Effect of pharmacologically induced changes in milk ejection on suckling in Bos taurus.

This experiment was to test the hypothesis that suckling behavior in Bos taurus is related to milk ejection. Intra-gland milk transport was manipulated by applying four different treatments to four cow-calf pairs: T1, injection of oxytocin during the post-stimulation period; T2, injection of oxytocin before a meal; T3, injection of saline solution at the same times as oxytocin was applied (control) in T1 and T2; T4, injection of an oxytocin antagonist in a similar way as T1. Drugs were applied i.v. and by remote control in order to prevent the animals from noticing the injection. All non-control treatments resulted in significant changes in the time calves spent performing uninterrupted suckling at a specific teat.