Limited trials with Promone, a progesterone-like hormone, showed considerable promise for increasing weight gains and feed efficiency of heifers in the feedlot. The trial reported here tested the feedlot performance of heifers when implanted with 200 and 400 mg of Promone, as compared with stilbestrol implants and with a control group.

“Promone” is the trade name for a product prepared by the Upjohn Company and made available for this trial.