Copper oxide needles for cattle: a comparison with parenteral treatment

Two trials of oral copper oxide needles for cattle are described. In one, a dose of 13.0 g copper oxide/100 kg liveweight in yearling bullocks was compared with parenteral copper at a total dose rate of 400 mg copper. In the second, three oral dose rates (3.5, 7.0 and 10.5 g copper oxide/100 kg liveweight) in calves were compared over two years with a total dose of 500 mg parenteral copper. In both trials liver copper values reached a peak at about six weeks after oral dosing and in the second trial the peak was dose related. Thereafter liver levels declined in all the oral treatment groups; normal levels of more than 30 mg/kg liver dry matter were maintained for 30 weeks in the first trial and for 40 to 47 weeks, depending on dose rate, in the second. In both trials repeated parenteral treatments were required to maintain liver levels within the normal range. The results support earlier findings that an adequate dose of copper oxide needles can maintain the copper status of cattle for periods of at least six months.