Abstract
In April 1988, a 151-days-old calf on a dairy farm was abandoned due to chronic diarrhea and emaciation, Trichuris eggs were found 1, 000 eggs per gram (EPG) upon fecal examination. Large numbers of Trichuris sp. worms were observed in the cecum and colon by autopsy. There were 45 worms per 5 cm2 cecum. The colonic wall was thickened and some tubers were observed on the mucosa. Histologically, edema of the lamina propria, Trichuris worms in the submucosa, epithelical desquamation and cell infiltrationwere observed in the mucosa. These findings suggested that this chronic diarrhea should be owed to parasitism of Trichuris sp.
In the survey of 79 calves on 21 farms Trichuris eggs were observed in 22 calves on 8 farms. The EPG ranged from 1 to 1, 647 by the suger centrifugal-flotation technique. Three calves having large numbers of eggs (1, 647 ; 577 ; 196) showed diarrhea or soft feces.
High egg reduction was observed in the calves treated with Ivermectin, whereas, a slight reduction was recognized in the calves treated with Negvon.
