Biochemical parameters useful for the diagnosis of mild molybdenosis in sheep.

Abstract

Three groups of ten young ewes (29 kg) received a basal diet or a diet enriched in sulphur (3 g/kg DM) or sulphur (3 g/kg DM) plus molybdenum (13 mg/kg DM). The total plasma copper increased in the S + Mo group. The trichloracetic acid (TCA) insoluble copper fraction of this group rose sharply from the second week of experiment. A decrease in ceruloplasmin oxidase activity could be detected in non-saturating or saturating substrate conditions in the enzyme assay, either with paraphenylenediamine or o-dianisidine as substrate. It was concluded that the decrease was due to failure of synthesis rather than inhibition. The plasma TCA insoluble copper fraction is thus the earliest and most reliable parameter for molybdenosis diagnosis in sheep.