Ejection of Milk in Relation to Oxytocin Injected Intravenously

Oxytoein varying from 0.05 to 20.0 USPU was injected intravenously into 48 cows to study the effect on ejection of milk from the fine ducts and alveolL The effects of exogenous oxytoein on milk ejection were measured by changes in the time from injection to the beginning of milk flow (latent period), the duration of milk flow, and milk yield.With increasing oxytocin to 0.25 USPU, the length of the latent period decreased.The duration of milk flow increased with increasing oxytocin to 0.5 USPU, and milk yields increased with increasing oxytocin to 1.25 USPU.The shortest latent period was at 10.0 and 20.0 USPU (0.3 rain).Duration of milk flow was longest (6.6 min), and milk yield greatest (1.61 kg) at 1.25 USPU of oxytocin.