Whipworm (Trichuris discolor) infection in dairy replacement heifers.

Trichuriasis caused by Trichuris discolor was diagnosed in a 19-month-old Holstein heifer examined because of emaciation, diarrhea, recumbency, and oral ulceration. The heifer's problem was representative of a herd problem involving pastured replacement heifers. Euthanasia was elected due to the heifer's moribund state and poor prognosis. Gross necropsy revealed subcutaneous edema and diffuse edema of the colon, with hundreds of adult Trichuris discolor in the cecum and colon. Histologic examination revealed multifocal subacute necrotizing colitis, with many adult Trichuris discolor embedded in the mucosa. Treatment instituted on the farm consisted of levamisole hydrochloride at a dosage of 6 mg/kg of body weight. Favorable response was documented by clinical improvement and elimination of fecal shedding of trichurid eggs.