Diethylstilbestrol is a synthetic estrogen had been used for removal of placenta, after delivery in humans long before 1970. It has been excessively used.
However, it had been observed that this synthetic hormone is responsible for caner of humans. So it is banned long before. It also had been used in dairy animals for induction of estrus and has been marketed by Mayamol beaker.
As it is carcinogenic, so it is withdrawn from the market. However, it is available from the back door and is used for induction in lactating animals which is harmful. Estrogen 17 (beta)-estradiol is available in the market and marketed by Virbac. Now it is used for induction of estrus and in cows of retained placenta. So please do not use diethylstilbestrol in cows.