Many sheep may require supplementation with cobalt or selenium, whilst many also require copper for the prevention of swayback. Often more than one are in short supply and blanket supplementation is often the answer, but this could result in problems of toxicity especially with copper in sheep. This trial was carried out on a flock known to be copper sufficient to investigate the supplementation of extra copper in the form of a sintered soluble glass bolus being used to supply selenium and cobalt to the flock.

Two batches of Lleyn sheep were selected, the first were forty ewe lambs, whilst the second set were thirty gimmers. The ewe lambs were randomly split into two groups one being given a copper, cobalt and selenium bolus (Cosecure®, Telsol Ltd) with the other group remaining untreated as controls.