Ultrasonogram of the abomasum. Ultrasonogram of the abomasum of a 17-day-old calf with ruminal drinking syndrome. The 5.0-MHz linear transducer was held parallel to the ventral midline in the left lower abdominal area. The abomasal content appears heterogeneous and echoic, and abomasal leaves are seen as curved structures. 1 Ventral abdominal wall, 2 Abomasal wall, 3 Abomasal leaves, 4 Ingesta, Cr Cranial, Cd Caudal.