(Pfizer Animal Health) Factrel is indicated for the treatment of ovarian follicular cysts in cattle. Each ml of Factrel solution contains 50 micrograms of synthetic gonadorelin hydrochloride. Gonadorelin is the gonadotropin releasing hormone (GnRH). Factrel (gonadorelin hydrochloride) has the identical amino acid sequence as endogenous gonadorelin. The recommended dosage of Factrel is 100 mcg (2 ml) per cow, given IM. Gonadorelin (GnRH) hydrochloride.