Use of cupric oxide needles in the prophylaxis of induced copper deficiency in lambs grazing improved hill pastures.

Cuprix oxide needles as a single oral dose were administered to ewes in the prepartum period, and to one member of each pair of twin lambs at between three and five weeks of age when grazing hill pastures improved by liming and reseeding. Lambs derived from dosed or undosed ewes and treated at three to five weeks of age were maintained in normocupraemia and showed no signs of ill-thrift. Lambs derived from dosed or undosed ewes but not themselves dosed showed hypocupraemia and ill-thrift. The lambs derived from the dosed ewes took longer to become hypocupraemic, but showed only a transient benefit from the ewe treatment. The dosed ewes showed a delay in the onset of hypocupraemia compared with the undosed ewes but there were no definable differences in performance between the two groups.