Trace Mineral Nutrition

Knowledge Nuggets

• Most feed grown in Canada is deficient in copper, zinc, selenium, cobalt, iodine and manganese for beef cattle. These minerals are required in trace amounts but have huge impact on animal health, productivity and reproductive capability.

• Many symptoms of deficiency have been identified but are often inconclusive as cattle may exhibit a wide range of symptoms depending on the severity and the length of time the animals have been deficient. Most symptoms are of sub-clinical nature.

• Diagnosis of trace mineral deficiencies can be very difficult. Most of the work has been done with individual elements and the effects of multiple trace element deficiencies have received little attention.

• Improvements in reproductive performance of cows and heifers occur with adequate trace element supplementation where cows conceive earlier in the breeding season resulting in increased weaning weights and fewer open cows.

• Copper, zinc, manganese and selenium are required for optimum functioning of the immune system in cattle. This suggests that adequate supplementation of these trace elements would be beneficial in helping the cow and her calf cope against disease stress.

• Some evidence suggests that more selenium is required to optimize immune function than is required to prevent white muscle disease, retained after-birth and other problems commonly associated with deficiency of this element.

• Selenium requires adequate amounts of vitamin E to improve immunity. One will not function without the other.

• Trace element nutrition is extremely complicated. Many complex and poorly understood interactions occur between the trace elements and between trace elements and other nutrients. In addition, the quantity of trace elements needed is very small and are toxic if fed in excess. For these reasons, trace element nutrition should be done in consultation with a qualified nutritionist.

• The benefits of trace mineral supplementation outweigh the relatively small cost of feeding a trace mineral supplement.

• Feed testing is the easiest way to determine which minerals are low in the feed and what levels are required to overcome shortages.

• To promote consumption of unpalatable mineral, mix the salt and mineral and feed this combination as the only source of salt.