Accumulation and Depletion of Cadmium in the Blood, Milk, Hair, Feces, and Urine of Cows During and After Treatment.

The objective of this study was to assess the accumulation and depletion of cadmium in the blood, milk, hair, feces, and urine of Holstein cows during and after treatment. Three Holstein cows received daily oral cadmium administrations (as cadmium chloride) of 0.182 mg/kg body weight/day for 21 days followed by a 63-day withdrawal period. Blood, milk, hair, feces, and urine were collected during treatment and withdrawal periods. Cadmium concentrations were measured by inductively coupled plasma mass spectrometry (ICP-MS). Cadmium concentrations in blood (0.61-1.12 μg/L), milk (0.39-1.04 μg/L), and urine (0.41-2.05 μg/L) were low. Comparatively, cadmium concentrations in feces were higher, especially on treatment day 14 (20.11 mg/kg dry matter). Fecal cadmium concentrations decreased to baseline levels (0.12 mg/kg dry matter) on withdrawal day 21. Hair cadmium concentrations increased with treatment, reaching the highest levels on withdrawal day 7 (24.33 μg/kg). Most of the cadmium was excreted via the feces and very little was present in urine or milk. Cadmium residues were detected in blood and milk more than 63 days after cadmium withdrawal. Hair cadmium concentrations may reflect exposure to the metal.