Mineral programs with copper recommended for cattle on Wyoming rangelandsWritten by Natasha Wheeler
A balanced mineral program can be complex, and each situation should be evaluated carefully when issues arise. In Wyoming, copper is one of the minerals that can become deficient in the diets of grazing cattle.
“Copper is a trace element that is important for cattle. It’s important for the immune system and for metabolism,” comments Steve Paisley, University of Wyoming Extension beef specialist. “Copper and zinc are probably the two trace minerals that western rangelands are typically deficient in.”
Most commercial mineral programs include some levels of copper, although there are a few points throughout the year where adequate levels may be especially important, such as calving through rebreeding and prior to weaning.
“Making sure we have good adequate mineral available to our animals 60 days before weaning is key because copper is so important from an immune status standpoint,” he mentions.
Looking for deficiency
Traditionally, a copper deficiency could be recognized by a reddish tint in an animal’s hair color, but that may not always be an accurate indicator.
“My approach is to look for anything out of the ordinary,” notes Paisley.
Abnormally high levels of illness, low rebreeding rates, poor calf health or other issues that don’t seem to be related to poor nutrition or management may be signs of imbalances in mineral intake.
“An initial way to test for deficiency is to sample the forages,” he says. “When we do that, we try to mimic the diet the cattle are taking in, so we can test the forages and evaluate whether they are meeting nutritional requirements.”
Paisley suggests sampling the top third of grazed forages, which is the portion of the plant that the cattle typically eat. Samples should also be collected in areas where the animals usually graze and include the desirable species that are normally ingested by the cattle.
“We should also probably test the water to get a good idea of whether or not our mineral program is complete,” he adds.
If forage and water samples fail to provide a better understanding of mineral issues, liver biopsies can also be used to help evaluate copper levels in the herd.
“Liver biopsies involve making a small incision on the side of the animal and using a hollow needle to remove a small tissue sample with minimal impact to the animal,” he describes.
Because challenged animals can sequester copper, Paisley recommends sampling healthy animals from the main herd to ensure accurate results.
In Wyoming, one of the issues producers also run into is a secondary deficiency. A secondary deficiency occurs not when copper levels are too low but when competing mineral levels are too high, making it difficult for animals to absorb the copper.
“We can run into that with iron, high sulfur or molybdenum. By forage sampling and testing the water, we can get an idea of whether or not we have adequate copper and also if we have other elements that may be competing with copper and causing a secondary deficiency,” Paisley explains.
If one of these issues is detected, a mineral program with adequate copper levels may be sufficient, although a more extreme case may require looking into copper sources that are easier to absorb.
“Minerals that have compounds attached to them, know as organic or chelated minerals, cause more complete absorption,” he mentions.
Chelated minerals have been combined with organic compounds to create complexes, and they represent one of the many kinds of sources that increase the biological availability of minerals for livestock.
In Wyoming, too much copper isn’t much of a concern in cattle, but sheep are another story.
“While sheep still have a requirement for copper, they tolerate much lower levels than cattle do. We can’t feed a cattle mineral to sheep without some major issues because sheep have a real toxicity problem with copper,” warns Paisley.
Producers who place mineral in areas where sheep may have access to it should exercise extra caution to prevent harming the sheep.
Paisley also suggests looking for a second opinion when mineral deficiency or secondary deficiency issues arise.
“What’s available, what’s absorbed and any interactions that may exist – those are all important things to consider. It is good to have a few opinions from other people to help make those decisions,” he comments, adding that local veterinarians, nutritionists and university or Extension personnel are always good sources for producers seeking more information.