The Use of Oestrogen, Progesterone and Reserpine in the Artificial Induction of Lactation in Cattle

Abstract

Oestradiol-17 p, progesterone and reserpine were utilized in three experiments in an attempt to improve the success rate and the magnitude of hormonally induced lactations. Onset of lactogenesis induced by steroid administration was measured by a surge in the lactose content of the mammary secretion and lactations were regarded as being successfully induced if milk yields exceeded 3 kg/day. In all experiments, the dose rate of oestradiol-17 p was standardized at the reduced level of 20 mg/day (approximately 0·05 mg/kg body weight daily), and progesterone maintained at 100 mg/day (approximately 0·25 mg/kg body weight daily) for the initial 7 days (days 1-7). The halving of the dose rate of oestradiol-17 p from the commonly used 0·1 mg/kg body weight daily eliminated the occurrence of noticeable physical injuries in the 60 animals so treated.