[Control of the use of bovine somatotropin (bST) by the determination of bST and insulin-like growth factor I (IGF-I) in blood and milk of cows].

bST, a milk production-enhancing compound not yet registered in the EG and the USA, has been evaluated as safe for the consumer. Nevertheless, actual discussions include a possible ban of applications; therefore, effective measures of control are demanded. The evaluation of bST plus IGF-I in blood only allows a monitoring of bST treatment. Under the condition of two blood samplings from each cow with a 7-day interval and the favorable experimental design (1. sampling rigorous on days 4 or 6 after injection of a bST depot preparation), an efficiency of 96% correct evaluations could be obtained; under field conditions, despite analytical efforts, about 20% false estimations must be taken into account. There is no means of monitoring milk and other products of cows treated with bST, hence analytical measures for the control of imports seems to be useless.