Original Research

Evaluation of a commercially available molybdate formulation and zinc oxide boluses in preventing hepatic copper accumulation and thus enzootic icterus in sheep

C.J. Botha, A.S. Shakespeare, R. Gehring, D. Van der Merwe
Journal of the South African Veterinary Association | Vol 72, No 4 | a650 | DOI: https://doi.org/10.4102/jsava.v72i4.650 | © 2001 C.J. Botha, A.S. Shakespeare, R. Gehring, D. Van der Merwe | This work is licensed under CC Attribution 4.0
Submitted: 09 July 2001 | Published: 09 July 2001

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C.J. Botha,
A.S. Shakespeare,
R. Gehring,
D. Van der Merwe,

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The efficacy of a molybdate formulation and a zinc oxide bolus as prophylactic agents for enzootic icterus was evaluated in sheep. Before copper loading, liver biopsies were performed on 12 male, 6-month-old, Mutton Merino sheep to determine hepatic copper (Cu) and zinc (Zn) concentrations. The animals were restrictively randomised according to liver copper concentrations to 3 treatment groups (n = 4) to achieve similar mean liver copper concentrations per group. All sheep received 4 m /kg of a 0.5 %aqueous solution of CuSO4·5H2O intraruminally 7 days per week for 10 weeks. On Day 0 the sheep in the Mo-group were injected subcutaneously with 42 mg molybdenum (Mo) contained in a commercial molybdate formulation. The animals in the Zn-group each received a zinc oxide bolus, containing 43 g zinc oxide, via a rumen cannula. Treatment was repeated on Day 42. Four animals served as untreated controls. Urinary copper excretion, plasma copper concentration, haematocrit and glutamate dehydrogenase (GLDH) activity were determined throughout the trial. The animals were sacrificed after 10 weeks and liver samples were submitted for histopathological examination. Liver and kidney copper and zinc concentrations were determined. Neither the molybdate treatment nor the zinc oxide boluses prevented hepatic copper accumulation. The urinary copper excretion, plasma copper concentration, haematocrit and GLDH activity were not significantly different (P > 0.05) from the controls.


Chronic Copper Poisoning; Copper; Molybdate; Sheep; Zinc


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