- poisoning (toxicity) is most often the result of copper-molybdenum imbalance in feed. Excessive dietary intake of molybdenum produces secondary copper deficiency. Ruminant species are most frequently affected, and clinical signs may include poor growth, infertility, diarrhea, lameness, ataxia, as well as osteoporosis. Copper supplementation to address the mineral imbalance is the most effective treatment.