The rôle of the breed of dam and of the breed of lamb in determining the copper status of the lamb. 2. Under a dietary regime moderately high in copper

Abstract

ABSTRACTThe relative importance of the breed of dam and the breed of lamb in determining the copper status of the lamb was investigated by transferring embryos reciprocally between Scottish Blackface and Welsh Mountain ewes. A diet moderately high in Cu (8 mg/kg dry matter (DM)) was fed both to the ewes from mating onward and subsequently to their lambs.At birth, 9 and 24 weeks of age the concentration of Cu in the liver of lambs was the same for the two maternal breeds but within breed groups there was correspondence between full sibs when they were born to the same dam.By 9 weeks and at 24 weeks of age Welsh lambs, irrespective of their dam's breed, had greater concentrations of Cu in liver than Blackface lambs. The average concentration at 9 weeks was 190 and 130 mg/kg DM respectively for the two breeds of lamb.Results are also given for concentrations of Cu in plasma, kidney, brain, milk and faeces.The results differ from those found in the previous paper under a regime of low dietary Cu where the maternal breed affected concentration of Cu in the liver of lambs up to 9 weeks of age.