[Use of megestrol acetate in estrus synchronization of heifers under industrialized conditions of cattle breeding].

Daily doses between 30 and 35 mg megestrol acetate were administered to 4,000 heifers over roughly two weeks and produced highly synchronising effects which, however, were lower in response to lower doses. Rectal checks were applied to the ovaries of heifers which had received megestrol acetate and showed that here the number of mature follicles was higher than recorded from animals that had been given chlormadinone acetate. Megestrol acetate, applied in granular form blended into mixed fodder, proved to be the most favourable variant of application. Synchronisation of oestrus on the basis of the above approach was found to yield per animal savings between 4.30 and 22.70 roubles under practice conditions.