Copper deficiency has been diagnosed in beef cattle herds in many areas of the intermountain west. Copper supplements are not widely used, even though several products are available. It is difficult to correct a deficiency because too much copper can result in copper toxicity or poisoning. Toxicity is less a hazard with cattle than with sheep, but it is still a problem to guard against. Periodic monitoring of the herd’s copper status is essential for proper supplementation.
Bagley, Clell; Stenquist, Norris; and Worwood, Dennis, "Clinical Trials with Copper Supplementation" (1997). All Current Publications. Paper 409.