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 contrastmilk (milk:barium sulphate contrast 6:1). A: Note a small amount of residual bariumsulphate evident in the cranioventral aspect of the abdomen consistentwith 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
fluid–fluid interfaces (black arrow). The double interface ismost likely due to radiographs taken immediately after the calves stopped drinking, before the fluid finds its true level, causing
layering of the fluid.