Iron-induced copper deficiency in dairy cows

摘要

Sings of periorbital alopecia were increasingly observed in a dairy farm with approximately 55 lactating Holstein Friesian cows. Convequently, significant copper deficiency was suggested Three affected cows were selected for diagnostic purposes Blood and hair samples were collected for the determination of copper and molybdenum levels in plasma and molybdenum in hair, respectively Additionally. from diet components the elements copper, molybdenum, sulphur and iron of different of the diet were determined. The grass silage was intensively Contaminated by soil Clinical symptoms like low heart rate, diarrhoea, and ovarian cyst were found in some but not all aimals examined Haematology revealed anemia in all animals Across cows examined. haemoglobin levels were marginal to deficient and total erythrocyte count levels deficient to normal, respectively Total leucocyte count level was within the reference range However. differential counts showed a marked increase in neutrophil subpopulations. Low level of plasma copper (52 to 63 mu g/dl) was observed in all animals examined. Concentrations of molybdenum in the plasma were not elevated and ranged from 9 to 25 mu g/L In contrast. high levels of molybdenum in the hair (688 to 2644 mu g/kg dry matter) were found in the animals examined In total mixed rations iron was increased in the range from 863 to 1285 mg/kg dry matter, resulting from soil contamination of grass silage, of grass which presumably induced the diagnosed secondary copper deficiency in the affected dairy cows.