Fig. 5.

Gram stain of feces from a calf with clostridial enteritis (original magnification, ×1000). Note the group of large Gram positive rods within the background of other bacterial flora. Cytologic evidence of high numbers of large Gram-positive rods in ingesta or feces is suggestive of, but not definitive for, clostridial abomasitis and/or enteritis. The presence of white blood cells, red blood cells, and sloughed mucosal epithelium indicates inflammation with mucosal necrosis and hemorrhage. In early cases of abomasitis or enteritis, changes in fecal flora may not initially be observed.