Modulation of plasma copper and zinc concentrations by disease states in ruminants
Corrigall, W.; Dalgarno, A.C.; Ewen, L.A.; Williams, R.B.
Veterinary Record 99(20): 396-397
1976
ISSN/ISBN: 0042-4900 PMID: 997184 Document Number: 104455
Six Suffolk-cross lambs aged 6 to 7 months were offered a mixture of bruised oats and a commercial pelleted sheep diet and after 4 weeks the diet was changed for other experimental purposes to a semisynthetic one, based on a mixture of barley and urea. This diet was supplemented with Cu and Zn as sulphates to contain 6 and 30 mu g/kg, respectively. At the end of the 10th week, 3 of the lambs were offered the same diet but unsupplemented with Zn; the Zn content of this diet was 11 mg/kg. Jugular blood samples were obtained weekly and plasma Cu and Zn were estimated. At the end of the 8th week one lamb showed clinical signs suggesting congestion of the lungs and raised temperature. At the end of the 12th week a further lamb showed similar signs; both lambs showed a rise in plasma Cu and a fall in plasma Zn. Two further lambs showed some divergence of Cu and Zn plasma values but clinical disease was not apparent. Subsequently plasma Cu and Zn were estimated in 22 sheep and cattle regarded as clinically normal controls and 18 sheep and cattle with clinical disorders. Where no positive diagnosis was made, clinical signs are given. In the diseased animals there was a similar divergence of Cu and Zn values in plasma. In animals with acute conditions Cu and Zn values were notably altered, whilst in animals with chronic conditions, in which there was little or no systemic illness, changes were slight. It is suggested that effects of disease states may confuse the results of tests designed to investigate potential mineral deficiency or toxicity. The results show that low plasma Zn can indicate disease during the incubation period, may have considerable value in control or diagnosis of disease outbreaks in intensive systems and may merit wider attention.