Cattle: It is administered as a subcutaneous ear implant (containing 3 mg norgestomet; to be removed after 9 to 10 days), in combination with a single intramuscular injection containing 3 mg norgestomet and 5 mg oestradiol valerate. The injection is to be given immediately after application of the implant.

Estimated values at which 50% of the specific binding of 16 nM [3H]progesterone was competitively inhibited separately by unlabeled norgestomet or progesterone, were 2.44 nM and 17.7 nM, respectively. Half-maximal stimulation of response by norgestomet was approximately 50 uM, although stimulation never exceeded 50% any of the concentrations used, and the relative estrogenic activity of norgestomet was 20 million-fold weaker than the activity of 17b-estradiol. Estrogenic activity was observed only above 1 uM (about 0.3 ug/ml). Addition of norgestomet (10 uM) to culture media increased (p<.01) estrogenic activity