DUODENAL ULTRASONOGRAPHY IN THE NORMAL ADULT HORSE

Ultrasonography was used to evaluate the duodenum of 6 clinically norm al horses. Examinations were performed in horses which each, alternati vely, received diets of; 1) concentrates and hay, 2) hay only, or 3) a fter 36 hours of starvation. The duodenum was constantly visualized ju st ventral to the right kidney at the 16th and 17th intercostal spaces on a line joining the olecranon and tuber sacrale. Cranial to the 16t h intercostal space visibility depended on thickness of interposing li ver and lung field interference. Duodenal distensions, contractions an d content are described. Starved horses had fewer contractions and dis tensions than horses on hay, or hay and concentrate diets but the diff erence was not significant. Duodenal wall thickness ranged from 3-4 mm . Ultrasonographically five layers, corresponding to the mucosal surfa ce, mucosa, submucosa, muscularis propria and serosa, could be identif ied. A necropsy specimen of the duodenum was evaluated histologically and ultrasonographically in a water bath for comparison.