The use of copper levels in hair to diagnose hypocuprosis.

The possibility of using hair to help diagnose hypocuprosis was investigated. Diets containing different levels of molybdenum and sulphur were fed to nine Hereford steers. Liver reserves of copper were depleted rapidly when dietary levels of molybdenum and sulphur exceeded 2.7 mg/kg and 3.8 g/kg respectively. Following the onset of diarrhoea, liver reserves of copper were repleted by injecting copper glycinate. Samples of liver, blood and hair were collected at regular intervals and analysed for copper. Progressive changes in liver levels of copper were closely paralleled by changes in copper levels in hair and plasma. Relationships between copper levels in liver and plasma, and the liver and hair were both shown to be asymptotic. Plasma and hair levels were sensitive to changes in liver reserves below about 20 microgram/g, but changed little above this level. Sampling variation was shown to be less with hair than with plasma. It was concluded that copper levels in hair are a useful diagnostic aid in detecting hypocuprosis. Hair provides an integrated record of copper availability during its period of growth, and thus may be preferred to blood plasma which represents only a spot sample in time.