Lateral-lateral abdominal computed radiography (Kodak DirectView CR 850) with a focus film distance (FFD) of 140 cm using a grid (potter bucky) on standing calves was performed. Exposure factors were 90 kV and 32 mA-s.
A pilot study was performed in one calf (different from the experimental animals) to assure that milk in the rumen could be distinguished from milk in the abomasum, as shown by Lateur-Rowet and Breukink [3] in calves and Phillipson [18] in lambs. One hundred millilitres barium sulphate was administered to the rumen through an oesophageal tube (Fig. 1A). Immediately thereafter, the calf was allowed free intake of warm whole milk mixed with the contrast through a small aperture teat, as with the experimental calves. The abomasum and rumen could easily be discerned on radiographs after intake of 4 l of milk (Fig. 1B).