A study of the effects of copper deficiency in Scottish blackface lambs on improved hill pasture.

One member of each pair of twin lambs from 37 five-and six-year-old Scottish blackface ewes, grazing reseeded pasture suspected of causing a molybdenum-sulphur induced copper deficiency in sheep, was given an injection of 12.5 mg copper calcium edetate at about eight weeks of age. Plasma copper concentrations of these lambs were maintained in the normal range by further injections of copper as required (treatment group). The remaining member of each twin pair received no copper therapy (control group). The control lambs and all ewes showed marked hypocupraemia throughout lactation, whereas the plasma copper concentrations of the treatment lambs, and also of single lambs with continuous access to unimproved hill grazings, remained normal. The live-weight gain of the treatment lambs was significantly greater than that of the control lambs, the difference in mean live-weights after 12 weeks being 2.5 kg. All lambs showed some degree of osteoporosis; this was most severe in the control lambs which had less dense bones and were also more susceptible to bone fractures and to disease. Differences between treatment and control lambs were also observed in haematological parameters and in fleece characteristics.