Efficacy of fenbendazole for endoparasite control in large herds of nondomestic ruminants.

An experimental 4% fenbendazole premix was milled into the feed of 55 nondomestic ruminants (37 antilopines, 12 hippotragines, and 6 caprines). Efficacy of the premix against endoparasites in the ruminants was determined by comparison with pre- and posttreatment fecal egg counts. Dosages calculated from feed consumption percentages were 3.6 to 8.5 mg/kg. Dosages less than 5 mg/kg resulted in 80% to 100% reductions in fecal egg counts, and dosages greater than 5 mg/kg resulted in 98% to 100% reductions in fecal egg counts. With all dosage groups considered, Strongyloides and Nematodirus eggs were most sensitive to treatment, with 100% reductions in fecal egg counts. Strongyle and Trichuris egg counts were reduced 90% and 96%, respectively.