The Absorption of Copper and Zinc by Cattle Consuming Diets
 Containing the Antagonists Molybdenum, Sulfur, and Iron

Table 1. Classification of trace elements relative to their ability to meet either dietary requirements or cause an antagonistic problem with other trace elementsa.

Trace Minerals Deficient,ppm Marginal,ppm Adequate,ppm
Copper <4 4-7 7+
Manganese <20 20-40 >40
Zinc <20 20-40 >40
Cobalt <0.1 - 0.1-0.25
Selenium <0.1 0.1-0.15 0.15-0.3
Copper: Molybdenum Ratio <4:11 4-4.5:12 4.5-5:12
Trace Mineral

Antagonist

Iron

50-200

400
Molybdenum

<1

>3

a Adapted from Corah & Dargatz (1996)
1 Ideal Copper:Molybdenum ratio.
2 Copper:Molybdenum ratio greater than four can cause copper "tie-ups".