Cranial abdominal radiograph (head oriented to the right) taken at test day 7 before administration (A) and after sucking 2 (B), 4 (C) and 6 (D) litres of contrast milk (milk:barium
sulphate contrast 6:1). A: Note a small amount of residual barium sulphate evident in the cranioventral aspect of the abdomen consistent with the location of the abomasum (arrow). B/C/D: Note that radiopaque material is present in the abomasum and no visualization of the rumen. D: The lateral abdominal radiographs of standing calves are acquired using horizontal beam. The fluid level refers to an interface between fluid and gas (gas-fluid interface, white arrow) in the stomach. In addition to the gas-fluid interface there are occasionally visible
fl
uid
–
fl
uid interfaces (black arrow). The double interface is most likely due to radiographs taken immediately after the calves stopped drinking, before the
fl
uid
fi
nds its true level, causing
layering of the
fl
uid