Though there has been a considerable amount of recent research on the early weaning of calves, few scientific papers have been published. Preliminary studies at the Rowett Institute have indicated that early weaned calves show greater thriftiness and increased liveweight gains when small quantities of antibiotics are included in the diet (Preston, 1955). Pilot trials carried out at Cockle Park in 1955/6 suggested that there is little difference between the performance of abruptly and gradually weaned calves (Quayle, 1956a). This present study has been carried out to verify these observations, and includes some comments on nutritional scouring.