[Results of clinical tests on the fattening-stimulating action of the steroid estrogen mestranol in bulls].

Three experiments were conducted with 5 mg Mestranol per animal and die over 70 to 80 days and resulted in daily surplus gains of twelve, 14, and 18 per cent in terminal fattening of Frisian bulls. Also achieved were fodder savings by 1 kg dry matter and energy savings by 0.7 kEFr for each kilogram of gain as well as increase in slaughter weight by 8-9 kg per animal. Those favourable effects were attributed to anabolic and sexual-inhibiting action. A sedative effect on the nervous system is assumed. Combination with CAP failed to give any advantage regarding sexual inhibition and fattening result, but it rather entailed certain shortcomings, such as lower slaughter weight and stronger fat development. The development of an anabolic medicament for veterinary bio-engineering in terms of growth stimulation is suggested.