In vivo effect of selected medicinal plants against gastrointestinal nematodes of sheep.

Nematode resistance to anthelmintic drugs affects small ruminant production globally. This study evaluated in vivo effects of five plant extracts as alternative nematode treatments. Animals were divided into six groups. Each group was randomly assigned a treatment: Abamectin and Praziquantel (CAP) (positive Control), ethanol extracts of Ananas comosus (AC), Aloe ferox (AF), Allium sativum (AS), Lespedeza cuneata (LC) and Warburgia salutaris (WS). These were applied as an oral dose (100 mg kg(-1) BW), one dose per week per sheep for 42 days (Phase 1). From day 42 sheep were orally dosed for 3 consecutive days with the same treatments in the same groups (Phase 2). Rectal faecal samples were taken every 7 days up to day 63. Eggs per gram of faeces were counted in individual rectal samples, L3 larval stage was counted in faecal cultures, with four replicates per group. For plant extracts, EPG decreased (P < 0.001) with time and efficacy of plant increased (P < 0.001) with time. Ananas comosus and L. cuneata treatments had the highest efficacies of 58% and 61%, respectively, in Phase 1; and 77% and 81%, respectively, in Phase 2. Continuous treatment with these plants could further reduce nematode parasites and improve host health.