zinc, to prevent foot rot," he adds.

Based on Montana research, Paterson recommends a trace mineral supplement that has a ratio of four parts zinc to one partcopper. Single element supplementation may not be as effective as providing a balanced trace mineral supplement.

Don't Forget Salt Beef cattle need salt, which contains sodium and chlorine. They are usually inadequate in forages, so you need to provide salt year-round, suggests Davis. Salt deficiency can retard growth, cause weight loss and lower milk production.

Hill recommends feeding free choice salt in areas where mineral intake may be high. "Cows crave salt but they don't know what is the proper amount," he explains. "That's why I like to have people put out free choice salt and try to get them another salt source so mineral intake can be controlled."

How does the feed tag help you get the best value for your money when you buy trace minerals?

Jeff Hill, Farmland Feeds, has these practical suggestions:

* The more guarantees listed on a tag, the better. "If there's not a guarantee with hard fast numbers, I wouldn't count on it being there," Hill says.

* Know how available to your cattle each listed ingredient is. Look at both the content and ingredient panel at the same time to get the answer.

Ingredients do vary. Copper is a good example. "The tag may say 'copper 1,300 ppm,' " Hill notes. "You check and find the only form of copper listed is copper oxide, which is not very available. So the value of copper listed on that tag is pretty low."

* Don't let the color of the mineral supplement fool you.

"Most of them are red and brown in color due to the addition of iron oxide which has no value to the animal," Hill notes. "Don't buy a brand just because you like its color."

* Try to keep trace mineral ratios as constant as feasible. Overfeeding copper relative to zinc, for example, can be as bad as underfeeding.

* Compare costs relative to what is being supplied to the animal. Don't buy a brand based only on cost per ton or per bag.

"Save money by matching supply to actual needs," Hill concludes.