Prevalence and anthelmintic resistance of strongyle parasites in dorper lambs reared in a Zimbabwean commercial stockbreeding flock

Abstract

Prevalence of infection and level of anthelmintic resistance (AR) of strongyle nematodes to ivermectin (IV), albendazole (AB) and levamisole (LV) in Dorper lambs were determined. The overall prevalence was 67.0% and mean eggs per gram (EPG) of faeces was 357. Infection was light in 92.5%, moderate in 4.5% and high in 3.0% of animals. Proportion of L3 in coproculture was: H. contortus 92.0%, Trichostrongylus spp. 4.0%, O. columbianum 3.0% and Cooperia spp. 1.0%. Anthelmintic resistance was assessed through faecal egg count reduction (FECR %) and identification of pre- and posttreatment L3 strongyles on 28 lambs, in four equal groups. Anthelmintics were administered at recommended dose rates. FECR% in IV group was 19.6%, in AB group 22.8%, and in LV group 53.7%. H. contortus was the main resistant species to all tested anthelmintics. Farm management should practice new strategies against the emerged AR situation to limit the spread of resistant strongyles in Zimbabwe.

Keywords: Prevalence, anthelmintic resistance, strongyle nematodes, Dorper lambs