Transfer of tropane alkaloids (atropine and scopolamine) into the milk of subclinically exposed dairy cows

Tropane alkaloids are toxic secondary metabolites found in agricultural weeds, like jimson weed (Datura stramonium) and henbane (Hyoscyamus niger). The intake of food and feed contaminated with tropane alkaloids led to several incidents of poisoning in humans and animals. Because data on the transfer of tropane alkaloids into the milk of exposed dairy cows were not available in scientific literature, the present study was carried out. Four cows received tropane alkaloids (atropine sulfate and scopolamine hydrobromide trihydrate) orally in three increasing dosage levels for five days each. The total doses of pharmacologically active alkaloids (sum of L-hyoscyamine and scopolamine) at the levels 1, 2, and 3 were 93, 186, and 279 μg/kg body weight/day, respectively. None of the applied dosage levels induced obvious clinical symptoms in the cows. The alkaloid content in composite milk of individual cows was measured for each milking time. Even though the maximum mean transfer rates (atropine: 0.037%, scopolamine: 0.007%) were very low, a transfer of tropane alkaloids into milk could already be proven at the lowest dosage level. At the highest dosage level, the biologically active substances were detected in milk at a mean level of 1.60 ± 0.07 μg/kg. The results obtained in this study indicate that under particular circumstances contaminated raw milk may contribute to the exposure of consumers to tropane alkaloids.